Psychology
Cognitive Psychology
Higher
7739
Autumn 2000
HIGHER STILL
Psychology
Cognitive Psychology
Support Materials
*+,-./
CONTENTS
Section 1: Guidance for Teachers
Statement of Standards
Integration with other Units
Guidelines for teachers
How to use this pack
Recording Student Attainment
Student Materials
Section 2: Outcome 1 – The Concepts
Perception
Attention
Section 3: Outcome 2 - Major Studies
Section 4: Outcomes 3 & 4 – Research Methods
Section 5: General References
Psychology: Cognitive Psychology (H)
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Psychology: Cognitive Psychology (H)
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SECTION 1: GUIDANCE FOR TEACHERS
Psychology: Cognitive Psychology (H)
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Psychology: Cognitive Psychology (H)
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STATEMENT OF STANDARDS
OUTCOME 1
Explain key concepts in cognitive psychology.
Performance criteria
(a) Key concepts in cognitive psychology are explained accurately and
comprehensively.
(b) The applications of key concepts in cognitive psychology in particular fields are
explained clearly and accurately.
Evidence requirements
To demonstrate satisfactory attainment of this outcome, candidates should produce
written or oral responses to cover all performance criteria. They are required to do so
for two of the following concepts: perception, attention, thinking, memory, and
language. Relevant example(s) should be used to illustrate at least one application
for each concept studied.
Written/oral responses will typically be restricted responses to specific questions.
OUTCOME 2
Explain major studies in cognitive psychology.
Performance criteria
(a) Aims of major studies in cognitive psychology are explained accurately.
(b) Methods of research used in these major studies are explained accurately.
(c) Conclusions of these major studies are explained accurately.
Evidence requirements
To demonstrate satisfactory attainment of this outcome candidates should produce
written or oral responses to cover all performance criteria. They are required to cover
one major study for each of the two concepts studied in Outcome 1. The major
studies used must be different from the examples of studies used in Outcome 1.
Written/oral responses will typically be restricted responses to specific questions.
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OUTCOME 3
Undertake an investigation in cognitive psychology.
Performance criteria
(a) The investigation is implemented using a given design and data according to
agreed procedures.
(b) Use of statistical methods is clear and accurate.
(c) Presentation of data is clear and accurate.
Evidence requirements
To demonstrate satisfactory attainment of the outcome, candidates should produce
written or oral responses to cover all performance criteria. Candidates should employ
at least one statistical method and at least one form of presentation of data.
Written/oral responses will typically be a research report of between 1000 and 1500
words integrating Outcomes 3 and 4.
Note on range of the outcome
Statistical methods: measures of central tendency, measures of dispersion.
Presentation of data: tables of score, graphs, bar charts, pie charts, and scattergrams.
OUTCOME 4
Evaluate an investigation in cognitive psychology.
Performance criteria
(a) Results produced are described clearly and accurately.
(b) Conclusions are described clearly and accurately in terms of the aims of the
investigation.
(c) Strengths and weaknesses of the investigation are described clearly and accurately.
Evidence requirements
To demonstrate satisfactory attainment of the outcome, candidates should produce
written or oral responses to cover all performance criteria.
Written/oral responses will typically be a research report of between 1000 and 1500
words integrating Outcomes 3 and 4.
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INTEGRATION WITH OTHER UNITS
This is an optional component unit of Higher Psychology. This unit has a value of
one credit at Higher.
Unit content
The unit has four outcomes:
1.
2.
3.
4.
Explain key concepts in cognitive psychology.
Explain major studies in cognitive psychology.
Undertake an investigation in cognitive psychology.
Evaluate an investigation in cognitive psychology.
Content of this pack
It should be noted that this pack contains resources that will assist the teacher/lecturer
with the delivery of this unit and contains material relevant to all of the Outcomes.
Core Skills
It is likely that attainment of this unit would lead to the automatic award of:
• Planning and Organizing at Higher
• Reviewing and Evaluating at Higher
• Critical Thinking at Higher.
Additional details may be obtained from SQA.
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GUIDANCE FOR TEACHERS
Approaches to teaching and learning
In delivering these units, it is useful if teachers/lecturers achieve a balance between
teacher/lecturer exposition and experiential learning. It is important to recognise that
learners acquire and process information in a number of ways to help them learn.
These include visually, aurally, in discussion or exchange with others, during groupbased problem solving activities, and during solitary reflection.
Students/pupils should be encouraged from the beginning to draw on their own
experiences, perceptions, and their previous and current learning. Personal
experience of interacting with a variety of people, and in a number of different
situations is an invaluable source of knowledge and is highly relevant to cognitive
psychology. The sharing of experiences and insights will promote general awareness
that cognitive psychology assists self-understanding and an understanding of humans
in a variety of contexts.
Students/pupils should also be encouraged to gather and use information about
different people’s actions, thoughts and feelings and to consider how these affect
themselves and others. Relevant quality newspapers and/or magazine articles and
video/film productions are useful resources, which bring cognitive psychology to life
so that it can be shared, by comparatively large groups of people at any one time.
This remains appropriate even when the material is fictional, provided it presents us
with a true picture of the human condition, which is not deliberately sensationalised.
In delivering this unit it is appropriate that a multicultural approach is taken since the
learning needs of individuals vary according to their cultural background. Case
studies, role-play and simulations should incorporate characters and elements from
different social and cultural backgrounds wherever possible.
Unit induction
At the beginning of the unit ‘Cognitive Psychology’, teachers and lecturers should
ensure that students/pupils are clear about its nature and purpose. Induction for this
unit should last about two hours and should include an introduction to the content of
the unit, provide a programme of work and explain the arrangements for assessment
and reassessment. At this point students/pupils can be given the Candidates Guide
from the Unit Assessment Pack. This helps explain what the unit is about and how it
is assessed.
In order to allow students/pupils to make a confident start, reference should be made
to links with previous or other current learning with which they are familiar. It is also
important to discuss and explore the nature of the Course or Group Award being
undertaken by the group.
It may be necessary to include induction exercises, particularly if the group is a new
one. The type and number of exercises used will however depend on the nature of the
particular group, their familiarity with each other and with the teacher/lecturer
concerned.
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Learning Environment
The expertise of the teacher/lecturer is invaluable in developing skills in, approaches
to, and insights about the subject of cognitive psychology. Teachers/lecturers should
aim to create a relaxed and enjoyable learning environment, which is both motivating
and supportive.
In order that a ‘people’ perspective is always present the following conditions should
be met:
•
•
•
the provisions of a learning climate in which students feel supported and able to
express their thoughts and ideas.
a teaching style that promotes a supportive learning climate.
teaching and learning methods which draw on students’ past and present learning
experience and which enable them to integrate new ideas and skills during their
interactions with others.
Further guidance can be found in the Psychology Subject Guide.
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HOW TO USE THIS PACK
Purpose of the pack
This pack is designed to provide guidance and support materials to help
teachers/lecturers in the delivery of the unit. The student information and activities
are designed to be used by teachers/lecturers in the way that suits their preferred style
of delivery and the needs of their particular student group.
This pack has not been designed for open learning purposes. Answers to exercises
and worksheets will be provided and facilitated by the teacher/lecturer. The student
activities in the pack will require to be followed up and brought together by the
teacher/lecturer in whatever way is most appropriate.
The student activities in this pack cover the four outcomes and their performance
criteria at Higher level. The material is presented in such a way that Outcome 1
(Explain key concepts in cognitive psychology) is covered first. Outcome 2 (Explain
major studies in cognitive psychology) is covered second. Outcome 3 (Undertake an
investigation in cognitive psychology) and Outcome 4 (Evaluate an investigation in
cognitive psychology) are dealt with in the final section of the pack.
This sequence of delivery is by no means compulsory and may be rearranged at the
discretion of the teacher/lecturer responsible for delivering the unit.
Using the materials
The student activity and information materials in the pack have been identified as
either:
•
•
Information
or
Student Activity.
The essential knowledge required for the unit has been covered on those pages that
are headed Information. This is particularly useful as handout material. These
information sheets could also be used as the focus of input by the teacher/lecturer and
to develop ideas further as part of question and answer sessions and group
discussions.
These information sheets can be photocopied, as a separate pack should the
teacher/lecturer prefer to use them either as teaching notes or as separate handout
materials. Alternatively, the materials could be assembled into smaller topic packs.
All worksheets, assignments, exercises and group activities have been covered on
those pages that are headed Student Activity. These general activities have been
developed to include exercises for individuals, pairs, triads and small groups to
conduct. Teachers/lecturers may well wish to alter the way in which these activities
are carried out according to the needs of their particular group.
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RECORDING STUDENT ATTAINMENT
A recording proforma for teachers/lecturers to complete for individual candidate
attainment is available in the Unit Assessment pack.
•
•
Candidate’s record of progress - for individual candidates to have a record of their
attainment.
Internal Assessment Record - to record their internal assessment results of the
whole student group.
Teachers/lecturers may devise their own alternative system for recording student
attainment.
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GUIDANCE ON THE CONTENT AND CONTEXT FOR THIS UNIT
By introducing students to a range of concepts in cognitive psychology, it is intended
to develop knowledge and understanding of Cognitive Psychology generally and to
emphasise the significance of this area to the whole of Psychology.
To emphasise the importance of research evidence in Psychology, the support pack
also includes a summary of one of the major summaries specified for Cognitive
Psychology for each of the concepts in the pack and examines the methods of
investigation used by psychologists. Major studies in Cognitive Psychology may be
taught in the context of concepts studied to provide examples and illustrations of
research in this area. Concepts should be contextualised in appropriate and relevant
application areas.
The unit also introduces students to a practical investigation in psychology.
A choice of concepts and a practical investigation is a feature of this unit. This
provides flexibility for centres to accommodate different needs and interests in
studying cognitive psychology at this level.
Fuller information on the content of this unit is provided in the course details.
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GUIDANCE ON LEARNING AND TEACHING APPROACHES FOR THIS
UNIT
General proposals regarding approaches to learning and teaching are contained in the
course details. Learning and teaching approaches should be carefully selected to
support the development of knowledge and understanding, investigation and
application. The learning experience at this level should be interesting, to encourage
enthusiasm for the subject and to stimulate and prepare candidates for independent
study.
The unit should be approached using a wide range of stimulus materials and teaching
approaches. Candidates should be encouraged to draw upon their own experiences
and should have access to resources. The material should be up-to-date and relevant
to the unit, the level of study and the interests of the candidates. The emphasis
throughout should be on active learning, whether as part of a whole class, in small
groups or as individuals. The outcomes are interconnected and should be approached
as such. It is recommended that, wherever possible, outcomes should be covered in
an integrated way. An outcome-by-outcome approach, which could lead to a
compartmentalized view of psychology, should be avoided. If it is
appropriate, the unit may be integrated with the approaches and methods unit.
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GUIDANCE ON APPROACHES TO ASSESSMENT FOR THIS UNIT
The National Assessment Bank will provide assessment instruments and guidance on
implementation. This does not preclude teachers/lecturers from devising their own
assessment tasks. Evidence of attainment of the outcomes for this unit may be
provided through a variety of methods. However, restricted-response questions and a
research report are considered to be most appropriate. Where an integrated approach
is used for assessment, it will be necessary to identify in the candidate’s response
where each outcome has been met. It is possible to integrate assessment of this unit
with assessments for other Higher units.
Where assessment evidence is gathered by means of a single assessment towards the
end of the unit, care should be taken to ensure that sufficient time is allowed for
remediation and reassessment if required. Where a candidate has failed to achieve
one or more of the outcomes it is only necessary to reassess those outcomes that the
candidate has failed to achieve.
Where assessments are set which allow candidates to demonstrate performance
beyond the minimum standard required, evidence gathered for internal unit
assessment might also be used for grade prediction and for appeals for external course
assessment. For details of the grade descriptions for external assessment, please refer
to the Higher Psychology course specification.
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SECTION 2: THE CONCEPTS
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Information
What is cognitive psychology?
Cognitive psychology concerns the study of our cognitive processes. Cognitive
processes are the ways in which we obtain and use information from our world in
order to operate successfully within it. In this support pack we will first explore
cognitive psychology generally in an attempt to understand what cognition means.
Secondly, we will look at two key concepts that enable us to gain and use knowledge
of the world around us. These key concepts are taken from the whole range of
cognitive processes that include perception, memory, attention, language and
thinking. All of these human abilities or higher-level processes are inferred and
cannot be observed directly. This unit will explore two of these different aspects of
cognition as key concepts i.e. perception, memory and language and how they
might apply. Choice of other cognitive processes studied and related applications, is
at the discretion of the teacher/lecturer and candidates.
The study of cognitive psychology
Cognitive psychology is the study of the information processes that we use:
‘To take in information coming to us from our outside world; to
make sense of this information and to use our interpretation of this
information to act upon; and in; our external world.’
These information processes are our five senses: vision, touch, hearing, taste and
smell.
A knowledge of cognitive psychology is useful in that we tend to react to stimuli
(events/objects/people) on the basis of what we each individually believe is
happening. While all healthy human beings share the same cognitive processes - we
each reach a conclusion as to what is happening (and thus how to behave/react) on the
basis of our individual cognitive processes and meaningful past experiences using
them. This can mean that two people can respond totally differently to the same
thing. A good example of this would be that of two women, one of whom has
experienced domestic violence. When they see a man walk towards them in the street
they both see a man, but their individual thoughts, feelings and behaviours concerning
him will be different. The theme of similar but different environmental experience
affecting each individual’s own thoughts, feelings and behaviours runs throughout
cognitive psychology; as does the importance of realising the inter-relationships
between all our cognitive processes (perception: attention: language; memory and
thinking).
The study of what goes to make up cognitive psychology i.e. cognitive processes is
challenging. This is because our cognitive processes do not exist in reality. They are
hypothetical constructs. If something does not exist in reality it is extremely
difficult, if not impossible, to measure or observe it directly. For a good part of the
20th century psychology placed a great emphasis on experimentation to generate
objective empirical data (hard scientific fact) about the phenomena it was interested
in. This proved extremely difficult to do in cognitive psychology.
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Eventually, mainly due to the influences of Edward Tolman and Jean Piaget, the
study of cognitive psychology progressed because cognitive psychologists realised
they could study and produce objective empirical data concerning their subject matter
- by studying it indirectly. It should therefore be emphasised that what we study in
cognitive psychology is inferred.
Cognitive psychology thus concerns a study of the following internal cognitive
processes:
• Perception
• Attention
• Language
• Memory
and
• Thinking.
And as a consequence, the psychological subject matter of cognitive psychology
concerns representations i.e. an individual cognition like thinking or language or the
content(s) of our cognitions that represent a thought, word, symbol or image. Put
another way, a representation is how we think about our world (cross-reference with
amongst others Piaget and Bruner).
While the study of cognitive processes should not be exclusive to just one, two, three
or more processes, and with an understanding that they are each related to one
another, SQA do emphasise here the key concepts of perception and attention.
The Philosophical and Psychological Roots of Cognitive Psychology
Before examining the key concepts of perception and attention, it may be useful to try
to understand where cognitive psychology has come from.
Remembering back to Psychology: Approaches and Methods your teacher/lecturer
may have mentioned that the cognitive approach (and thus cognitive psychology)
grew out of criticisms of the behaviourist approach. Behaviourism emphasises that
psychology should only study actual observable behaviour and that human beings can
be understood in terms of all the stimulus-response units of learnt behaviour (got via
classical and operant conditioning) accumulated to date. There are good reasons for
this, but a study of actual observable behaviour alone is not enough to understand why
and how it is we think, feel and behave as we do. The study of the human mind is
also important.
Due to the tremendous influence of behaviourism a scientific study of the human
mind was difficult until a ‘soft’ behaviourist called Edward Tolman (1930)
discovered (by externalising the cognitive process of thinking) in his ‘rats in mazes’
experiment that his rats appeared to have done something with their units of learnt
behaviour about the maze. When a rat was put into the maze, it initially sniffed about
and explored it in an erratic fashion. It eventually discovered food placed in a
particular position within the maze by Tolman. When later put back into the maze the
rat(s) went straight to the food. They did not go down blind alleys, turn back on
themselves, etc. - as when first introduced to the maze.
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Tolman concluded on the basis of measurement, control and observation, that the
rat(s) had formed primitive cognitive maps of the maze in their heads based on their
earlier experience. As a result the rats were able to understand and react to this
environment better in that they were now aware of blind alleys and cul-de-sacs and
were able to anticipate and take short cuts to the food. The behaviourists seemed to
be wrong. Tolman’s rats suggest that organisms (what behaviourists call people and
animals) actively do something with previously encountered sensory experiences in
order to behave in a more enriched and enlightened way when they encounter the
same stimulus again.
1956 was a very important year- Chomsky’s paper on the theory of language and
Miller’s paper on magic number 7 in STM. Also, it marked the first systematic
attempt to consider concept formation from a cognitive psychological perspective as
reported by Bruner, Coodnow and Austin. In addition it was seen as the date of the
founding of artificial intelligence at the famous Dartmouth conference.
Discussion Point
Why was the early scientific study of cognitive
psychology elusive? What criticisms were made of
cognitive psychology in its early days? How were these
problems overcome?
A study by Saaranin (1973) suggests humans do the same thing. The human
equivalent of a cognitive map is called a neural network. Saaranin got American
college students to draw maps of their campus. Students tended to enlarge those
buildings that were most important to them and shrink those less important. They
were often found to be completely wrong when describing campus areas that were not
as familiar to them.
Similarly, Briggs (1971) discovered, on asking people to judge how far they thought
one landmark was from another, that they tended to underestimate the distance
between familiar landmark objects and over-estimate the distance between unfamiliar
landmarks. This is further illustrated when as adults we return to a once familiar
childhood haunt and find it is a lot smaller and far less exciting than we imagined.
The perception of Girvan for a Glaswegian whose only experience of the place was
during his primary school years was dramatically brought into focus when returning
to the town 35 years later. It was just not the same.
Discussion Point
Think about a situation where your perception was
totally different to others around you. What was this
perception? Why was your perception different?
Whose perception was the more correct?
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Cognitive psychology thus concerns an understanding of what are called our internal
mental structures and higher-level processes. We will now look at our senses in
order to understand generally the structure and role of the five higher-level cognitive
processes of perception; attention; language; memory and thinking. Each of our
cognitive processes can be studied individually but to understand cognitive
psychology completely their inter-relationship with each other should be emphasised.
Practical applications of cognitive psychology include, for example, advertising,
eyewitness testimony in courts, etc.
Perception
In relation to the study of perception this support pack will emphasise:
• processing sensory information
• the active nature of perception
• cultural variations in perception
• social and emotional influences on perception
By the end of this key concept you will have been introduced to the area of perception
and be able to make a distinction between sensation and perception with reference to a
variety of illustrations and practical demonstrations. Examples of such will include
perceptual constancies and perceptual set. Students/pupils should note that that those
sensory receptors involved in sight, hearing, taste, smell and touch carry a very large
volume of information to the human brain. Perception is the organization and
interpretation of these sensations. However, perception is more than our senses.
Emphasis throughout is that perception is an active process involving us the organism
in the selection and organization of stimuli. This will be demonstrated when we look
at how the brain interprets information when the information is ambiguous or
incomplete. Reference to studies in perception will also show that perception may be
thought of in terms of hypothesis testing.
Perception is the selection and organisation of stimuli based on our senses, plus
innate abilities and our understanding of previous experiences in the world. The
study of visual perception will provide interesting examples of how psychologists
have tried to identify how we organize our sensory world, identify what innate
abilities we might have and also understand the contribution social, emotional and
cultural factors have on perception.
Perception will be discussed with reference to relevant applied examples i.e. the
application of visual perception studies in the area of advertising and media
presentations.
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Student Activity
1.
What do you understand by the term ‘cognitive psychology’?
2.
What do you understand by the term ‘cognitive processes’?
3.
Why did the behaviourists criticise the study of cognitive psychology?
4.
How did cognitive psychologists overcome this criticism by the behaviourists?
5.
What two research methods do you think cognitive psychologists use to
investigate cognitive processes?
6.
Why is it that despite seeing the same 90 minutes of ‘old-firm’ football a Rangers
and Celtic fan will report entirely different versions of the game?
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KEY CONCEPTS IN COGNITIVE PSYCHOLOGY
PERCEPTION: INTRODUCTION
As usual in psychology we try to first define the concept we are looking at. The study
of perception is no exception.
Perception is an active cognitive process that entails us processing, organising
and interpreting information coming to us from our outside world via our senses.
Or to put another way:
‘Perception is...the process of assembling sensations into a usable
mental representation of the world...which...creates faces, melodies,
works of art, illusions etc.’
Coon (1983)
Or another:
‘Perception is not determined by stimulus patterns, rather it is a
dynamic searching for the best interpretation of the available
data...perception involves going beyond the immediately given evidence
of the senses.’
R.L. Gregory (1966)
We should be careful however for:
‘To perceive seems effortless. to understand perception is nevertheless
a great challenge’
Dodwell (1995)
Perception is the
active cognitive
information
process by which
we take in raw
sensations from
our environment
using our senses
and interpret these
sensations using
our past knowledge
and understanding
of the world in
order that the
sensation or what
we are sensing,
becomes
meaningful to us.
It may now be said that:
You’ll understand why you were forced to do what you just did by the end of the
cognitive psychology course.
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How do we perceive?
An understanding of how we perceive has intrigued cognitive psychologists for
decades. To date three explanations have emerged, each enriching our knowledge of
perception.
1.
The Ecological View (Gibson; Gestalt - ‘organised wholes’): where it is said we
perceive most clues from our environment directly and without interpretation
(we perceive ‘exactly’ what we see/hear/smell/touch and taste). The ecological
view is popularly known as ‘bottom-up processing’.
2.
The Constructivist View (Gregory; Bruner): where it is said our perceptual
system must often make a reality indirectly out of bits of sensory information due
to the absence of other information. The constructivist view is better known as
‘top-down processing’. It is perception by hypothesis testing.
3.
Top-Down/Bottom-Up Symbiotic View (Neisser) that says we use the most
appropriate of the above two processes depending on the situation we find
ourselves in. The two processing models work together. When one type of
perceptual process, or aspect of it is impaired (the other process, or an aspect of
the other process) ‘fills’ in or compensates to give us, at the end of the day, as
much an understanding of the stimulus as possible. Symbiotic processing is best
explained in the area of visual perception using Marr’s Computer Analogy where
he says we first adopt a ‘bottom-up approach’ to extract visual information from
an image/object/event in four stages and put it all together again in the brain in
what he calls a symbolic representation of the stimulus. ‘Bottom-up’ and ‘top
down’ work together in the area of visual perception.
Whether you advocate an ecological (bottom-up); constructivist (top-down) or
symbiotic explanation of perception, it is interesting to note the influence of the
nature-nurture debate to your position. While most of the theorists above
suggest an empirical basis to our perceptions (that what we perceive or ultimately
understand from what our senses are telling us is the result of learning and
experience), the influence of Gestalt psychology in the early years of research
into this topic does raise the nativist position. This says our perceptual ability is
innate, and needs little if any ‘learning’ to enhance it.
At the end of the day, we can say that perception is influenced by our innate
abilities as human beings but also by the cognitive apparatus we are born with as
used to make meaningful sense of the myriad of sensory experiences we
encounter. What we perceive, or understand, we are sensing is also strongly
influenced by what we have learned from past experience of the same, or similar,
sensations. Perception is further influenced by social, emotional and cultural
factors including expectations and motivation.
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Student Activity
1.
Define ‘perception’.
2.
What aspects of being human processes are involved in perception?
3.
What are the three views taken by psychologists as to how we perceive our
world?
4.
Briefly explain these three views.
5.
What one best explains perception? Give reasons for your answer.
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PROCESSING SENSORY INFORMATION
Sensation and Perception
In our original working definition of perception we said that perception concerns
sensing plus our interpretation of this sensation based on meaningful past experience
of it. Central to perception must therefore include knowledge of how we receive
information from our environment in the first place. This is of course via our senses.
We use our traditional five senses to receive information from our external world i.e.
sight, hearing, touch, taste, smell. Psychology is also able to tell us we have at least
one other sense that is called our KINAESTHETIC sense. This is a sense from
within our own bodies that tells us about movement, or the feel of our muscles or
joints. Our kinaesthetic sense tells us about balance.
Our Visual Sense
Our sense of vision is in many respects our key sense. Vision, our visual system
and visual perception is the most studied information process of all by cognitive
psychologists, so much so, it is looked at in more depth in a later section entitled
‘Our Visual System’. Our sense of vision comes to us via our eyes, the structure
and location of which allow us to perceive our world in three dimensions, sense
colour, sense depth etc.
Our Tactile Sense
Touch, is one of our five senses, allowing for our perception of pressure, touch,
temperature (principally temperature change), pain, and hair movement. We
experience touch using sensory cells called receptors that are nerve endings in the
skin. Touch receptors are either free ending (in the dermis and around hair follicles)
or encapsulated (branched or coiled, enclosed in a capsule). Receptors in our skin
respond to a specific type of stimulus and are not evenly distributed over the body.
The sensitivity of fingertips, for example, results from a large number of touch
receptors we have at this extremity.
Once a receptor is stimulated, it sends nerve impulses to the brain. This locates and
identifies the stimulus involved and assesses its significance. The more intense the
stimulus the greater frequency of nerve impulses.
The skin's sensory system is important in alerting the body to changes in its external
environment. Potentially harmful stimuli may cause pain that results in either
protective reflex actions (such as dropping a hot object) or storing a memory (e.g. to
remind you to avoid future similar hazards). The perception of pain is unusual as it
is also strongly affected by the emotions and the circumstances in which it is
experienced.
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Our Auditory Sense
The ear is our organ of hearing and balance. It is composed of three parts external, middle, and internal - the greater part of which is enclosed within the
temporal bone (see diagram on following page). The external ear is that portion of
the hearing apparatus lateral to our eardrum, or tympanic membrane. The eardrum
comprises the auricle, or pinna (the external flap of the ear) and the external
auditory canal which is 3 cm (1.25 in) in length.
The middle ear, on the inner side of the eardrum, houses our mechanism for the
conduction of sound waves to the internal ear. It is a narrow passage, or cleft, that
extends vertically for about 15 mm (0.6 in) and for about the same distance
horizontally. The middle ear is in direct communication with the back of the nose
and throat by way of the eustachian tube which allows for passage of air into and
out of the middle ear. Traversing (i.e. going across) the middle ear is a chain of
three small, movable bones called the ossicles: the malleus, or hammer handle; the
incus or anvil; and the stapes or stirrup. The ossicles connect the eardrum
acoustically to the fluid-filled internal ear.
The internal ear (or labyrinth) is the part of the temporal bone containing the organs
of hearing and balance to which the filaments of the auditory nerve are distributed.
It is separated from the middle ear by the fenestra ovalis or oval window. The
internal ear consists of membranous canals housed in a dense portion of the
temporal bone and is divided into the cochlea (Greek, ‘snail shell’), the vestibule
and three semicircular canals. All these canals communicate with one another and
are filled with a gelatinous fluid called endolymph. The disposition and orientation
of endolymph also helps us experience our sense of balance.
The Ear and Balance
The semicircular canals and the vestibule are concerned with our sense of
equilibrium or balance. Hairs in these canals, similar to those that form the organ of
Corti, respond to changes in the position of the head.
The three semicircular canals extend from the vestibule approximately at right angles
to each other, providing sensory organs to record movements of the head in each of
the three planes of space: up and down, forwards and backwards, and to the left or
right. Lying over the hair cells in the vestibule are crystals of calcium carbonate,
known technically as otoliths and popularly as ear sand. When the head is tilted, the
otoliths shift, and the hairs beneath respond to the change in pressure. The eyes and
certain sensory cells in the skin and internal tissues also help to maintain equilibrium
but when the labyrinth of the ear is damaged or destroyed, disturbances of equilibrium
invariably follow. With eyes closed, a person with a disease or disturbance of the
internal ear may be unable to stand without swaying or falling.
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How Do We Hear?
Sound waves, which are actually changes in air pressure, are carried through the
external auditory canal to the eardrum, causing it to vibrate. These vibrations are
communicated by the ossicular chain in the middle ear through the oval window to
the fluid in the inner ear. The movement of the endolymph stimulates the
movement of a set of fine hair-like projections called hair cells as the cochlea
vibrates. Collectively these projections are called the organ of Corti. The hair cells
transmit signals directly to the auditory nerve, which carries information to the
brain. The overall pattern of response of the hair cells to vibrations of the cochlea
encodes information about sound in a way that is interpretable by the brain's
auditory centres.
The range of hearing, like that of vision, varies in different people. The maximum
range of human hearing includes sound frequencies from about 16 to 28,000 cycles
per second. The least noticeable change in tone that can be picked up by the ear
varies with pitch and loudness. A change of vibration frequency (pitch)
corresponding to about 0.03 per cent of the original frequency can be detected by
the most sensitive human ears in the range between 500 and 8,000 vibrations per
second. The ear is less sensitive to frequency changes for sounds of low frequency
or low intensity.
The sensitivity of the ear to sound intensity (loudness) also varies with frequency.
Sensitivity to change in loudness is greatest between 1,000 to 3,000 cycles, where a
change of one decibel can be detected—and becomes less when sound-intensity
levels are lowered.
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The variation in the sensitivity of the ear to loud sounds causes several important
phenomena. Extremely loud tones produce in the ear entirely different tones that
are not present in the original tone. These subjective tones are probably caused by
imperfections in the natural function of the middle ear. The harshness in tonality
caused by greatly increasing sound intensities, as when a radio volume control is
adjusted to produce excessively loud sounds, results from subjective tones produced
in the ear. The loudness of a pure tone also affects its pitch. High tones may
increase as much as a whole musical-scale note; low tones tend to become lower as
sound intensity increases. This effect is noticeable only for pure tones. Because
most musical tones are complex, hearing is usually not affected to an appreciable
degree by this phenomenon. In sound masking, the production in the ear of
harmonics of lower-pitched sounds may deafen the ear to the perception of higherpitched sounds. Masking is what makes it necessary to raise one's voice in order to
be heard in a noisy place.
Our Gustatory Sense
Taste, is another of the five senses, effected by the contact of soluble substances on
our tongue Although humans can distinguish between a wide range of flavours, the
sensation of taste is actually a response to a combination of several stimuli,
including texture, temperature, and smell, as well as taste. In isolation, the sense of
taste can only identify four basic flavours: sweet, salt, sour, and bitter, with
individual taste buds particularly responsive to one of these. The 10,000 or so taste
buds found in humans are distributed unevenly over the top of the tongue, creating
patches sensitive to specific classes of chemicals which give the taste sensations.
Usually sweet and salt are at the tip of the tongue, sour at the edges, and bitter at the
base. Chemicals from food are dissolved in the moisture of the mouth and enter the
taste buds through pores in the surface of the tongue where they come into contact
with sensory cells. When a receptor is stimulated by one of the dissolved
substances, it sends nerve impulses to the brain. The frequency of the repetition of
the impulse tells the brain how strong a flavour is and the type of flavour is
probably registered by the nerve cells that responded.
Our Olfactory Sense
Smell, is one of the five senses by which odours are perceived. The nose, equipped
with olfactory nerves, is the special organ of smell. The olfactory nerves also
account for differing tastes of substances taken into the mouth, in that, most
sensations that appear introspectively to us as tastes are in essence really smells!
Sensations of smell are difficult to describe and classify, but noting the chemical
elements of odorous substances has made useful categorisations. Research has
pointed to the existence of seven primary odours—camphor-like, musky, floral,
peppermint-like, ethereal (dry-cleaning fluid, for example), pungent (vinegar-like),
and putrid—corresponding to the seven types of smell receptors found in the
olfactory-cell hairs. Olfactory research also indicates that substances with similar
odours have molecules of similar shape. Recent studies suggest that the shape of an
odour-causing chemical molecule determines the nature of the odour of that
molecule or substance. These molecules are believed to combine with specific cells
in the nose or with chemicals within those cells. This process is the first step in a
complex series that continues with the transmission of impulses by the olfactory
nerve and ends with the perception of odour by the brain.
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How do taste and smell work?
Smell and taste are a part of our sensing system much like vision and hearing.
Molecules released by substances around us stimulate special nerve cells in the
nose, mouth or throat. These special nerve cells transmit electric impulses to special
areas of the brain that recognise smell and taste. Olfactory nerve cells are
stimulated by odours around us such as flowers, baked goods, perfumes, etc. These
olfactory nerve cells are located in a tiny patch high up in the nose. They connect
by nerve pathways to areas in the brain.
Taste cells react to food and drink, mixed with saliva, and are located in the taste
buds of the mouth and throat. Many bumps on the back of the tongue contain taste
buds. These taste cells send information along nerve pathways to the brain. Unlike
other nerve cells, taste and smell cells are replaced when they become old and
damaged.
Another set of cells in the nose and mouth have non-specialised nerve endings
which are stimulated by strong and irritating sensations like ammonia, chilli
peppers, onions, etc.
As stated above, we can commonly identify four basic taste sensations: sweet, sour,
bitter, salt. There is some evidence that other taste sensations can be appreciated.
But the sense of smell is necessary to identify flavours such as chocolate. The
sweetness is identified by the nerve cells of the tongue and mouth. The combination
of saliva with the chocolate releases odours and molecules that travel up the nasal
passage from the back of the throat. The nasal cells are stimulated and the smell
and flavour of chocolate will be recognised. This is why people who complain of
taste problems really often have a smell disorder that interferes with the ability to
identify the flavour of foods.
Our internal and external senses interact with each other because we are constantly
linking together information from differing sensory MODES e.g. seeing, hearing,
etc. This involves us in what is called cross-modal transfer - where information
gained using one mode (e.g. sight) is applied to information from another sensory
mode (e.g. hearing). Cross-modal transfer gives rise to a richer array of sensory
information upon which we base our interpretation of our own realities (world) - but
by that we often become confused.
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Characteristics of our Sensory System
Our six modalities (or senses) have certain common characteristics:
Before looking at what these are please copy out the table and list below both the
common and scientific name for each:
Apparatus
1.
Eye
Sense
Visual
2.
3.
4.
5.
6.
Each responds to a particular form of energy or external information e.g. light
waves; sound waves; skin pressure etc.
Each has a sense organ or ‘accessory structure’, which is the first port of call for
any incoming information on the road to processing, and full understanding of the
perceived stimuli.
Each accessory structure has sense receptors called ‘transducers’. These are
specialised cells that are sensitive to particular kinds of energy. It is as the
stimuli impinge on these transducers that the conversion of the stimuli into
electrical nerve impulses occurs. This electrical activity is the only kind of
energy that can be processed and understood by our brains.
Each sensory modality involves a different part of the brain. We are here able to
interpret messages received from our sensory receptors which gives us the
experience of conscious awareness of an object; a person, a word, a sound, a
taste, etc. A certain minimum stimulation of a sense receptor is needed before we
can become consciously aware of the sensory experience that is happening.
These minimum requirements are called absolute thresholds, which are based on
a value given to a stimulus when we can detect it 50% of the time. The threshold
at which we can notice a stimulus differs among and between people, and can be
affected by an individuals physical state, time of day, motivation, the way the
stimulus is presented, etc.
This is the area of psychophysics within psychology (the interface between the
physical stimulus and our subjective experience of it), which is of great importance to
the development of psychology as a subject in its own right (see Wilhelm Wundt,
1879).
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Student Activity
1.
What do you understand by:
• our visual sense
• our tactile sense
• our gustatory sense
• our auditory sense and our olfactory sense?
2.
Describe and explain our kinaesthetic sense.
3.
How do we first begin to interpret information coming to us from our
environment? What is particularly interesting about this from the point of view
of psychophysics?
4.
What does cross-modal transfer mean? Why is cross-modal transfer important?
5.
What do you understand by the term ‘absolute threshold’? Give three examples
from your reading. Cite your sources using e.g. Harvard Referencing System.
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Our Visual System
Vision and visual perception is by far the largest area of investigation undertaken by
cognitive psychologists. A full understanding needs a little introduction to the eye.
The eye, according to Ornstein (1975) is ‘the most important avenue of personal
consciousness’. We receive around 80% of our information about our world via our
visual system.
Our Visual Sense
As was said previously sight or our sense of vision is probably the most studied of
all our senses due to the vast amount of work which has been done in the area of
visual perception.
A basic understanding of the structure and function of the eye is therefore of
relevance - if only to give us a clue as to how and why we receive 2-D type
photographic images on our retinas but interpret these 2 dimensional images in 3
dimensions. A knowledge of our visual system is also important to our
understanding of how and why it is we can perceive colour and depth in our world and why it is we can see in the dark (but not as well as cats and other nocturnal
animals)!
Structure and Function of the Human Eye
The pupil: is the black circle at the centre of each of our eyes. The pupil controls
the amount of light taken in by the eye. In dark conditions, our pupil dilates to its
maximum size in order to maximise the amount of light entering the eye and thus
our ability to see (not too well) in the dark. In light conditions our pupil also dilates,
or ‘shrinks’, in response to the intensity of light we experience. Pupil size is
controlled by our autonomic nervous system (ANS). This controls organs and
glands. The ANS is linked to our central nervous system (CNS) (our brain and
spine). Interestingly the ANS has two branches:
i.
The parasympathetic branch which in this instance changes pupil size in
response to illumination, and,
ii.
The sympathetic branch that in this instance dilates the pupil under
conditions of strong emotional arousal.
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The two branches of the ANS are self-regulating rather than under our conscious
control. Regulatory control of the ANS is directed by the hypothalamus found in
the brain. Both branches of the ANS are what psychologists call antagonistic to one
another.
Vitreous is the clear, jelly-like
substance that fills the middle of the
eye.
Dilation of the pupil is controlled via
the ciliary muscles found in the iris.
The lens of the eye is held in place by
suspensory ligaments. Much like a
camera the lens focuses light on the
retina as an inverted or upside down
image. Ciliary muscles control the
shape the lens forms as it focuses light
energy on the retina.
The lens thickens and
increases in curvature when
focusing on nearby objects and
becomes flatter when we are
focusing on objects far away.
Muscles around the eye adjust
the shape of the lens to focus
on an object either nearby or
far away. The lens gets
thicker when focusing on near
objects (3), and thinner for
distant objects (4). The size of
the image reflected on the
retina changes, too.
The retina, which is found at the back of the eye, upon which images we see are
thrown, has three layers. Each of the layers helps explain certain human visual
abilities. These three layers are found at the macula: a small area in the retina that
contains special light-sensitive cells. The macula allows us to see fine details
clearly.
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The Three Layers of the Retina
The first layer of the retina contains what are called rods and cones.
•
Rods and cones are photosensitive transducer cells that convert light energy
into electrical nerve impulses. Our 120M rods help us see in ever decreasing
light.
Our 7M cones allow us to experience chromatic (colour vision).
Different cone types respond to the three primary colours of red, green and
blue. This is because each of these colours has different wavelengths.
Mixtures of red, green and blue allow us to experience all the colours found in
the colour spectrum.
•
Bipolar cells, a second layer in the retina, are connected to our rods and cones.
They help relay information to the visual cortex in our brain.
•
Finally in the retina we find a third layer called ganglion cells. Ganglion cell
fibres (axons) help form the beginnings of the optic nerve.
Three types of ganglion cell ‘fire’ in response to the contours and movement of
objects in our visual array or field of vision.
Simple cells which have been found to respond to simple features of a stimulus i.e.
straight lines, edges, slits, etc. when found in a particular orientation, or way-up, in
our visual field.
Complex cells which are found to respond to lines of particular orientation
wherever found in our visual field, and,
Hypercomplex cells which deal with the length of visual stimuli.
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The Visual Pathway
The visual pathway from each eye to the visual cortex in our brain is called the
optic nerve. Each optic nerve converges and crosses over at the optic chaism or
chiasma, thus information from our right eye goes to the left visual cortex and
information from our right eye goes to the left visual cortex. At the visual cortex we
find three other types of cell structure. These again give those with an interest in
cognitive processes in general and visual perception in particular clues as to why we
can see as we do. These three cell structures are as follows:
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Let's take a journey along the visual pathway. Light rays from sources either artificial
or natural are reflected off distant objects in our surroundings. These light rays first
enter into the eye by passing through a clear tissue called the cornea. From the
cornea, light then passes through a clear fluid termed the aqueous humour and then
passes through the pupil opening of the iris in order to reach the crystalline lens.
Using its two muscle band in bright situations, the iris constricts to protect the retina
from too much damaging light while during dim light situations, the iris dilates to let
in as much light as possible. The pupil, which appears as a black dot in the middle of
the coloured iris, is actually not a structure but an aperture controlled opening or hole!
Through the pupil, light reaches the crystalline lens. The lens - in conjunction with
the cornea - acts to bend or ‘refract’ the light in order to focus the rays onto he retina.
By its name you might believe the crystalline lens to do most of the refracting of the
eye but this is not the case. It is the cornea that is the primary refractive surface of the
eye. Eighty-five percent of the job of bending light is performed by the cornea while
the remaining fifteen percent is done by the lens. The crystalline lens does have one
advantage over the cornea. The power of the cornea to bend light is fixed where as
the crystalline lens can flex to provide more power in order to see near objects. The
lens is held in place behind the pupil by hundreds of fibrils termed zonules. When we
focus on near objects, these fibres relax allowing the lens to curve outward thus
increasing its power to refract light. When looking at distant objects, the zonules pull
tight and the lens flattens. The process of lens flexure in order to see near objects is
termed accommodation. From the crystalline lens, light rays travel through another
clear medium termed the vitreous humour until it reaches the retina.
When light enters through this whole optical system, it is actually inverted by the
process. An image in the outside world is actually upside down and backwards when
reaching the retina. It is the brain that later processes the image the correct way. The
retina is the central mechanism for collecting light rays and converting light energy
into electrical impulses that the brain can ultimately understand. The retina contains
millions of nerve cells with photoreceptors attached to each one. There are two major
photoreceptors located in the retina. Rods are long, slender receptors that occupy the
peripheral retina. Rods are responsible for detection of movements, detection of
shapes and night-time vision. Our fine detail and colour vision is provided by the
Cone receptors. These cone shapes cells occupy only a small portion of the retina and
are found huddled together in what is called the macula. The portion of vision
responsible for the most detail actually takes up the least amount of room on the
retina. Cones are divided into three subtypes - Red, Blue and Green.
When light hits these red, green and blue photoreceptors, a light activated chemical
reaction occurs within the cells converting a photon of light into an electro-chemical
impulse. Visible light is a spectrum like that of a rainbow. Each colour of the
rainbow has a particular frequency in that spectrum. The complex process of colour
vision occurs when light of a particular frequency stimulates either the red, blue or
green cone that is most sensitive to that given frequency. The quantity of
photoreceptors - as well as the type of receptors stimulated - is later interpreted by the
brain as intensity and colour.
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From stimulation, light energy is transformed into an electric current for the body.
This current then flows along each individual nerve until it reaches the optic nerve of
the eye. The optic nerve is termed a nerve but it is actually a collection of about a
million nerves rolled into one. We have two optic nerves: one for each eye. The
optic nerve extends from the back of each eye. They then enter into the skull through
a small opening in the back of the bony orbit that protects the eye. From here the
optic nerves travel a short distance before they meet up with each other at a structure
known as the optic chiasma/chiasm. At the optic chiasma, some of the nerve fibres
from the right optic nerve cross over to the left side and vice versa. This crossing of
optic nerve fibres causes everything we see off to the right in each eye to be processed
by the left-brain and everything off to the left in our surroundings to be processed by
the right brain. After parts of each optic nerve crosses at the chiasma, they continue
on into what is called the optic tract. This is where the optic nerves travel around the
brainstem, one nerve to the right hemisphere and the other to the left hemisphere of
the brain. From here everything mentioned occurs on both the right and left sides of
the brain. The optic tract carries impulses to another processing area in the brain
called the Lateral Geniculate Nucleus (LGN). This structure is like a switching
station. Before the impulses even reach the LGN, a small amount of fibres from the
optic tract split off to other areas of the brain that control dilation and constriction of
the pupils. After the LGN, each nerve ‘fans’ out into what is called the optic
radiations. Some of the nerve travels over the parietal lobe of the brain while others
travel the low road over the temporal lobe. The nerves continue on until they reach
the back portion of the brain called the occipital lobe. At the occipital lobes all the
impulses from the right and left eyes are processed into what we perceive as our
visual reality. The information between the two eyes are also compared to create our
three dimensional world.
DISCUSSION POINT
What do you understand by the term ‘sensation’? How
does a sensation differ from a perception: properly
known as a percept?
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WHERE ALL SENSORY INFORMATION ENDS UP TO BE PROCESSED
AND UNDERSTOOD
This is of course in our brain, the organ concerned with consciousness.
Consciousness is our awareness plus perception; attention; language; thinking and
memory) and the overall control of the body. The human brain is a relatively small
structure, weighing about 1.4 kg (3.1 lb) and making up about 2 per cent of total body
weight. It is contained within the skull, which acts as a protective casing. Although
the brain is only a small proportion of overall body weight, information received
about the outside world and from the rest of the body converges at the brain to be
processed. Sensations therefore ultimately arrive at the human brain and are
processed. We first begin to perceive what a particular sensation is (and therefore
what it is we are experiencing) on the basis of how good, bad or indifferent our
various senses are individually and collectively (remember cross modal transfer).
How we reach individual understanding of what particular sensations mean for us is
further based on some innate abilities plus any previous past experiences we have had
in connection with it.
Cortical Area
Function
Prefrontal Cortex
Problem Solving, Emotion, Complex Thought
Motor Association Cortex
Co-ordination of complex movement
Primary Motor Cortex
Initiation of voluntary movement
Primary Somatosensory Cortex
Receives tactile information from the body
Sensory Association Area
Processing of multisensory information
Visual Association Area
Complex processing of visual information
Visual Cortex
Detection of simple visual stimuli
Wernicke's Area
Language comprehension
Auditory Association Area
Complex processing of auditory information
Auditory Cortex
Detection of sound quality (loudness, tone)
Speech Centre
(Broca's Area) Speech production and articulation
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PROCESSING SENSORY INFORMATION
Conclusion: Sensation and Perception
What we see is more then just light focusing on the retina of the eye. Vision is an
enormously complex process. That which is seen must be captured by the optical
system, transmitted and processed by the retina then passed along to the brain for
even further more detailed processing. Areas of the brain must extract and interpret
the essence of all that we see. It must recognise colour, contour, shape, texture,
movement and perspective then compare all this information to our ‘internal database’
(or meaningful similar or same previous past experiences). A tiny two-dimensional
image hitting the retina must be transformed into a three three-dimensional world all
(pardon the pun) in the blink of an eye!
Vision is defined by two components: sensation and perception. The concepts of
sensation and perception are difficult to separate but
G Sensation is the detection and encoding of visual stimuli whereas
G Perception is the higher-level cognitive process of processing, organizing and
interpreting this visual sensation.
Perception should be seen as an active cognitive process influenced by our internal
and external world. These aspects of perception will now be addressed.
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Student Activity
Interactive Cognitive Psychology
Steadily fixate on the black light bulb for thirty
seconds or more. Try not to avert your gaze.
Immediately turn your gaze to the white region
on the right next to the bulb (or a blank white
sheet of paper). You should see a glowing light
bulb!
So What's Going On?
The glowing white light bulb you see on the white screen after staring at the black
light bulb figure is called an afterimage. When you focus on the black light bulb,
light sensitive photoreceptors (whose job it is to convert light into electrical activity)
in your retina respond to the incoming light. Other neurons that receive input from
these photoreceptors respond as well. As you continue to stare at the black light bulb
your photoreceptors become desensitised (or fatigued).
Your photo pigment is ‘bleached’ by this constant stimulation. The desensitisation is
strongest for cells viewing the brightest part of the figure, but weaker for cells
viewing the darkest part of the figure. Then, when the screen becomes white, the least
depleted cells respond more strongly than their neighbours, producing the brightest
part of the afterimage: the glowing light bulb. This is a negative afterimage, in which
bright areas of the figure turn dark and vice versa. Positive afterimages also exist.
Most afterimages last only a few seconds to a minute, since in the absence of strong
stimulation, most nerve cells quickly readjust.
Desensitization of the retina can be important for survival. A constant stimulus is
usually ignored in favour of a changing one by the brain, because a changing stimulus
is usually more important. But desensitisation also leads to afterimages.
Afterimages are constantly with us. When we view a bright flash of light, briefly look
at the sun, or are blinded by the headlights of an approaching car at night, we see both
positive and negative afterimages.
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To prevent permanent damage to your eyes, NEVER look at any bright light source,
in particular the sun. The British psychologist Kenneth Craik burned a tiny hole in his
right retina and permanently scarred his eye at that spot, when he stared directly into
the sun for two minutes. DON'T TRY THIS AT HOME! For the first few days
following his experiment - in which he wanted to find out whether such a lesion in the
eye is visible - he saw a dim orange disk with closed eyes (positive afterimage) and a
black afterimage with open eyes. Fortunately, after a year or so, Craik’s vision at that
location in his eye appeared to return to normal. His brain cleverly filled-in
information at this damaged piece of retina.
Second Experiment:
Notice that if the afterimage is viewed on the screen or on a nearby sheet of white
paper, it appears relatively small. If it is viewed on a distant wall, however, it appears
much larger, even though the size and shape of the retinal image remains the same.
The perceived size of the afterimage varies directly with the distance of the surface
on which it is viewed. This relation is an instance of a more general perceptual
relation known as Emmert's law: The perceived size of a particular visual angle is
directly proportional to its perceived distance.
The illusion of afterimages appearing to vary in size despite a constant retinal image
is precisely what one would predict if perceived size is governed not only by visual
angle but also by distance. The two seemingly different facts, that images of the same
size lead to perceptions of different size (Emmert's law), and that images of different
size lead to perceptions of the same size (size constancy), actually, illustrate the same
principle: Distance is taken into account in computing the size on an perceived object
from the size of the image falling onto the retina, which is another example
illustrating that we do not just see what our eye tells us.
Third Experiment:
When you close your left eye and adapt to the figure with your right eye, only your
right eye will see an afterimage when looking at a white region, not your left eye.
The afterimage does not transfer between eyes. This helps scientists determine where
in the visual system this effect arises. This type of aftereffect is caused by cells in the
retina fatiguing, rather than by cells in the visual cortex, where information from the
two eyes is combined.
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The active nature of perception
Factors, which further explain perception and help explain our perceptual world, are
embodied in what are called ‘The principles of perceptual organisation’ which
include:
•
•
gestalten and Figure & ground
Perceptual constancies, with particular reference to, depth perception
Gestalt psychology and gestalten
As was stated at the beginning of our cognitive psychology course, one way of
looking at perception is from the point of view of Gestalt psychology (Kohler; Koffka
and Wertheimer). It is easily understood. Gestalt psychology, which was in vogue in
Germany in the early part of the 20th century, believes we have an innate disposition
to perceive objects using our inbuilt principles of grouping, or Gestalten. What
gestalten means is our innate ability to construct our world in terms of organised
‘wholes’? It is as if we have a natural ability to ‘tidy up’ stimuli as we sense it.
Their Law of Pragnänz captures the principles behind gestalten, which are our innate
way of perceiving things in terms of symmetry; uniformity and stability. Individual
Gestalten are Proximity
Objects that are close together are perceived by us as a ‘whole’ e.g.
a)
b)
. . . . . .
.......................
How do you perceive a) and b) above?
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Similarity
Similar objects are normally perceived by us as belonging to the same group
Above, what similar sets of objects do you perceive as a group and what other one
which does not exist in reality? Storm the reality studios!
Continuity
Sensations appearing to create a continuous form are perceived by us as belonging
together e.g. a fence with slats missing is still perceived as a fence. We organise
sensations appearing together to form a continuous whole e.g.
x
x
x
x
x
x
x
x
x
x
Do you perceive the above as a square shape made up of X’s, or 10 separate and
individual X’s?
Closure
Where we, at an unconscious level, fill in contours/gaps in stimuli to form a complete
whole in order to make perceptual sense of it NB the importance of previous past
experience and perception. This is illustrated below. What do you make of these
stimuli? Your teacher/lecturer should explain the significance of this simple
demonstration.
The whole is greater than the sum of its parts
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Texture
Is another principle of gestalten where objects of the same texture are perceived as
belonging to the same group e.g. grains of sand and pebbles at the seaside form for us
a ‘beach’. Or leaves on a forest floor!
Simplicity
Where we have a tendency to group stimulus features together in a way that provides
the simplest interpretation of the world for us e.g. houses as opposed to their make-up
e.g. windows, doors, roofs, walls and ceilings. The notion of simplicity does have a
link with the social psychological phenomenon of stereotyping and attribution theory.
Common Fate
This strange term means the principles where individual objects moving together at
the same rate are perceived by us as a group. We group, by common fate, flocks of
seagulls and swarms of wasps. We do not perceive each individual in the flock or
swarm. We innately organise the stimuli into a ‘whole’ in order to perceive and
understand it.
Innate principles behind gestalten and gestalt
psychology, which are biological in origin, go some way
to explain perception. Perception is therefore more than
mere ‘seeing’. We often find in psychology that
abilities which seem to be innate have survival value for
us.
Evaluation of the Gestalt Contribution to our Understanding of Perception
Gestalt psychology is of immense importance not only to our understanding of
perception but also to a wider philosophical question within psychology known as the
nature-nurture debate. This debate considers whether we are as we are as a result
of innate abilities or as a consequence of our experiences in our environment (is it
nature – our genetics/biology/physiology - which makes us what we are; or nurture –
our environment - which makes us what we are? This is a hugely important question
that has been considered since the beginnings of time itself. Man, in the generic
sense, has always asked the big picture questions as regards ‘Who am I?’ ‘What am
I?’ and ‘Where have I come from?’ Someone who thinks we are as we are as a result
of our genetics//biology physiology is termed a nativist in psychology while those
who think environment is more influential are called empiricists. For hundreds of
years philosophers such as John Locke have tried to discover which side of the debate
is the more correct. Modern day scientific advance would seem to suggest that the
truth to the question ‘Why am I as I am?’ lies somewhere between the two opposing
sides in the debate. Nature and nurture both play a part. They individually and
together make us who, what and why we are.
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What of the innate, and thus nativist position, of Gestalt psychology? Do we have
innate, or inborn, perceptual abilities?
1.
Bower (1966) is, amongst other things, famous for his peek-a-boo experiment
into size constancy (relative size). He set out to discover if size constancy in
babies was learnt (the empiricist position) or innate (the nativist and thus Gestalt
position). He conditioned young babies (neonates) of 2 months to turn their heads
on the presentation of a 30-centimetre cube at 1 metre away from them. They
were then presented with three further conditions of the independent variable i.e.
•
•
•
a 30 centimetre cube at three metres
a 90 centimetre cube at one metre and
a 90-centimetre cube at three metres (which produces the same size of
retinal image as the 30 centimetre cube at 1 metre).
He recorded the number of times each stimulus produced the conditioned
response (head turning) and his results showed Condition 1 (30 cms x 1 metre): 98 head turns
Condition 2 (30 cms x 3 metres): 58 head turns
Condition 3 (90 cms x 1 metre): 54 head turns
Condition 4 (90 cms x 3 metres): 22 head turns
The finding that most head turns occurred in response to the first stimulus shows
that the babies were responding to the actual size of the cube irrespective of
distance. This supports the nativist and Gestalt position of size constancy being
innate. Further research by Slater (1989) supports Bowers findings and suggests
that size constancy (our ability to perceive the true size of an object) is actively
and provably present as young as 18 weeks old.
2.
A further study by Bower investigated the Gestalt principle of closure. He
conditioned neonates to respond to triangle number 1 and then presented them
with 2, 3, 4 and 5.
Number 1
Number 2
Number 4
Number 5
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Bower found that the conditioned response was generalised more by the babies to
the complete triangle (Number 2). It is suggested that with Number 1 the young
babies initially perceived an unbroken triangle to lie behind the black bar and that
this indicates the gestalt principle of closure to be innate in us all. These gestalt
principles are the basis to further and more complex perceptual organisation.
Figure and Ground
What do you make of the visual stimuli below?
This stimulus is known in psychology as Rubin’s Vase and is often used to
demonstrate illusions. Danish psychologist Edgar Rubin made the vase/profile
illusion famous in 1915. As you might be able to ‘see’ from Rubin’s Vase our visual
perceptual process puts some aspect of the 2-D stimuli to the ‘front’ or foreground
(figure) and another aspect to the meaningless background (ground). Some part of
the image always stands out as ‘figure’ and some other part ‘ground’. With Rubin’s
vase the principle is reversible. What is meant here is that you will either perceive a
vase to the front or two faces squaring up to each other! Often what you perceive (as
above either a vase or faces) is related to:
1. Our expectations
2. Our culture
3. Our experience of the stimuli
4. Our motivation
5. Our social world
All of these influences on perception are collectively called ‘perceptual set’
Please answer the questions that follow.
.HHS
RII WKH WKH
JUDVV
Perceptual Set?
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Student Activity
1.
What do you make of the stimuli below? Give an explanation for your answer.
When did this phenomenon happen for you earlier?
E
A
D
16 15 14
13 A
B 12
the cat sat on the map and licked its whiskers
2.
Below are what might appear as blobs when you first look at them. Your
impression of the blobs provides an example of awareness at a sensory level. If
you continue to look at the blobs, four words will emerge. You need not try to
organise the blobs. The organisation process will occur without any overt
striving on your part. These blobs have been created to slow the perceptual
process so that you can experience what typically occurs speedily in subjective
time.
After you have perceived what they are use the explanatory thumbnail to explain
what you have just done.
Your first and seemingly immediate
awareness, which more or less
corresponds to the energy stimulation
patterns, is referred to as ‘sensation’.
‘Perception’ can be distinguished from
sensation in that it refers to a process that
requires more organisation than
sensation, is more heavily dependent on
learning than sensation, and requires
more time for completion than sensation.
Explain the difference between a
sensation and a percept.
3.
Without looking back three pages previous what was the saying in the triangle?
Please now look back and read what is inside the triangle carefully. What does it
actually say? Why were you so sure about what you thought it said the first time
round? How was your perception affected? Explain what you have just done in
terms of perceptual set NB expectations, culture experience motivation and your
social world.
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4.
Below is the most famous illusion in psychology attributed to Boring. From the
point of view of your perception what is at you first perceive? Can you perceive
anything else? Explain this illusion in the light of factors that influence
perception.
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THE ACTIVE NATURE OF PERCEPTION
Perceptual Constancy
So far we have identified that perception depends upon bodily structures and
processes, our innate principles of gestalten and the way we impose three-dimensional
meaning on two-dimensional visual experience on the basis of expectations, culture,
experience, motivation and our social world - sometimes wrongly! Perception is
actively influenced by all these factors working individually and together. Where this
all ultimately happens is within the human brain centring on the hypothalamus in
particular.
We also have a perceptual ability, called together perceptual constancies, which
helps us to perceive our world. Where our perceptual constancies of size, shape,
brightness and depth come from is not fully understood. Cognitive psychologists
disagree as to whether they come about as a consequence of our biology and genetic
inheritance (nature) or as the result of learning and experience (nurture). It should be
said however, that as far as depth constancy is concerned, there is good psychological
evidence to suggest that depth perception is innate.
Perceptual constancy is our ability to perceive sameness of visual stimuli even when
the sensory evidence is to the contrary. We have a perceptual constancy in the four
areas below that also help us make sense of our perceptual world.
1
2
3
4
size
shape
brightness
depth
Perceptual constancies occur when our brains correct or modify our rapidly
changing sensory inputs to give us a more constant perception of the world. For
example, size constancy ensures that as we watch a friend walk off into the distance,
although the image of the person projected onto our retina is rapidly decreasing in
size, we do not perceive that our friend is actually shrinking! The knowledge that as
the proximal stimulus (the internal sensory image) changes, the distal stimulus (the
external object being perceived) does not, allows us to correct our sensations and
maintain constant perceptions.
Cognitive psychology has over the years had three theories about perception. It is in
the area of perceptual constancies that much supporting evidence to which theory is
the more correct has emerged.
These theories are summarised overleaf.
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Three Theories of Perception
1. Bottom-Up (Ecological View): (Gibson; Gestalt - ‘organised wholes’): where it
is said we perceive most clues from our environment directly and without
interpretation (we perceive ‘exactly’ what we see/hear/smell/touch and taste).
The ecological view explains perception as being ‘bottom-up’ - our world
impinges on our senses which processes the information to the brain where it is
directly interpreted, understood and acted upon. Bottom-Up theory cannot explain
illusions.
Discussion Point
Why do you think the bottom-up theory of perception
cannot explain illusions? Why can bottom-up theory
not be dismissed altogether? Give reasons for your
deliberations.
2. Top-Down (Constructivist View): (Gregory; Bruner) who say our perceptual
system must often make a reality indirectly out of bits of sensory information due
to the absence of other information. They are top-down in their explanation of
perception. Higher-level cognitive functions play a part. We perceive things
often in the absence of bits of sensory information by hypothesis testing or ‘best
guessing’ on basis of previous (in) experience of what it is we sense.
Discussion Point
What is the key to a top-down theory of perception?
What other influences would operate on a top-down
perceptual understanding of our world?
3. Top-Down/Bottom-Up (Symbiotic View): (Neisser: Marr) who say we use both
top-down and bottom-up information processes in the perception of our reality.
Nature and nurture both play a part. Both enhance perception individually and
collectively. When one perceptual process, or aspect of it is impaired, the other
process, or an aspect of it, ‘fills’ in or compensates to give us at the end of the day
as best an individual understanding of the image/object/event as possible.
Symbiotic processing is best explained in the area of visual perception using
Marr’s Computer Analogy where he says we extract visual information from an
image/object/event in four stages and put this all together again in the brain in
what he calls a symbolic representation of the stimulus. Marr’s computational
model as an explanation of visual perception is illuminating in that it helps
emphasise the role of both bottom-up and top-down processing independently,
collectively and integratively.
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Discussion Point
For next day summarise each of the three
theories/approaches to an understanding of perception.
In your opinion, which appears the more, correct? Give
reasons for your answers. It is to be hoped that the good
student will refer to both psychological and everyday
examples in their deliberations.
A brief overview of Marr’s Computer Analogy follows.
Marr, David (1945-80)
Marr was a British psychologist who made important contributions to the study of
visual processing. In doing so, he integrated results from psychology, AI, and
neurophysiology. His classic book, Vision: A computational investigation into the
human representation and processing of visual information, is considered one of
the most important works in cognitive science. In addition to his work on vision,
Marr developed a general account of information-processing systems in terms of
three levels of analysis: (1) the level of computational theory of the system, (2) the
level of algorithm and representation, which are used make computations, and (3)
the level of implementation: the underlying hardware or "machinery" on which the
computations are carried out.
Algorithm
An algorithm is a mechanical and completely reliable procedure or set of instructions for completing
an operation in a finite number of steps. For example, ‘To unlock a door with an unfamiliar set of
keys, try each one until one of them does unlock.’ Another example, from logic, is truth-tables,
which determine whether a formula is a tautology. In mathematical contexts, an algorithm is a
mechanical procedure for computing a result or outcome. Use of an algorithm always provides a
solution to a problem, unlike a heuristic.
In an attempt to understand the complex make-up of our visual perception David
Marr (1982) in ‘Marr, D. (1980) Visual information processing: the structure and
creation of visual representations. Phil.Trans.R.Soc.Lond.B, 290, 199-218’ thinks
neural activity transforms sensory (essentially visual) stimulation into our experience
of reality. This is done gradually, by us by extracting and deconstructing specific
information from the object we ‘see’, in four stages and then putting all this
information together again in our attempt to recognise and understand what is we are
(visually) perceiving. This he calls a symbolic representation.
Representation
'Representation' can refer to a symbol or thing, which represents ('refers to', 'stands for') something
else, or it can refer to the relation between a representation (in the sense just described) and what it
represents. In either case, there are many kinds of representation. For instance, there are linguistic
forms of representation (as exemplified by the words in this sentence) and non-linguistic forms of
representation (as exemplified by maps and models). General questions about representation focus
on the nature of the relation between a representation and what it represents, features which
distinguish representations from other, non-representational items and features which distinguish
different kinds of representation. Questions about representation which arise in connection with
mental states and cognition involve the representational nature of imagery (is it more picture-like or
language-like?), the creative use of representational systems, and the relationship between language
and thought. These questions are of particular concern for computational models of mind, which
require that mental representation be in a form suitable for computation.
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Marr’s (1982) 4 Module Computational Theory Of Vision
1.
The image or grey-level description
Represented by the intensity of light at each point in the retinal image. This
allows us to discover the boundaries of and regions in the image. Marr thinks our
ability to identify boundaries and regions on this basis is the beginning of visual
perception.
2.
Primal sketch
Here Marr says we go on to identify surface markings, object boundaries and
markings using the gestalt principles of grouping.
3.
2½-D sketch
A third stage where in the deconstruction of an image we give it depth and
orientation. It is not yet 3-D. Object recognition needs the input matched against
memory so that non-visible points are accounted for (perceptual constancy).
4.
3-D Model representation
Where the nature and construction of the object is at this final stage
confirmed/denied using higher level top-down processing functions and abilities.
This gives rise to a symbolic representation of our visual reality and is, for Marr,
true object recognition.
Three Theories of Perception and their Explanations of Constancies
1. Size Constancy
As previously explained, size constancy refers to the fact that although retinal
images of objects get smaller as the object recedes into the distance, we perceive
that the object does not change in size.
Taking size constancy into account, the constructivist view of perception
maintains that size constancy develops because we learn through experience that
objects do not actually shrink as they move away from us. Some cross-cultural
evidence is consistent with this view, in that sometimes people from the dense
jungle or heavily wooded regions, who are not accustomed to viewing objects at a
distance, mistakenly perceive distant objects as being very small. Ecological
direct-perception theory on the other hand maintains that size constancy occurs as
a direct result of the information taken in by our senses and that failure to
conserve size results only when the situation does not provide us with enough
direct sensory information.
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2. Shape Constancy
Shape constancy, is our ability, innate or learned, to perceive the shape of an
object as being constant even although our retinal image of the object is
changing. An example of this would be the chalkboard at the front of your class.
Regardless of where you are sitting we all perceive the chalkboard as a
rectangular shape despite the fact that we all have different retinal images of it
depending upon where we are sitting.
Constructivists, or top-down theorists, see shape constancy coming about as a
product of learning in our environment whereas bottom-up theorists see shape
constancy as being somehow innate and part of the experience of sensation.
3.
Brightness Constancy
Lightness, or brightness constancy refers to our perceptual ability to adapt to the
situation where the illumination (brightness) of an object changes but we
continue to perceive its brightness and colour as the same or constant. A white
sheet of paper first perceived in bright sunlight will still appear white and of
approximately the same shade when later perceived by us under the shade of a
tree. Constructivists (top-down theory) explain brightness constancy in our learnt
knowledge that objects do not change their ‘brightness’ as lighting conditions
change. Ecological theory takes a bottom-up explanation of brightness
constancy. They say that enough information is present in the sensory experience
itself to allow us to maintain a constant (lightness) perception of the object.
Who is the more correct is very difficult to ascertain. Because babies cannot
communicate very well when born, we have little way of knowing if these
constancies are present from birth, or learnt (however quickly), as the result of
experience. We may find a more accurate explanation to the origins of perceptual
constancies in an examination of depth perception.
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Student Activity
Depth Perception
An awareness of depth perception will help us understand why it is we visually sense
the world in 2 dimensions (like a photograph) but perceive what we see in three
dimensions!
This is demonstrated below:
Above is a Swedish stamp based on the original diagram on the right by the British
physicist Roger Penrose (1954) called an Impossible Triangle. They are each
obviously two dimensional. Are you currently experiencing both in three dimensions?
Shut one eye. Do you still experience both in 3D? If you are this definitely
contradicts direct perception bottom-up theory as an explanation of perception.
Now the hard bit: Why is this the case?
Without depth perception we would find walking, reaching driving and playing games
difficult (among other things). We see depth in our visual world because of
i)
monocular depth cues
and
ii) binocular depth cues.
Monocular depth cues
Monocular depth cues come about due to seeing the world with one eye; or our two
individual eyes singularly...think about it!! Monocular depth cues, or cues to depth,
come to us from our external world. Put simply, what things are and where things are
in our external world, gives us cues or clues to depth.
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Even if we visually experience our world with one eye, and the image which is
striking our retina is definitely two-dimensional, where things are in our visual field
allow us understand or perceive our world in three dimensions. Monocular depth cues
include inter alia interposition, linear perspective and relative size.
• Interposition/Superposition
One monocular depth cue we call Interposition or overlapping. Interposition is the
monocular cue we use to perceive depth when we see a scene where one object is
partially obscuring another. The object we can fully see we perceive as nearer than
the partially obscured object - which we perceive as behind. If your teacher or
lecturer sits down behind their desk we can adjudge that the desk is nearer you than
they are: you can fully see the desk and only the top half of their body. The
interposition of the desk and the teacher/lecturer is here a monocular depth cue.
A
B
C
How is interposition working in the above example?
•
Shades and Shadows
GK
When we know the location of a light source and see objects casting shadows on other
objects, we learn that the object shadowing the other is closer to the light source. As
most illumination comes downward we tend to resolve ambiguities using this
information. Shadows in 2-D images are used by the advertising industry and sign
writers to attract our attention to the ‘fact’ that the words seem to stand out from their
background, giving the impression that the background is further away from the
letters. Why? We notice it more!
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Another monocular depth cue is:
• Linear Perspective
Linear perspective is another monocular depth cue. If we see two parallel lines
converge into one another in the distance this tells us about depth. This is easily
demonstrated in a railway station. When it is safe (!) look down at the railway lines.
They are parallel to one another. Now look up the track and you will see the rails
converge (come in on one another). This is linear perspective. If we see this
happening this is a monocular cue to depth or distance. Linear perspective can even
work in two dimensions i.e.
Which of the two horizontal lines above is larger? The one at the top or the one at the
bottom? Measure them. What do you find? Why did you perceive what you did?
• Relative size
Relative size is another monocular depth cue. Relative size occurs when we see two
objects, like two houses, against their backgrounds in our visual field. We see in two
dimensions, that one house is smaller than the other. Indeed the 2D visual
information we receive about the smaller of the two houses would appear to suggest it
is the size of a match-box! This is not the case. We perceive on the basis of relative
size that the visually smaller house is further away from us. The larger of the two we
perceive as nearer:
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Paintings take advantage of the monocular depth cue of relative size. Take the
painting shown above, ‘Sculls’ by Gustave Caillebotte. Note the two people rowing
the boat, the closer one is painted much larger than the other. Even the two paddles
near each other in the middle right-hand side of the picture show the use of relative
size. The paddle from the closer boat, which is off the painting, is painted larger that
the paddle from the main boat that Caillebotte is depicting.
Note one additional feature about relative size: The boater in the background does not
look abnormal in any way. Despite being painted smaller, the person does not look
like a midget. The normal size of the more distant person is due to size constancy
discussed earlier.
The human visual system interprets depth in sensed images using both physiological
and psychological cues. Some physiological cues require both eyes to be open
(binocular); others are available also when looking at images with only one open eye
(monocular). All psychological cues are monocular. In the real world the human
visual system automatically uses all available depth cues to determine distances
between objects.
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Binocular Depth Cues
Binocular physiological depth cues are easy to understand. Binocular depth cues
come about due to the fact we have two eyes. Binocular cues to depth in our visual
field result because of the fact that each of our eyes receives a slightly different
picture of the same scene our nose sees to that.
The dual and overlapping picture we get as
a result is called stereopsis. Stereopsis
gives us binocular cues to depth because
most of us enjoy binocular (two eye)
vision. We can lose the ability for
binocular depth cues to our visual world
due to a blow to the head (that gives us
double vision) or damage to the eye due to
strabismus (squints) etc. Sports people
generally have excellent binocular vision.
You will find that professional sports people whose game involves a ball of some
description are usually excellent at other ball sports they take as a ‘hobby’. The world
famous snooker player, Scot, Stephen Hendry is an excellent golfer. The goalkeeper
Andy Goram has Scottish caps for both football and cricket. Ian Botham played both
professional cricket and professional football - though not at the same time of year.
If we have two eyes, when objects get closer to us, each eye turns inwards. As
objects, or percepts, move further away each eye turns outwards. The brain interprets
this as a binocular cue to how near or how far the percept (image/object) is from us.
This inward and outward movement of our eyes in response to how near or how far a
percept is from us is called binocular convergence. Because each eye has a slightly
different view of the same visual world, this similar, but different information is also
used to judge depth. The closer each retinal image (or picture) is to one another, the
nearer our brain interprets an object is to us. This is called binocular disparity.
We therefore achieve depth perception due to monocular and binocular depth cues.
Monocular depth cues come from our visual environment. Binocular depth cues arise
because we have two eyes. The biology of the human body gives rise to binocular
depth cues. Our external environment gives us monocular depth cues.
Monocular Depth Cues
Interposition
Relative Size
Linear Perspective
Depth Perception
Bionocular
Convergence
Binocular Depth Cues
Bionocular Disparity
Student Activity
‘‘D
Deessccrriibbee aanndd eexxppllaaiinn hhoow
ww
wee ppeerrcceeiivvee ddeepptthh iinn oouurr w
woorrlldd??’’
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A Word about Motivation
Motivation, in psychology, concerns what prompts us to action or to behave in a
particular way. Motivation can effect our perception of objects, events, people stimuli
etc. Motivation in psychology is a study all in itself. Cognitive psychology
understands that our motivation to react, act and behave in a particular way is affected
by two things: our
•
internal biology and
•
external environment.
Sometimes our internal biology and external environment come together to make us
think, feel and behave in a particular way. The interaction of our biology and
environment as they motivate us to be more perceptually aware produce interesting
and - expensive - results.
When our body needs fuel i.e. food it tells us so when we experience hunger pangs.
This is our body’s internal signal or cue to us to eat. Our biology affects our
perception in that when we are hungry and experience hunger pangs we perceive food
much more vividly. It is fatal to go food shopping in a modern supermarket if you are
hungry. The fruit appears more appealing; the home baking that more delicious; the
meat and fish that more tasty looking! We perceive the colour of food more. We
perceive the smell of food more. Perception of food is heightened by internal bodily
factors. External factors like the clever use of lighting to illuminate fruit colouring
more and the bakery in the supermarket constantly baking bread and cakes also
influence and motivate us to perceive food more when hungry. The internal and
external factors of motivation will greatly influence your perception of food and in
this situation you may end up buying and spending much more than you needed!
Supermarkets of course are aware of this. A knowledge of cognitive psychology can
affect your waistline, wallet and purse.
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Cultural Variations on Perception
In 1966 Mundy-Castle investigated the interpretation Ghanaian children of between
5-10 put on their line drawings. They were presented with a series of drawings each
of which used only a limited number of depth cues. These being height in plane;
interposition and relative size. Each picture saw a man and a deer at the front and an
elephant at the back in different combinations. i.e.
Mundy-Castle1 discovered that the children’s’ interpretations were significantly
different from that made by a similar sample of European children. The Ghanaian
children were unable to use such depth cues as the road to interpret the picture. Their
culture, which did not give them experiences of roads (and deer – they called these
goats or similar) influenced their perception. Similar findings into (faulty) depth
perception have been found when people are transposed out of their own environment
into an alien one, for example, from a desert or arctic landscape into a city and vice
versa. Depth perception is grossly influenced as a result of cultural past experience.
They just cannot function efficiently. Culture must therefore play a part in the
formation of all our perceptions.
1
Mundy-Castle, A C. (1966) Pictorial Depth Perception in Ghanaian children International Journal of
Psychology 1 290-300
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Further Examples of Cultural Variations on Perception
Student Activity
Consulting the likes of ‘Cognitive Psychology’ Richard Gross and Rob McIlveen
(Hodder and Stoughton 1997), consider and report on further examples of cultural
variations on perception as investigated by:
a)
Rivers (1901) and his use of Muller-Lyer and horizontal-vertical illusions in a
cross cultural study with Murray Islander adults and children
b) Allport and Pettigrew (1957) use of the rotating trapezoid illusion in a cross
comparison study between western and Zulu cultures
c)
Stewart (1973) and his use of the Ames distorted room with Tongan children
d) Give one other cross-cultural example not listed above. What does your evidence
tell you about the influence of culture on perception?
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Social and emotional influences on perception
Culture is bound up in our social world which itself provides the circumstances within
which we feel and express emotions. Lord Derry Irvine is an extremely rich man.
When New Labour came to power in 1998, Lord Irvine (a longtime friend of Prime
Minister Blair) became the Lord Chancellor and, automatically, speaker of the Lords,
i.e. head of the English legal system and a member of the Cabinet. He set about
refurbishing his official residence at taxpayers’ expense and could not understand the
reaction to spending tens of thousands of pounds on chairs and curtains. Because of
the social world he lived in, his perception of what was spent on this redecoration was
entirely different from the vast majority of the British population.
Allport (1955) reports a study concerning prejudice and perception. Prejudices arise
from the social world we find ourselves in. Prejudice is learnt - formally and
informally. Prejudice influences perception.
Using a stereoscope (a device for presenting a separate picture to each eye
simultaneously) the experimenters showed participants mixed-race pairs of
individuals; one member of each pair shown to each eye. Generally people were
better and more definite when picking out and categorising members of their own
race. They were more unsure and cagey when categorising people of other ethnic
groups. Afrikaaners, long noted for their prejudice towards black people,
differentiated far more quickly and definitively between people of different ethnic
groups presented via the stereoscope. They had a very definite perception and raised
emotional awareness towards differing racial groupings. Allport interpreted this as
showing the strongly racist views held by Afrikaaners had influenced their perception.
In 1948, Postman, Bruner and McGinnies discovered using a tachiscope that sexual
and other taboo words had a higher recognition level than ordinary language.
Participants took longer to process these types of words than neutral ones. Postman et
al suggest that this longer processing time is a type of perceptual defence — to defend
us from the unacceptable. However, Bitterman and Kniffin (1953) found that the
time difference disappeared if participants were allowed to write down these taboo
words. They said that Postman et al’s earlier work suffered from a methodological
response bias. Participants were simply less willing to say swear words aloud than
neutral words. So who is the more correct?
Worthington (19691 subliminally presented participants with taboo words. So
subliminally that participants were completely unaware of their presentation. They
were cleverly embedded at the centre of a dot of light projected onto a screen. Dots
were presented in pairs and the participants had to say which dot was brighter,
dimmer or were they both the same. Dots with taboo words embedded on them were
consistently rated as being dimmer than those with neutral words. The perceptual
defence argument therefore has some merit.
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Carpenter, Weiner and Carpenter (1956) engaged participants in the completion of
sensitive topics like personal inadequacy, sex, hostility, etc. They categorised
participants as either ‘sensitive’ or ‘repressed’ as a result. Sensitive participants
perceived taboo or disturbing words more easily. Repressed participants perceived
such words less readily and quickly. Personal differences in values and attitudes can
thus greatly influence perception. These we get from our social world.
Solley and Haigh (1958) reported on a study to show the influence emotion has on
perception. Children were asked to draw pictures of Santa Claus in December and
January. Representations were larger and included more presents in the month of
December in comparison to January. In January the drawings shrank and the presents
got fewer! Solley and Haigh (1958) imply that emotions such as excitement and
anticipation can influence perception.
Think about something you looked forward to for a long
time.
What mental representations did you have in
anticipation of it? What emotions did you feel? Was
the event as brilliant as you first perceived it to be?
In 1951, Lazarus and McCleary conducted an experiment that gave mild electric
shocks to participants when presented with a nonsense syllable. This provoked an
avoidance response to them in the future! Interestingly, they also found an avoidance
response when participants came across the nonsense words subliminally. This
implies that the perceptual system works at both a conscious and unconscious level
and that consciously and unconsciously our perception of our world can be influenced
by previous past experiences.
Student Activity
‘‘D
Deessccrriibbee aanndd eexxppllaaiinn ccuullttuurraall,, ssoocciiaall aanndd eem
moottiioonnaall iinnfflluueenncceess oonn ppeerrcceeppttiioonn..’’
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APPLICATIONS OF PERCEPTION
RL Gregory is a cognitive psychologist who takes a constructivist approach to
perception. He says that we often (have to) go beyond the evidence of sensory
information alone to understand and behave appropriately in our world. He believes
experience in our environment has a part to play here. He used visual illusions in an
attempt to prove his point. Visual illusions see us interpreting them as more than just
sensory input alone. This was demonstrated earlier. With the old woman/young
woman illusion did you first/always see a young or an old woman. Which is the more
correct interpretation of the stimuli? We often use knowledge of visual illusions to
our advantage. DIY programmes are about altering perceptions to make rooms more
appealing. If you have a small bathroom or kitchen and want to create an illusion of
size, DIY programme presenters often use the Muller-Lyer illusion and paint
horizontal lines on alternate rows of tiles giving an impression of depth, or use
vertical lines to create height – where none in reality exists. By using the natural
contours of the room, like corners, they work on our environmental experiences of
cue’s to depth i.e. two railway lines that appear to converge into the distance are used
as an external clue to depth in our world. This is illustrated at b) over.
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a)
b)
On the other hand there are psychologists like Gibson and Walk (1960) who believe
more in an ecological or bottom-up approach in their understanding of our perceptual
processes — at least as far as depth perception is concerned. As can be seen on page
74, in their famous visual cliff experiment, they discovered in their work with kittens
and neonates that depth perception is probably innate in humans as it is in kittens.
This suggests the application of those innate perceptual abilities we have as being
important from the point of view of personal survival. They have come about as a
result of evolution. It would appear in the application of perception we benefit from
both theoretical positions. Some abilities that influence perception appear innate –
but experience of environment and what we learn in it is important as well.
Perception and Advertising
Student Activity
In 250 words or thereabouts identity, describe and explain from a psychological point
of view the application of perception in the advertising and/or marketing world. Your
answer should include reference to psychology (!) and might begin by defining what
you understand perception to be. It must include mention of three examples of
advertisements or campaigns which use external factors to perception such as size,
colour, movement, novelty, culture, social or emotional factors that see us go from
mere sensing to perception and ultimately thinking, feeling and behaving in a
particular way towards an individual, object event etc.
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Student Activity
Interactive Cognitive Psychology
What is this picture? As you search for meaning in this picture your brain strives to
make sense of the seemingly meaningless spots. If, after a while, you still see no
meaning in the picture read the answer below. Once you ‘see’ the solution it will
never again be meaningless to you.
So What's Going On?
This experiment shows that past experience can affect your perception of such
properties as form or depth. Consider what happens when you view this illustration.
At first most people cannot tell what this picture depicts, but with continued
inspection or a hint, the fragments suddenly are perceptually reorganised and
recognised, in this case, as a Dalmatian dog. A recognisable image emerges that had
no perceptual reality before. Hence, there is some sort of perceptual change among
the neurons in your brain. This also leads to a change in the way in which you
perceive the shape and depth of the scene. Perhaps most importantly, the figure now
looks like the object it was supposed to represent - it now has the shape and depth
relations of a Dalmatian dog.
Sometimes being told that a Dalmatian hides in this scene can provide the visual
system with enough of a hint to recognise the dog. This is a case in which a highlevel brain area underlying language comprehension tells a lower-level area, in this
case the cortical areas dedicated to visual scene analysis, what might be going on.
This is another example of why the study of cognitive psychology should be seen
holistically.
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If this dog were animated then it would be immediately apparent. Common motion
of a group of otherwise unrecognisable blobs is a very powerful cue for our visual
system. It enables our visual system to realise that it is dealing with a single object.
This effect is termed grouping. It is important that an animal can do this well;
otherwise, it might not easily spot a predator, prey or other food. Animals must be
able to separate the figure from the ground. What we call camouflage is an attempt to
deceive these processes. A stalking cat moves cautiously and freezes from time to
time to avoid giving motion clues to its prey.
It has even been suggested that our good colour vision evolved to enable our primate
ancestors to spot coloured fruit against a confusing background of green leaves. What
gives us so much visual pleasure may originate as a device to spot our food and to
break camouflage.
In most illustrations, we tend to perceive a figure that stands out from the background.
In printed material, the figure is usually darker than its background. Figures also tend
to be smaller and more regular than backgrounds. Sometimes these principles do not
hold, and we have difficulty distinguishing figures from their backgrounds. However,
this difficulty disappears when our brain somehow organises these difficult visual
images into a meaningful and recognisable pattern. When this is done, only the figure
and background can be seen, and whatever was seen before is gone forever! Once
you understand what is being presented, your perception changes, and you will be
fixed on the ‘correct’ interpretation forever.
Since these types of figure/ground figures do not lead to immediate identification, the
mental recognition of the ‘correct’ figure must be perceptual in character. After all,
the image does not change on your retina. Thus, we can assume that some mental
process that precedes or accompanies the moment of recognition entails a perceptual
reorganisation.
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Second Experiment
Now that you have recognised the Dalmatian dog, try perceiving the image in its
original meaningless way. You will find it almost impossible to do.
Once you have recognised the Dalmatian dog, it becomes almost impossible to see the
picture in its original meaningless interpretation. The picture becomes permanently
meaningful. This is in contrast to an ambiguous figure that has two equally likely
interpretations. The ambiguous figure will ‘flip’ between two states, because your
brain cannot decide which one is more meaningfully biased over the other one.
In the case of the Dalmatian dog, however, once your brain perceives the ‘correct’
image and ascribes meaning to the picture, your brain will not be able to perceive a
meaningless image again because the meaningless interpretation is no longer equally
biased with that of your past experience with Dalmatian dogs.
During all the time you were staring at the picture, the image on your retina did not
change. Rather, your brain worked to construct a correct interpretation of the image,
trying out different interpretations, until your brain ‘recognised’ something. This
emphasises that perception is an active process of constructing a scene description.
Using your knowledge of cognitive psychology write a short essay
explaining the psychology behind the Dalmatian Dog experiments.
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ATTENTION
In relation to the study of attention, this support pack will consider:
•
•
•
models of attention
sustained/divided attention, maintaining vigilance
factors in attention - motivation, expectation, emotion and culture.
By the end of this key concept you will be aware that humans have the capacity to
attend selectively to something while ignoring something else. Sometimes however
even that which we do not attend to directly can be perceived. You will discover that
factors such as motivation, expectation, emotion and culture influence how humans
select information from the environment. The close relationship between perception
and attention will be explored in the context of active information processing.
Different models of attention will be looked at using examples such as the cocktail
party effect. You will be introduced to the study of sustained attention and vigilance
and their practical implications in understanding how long people can maintain
concentration before beginning to make errors. Areas of application which will be
brought to your attention (sic) include situations where vigilance is required, e.g. the
police, security personnel, aircraft pilots.
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WHAT IS ATTENTION?
Our definition of attention is perhaps entirely appropriate:
Attention is:
‘… the taking possession by the mind in clear and vivid form, of one of
what seems several simultaneously possible objects or trains of thought.
Focalisation, (the,) concentration of consciousness are of its essence. it
implies withdrawal from some things in order to deal effectively with
others.’
William James (1890)2
A study of the cognitive process of attention essentially involves us considering four
areas selected attention, divided attention and the implied objective and subjective
factors associated with why we attend to some stimuli to the exclusion of others. It
must be emphasized that attention is close to perception in the family of cognitive
processes in that:
‘The topics of perception and attention merge into each other since both
are concerned with the question of what we become aware of in our
environment. We can only perceive things we are attending to and
attend to things we perceive.’
Greene & Hick 1984
As you should be aware by now, cognitive psychology is dominated by what is called
an ‘information-processing paradigm’. We study information processes like
perception, attention, language, memory and thinking from the point of view of the
information processes involved, or models of what we think is involved.
A study of attention therefore sees psychologists engaged in looking at two main
areas i.e.
Selected attention: whereby the study of attention is seen in terms of the
mechanisms by which certain information is registered and other information is
disregarded (and whether or not it enters our consciousness).
Divided or Capacity attention: where the study of attention concentrates on the
upper limit to the amount of processing that we can perform on incoming stimuli
at any one time.
2
A man with an amazing energy to explore and write about the science of mind and one of the
foremost American thinkers of the 19th Century. A ‘functionalist’ is someone who believed in the
practical, functional aspects of the human mind). He did much to contribute to the separation of
psychology from philosophy.
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HOW DO WE STUDY ATTENTION?
The research methodology adopted in the study of attention is almost exclusively that
of the laboratory experiment using the experimental method. More specifically,
psychologists in this field utilise a number of interesting strategies namely:
a) Shadowing: where subjects are presented with two concurrent messages (known
as dichotic listening) simultaneously into their left and right ears, being asked to
attend to one message only and the
b) Dual-Task Technique: used to study divided attention where subjects are
presented with a variety of incoming stimuli and are asked to respond to one,
some or all of them. Task performance is found here to be affected by task,
similarity, task practice and task difficulty.
c)
Split-span studies: popularised by Donald Broadbent in 1954 a split-span
procedure saw him present numbers like 9, 1 and 2 via headphones to one ear at a
speed of one every half a second while simultaneously presenting another series
of digits like 7, 3 and 4 at the same speed to the other ear. Participants had to
listen to the presentations and then write down as many as they could remember.
He asked them to recall in two different ways. The first was as the particular
series was presented to each individual ear i.e. 9,1 2 or 7,3,4 (ear-by-ear recall).
The second was the way the numbers were chronologically presented to both ears
i.e. 9,7, 1,3 4,2 (pair-by-pair recall). Ear-by-ear recall was found to be better than
pair-by-pair. Recall in any case was only accurate 65% of the time in comparison
to 95% accuracy of serial recall when a split-span procedure was not used.
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Theories of Selective Attention
Theories on selective attention (how we seem to attend to some stimuli to the
exclusion of others) have traditionally said that somewhere along the informationprocessing pipeline there is a ‘bottle-neck’ where we have to filter out unwanted
messages (or deal with them to only a limited degree) to allow important ones to pass
through our higher-level processing system. Indeed, the absence of this seemingly
innate neurological ability would make life impossible for us.
The aptly named single-channel theories of attention (Broadbent; Deutsch &
Deutsch; Triesman; Norman) differ over where the filter is and how much, and what it
is, we process of the non-attended message.
Models of Selective Attention:
Broadbent’s Filter Model (1958)
LTN
Longterm
Memory
Senses
Sensory
Buffer
Store
Selective
Filter
Limited
Capacity
Processor
Response
Processes
The study of perception began in earnest for cognitive psychology in 1958 with the
publication of Broadbent’s ‘Perception and Communication’. Broadbent says our
world has too many stimuli in it for us to handle at any one time. To deal with this,
we utilise a filter mechanism to process some - and block out other - incoming
information. As a consequence a bottleneck3 of data (attracted to us in the first place
on the basis of its physical properties) occurs early on.
What he is saying is that we first attend to objects etc. on the basis of certain objective
physical properties. These, he said, were characteristics of the stimuli such as
volume, brightness, intensity and novelty (see relationship here with our earlier
example of Perception and Advertising).
This did not answer our cocktail party ability4: the phenomena that got Broadbent
himself interested enough to develop what are known as split-span procedures5.
From this research he postulated that each ear acts as a separate channel of
communication i.e. each ear deals with incoming aural stimuli singularly and
selectively. Later work believes his rnode1to be too simplistic.
3
SoIso (1995) pipeline theory concerning our limited capacity to process information.
Popularised by Cherry (1954). The ‘Cocktail Party Syndrome’ – where above the hubbub of the
party we can uncannily pick out our name being used on the other side of the room!
5
Subjects heard six digits; three to each ear and were asked to recall them either pair-by- pair or earby-ear.
4
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Indeed, there is some evidence to suggest that he did not satisfactorily account for the
fact that some aspects of the unattended-to message during his split-span procedures
were able to be later recalled by participants. This is related to one of the major
subjective reasons for us paying particular attention to some things e.g. how much a
certain stimuli means to us.
Triesman’s Attenuator Model6 (1964)
This holds with much of Broadbent’s initial concepts but sees the bottleneck as being
much more flexible. Triesman’s theory agrees that that initial screening of the
stimulus occurs based upon its physical characteristics, but instead of ‘irrelevant’
messages being disregarded, the perceptual filter or attenuator turns down their
volume so to speak. They are still available for higher-level processing.
‘The channel filter attenuates irrelevant messages rather than blocks
them completely.’
Triesman (1964)
What is particularly interesting is that Triesman’s Attenuator Model also brings to our
(individual) attention that further analysis is based upon individual words,
grammatical structure and word meaning. It aptly deals with an explanation for the
cocktail party phenomena in that we can hear something without attending to it and do
‘attend’ to it when it ‘means’ something to us. We seem to be able to pay attention
(consciously and unconsciously) more on the basis of personal meaning than the
physical characteristics of the message itself.
THE PERTINENCE MODEL
Deutsch & Deutch, 1963; Norman 1969, 1976
The latest single channel theory of why we attend to certain things is based on what
is deemed pertinent to the individual. This simply means that we attend and perceive
On the basis of what is subjectively valid (meaning something) to ourselves.
Put another way attention/perception is influenced by selfishness!
Pertinence model theorists put the bottleneck in our ‘single channel’ of attention
much nearer the response end of the processing system. They say we fully analyse all
signals and pass them on to the attenuator which passes on the signal to be further
processed but in a more toned down form. We attend to certain things more than
others because something about it is more relevant for us. The Pertinence Model
suggestion that we analyse everything has been criticised by Solso and Professor
Michael Eysenck as too rigid and inflexible In general terms, criticisms of the
Pertinence Model are worries about a single all-purpose limited capacity central
processor. Single-channel theory seems all too inclusive a theory to account for the
complexities involved in the unique human experience of attention.
6
For a fuller explanation see the enclosed key study on Triesman (1964) Outcome 2.
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ALTERNATIVES TO SINGLE-CHANNEL THEORIES OF ATTENTION
A major criticism of the single-channel theories of attention is that of inflexibility. As
a result a few more ‘flexible’ theories of attention have been proposed to challenge
the notion that we can really only properly attend to, perceive and act upon one thing
(stimulus) at a time. Johnston and Heinz (1979) and Johnston and Wilson (1980)
conclude findings that indicate we process what we attend to in a more flexible
fashion than single channel theorists suggest. In auditory attention tasks using
Broadbent’s split span technique they found that subjects processed words to both
ears when they did not know to what ear particular ‘target’ (the words they were to
recall) were being directed – but did not do this when they did know. It suggests that
we attend to things only to a ‘need to know’ level. After we determine a need/not
need to know to know attention of it at a deeper level is continued/discontinued.
Much more agreement has been found in the second area of enquiry into attention in
cognitive psychology. In a simple sense this is all about our ability or otherwise to do
two or more things at one and the same time. How is it, they ask, can someone give
their attention to the writing of these support notes using a variety of sources while at
the same time being more or less aware of music or television playing; my nine-year
old child Toni quarreling in her room with her friend over a game and my partner
saying something quite unintelligible to me about going over to her mother’s for some
reason? This is the subject matter of:
DIVIDED ATTENTION
Divided attention is our ability to attend to lots of things at one and the same time.
Inherent in divided attention is the related concept of focused attention.
Focused attention is our sometimes super- ordinate ability to concentrate
on one task.
Selected/divided attention has more things in common with each other than one might
initially think. Focused attention is involved in both situations to some degree or
another, as
‘….anything which minimises interference between processes, or keeps
them further apart, will allow them to be dealt with more readily either
selectively
or together.’
Hampson (1969)
Shaffer (1975) illustrates well the effect interference has on a dual-process task.
Here, he got a skilled audio typist and, using headphones, presented her to one ear
with information which she had to type. The two concurrent independent variables
were:
a) a shadowing task where a shadow message was sent to her other ear, and
b) a reading-aloud task of visually presented material.
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In both cases, this affected the dependent variable of total performance interference
when compared with when she performed the interfering tasks separately from the
audio typing task. When we look at this closely, Shaffer’s experiment neatly captures
what divided attention is really all about. Quite simply we are at our best performing
a variety of tasks that are both different and well known to us. Task similarity, task
practice and task difficulty all have a part to play in our ability to maintain
vigilance/attention to more than one thing at a time.
Student Activity
1
2
Summarise the models of selective attention.
What do you understand by the concept of focused attention?
Factors that affect dual-task performance
Eysenck and Keane (1995) identified 3 factors that influence dual-task performance
•
•
•
Task difficulty
Task practice and
Task similarity
Task difficulty: generally the harder a task is the more difficult it is to attend to more
than one thing at the same time.
Task practice: practice it has been found improves dual task performance.
Task similarity: dissimilar tasks can be attended to and dealt with at one and the
same time. Allport et al (1972) found that participants could successfully learn
pictorial information whilst also being ‘shadowed’ by auditory messages, they could
also later recall. This may be due to the different sense modalities used in each
process – visual and auditory. On the other hand it has been found that two similar
tasks being dealt with at one and the same time interfere with ultimate performance on
both.
Performance affecting variables such as task similarity, task practice and task
difficulty come into their own in the consideration of what is called automaticity.
Automatic Processing (Automaticity) or Ability
This is easily demonstrated when we think about driving a car. Initially we exercise
focused attention in the mastering of all the individual ‘S-R’ units of driving. The task
difficulty here is immense, especially when you have to put all the learning units
together in a fluid action and pay attention to all that is happening around you;
(including the disapproving driving instructor beside you). Stress is thus a factor in
the effort involved in focused attention. Confidence follows with task practice,
culminating in the rather gallus automatic processing ability of being able to drive
while simultaneously exercising divided attention by having a conversation with
someone on your mobile, changing tapes, lighting a cigarette and using your mirror to
put on your make-up. We must be able to go through a series of ‘states of attention’
depending upon changing situational variables such as task similarity, task practice
and task difficulty.
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SUSTAINED ATTENTION AND VIGILANCE
This must have relevance to those working in tedious jobs where inattentiveness could
lead to health and safety problems.
In a factory in Scotland whisky maybe bottled on an assembly line. It comes in one
end in huge vats and goes out the other, bottled, labelled and boxed to be sent all over
Britain and the world. Each individual bottle undergoes microscopic scrutiny for
flaws. Each girl on the line spends a maximum of 20 minutes, at any one time,
concentrating looking through a large eyepiece at bottles as they pass along the line to
be boxed. Millions of gallons of whiskey are bottled there every year.
The company has no doubt found out to their cost the price of sustained attention and
vigilance7.
Mackworth (1950) researched sustained attention and vigilance getting subjects to
concentrate on very boring tasks. He wanted to investigate how long someone could
sustain a boring task and still keep alert. He set up a number of signal-detection
tasks where subjects had to press a key on hearing/seeing a particular auditor/visual
signal. Every now and again a tone would sound or a signal appear that was louder or
larger than the rest. Participants had to press the key on detection of this. Mackworth
compared the signals given with the number reported and the errors made (this is
another indication of externalizing a cognitive process). As a result Mackworth put
forward a number of factors which influence vigilance which he calls performance
decrement. At a general level the longer the task the greater the performance
decrement.
We can sustain concentration longer and reduce performance decrement by looking at
the factors that influence our ability to attend to stimuli.
These factors depend upon:
1. the task itself
2. the person
3. the situation
Mackworth found that in the light of the task itself the brighter and longer a signal the
greater the performance decrement. As regards the person he discovered feedback on
performance; moderate stimulants and the personality of the person could aid
sustained attention while in the situation occasional interruptions and irritants like
phones ringing in the background and bosses lurking nearby saw an increased ability
to concentrate on the task on hand: a task we might have performed a million times
before.
7
A Conundrum
To celebrate the release of Nelson Mandela, the author who lives close to where whisky is bottled, was
invited to South Africa by his cousin, a much respected and successful South African businessman. He
bought a bottle of whisky in the duty free at Heathrow Airport for £20 as a symbol of ‘Hands across
the water…’ as Rab C would say. Thousands of miles later in Cape Town he saw an identical bottle of
whisky on sale for £4.50. Howzat?
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APPLICATIONS OF ATTENTION
In looking at an application of ‘attention’ we could consider, among other things,
attention and security personnel. The use of the Cognitive Interview Technique by
Criminal Investigation Departments of police forces all over the world might be a
useful example.
WHAT IS THE COGNITIVE INTERVIEW TECHNIQUE?
As the name implies the cognitive interview technique (CIT) is a ‘structured’
interview where a knowledge of cognitive processes and factors influencing our
cognitive processes, are used to maximize witness recall of an event; much of it detail
of which the witness was unaware that they had paid any attention! The CIT is
particularly relevant to perception, attention and memory – and when you think about
it language and thinking as well. Once again, the integrative nature of our five
cognitive processes is emphasised.
Information is the most important element in any criminal investigation. The ability
of police to get accurate and useful information from witnesses and/or victims of
crimes is crucial to the prosecution of crime. Often an eyewitness will tend to focus
on the victim, or on a weapon, with other important detail becoming lost or forgotten.
Standard interviewing techniques have not always been found to be effective in
obtaining reliable testimony. Because of this, the techniques of investigative or
forensic hypnosis are often employed.
The cognitive interview was developed by researchers in the USA who wanted a nonhypnotic memory retrieval technique that would enhance the completeness and
accuracy of eyewitness reports. Standard procedure interviews have been lacking –
very often seriously jeopardising the pursuit of justice.
The Los Angeles Police Department and UCLA (1985) research results showed that
the cognitive interview and hypnosis got significantly more correct information than
the standard interview. The study also demonstrated that there was no significant
increase in incorrect information. Tables 1 and 2 help illustrate the results of the
UCLA study.
TABLE 1. FACTS RECALLED IN THREE TYPES OF INTERVIEWS
TYPE OF INTERVIEW
COGNITIVE
HYPNOSIS
STANDARD
41.15
38.00
29.40
Number Correct
7.30
5.90
6.10
Number Incorrect
TABLE 2. RECALL OF THE 20 MOST CRITICAL FACTS
TYPE OF INTERVIEW
COGNITIVE
HYPNOSIS
STANDARD
12.0
12.3
9.2
Number Correct
1.1
1.7
1.4
Number Incorrect
In all, there were five different experiments conducted where it was found that the
cognitive interview and hypnosis had very similar results. However, standard
interviewing techniques were found to be less effective.
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The cognitive interview shifts the focus on to how people remember. The more
elements a memory retrieval aid has in common with the memory of the event, the
more effective the aid is. Memory has several access routes, so information that is not
accessible with one retrieval cue may be accessible with a different one.
The cognitive interview uses four general methods and several specific methods of
cuing memory. The first two methods attempt to increase the overlap of retrieval
cues and stored memory. The last two methods try to increase the amount of
retrieval access routes into memory.
CID encourages the eyewitness to (1) reconstruct the circumstances, (2) report
everything, (3) recall the events in a different order, and (4) change perspectives. The
method is systematic and the order of the techniques is important.
Reconstruct the Circumstances
Here the officer asks the witness to reconstruct the circumstances of the event in
general. The witness essentially tells their story. This will give a general over view
of the incident. The starting point is the story of their day well before the incident
itself. You ask them what they were doing, feeling, thinking
Report Everything
With an eye to the personal nature of attention and perception, here you encourage the
witness not to withhold any detail however trivial they might feel it is. Interestingly
the interviewer will here use statements in the present tense like ‘What do you see?
What is your immediate reaction?’ They are trying to make the person live it.
Recall the Events in a Different Order
Quite simply here you would get the person to recount the story, once told, from the
end to the beginning or from a particular point which the witness remembers lots of
detail. This is divided and focused attention writ large! Other variations on this is the
officer using their knowledge of figure and ground i.e. asking questions like ‘Of what
you have told me, what stands out?’
This method is good at finding out lies, too. Lies are created in a logical order.
Having the witness start at various stages confuses that order. As the truth is a matter
of recall, not creation, the order of repeating can actually aid in the memory process.
Change Perspective
This is where the officer tries to get the witness to recall the incident from another
person’s point of view or loci (to use the police language) by asking questions like
‘What was Richard doing in the Kay Park Tavern at the time?’ or ‘If you were
standing where Richard was standing what would you have seen?’ etc.
Having the witness mentally change perspectives while recalling an incident enhances
the quality of information about the incident or event. Often a witness has a variety of
perspectives on the incident, but most people will report what they remember from
only one perspective.
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Neat tricks include
Physical appearance: ‘Does the individual remind you of anyone that you know - a
friend? a movie star?’ ‘Try to think of why?’ ‘Was there anything unusual about the
individuals clothing or appearance?’ ‘Is it a pleasant face?’ ‘What makes it
pleasant?’
Names: In trying to recall an unusual name – ‘How many syllables did the name
have?’ ‘What letter did the name start with?’
Numbers: In trying to recall a car number plate: ‘Were numbers involved?’ ‘Was it a
high number or a low number?’ ‘Were letters used along with the numbers?’ ‘Were
there colours involved?’
Speech Characteristics: Asking questions like ‘Was the voice rough? Pleasant?’
‘Was there any kind of accent?’ ‘Does the voice remind you of anyone?’ ‘If the
voice reminds you of someone, why?’
Conversation: ‘Think about what was said . . . were there any unusual words or
phrases?’ ‘What was your reaction to what was said?’ ‘Was the voice excited,
threatening, young?’ etc.
A Word of Warning
Better than the standard interview of old, the cognitive interview technique has come
under a deal of criticism of late. Memon & Stevenage (1996) outline a number of
mainly theoretical issues that concern the cognitive interview. These include the
generalisability of the term itself and the fact that in many police forces the CIT as
first proposed is now an amalgam of interview techniques (often random and
haphazard). Any type of interview technique, to be successful, needs training. In all
circumstances pleasantness in interpersonal interaction will be emphasised! Perhaps
it is this factor that accounts for whatever Memon & Stevenage (1996) think the CIT
may have become?
Student Activity
(a) You are a student of cognitive psychology with an internal assessment in three
weeks. Apply your knowledge of cognitive processes in general and sustained
attention in particular to come up with a bulleted list (hint; hint) of studying
aids/devices to help you remember as much as possible in the short time
remaining before the assessment.
Write 250 words giving reasons for your strategies. NOW USE THEM!
(b) With reference to subjective and objective factors of attention such as personal
meaning, size, colour, movement, culture, social and emotional factors etc. how
would you go about studying to enhance your performance in your forthcoming
closed book internal assessment in cognitive psychology? Write a cognitive
studying strategy paper for next day.
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SECTION 3: MAJOR STUDIES
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SECTION 3: OUTCOME 2
Explain major studies in cognitive psychology.
Performance criteria
(a) Aims of major studies in cognitive psychology are explained accurately.
(b) Methods of research used in these major studies are explained accurately.
(c) Conclusions of these major studies are explained accurately.
Evidence requirements
To demonstrate satisfactory attainment of this outcome candidates should produce
written or oral responses to cover all performance criteria. They are required to cover
one major study for each of the two concepts studied in Outcome 1. The major
studies used must be different from the examples of studies used in Outcome 1.
This outcome examines a number of important studies conducted in each of the two
areas within cognitive psychology: perception and xyz: studied in Outcome 1It is vital
that the student has a clear understanding of these studies and their relevance to
cognitive psychology.
The student should be made particularly aware of the aims, method and conclusions
of each study and should be able to discuss these in detail.
The studies examined in this support pack are listed below:
Major Study (Original Reference)
a) Perception:
Gibson, E.J. & Walk, R.D. (1960), The visual cliff. Scientific American, 202, 64-71
Blakemore, C. & Cooper, G.F. (1970), Development of the brain depends on the
visual environment. Nature, 228:477-78
b) Attention:
Treisman (1964) Verbal cues, language and meaning in selective attention.
American Journal of Psychology, 77, 206-19
Stroop (1935) Interference in serial verbal reactions. Journal of Experimental
Psychology, 18, 643-61
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Perception:
Gibson, E.J. & Walk, R.D (1960) The visual cliff. Scientific American, 202, 64-71
Aim:
To discover if depth perception is innate or learned.
Participants/Subjects:
Children aged 6-14 months old
Animals aged 24 hours old
Method:
Laboratory experiment.
Independent variable: age of participants
Procedure:
Visual cliff constructed of glass over a box with black and white squares positioned to
show depth at one end.
Infants were placed in the middle and encouraged to move towards their mothers who
waited at the opposite end.
Animals, e.g. rats, chicks, turtles and lambs were also tested by placing them in the
‘middle’ and observing to which end they went.
Dependent variable: Whether baby crawled to deep side of visual cliff.
The reason why Gibson and Walk used both animals and humans in their study is that
babies could not take part until they can crawl (around 6 months) by which time the
learning of depth perception may have occurred. Non-human animals were used at an
earlier age (as young as 1 day) where it was fairly certain no learning of depth
perception could have occurred
Conclusion:
Conclusions suggest non human animals are born with innate ability to perceive depth
and that babies as young as 6 months could perceive depth, though there is no
indication if this is innate or learned.
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Perception:
Blakemore, C. & Cooper, G.F. (1970) Development of the brain depends on the
visual environment. Nature, 228: 477-78
Aim:
To investigate environmental effects on perceptual ability.
Participants/Subjects:
Kittens
Method:
Laboratory experiment.
Independent variable: a vertical environment or a horizontal environment.
Procedure:
Blakemore and Cooper (1970) raised kittens from birth in darkness. For five hours
each day, the kittens were put into a horizontally or vertically stripped drum. They
were sensorily deprived from seeing their own bodies so that stripes – horizontal or
vertical – were the only stimuli they encountered.
At five months old, the kittens were tested for line recognition by being presented
with a moving pointer going in either a horizontal or vertical direction.
Dependent variable: kittens’ response to particular visual line stimuli
Conclusion:
Conclusions suggest that those kittens raised in a vertical world only reacted to
vertical line stimuli, and kittens raised in a horizontal world only responded to
horizontal line stimuli. The kittens showed ‘behavioural blindness’ towards either
horizontal or vertical stimuli. Blakemore and Cooper (1970) further discovered that
this behavioural blindness was mirrored by ‘physiological blindness’. By placing
electrodes in the kittens visual cortex they found that cats raised in a vertical
environment did not possess cells that ‘fire’ in response to horizontal line stimuli with
cats raised in a horizontal world not possessing cells which fire off in response to
vertical stimuli.
The findings suggest that the type of environment some species are brought up in is
important to the development of some perceptual abilities. Some perceptual abilities
do seem to be partly learned.
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Student Activity
Questions:
Perception: Gibson, E.J. & Walk, R.D. (1960) The visual cliff.
(a) Who were the subjects in the Gibson and Walk (1960) study ‘The Visual Cliff’?
(b) What was the aim of the study?
(c) Which method was used?
(d) What procedures did Gibson and Walk use when carrying out this study?
(e) What is the independent variable in the study?
(f) What is the dependent variable in the study?
(g) Why did Gibson and Walk use both animals and humans in their study?
(h) What did the study suggest about animals’ ability to perceive depth?
(i) What was the conclusion regarding infants?
Perception: Blakemore, C. & Cooper, G.F. (1970) Development of the brain
depends on the visual environment.
(a) Who were the subjects in the study by Blakemore and Cooper (1970)
Development of the brain depends on the visual environment?
(b) What was the aim of the study?
(c) Which method was used?
(d) What procedures did Blakemore and Cooper use when carrying out this study?
(e) What is the independent variable in the study?
(f) What is the dependent variable in the study?
(g) How was vertical and horizontal stimuli presented to the kittens at 5 months?
(h) What ethical issues does this study raise?
(i) What were the conclusions?
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Attention
Stroop (1935) Interference in serial verbal reactions. Journal of Experimental
Psychology, 18, 643-61
Stroop’s paper (1935) is really three experiments. This sounds complicated but all
this was three presentations of pairs of stimuli symbolizing the same thing i.e. 3
pairings of 2 from the following Independent Variables.
I.
II.
III.
The name of a colour printed in the ink of another i.e. red printed in blue
A word stimulus i.e. the word red printed in normal black ink
A colour stimulus i.e. a colour splodge of red, blue, green, brown or purple.
Aim:
To investigate interference using pairs of conflicting stimuli on serial verbal reactions.
Participants/Subjects:
300 American college students in total.
Method:
Laboratory experiment
Experiment 1:
The effect of interfering colour stimuli upon reading names of colours serially.
Experiment 2:
The effect of interfering word stimuli upon naming colours serially
Experiment 3:
The effect of practice upon interference.
Procedure:
Participants presented with 100 pairs of conflicting stimuli across the three conditions
i.e. experiment 1 squares of colour against names of colours
Dependent variable: time taken to complete serial task of first identifying 100 squares
of colours and then 100 colours of colour words printed in another colour (red printed
in blue, green printed in red, etc.).
Conclusion:
Reading is an automated process. We read the word and its meaning before we can
deal with the colour it is written in. Automaticity interferes with serial recall in this
instance. Practice can reduce interference of serial recall but cannot eliminate it
altogether.
One cannot generalise Stroop to the whole population due to imbalance in his sample
from the point of view of ethnicity, gender and age. It must be said however that
there are now 700 variations of the Stroop Effect. In all cases the same influence of
automaticity is reported.
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Student Activity
WHY NOT DO THE STROOP?
An Experiment to Investigate the Stroop EffectΨ.
Introduction
The experiment involves subjects naming colours as quickly as possible in two
conditions to discover if interference can influence performance on a recall task.
In Condition 1 subjects name neutral words
In Condition 2 subjects name colour words
Your results should indicate that interference in attention recall occurs as a result of
automatic processing (Parkin 1987: Posner and Snyder 1975). The major reason for
the Stroop Effect is that we automatically first process the meaning of words. When a
participant sees the word blue but is to respond in an ink colour (say red) they process
the word and its meaning first: thus resulting in a slower response time. The Stroop
Effect is a mental race between the processes involved in naming the colour and those
involved in naming the word. Our experience of naming words over the colour of
words wins out. The difficulty experienced in naming the ink colour of the colour
word is therefore the consequence of the over-learned skill of reading which cannot
be brought under conscious control.
Settle on the following Experimental Hypothesis
H1: ‘That there will be a significant difference in participants information
processing times under two conditions as a consequence of the Stroop
effect.’
This is a two-tailed hypothesis.
As we have to compare subjects under two conditions, the most relevant design is
repeated measures. The advantages of this design are that there is good control of
irrelevant subject (extraneous) variables, our statistics are more sensitive and we need
fewer subjects. A major disadvantage is order effect. To overcome this it is
recommended that you use counterbalancing e.g. with 20 subjects present the
stimulus materials as follows:
Subjects 1-10 get Strips 1-3 to respond to first and Strips 4-6 to respond to second.
Subjects 13-20 get Strips 4-6 to respond to first and 1-3 to responds to second.
The rationale behind this is that if there is an order effect as a result of practice it will
affect both conditions of the experiment equally.
Ψ
Dedicated to, and much loved by, all those taught by the author on the HNC social science course at
Kilmarnock College. As Freddie said ‘These were the days of our lives’.
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It is further recommended that prior to the experiment proper participants should be
tested for colour vision deficit (red, green or blue) and be given a short simple reading
test. These are your confounding extraneous variables.
Prepare your six lists on card using the following key:
(B) = blue (Y) = yellow (R) = red (G) = green
Strip 1
Strip 2
Strip 3
Strip 4
Strip 5
Strip 6
Art (Y)
Cave (R)
Art (G)
Red (Y)
Blur (R)
Red (G)
Stove (B)
Stove (G)
Bottle (Y)
Green (B)
Blue (G)
Green (Y)
Cave (R)
Bottle (R)
Stove (R)
Red (G)
Yellow (R)
Green (Y)
Bottle (R)
Art (B)
Bottle (G)
Blue (R)
Red (B)
Yellow (G)
Stove (Y)
Stove (B)
Cave (R)
Yellow (R)
Green (B)
Blue (R)
Art (B)
Art (G)
Stove (B)
Green (Y)
Red (G)
Green (B)
Cave (Y)
Cave (Y)
Art (Y)
Yellow (G)
Blue (G)
Red (Y)
Art (R)
Bottle (G)
Bottle (B)
Red (B)
Yellow (G)
Yellow (B)
Bottle (G)
Stove (R)
Art (B)
Blue (Y)
Green (R)
Red (B)
Cave (B)
Cave (B)
Stove (Y)
Green (R)
Red (B)
Green (Y)
Stove (R)
Art (Y)
Cave (B)
Yellow (G)
Red (Y)
Red (B)
Bottle (Y)
Bottle (Y)
Bottle (R)
Green (B)
Red (Y)
Yellow (R)
Cave (G)
Art (R)
Stove (G)
Green (R)
Blue (R)
Yellow (G)
Art (G)
Cave (G)
Cave (Y)
Blue (Y)
Blue (G)
Blue (Y)
Stove (G)
Bottle (B)
Art (R)
Blue (G)
Yellow (B)
Green (R)
Bottle (B)
Stove (Y)
Cave (G)
Yellow (B)
Green (Y)
Blue (G)
Then divide them up.
PROCEDURE
Read the subject the following instruction, which should be on a piece of card.
‘I am going to present you with a list of six words, one at a time. Your task is to say
aloud the ink colour in which each word is written, starting at the top of the list and
working down to the bottom. You will be timed for each list and should try to name
the ink colours as quickly but as accurately as possible. Do you have any questions?
Here is the first list... When I turn the list over, name the ink colour in which the lists
are written.’
Time using a stopwatch to the nearest second. Enter the time in the Raw Data chart
like the one over:
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Time taken in Seconds
List 1
List 2
List 3
List 4
List 5
List 6
Subject 1
Subject 2
Subject 3
etc
After completion, you will have to work out the Mean and Median time for each
condition. For the mean add up each subject’s time for lists 1, 2 & 3 (neutral words)
and divide by 3. Do the same for Lists 4. 5 & 6 (colour words). To find the median
in each condition: arrange the three times in order from quickest to slowest, for each
participant. The median is the middle one e.g.
Colour Words
Mean
Median
Neutral Words
Mean
Median
Participant 1
Participant 2
Participant 3
Participant 4
etc
You are advised that a good graphical representation of what you have just done
would be in the form of two frequency histograms - (for each condition) or a
frequency polygon.
Student Activity
What conclusions to you draw from your study?
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Attention:
Treisman (1964) Verbal cues, language and meaning in selective attention.
American Journal of Psychology, 77, 206-19
British psychologist Anne Triesman, now Professor of Cognitive Psychology at
Princeton University, revolutionised cognitive psychology with her doctoral
Attenuator model of attention in the 1960s - which she has revised, refined and
progressed ever since. Attenuator theory says we can attend to particular stimuli even
although we are not aware of it. It built on Cherry’s ‘Cocktail party’ phenomenon and
influenced criticisms of Broadbent’s earlier theory that we consciously attend to
stimuli solely on the basis of physical properties and that attention to stimuli can only
be dealt with one at time.
Aim:
To investigate our ability to selectively attend to stimuli when it depends solely on the
identification of verbal or linguistic features of the message.
Participants:
Undergraduates and research students at Oxford University.
Method:
Laboratory experiment.
Independent variable: content: type and direction of messages to each ear (the
message to be attended to was sometimes switched ear-to-ear).
The content of the message, to be selectively attended, was a 150-word passage of
prose taken from Lord Jim by Conrad. The content (differing verbal characteristics)
of the irrelevant messages were:
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.
Prose from the same book in a man’s voice
Prose from the same book in a woman’s voice
Prose with an insertion of Latin in a woman’s voice
Prose on a technical discussion on biochemistry in a woman’s voice
French prose from a novel in the same voice as IV
German prose from a novel in the same voice as IV
Italian prose from a novel in the same voice as IV
‘Pigeon’ Czech in an English accent in the same voice as IV
Backwards English in the same voice as IV
French translation of the Lord Jim shadowed message in the same voice as IV
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Procedure
Participants were engaged in a dichotic listening task that involves asking
participants to listen to different information in each ear.
Using a technique called shadowing the Lord Jim message was presented as were the
ten irrelevant messages listed above with the participant being told to attend to only
Lord Jim and repeat it out loud.
Dependent variable: Interference on ability to recall Lord Jim message/recall of
attenuated messages.
Conclusion:
That when we are in a state of focused attention we selectively attend to stimuli using
what is called a filter. This filter does not work entirely on the taxi rank principle as
previously thought. Treisman’s attenuator model (1964) suggests that early
selection/attention is based on physical properties of the stimulus such as pitch,
loudness, etc. Attention is directed toward information that reaches a threshold of
recognition; but most crucially of all, that during selective attention several inputs
can be processed at the same time. We pay attention to unattended-to messages on
the basis of thresholds we set for attending to stimuli. Important stimuli have a low
threshold. Less important stimuli a high threshold.
The inputs we can still attend to at the weak (attenuated) level are those which are
most meaningful to us i.e. our name, gossip about yourself! Treisman’s work then,
and since, has demonstrated that unattended messages are more thoroughly processed
than previously thought.
She found that unknown foreign languages produced less interference on selective
recall than known ones and that we do seem to identify what we are attending to
discarding irrelevant stimuli quicker than more meaningful information which is then
processed/no processed at a deeper focused level depending on the task on hand.
This author remembers doing a part-time law course over 5 years. It was made up of
2 Units X 2 terms X 5 years giving 20 Units in all. The author used to no doubt bore
family and (rapidly departing!) friends by letting them know of his deep awareness of
particular legal matters every 12 weeks or so! Another interesting thing was that
once on a new unit, he forgot in large part the nitty-gritty of the old units he had
waxed on about at the time.
Are you the same with psychology?
Personal meaning is once again emphasised in the study of cognitive processes.
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SECTION 4: RESEARCH METHODS
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RESEARCH METHODS
Outcome 3 and Outcome 4
These outcomes involve implementing and evaluating a practical investigation in
cognitive psychology. At the end of these outcomes you should be able to undertake
an investigation in cognitive psychology and produce a report on the
Investigation you have carried out.
The investigation that you use will be carried out according to specific procedures.
You will use descriptive statistics in order to analyse the results of your investigation.
All results produced during the investigation should be presented clearly and
accurately. You should offer some conclusions and these must relate specifically to
the original aims of the investigation you have conducted. You must explore the
strengths and weaknesses of your investigation thoroughly and describe these clearly
and accurately.
The report of the investigation should be 1000 to 1500 words in total. The report
should be formal in style, use acceptable terminology and conform to the layout
typical of that used in standard psychology reports.
When you first begin to think about your practical investigation in cognitive
psychology you need to ensure that you have at least a preliminary understanding of
all of the research methods in psychology. However, you need to pay particular
attention to the concepts of:
• Hypothesis testing
• Variables, types of variables and manipulation of variables in the experimental
method
• Independent subjects and repeated measures in experimental design. The contrast
between assessing differences or correlations, populations, samples and types of
sampling
• Statistical techniques used in descriptive statistics - mean, mode, median, range
• Graphs and charts - line graphs, bar charts, frequency distribution curves,
scattergrams.
Carrying out your research in cognitive psychology
Psychology is a practical subject. Essentially what it does is go out and test specific
theories either in the laboratory or in the real world. As a student of psychology you
are expected to go through the process of testing theories. This is called ‘carrying out
a practical investigation’ or just simply ‘doing a practical’. Doing a practical is all
about you actively investigating ideas from cognitive psychology in a logical and very
organized way.
Your investigation of psychological ideas will involve you in planning, carrying out
and analyzing your own work. For this, you need to have a very good understanding
of methods of investigation, basic statistics, and experimental design. Much of this
information will have been covered in the unit ‘Approaches and Methods in
Psychology’ which ideally you will have studied prior to this unit.
Planning and interpreting your study is a creative process. It is demanding of your
time and energy, but is highly satisfying and great fun to do. I hope!
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At every stage in the research process you will discover challenges to your thinking
and obstacles to your planning. However, these also represent an opportunity for you
to produce new ideas and generate solutions based upon your own experience and indepth knowledge of the study which you alone control. You will soon become aware
of important issues such as the, reliability and ‘generalisability’ of your research
findings. These will challenge you during the course of your research and you should
raise them directly in the discussion and evaluation section of your report.
Practical investigations in psychology always require that you communicate your
research thoroughly and effectively by producing a report. Care should be taken to
ensure that presentation of findings and evaluations of research are clear, concise, and
highly accurate. For a written report, neatness is very important. Legible, clearly
written, typed or word-processed submissions are advised. Calculations should be
clearly hand written. Tables and graphs can be hand written or word-processed. All
material presented for assessment of the practical investigation should be in a logical
sequence and in a conventional framework. Your teacher/lecturer will advise you of
what is required for this and will support you throughout your practical investigation.
The practical investigation
The careful and systematic planning of a practical can save a lot of heartache later.
There are five main stages in planning an investigative study in cognitive psychology:
1. Select a suitable problem to study
2. Select the method and approach
3. Collect data
4. Record and analyse results
5. Write a report of the investigation.
Note that this series of stages illustrates an ‘ideal’ sequence. In practice, the process
of research is a complex one, and the stages will overlap and interact. However, if
this series of stages is carefully accomplished, then the practical can be successfully
undertaken. Also, the writing of the report will not prove to be too burdensome.
Each of the above four stages will now be discussed in turn.
Selecting a suitable problem to study
It is very useful when you are studying cognitive psychology to keep jotting down
ideas that occur for practical work. Often something that you read, or an idea
mentioned in a lecture or during class discussion can form the basis of a worthwhile
and very interesting investigation.
Before you do anything, however, you need to cheek the literature for previous
findings about the study you have chosen to pursue. This is because you need to
ensure that there is sufficient background material on the topic that you are interested
in to allow you to carry out a study and write your report. For example if post
traumatic stress disorder is your chosen topic to study, then you need to establish if
there are any theoretical discussions or empirical studies that relate to that specific
disorder. You might then decide to carry out a replication, or plan a modification.
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At this stage of your planning, there is a requirement for your research to have a
‘rationale’. This is usually provided by a summary of previous findings on the topic.
While you are reading about previous research, keep a note of your references.
These will be invaluable when you later come to produce the introduction to your
study as part of the final report.
You are likely to have two immediate and reliable sources to start you off in finding
literature on your chosen topic: one is your teacher/lecturer who may be able to give
you starting point of relevant journal papers or books. You will need to ask your
teacher/lecturer how deeply you are expected to go in studying the existing literature
on the topic of your investigation. The other source is the range of textbooks
available on the topic you are interested in. Start with your basic textbook and then
any more specialised books on your chosen topic that you know of or which is
mentioned in your basic text. Then go to your school or college library. You should
be able to find where any books on the topic are located by consulting the library
catalogue or database or by asking the librarian. It is often useful to know how a
book on your topic is classified in the library and then search look on the shelves
around that class number for books on similar topics. Many libraries now have a CDROM version of available books and journals. You type in key words, such as
perception and the computer then searches through its thousands of entries and
creates a subset of entries which contain this key word. You can search for particular
authors, journal titles, dates, etc. You can then have the selected abstracts displayed
on the screen, printed and even saved on your own floppy disk. Your library may
also have access to other computer-based databases that can provide valuable
reference material.
Remember that it is not necessary to find something exotic or highly complex or
something that no one has ever done before - a simple idea investigated appropriately
and accurately is more than sufficient for this investigation even if other
psychologists and/or psychology students have carried it out before.
If you wish to develop an idea of your own, you may do so. Make sure, however,
that your teacher/lecturer is aware of your idea at an early stage and has approved it
as suitable and realistic.
A major consideration at the outset is the need to select a topic that is feasible with the
resources available to you. Resources include your time, physical apparatus, and
access to appropriate types of subjects - there is no point in planning a study of
visually impaired children if you have no opportunity of meeting any such children! It
is also necessary to consider ethical issues. Some areas in cognitive psychology may
not be ethically acceptable because they increase the risk of the participants
experiencing physical or mental harm. This is particularly important where children
are involved. Obtaining permission/consent to carry out studies with young children
can be a real problem in itself, even if the study is ethically sound. This is because it
is not possible to obtain the consent of young children directly and obtaining consent
from parents/teachers etc. can be difficult and time consuming. A copy of the British
Psychological Society (BPS) statement on ‘Ethical Principles for Conducting
Research with Human Participants’ is available in these support notes and you should
receive a copy of this from your teacher/lecturer whenever you begin to plan your
investigation.
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When you have read a number of articles or book extracts, and have considered the
practical and ethical problems associated with your research, you should be in a
position to state the general aim of the particular study you intend to perform. Keep
this aim firmly in mind throughout the course of your study and resist the temptation
to stray from it. You will be required to refer specifically to your aim(s) at a later
stage when you are reporting on the success of your investigation.
Selecting the method and approach
Your reading of previous work will help you to become acquainted with what other
researchers have found out about the research topic that you wish to study. It will
also give you a great deal of knowledge about the way(s) in which the topic has been
investigated previously. You may decide to carry out your study in a way that is
similar to that of previous researchers, or you may decide to try a different method or
use a different technique of collecting data. Often it is quite feasible to use a range of
methods e.g. observation, experiment, survey. However you must decide which ones
are most likely to provide the most useful information.
Generally, your choice of method(s) will lead you to one of the following options:
•
Experimental approach
•
Non-experimental approach.
The experiment follows the traditional scientific model. In a study of this sort, a
specific hypothesis is being tested to see if it is likely to be true. It is important to
distinguish between the aim of the study and the hypothesis. The aim might be quite
general, the hypothesis is quite specific. The hypothesis is a precise prediction of
what will be the outcome of the particular study you are performing. For example,
teaching four year olds nursery rhymes will improve their reading skills.
If you are using an experimental approach, you must specify an independent variable
(IV) that you can manipulate, and observe its effect on the dependent variable (DV).
All other relevant variables are held constant. When you are using an experiment to
test a hypothesis, you are carrying out a test of difference - that is the effect that
different values or conditions of the IV will have on the DV. Make sure you know
whether your experimental hypothesis is directional or non-directional. If you predict
which condition will be superior, then you have a directional hypothesis (one tailed).
If you are simply saying that there will be a difference between the two conditions,
then you have a non-directional hypothesis (two tailed).
Strictly speaking, however, in an experiment it is the null hypothesis that is being
tested. The null hypothesis (H0) states that there will be no difference between the
scores of the groups. The null hypothesis is falsifiable. If it is proved wrong in your
experiment - you reject the null hypothesis- and this allows you to support the
experimental hypothesis (H1). You never say that an experimental hypothesis is
proven. If your evidence is such that your null hypothesis cannot be supported, you
reject the null hypothesis H0, and accept the experimental hypothesis H1.
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The experimental method uses two basic designs:
• Repeated measures - this design each participant performs in both the control
and the experimental condition
• Independent subjects - in this design, some participants perform in one
condition and some perform in the other (participants allocated randomly to each
group)
in
Since the control group is the same as the experimental group in the repeated
measures design, this method automatically ensures that there are no personality or
ability differences between the two groups. However, in some experiments
‘performance’ in one condition ‘pollutes’ the participant for use in the other
conditions. For example, it would not be possible to use repeated measures to
investigate different methods of learning to drive a car. Independent subjects design
may be a better option in some types of experiment, therefore. However, independent
participants always require more participants than repeated measures.
As a general rule when devising an experiment, keep to a simple design. Introduce no
more than two independent variables in a single study. If you want to know how
other factors influence the outcome of the study, it is often best to carry out a series of
separate studies rather than try to incorporate numerous conditions in a single
investigation.
Non-experimental approach
The non-experimental approach would include observation, surveys, case studies
and correlation methods. These could be used singly or a combination of these could
be used in any given study.
These differ in a number of respects from an experiment.
Observation
There are many situations where behaviour is so complex that it cannot be isolated
clearly enough to be manipulated experimentally. In addition, observation is often the
first crucial step taken when studying a type of behaviour not previously studied.
Observational studies must first be carried out before any hypothesis about the causes
of the behaviour can be tested.
Observations require careful planning. The observation needs to be structured and
organised in terms of a specific problem or hypothesis. A major problem with
observational studies is lack of time available to make a record of observations. If the
observer also has to record the type of behaviour seen, too much time might be spent
writing down observations and too little given to actually observing.
Since observations are often very open-ended, a way of organising data is essential.
This data must be recorded in a systematic fashion. Records of behaviour can be
made using any or a mixture of devices, such as:
• film/video recording
• still camera
• audiotape
• structured notes.
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When carrying out a case study, the investigator needs a clear understanding of the
aim and should always be aware of bias - case studies should not be used to
substantiate a preconceived position.
Case studies are not an easy form of study to accomplish successfully by students. If
such a method is to be undertaken, considerable thought should be given to what the
form the study will be, and how evidence will be recorded. Otherwise a case study
can just end up as a vague description.
Correlation
In a correlation study, your hypothesis will predict a relationship between sets of
scores. Here the interest is in how the change in one variable is associated with the
change in another variable. Since correlations are not causal designs, we cannot
really talk about an IV and a DV. This is because these two variables may not be
related at all, but simply occur together in a given situation.
When designing a correlation study it is important to state what the variables are that
are being studied. A crucial feature is that the investigator does not manipulate an
independent variable, and so has less control than in an experiment. The correlation
coefficient (a statistic which varies between +1 and -1) expresses the degree to which
two sets of data are related.
If two measures vary together, one of them may be causing the other. However this is
not a firm argument for establishing causation. If two variables, x and y, are
correlated, you cannot conclude that x causes y. It is possible that y causes x, or both
may be related to some underlying variable. Where a correlation is found to exist
between two variables, a researcher should in principle carry out an experimental
study in order to establish whether there is indeed a causal link.
When using non-experimental methods, as when using experimental methods, it is
important to know what it is you need to measure. Although non-experiments are less
restrictive than experiments, it is still crucial that you are fully aware of what you
expect to find as a result of carrying out the study.
This knowledge will enable you to distinguish between the aim of the study and the
hypothesis. If you are expecting to find a relationship between scores or differences
between groups of participants, you will be able to produce a hypothesis stating what
you predict the outcome will be.
Your hypothesis may appear to be very narrow compared with the aim you started
with. This is because your hypothesis is a precise prediction of what will be the
outcome of the particular study you are performing. You should be clear in your own
mind about whether you are predicting a difference between sets of scores or a
relationship (correlation) between them. Most importantly, you should understand
how this fits in with your hypothesis.
Your knowledge about the expected outcome of your study will influence your choice
of method(s) in a non-experimental study. Non-experimental methods allow you to
study behaviour in more natural settings and there is a greater amount of scope for
employing a range of different methods.
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However, it is important to remember that non-experimental methods give weaker
grounds for drawing conclusions about causation. Continue to be aware also, that if
two variables are correlated, it is not necessarily the case that one causes changes in
the other.
Carrying out the investigation
Collect data
As you create your study, your choice of methods and exact investigational procedure
will emerge. Basically, you must consider how to select your participants, decide on
any instructions you will need to give them and specify where the investigation will
be carried out. You must know in advance how to record and, if necessary, how to
measure variables. It is important that you understand how to translate your research
idea.
Selecting the participants
Which participants you use depend upon the aim of the study and whether people are
available to participate. You should ideally use a random or stratified sample to
ensure generalisability of results. In random sampling the names of those in the
sample are selected from the population by a random procedure, so everyone has an
equal chance of being included. To obtain a stratified sample, you divide the
population into strata such as age groups and then use simple random sampling within
each of the strata. Usually you use proportionate samples, so that if the population
has e.g. 30% of people in one age group then you ensure the sample has this
proportion too.
The benefits of randomly sampling respondents from a population are beyond dispute.
However, in practice you may find that you have to use respondents from a small pool
such as personal friends, family, fellow students/pupils, etc. In this situation you need
to consider carefully how far you wish to generalise the results you obtain from the
study. It is acceptable to use quite small numbers of people with no attempt to make
them representative of the general population. However, the choice of subjects and
associated drawbacks must be recorded for your report.
Preparation of materials
Your procedure and recording technique must be planned in advance. Have exact
written instructions ready to read out to participants. These should always include
statements about the right to withdraw from the study. This is important in order to
establish that you have carried out your study strictly in accordance with ethical
guidelines. A copy of these instructions should be kept for inclusion in the report
later.
It is important that everyone who is involved in carrying out the study follows exactly
the same procedure and uses identical sets of materials. This helps prevent variations
in procedure emerging as a result of having different individuals conducting the same
study.
Obviously you need to ensure that you have the appropriate materials for your
participants. These depend on the study itself but may include questionnaires for
participants to complete, printed sets of items to remember, interview schedules,
coding sheets for observations, or other ‘hard copy’ materials.
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It is also important to pre-prepare the data tables required to record the results of the
study as you discover them. The design of these will again depend on the type of
study you are carrying out. Remember that a fresh copy of all materials used will be
required for inclusion in your report. Check that the location is comfortable and free
from distraction. If an outside location is necessary (e.g. playground, shopping
centre) consider what is the best option from the point of view of the participants’
comfort and convenience. Plan to make the conditions in which you are expecting
your participants to operate as unobtrusive and non-threatening as possible. If
measurements, interviews, observations etc. are to be taken in a particular location,
practice first to ensure smooth running for the real thing.
Make sure all recording apparatus/pens/clipboards, etc. are ready for use. Have
plenty of extra copies of all necessary materials in case disaster strikes! If you are
working as part of a group of investigators, make sure that all members of the
investigating team are fully briefed and completely aware of what is happening and
what is required of them. Make a note of any problems/difficulties in carrying out
your procedures effectively and accurately. Also be aware of what worked well and
why. These points must be discussed in the evaluation section of your report.
Pilot Study
Before you undertake the study proper, you should always run a pilot on one or two
participants. This is like having a trial run in order to see whether the instructions and
task are understood. It allows you to make any final alterations that are needed.
Carry out your pilot as though you were running the study for real, but at appropriate
points ask participants whether what you are asking them to do is clear. Do they
understand what is expected of them? Do they know how to carry out any assigned
tasks, etc?
Try out your debriefing statement during the pilot study. This should take place in the
form of a dialogue in which you explain what the study was intended to do, and they
tell you whether in fact this actually happened. The aim here is to obtain as full an
account as possible of how the situation appeared to the participants who were
participating in the pilot study. As a result of this feedback you should have a clear
idea of whether, when you run the study proper, it is doing what you planned.
As a result of your pilot study, you are likely to need to make changes to the
instructions, procedure, or recording techniques of the study. When you have made
the changes, you may need to run another pilot just to make sure that the changes you
have made are in fact effective i.e. they overcome the problems you discovered during
your first pilot. Whether you need to run a second pilot or not depends entirely on the
type and extent of the changes made following your first pilot.
If these changes are significant (i.e. your original instructions left the participants
confused and uncomfortable), then a second pilot to check that the revised version is
clear is necessary. If the changes you have introduced are minor e.g. correction of
spelling errors, slight changes to layout, this may not be necessary.
The pilot study/studies and subsequent revisions to instructions, procedure or
recording techniques should be referred to in the report of the study.
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Ethical guidelines
Remember that participants make a ‘gift’ of their co-operation. Respect and
appreciation should be given. BPS ethical guidelines must be followed when you are
carrying out your study. You are responsible for protecting participants from physical
and mental harm during the investigation - this risk of harm should be no greater than
in ordinary life.
Protecting participants also includes protecting their privacy and their right to
confidentiality. If the research involves studying behaviour that is usually regarded as
personal or private, consent must be given. Observational research is only acceptable
where those observed would normally expect to be observed by strangers.
Withholding information or misleading participants is unacceptable if they are likely
to object or show unease later when they know about the aims of the study.
Intentional deception should be avoided whenever possible, and done only with the
approval of your teacher/lecturer. When deception is necessary, participants must
be given sufficient information as soon as possible.
Debriefing - explaining what the study was really about - is essential. It is your duty
to inform the participants so they understand the nature of the research. This should
ideally involve having a full dialogue with them about their experience in order to
ensure that they are not experiencing any negative effects as a result of taking part in
the study.
You should provide some detail about the ethics of your study in the write up of your
report.
Record and analyse results
Recording
You are now at the data collection stage of your research. Your aim should be to
obtain records that are clear enough for any investigator to understand and analyse.
As you gather the data from your participants, do check that the study seems to be
functioning as intended. If you find, after studying the first few participants, that
there are still problems with some procedures do not be afraid to halt the study, revise
the procedure and start again.
Analysis
Your method of analysis will be closely related to the design of the study. It is not
enough just to measure and count accurately. You have to ensure that other people
can understand your results. This means presenting them in a clear and concise form,
often having to summarise them so that they can be taken in at a glance.
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Summarising and describing the results graphically
1. Tables
The most basic organisation of numerical information is a table. The data in a table
are called raw data if they have not been summarised i.e. if they are the original
collection of measurements from participants, ready for calculations.
You can see at a glance from this table of raw data that results were collected from
five participants at both 1 and 3 metres:
Raw Data Chart: Distance/Eye Contacts
PARTICIPANT
CONDITION A AT 1 METRE
CONDITION B AT 3 METRES
1
2
3
4
5
8
12
10
5
10
20
18
30
12
21
The table also reveals that more eye contacts were made at 3 metres than at 1 metre
(this was a repeated measures experiment).
2. Graphs and histograms
There are two main types of graph, depending upon the type of data you have been
collecting:
Counting can he represented on a frequency distribution curve. Frequency
distributions are important graphical representations in statistics and in psychology.
When you have a set of scores, you can draw a histogram showing the frequency
distribution or represent the same distribution using a line curve. In both cases, the
scores (x values) are laid out along the horizontal axis with the number of times a
score occurred in each group represented by the height along the vertical axis.
Sometimes you will find the distribution is very asymmetrical. Like that below and
over graphically representing the distribution of IQ scores in a population.
FREQUENCY (number of people)
A frequency polygon
70
60
50
40
30
20
10
0
50
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IQ
100
150
106
Bar Chart: Childrens Telegraphic Utterences
70
Frequency
60
50
40
30
20
10
0
4.5
14.5
24.5
34.5
44.5
54.5
64.5
74.5
Number of Telegraphic Utterences
There are two ways of plotting frequency data: the frequency polygon and the
histogram.
It is very important to label the axes of all graphs so that other people can understand
your work.
•
Measurements can also be represented graphically on data curves. The graph
below shows the effect of different amounts of practice on the number of errors
made in a mirror-drawing task.
A data curve
25
Errors Made
20
15
10
5
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
Practice Trials
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It is also possible to have overlapping data curves on the one graph in order to show
comparisons. This graph below shows two sets of results simultaneously. The ‘thick’
line gives the number of helpful acts produced by children during a period of time
where they watched videos which encouraged helping behaviour, and the ‘dotted’ line
shows the number of helpful acts produced by children who watched ‘neutral’ videos
during the same period i.e. the videos did not show helpful or unhelpful behaviour to
any real degree. The study was taken over a four-week period.
Number of helpful acts produced - (cooperation)
Overlapping curve
16
14
12
10
8
6
4
2
0
Week 1
Week 2
Week 3
Week 4
With a data curve you can see at a glance the effect that the independent variable has
had on the dependent variable. The independent variable is displayed along the
horizontal x-axis, and the dependent variable is displayed on the vertical y-axis. In
this case helpful acts increased for the majority of children immediately after
watching the video but then reduced to a level close to that of the control group.
3. Pie charts
Pie charts are circles with segments cut out. The circle resembles a pie, thus the name
‘pie chart’. Each segment of the pie chart represents a percentage of the whole. Pie
charts give a very visual impression of the different proportions which various groups
or participants share.
It is possible to use a pie chart to display what proportion of all the families in Britain
lived in different types of family organisations i.e. one parent families, two parent
families, extended families. It is possible to find the official statistics for this;
therefore we can be sure we have an accurate total figure for all families we are
referring to. The pie chart therefore may look something like this (see over).
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One parent
families
8%
Single people
24%
Married
couples with
no children
35%
Other
5%
Married
couples with
children
28%
However, it is not really possible to use a pie chart if there is no way of obtaining
accurate totals for the population being studied. For example, we could not construct
a pie chart to show what proportion of aggression in primary school children involves
kicking, hitting, punching, etc if we do not have an accurate total figure for the
amount of aggression shown overall.
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4. Scattergrams
Scattergrams display the results of correlation studies graphically. Producing a
scattergram from your data will give a quick visual impression of the relationship
being tested. The scattergram overleaf shows the possible results from a correlation
study of the relationship between TV watching and IQ. Each plot on the scattergram
is the point where the pair of scores that each participant made on the two dimensions
named on the axes cross. One of the participants below spent 20 hours a week
watching TV and scored 95 on the IQ test. Looking at the general spread of the x
marks gives an idea of the extent to which the two variables go together. This
scattergram shows that the people who spend the most time watching TV have the
highest IQ scores. In a real study, it is highly unlikely that we would find a very
strong relationship between these two variables.
IQ/Hours Watching TV
30
Number of hours of TV watched
25
20
15
10
5
0
0
20
40
60
80
100
120
140
160
IQ Scores
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Summarising and displaying results in numbers — descriptive statistics
Where there are a large number of participants, it is sometimes not possible to see at a
glance what the results of your study actually mean. At this point it is necessary to
summarise your data numerically. This is not as difficult as it sounds —we do it
instinctively when they use the expression ‘on average
The average is a way of indicating where most of the scores lie when there is a
collection of scores. The average is found by adding up all the scores and dividing
the sum by the number of scores there are. This average is known as the mean:
The sum of the scores
Average =
The number of scores
The statistical term for the mean or average is a measure of central tendency. This
measure of central tendency is usually given in the form of a single figure. The single
figure, therefore, represents the set of scores. Apart from the mean, there are other
measures of central tendency for a set of scores.
The median is the value that divides the distribution of scores in half. To find the
median, put the scores in ascending order. If there is an odd number of scores, the
median is the middle score. If there is an even number of scores, average the two
middle scores in either case half of the scores in the set will be above the median and
half will be below it. The mode is the most frequently occurring value in a set of
scores. This is simply the score that occurs most often. If we construct a frequency
count, it is the score that has most marks against it.
The mean is the most commonly used measure of central tendency. However if you
have a few scores that are very different from the others, then the mean can be
misleading and you may have to choose another measure of central tendency that
represents the score more accurately.
Where you have a set of data consisting of ranked scores, the median is usually the
more appropriate measure of central tendency. Generally speaking the mode is not
commonly used in psychological statistics except for reporting the results of surveys,
when it can be useful to know which response or score was given most frequently.
Sometimes knowing the mean, median, or mode simply is not enough. It is also
important to know how ‘spread out’ the scores are. The simplest measure of this is
called the range. The range is the difference between the highest and the lowest
score. It is found by simply subtracting the lowest score from the highest score. In
the scores
57,63,72,81,86, the range would be 86-57 = 29.
The problem with the range is that, although it often gives a good indication of the
spread of scores, it depends completely on just two scores — the highest and the
lowest. It therefore cannot give an accurate description of a group of scores where
there is an odd or unusual score markedly higher or lower than the rest. Standard
deviation is more useful measure of distribution.
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This is because it is a measure of the distribution of scores around the mean. If the
standard deviation of a group of scores is large, this means that the scores are widely
distributed with many scores occurring a long way from the mean. If the standard
deviation is small, most scores occur very close to the mean (see below).
The lowest standard deviation is 0, indicating that there is no deviation at all (i.e. all
the scores are identical).
If the scores are normally distributed i.e. asymmetrical like the IQ scores shown
earlier, it is always the case that 68.26% of all scores lie between +1 and —1 SD from
the mean — that is, between one standard deviation above the mean and one standard
deviation below the mean. 95.44% of all scores lie between +2 and — 2 SD from the
mean.
The value of Standard Deviation (SD) is therefore given in terms of the scores that
you are plotting. For example for IQ in the general population the mean is 100 and
SD is 15 (for most IQ tests). Therefore 68% of the population scores between 85 and
115 IQ points and 95% of the population scores between 70 and 130 IQ points (see
below).
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Correlation expresses the extent to which two variables vary together. Correlation is
represented by a number between -1 and + 1 and is called the correlation coefficient.
This number is obtained by applying a test that tells you the extent to which two
variables correlate. The closer the co- efficient is to +1 or -1, the more perfect the
relationship. The closer it is to zero, the weaker is the relationship. For a correlation
of
(Positive) + 1, every rise in variable A is reflected by a rise in variable B. For a
correlation of 0, there is no relationship between A and B. For a correlation of
(negative) -1, every rise in variable A is reflected by a fall in variable B.
Children’s weight and height are positively correlated i.e. taller children tend to weigh
more than smaller children. This is only generally true since some tall children are
very light and some small children are very heavy. However, correlating the scores
for height and weight should produce a positive correlation overall. This would be
seen when a scattergram of the data is plotted. A correlation coefficient would be
obtained through the use of an appropriate test.
Another possible result that can be displayed using a scattergram is a negative
correlation. Negative correlation occurs when increasing the amount of one variable
goes with a decrease in the amount of another. For example, the amount of outdoor
games played by children may correlate negatively with the amount of rainfall in
Scotland! Also, a clear indication that no real correlation between two variables
exists (zero correlation) can be shown on a scattergram. Remember that correlation
can only describe a statistical relationship between two variables. It cannot explain
how that relationship comes about.
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Write a report of the Investigation
The report is the formal record of your research. The style of writing is important in
giving a good impression. Be clear and logical. Always write in a scientific,
objective way. Do not ‘personalise’ the language in your report i.e. use the term
‘participants’ rather than ‘ourselves’ or ‘my friend’. Similarly avoid using the terms
‘I’, ‘we’, ‘us’, etc. It is preferable to use the past tense when you are writing up the
report.
The approximate length recommended for the report is 1000 - 1500 words (not
including tables, figures, appendices etc.). The general structure that follows is the
conventional one for psychology reports. It is most appropriate for reports on
experimental work, but less so for case studies and qualitative work. For this reason,
you may need to vary the style and layout somewhat according to the nature of your
investigation. Keep mainly to the headings and subheadings given here however.
As the report forms part of the unit assessment, you need to ensure that you cover all
the parts of all the sections in your writing or you run the risk of losing marks. A high
proportion of the marks are for carrying out the investigation and for evaluating
your own methodology. These sections of your report should, therefore, be the most
detailed and thorough. The length and content of the other sections will vary
according to the nature of your investigation and findings.
What follows is some advice on each of the recommended sections of the report.
These sections are dealt with in the recommended order of presentation.
In your report you should clearly label each section heading.
A contents page, and numbered pages are very useful.
Your report will almost certainly contain appendices and, of course, a complete
references section at the end.
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The Structure and Recommended Content of the Investigative Report
■
Title
This is the first thing that the reader sees. Make sure it suggests what the
study was about in a clear and precise way i.e. ‘An Investigation into the
Stroop Effect’. Your title should ideally be less than a couple of lines in
length. Avoiding
spelling mistakes is always a god idea in order to create a good initial
impression. Place your title in a way that makes it stand out and be noticed
by the reader.
■
Abstract
This is placed at the beginning of the report but do not write it until you have
finished writing up all of your report. The abstract is a very brief and
concise
summary of the whole report. It should be 100 to 150 words maximum
length.
Consider it to be a short extension of your title. The abstract should indicate:
S
S
S
S
S
S
■
The problem being studied
The type of method/design used
Participants involved - who? How many? How selected?
IV and DV or variables if other methods such as correlation, observation
are used
Research hypothesis
Main results - literally in a short sentence.
Introduction
In the introduction you introduce the study by (1) summarising relevant
background literature, and (2) demonstrating how the study you are reporting
has developed from it.
The background to your investigation provides the justification for your choice of
study. This presents the reader with relevant psychological theories and some
previous studies of the area. Always support your comments in this section with
reference to psychological evidence. This usually means giving the name of a
researcher and the year of the research described e.g. Miller (1956). The full
reference should be given later in your reference section. You may want to talk to
your teacher/lecturer/librarian about how to cite references at the end of your
report proper?
You then need to make a link from the general introduction to what your
particular investigation will focus on. Briefly introduce the key point(s) of your
study. Explain why you are investigating the topic, state how your study differs
from the ones described, and mention what your investigation adds to your
understanding of this area of psychology. The aims of your study must be clear.
Crisply state your aim and relevant hypothesis associated with your research.
Your teacher/lecturer should show you how to phrase and cite your hypotheses.
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Brief details of any pilot study carried out could be given in the introduction
section. Alternatively, this could be placed at the beginning of the Methods
section of the report.
■Methods
The methods section of your report consists of a number of subsections:
Design
Participants
Apparatus
Procedure.
These parts of the Methods section detailed below should say what your design is,
describe the people who took part, list the apparatus and materials used and explain
the exact manner in which the study was carried out.
Design
This refers to the type of practical i.e. observation or experiment, correlation or
survey, etc / and to specifications such as whether it was a repeated measure
design or an independent subjects design. Descriptions of experimental designs
should mention the use of controls and conditions. Do NOT write at length here
about exactly how the study was carried out. Provide a very brief explanation
about why this particular design was chosen (no more than a sentence or two).
Detailed description about exactly how the study was carried out belongs in the
Procedures sub-section.
Participants
Tell the reader how many participants were used and give any relevant details
about them i.e. the population they represent their gender, age, and
class/educational background. Such, and other, characteristics are important
because they may have had some influence on the final results.
For example, for a study of hand-eye co-ordination, whether a participant is left
or right handed may be relevant. Do not list things such as participants’ names or
other personal details unless these are an integral part of the study. Always state
how your participants were selected (sampling).
Apparatus
Give a full list of any specialist apparatus that you have used and, if necessary,
explain how it was used. You may need to use a diagram to describe your
apparatus, especially where it is unusual or complex. Only include technical or
specialist apparatus. For example a computer screen should be included but a
pencil and paper need not be mentioned. If materials such as
schedules/tests/questionnaires etc. were used, these should be described here and
the complete version(s) made available in an appendix.
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Procedure
This section should be a simple, very concise, step-by-step summary of what the
researcher (you) and participants had to do during the study. It should constitute
a clear statement of how your study was carried out and you should say how any
difficulties were dealt with. The description should be sufficiently detailed that
readers could repeat the study for themselves. Reference should be made to all
instructions that were given to participants. These should be stated clearly i.e. in
quotation marks.
■
Results
This section contains the results of all data analyses performed. It is a
summary of your data, rather than the raw data itself. Raw data should be
put in the appendices of the report so that the reader may inspect them.
■
Present your results as clearly and concisely as you can, so that the reader is
easily able to appreciate them. There should be at least one table and one
graph/chart. These must be clearly and exactly identified and labelled. You
should provide a short explanation of any graphs or tables.
At the end of your summary of results you should comment (one or two
sentences) on what the results appear to show. Do not try to interpret your
results - this is carried out in the next section - but make it clear exactly what
the result was by stating whether the hypothesis was supported (remind the
reader of your hypothesis so that he/she does not need to search back to the
introduction to check what it was).
Discussion
First you should state whether results and statistical analysis support or do
not support the hypotheses you have been researching into.
You should point out any peculiarities or any unexpected features of the
result.
You go on to discuss the relationship of your findings to generally accepted
psychological theory and
Results from other relevant studies i.e. those studies mentioned by you in
your introduction section. Do your results agree or disagree with those found
by other researchers? Do your results agree or disagree with what the main
theories say about the topic you are exploring? In this way you are
effectively reviewing your findings in the light of existing psychological
knowledge.
It is important that you do this in your discussion section since marks are awarded on
the basis of your ability to evaluate your own work.
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If your hypothesis has to be rejected i.e. your results offer no support for it, or if your
results are in clear disagreement with previous research and/or theory, this is by no
means a disaster. Failing to produce the expected result is not necessarily a sign that
you have done something wrong; and obtaining the expected result does not mean that
it was a ‘perfect’ study! You will receive maximum credit for your research if you
make a comprehensive attempt to explain why an unexpected result occurred.
Conversely, even if your results were what you predicted, you are still expected to
comment on the design of the study and your performance as a researcher in a
‘critical’ way. As part of this review, you really should have some suggestions to
make about how your study could be improved for future use and what these
‘modifications’ might entail.
A failure to obtain the predicted effect may be due to faults in the way the study was
designed and/or conducted. These should be explained in your report. For example,
was your study poorly designed? Why? Perhaps you had failed to take account of
order effects, confounding variables or gave out tasks that were far too difficult for
people to do in the time available. Discuss these problems fully and offer
constructive improvements, suggesting ideas for further study that avoids them
happening again. Also, consider any problems which cropped up unexpectedly
during the course of the study e.g. equipment failing or the wrong set of instructions
being given out to participants. Admit to these ‘blunders’. They are part of the
process of you learning how to conduct research effectively. You will be completely
‘forgiven’ if you acknowledge your mistakes, point out where you went wrong and
explain how, the next time you do a study, you would avoid making the same
mistakes again.
Always try to be sensible and realistic when you ‘criticise’ your own study.
Psychological studies are rarely, if ever, carried out under perfect conditions. Do not
write paragraphs telling the reader about things you could not possibly control for
such as the fact that one of your participants’ car broke down or that it started to rain
unless of course these factors are highly relevant to your study. Overall your
discussion should show that you are aware of the strengths and weaknesses of your
study and be able to suggest logical and realistic modifications and improvements.
■
Conclusion
This should only be a brief statement of the outcome of the study.
■
References
The reference section is where you list all the books and journal articles you
have read in association with carrying out your research. In this section you
should list alphabetically (by author) all of the works you have read. Most
references contain the following information: author, date, title of
book/journal, article, where published. If journal articles are listed, the
volume number of the journal and the page numbers are also included.
-
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The following example shows how this is done.
Guilford, J.P. (1982) The nature of human intelligence. New York: McGraw-Hill.
Harlow, H.F. (1959) Love in infant monkeys. Scientific American 200(6): 64-74.
It is generally accepted that when a reference is listed, you are stating that you have in
fact read the book or the article listed. If you are listing references that you have not
in fact read, you must acknowledge this. This can be done by adding ‘cited in
handout’ after the reference or following details of the reference with a phrase such as
‘cited in Hayes, 1994’ where Hayes is the author of a textbook listed elsewhere in
your reference section. This implies that you have read the book by Hayes that refers
to the piece of work listed but have not read that piece of work in its original form.
■
Appendices
Materials used in studies (e.g. instruction sheets, raw data, observation
schedules, surveys etc) should be included in your report. This is so that they
are available for your teacher/lecturer and perhaps also an examiner to see. It
is not appropriate to include such items in the main report. Consequently,
they are put into the appendices at the end of the report.
These are simply a series of headed numbered sections using Roman numerals e.g.
• Appendix i: Instruction sheets
• Appendix ii: Raw data
Since the appendices are clearly labelled and numbered they can be referred to easily
whenever it is necessary to discuss their contents in the main report e.g. ‘A copy of
the interview questions that were used may be found in Appendix iv’.
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SECTION 5: GENERAL REFERENCES
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GENERAL REFERENCES
Mike Cardwell The Complete A-Z Psychology Handbook 1998 Hodder and
Stoughton.
Collins Dictionary and Thesaurus 1992 Collins.
Hugh Coolican Research Methods and Statistics in Psychology 1990 Hodder and
Stoughton.
Richard D Gross Psychology - The Science of Mind and Behaviour 3rd ed 1997
Hodder and Stoughton.
Richard Gross and Rod McIlveen Psychology: A New Introduction 1998 Hodder and
Stoughton.
Nicky Hayes Foundations in Psychology 2nd ed. 1998 ITP.
Gerard Keegan ‘Psychology at Kilmarnock College: Notes and Materials’ 5th ed.
1999 Kilmarnock College.
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