HUBERT KAIRUKI MEMORIAL
UNIVERSITY
TOPIC. PERCEPTION AND ATTENTION
FACILITATATOR. MR LEMA ISAAC
PRESENTER
.AYMAN MAHFOUDH
.ASHA SALUM
.ZENA MASOUD
.SIFA RAJAB
MAKRINA MSAGI
HALIMA HAMK
.FATUMA MISIAKI
.JAMES NOEL
CONTEXT
.INTRODUCTION
.OBJECTIVE
.DEFINITION
.MAIN DISCUTION
.SUMMARY
.CONCLUSION
.RECOMMENDATION
.REFERENCE
OBJECTIVES
At the end of this topic, one is expected to:
1.Be able to define the terms attention and
perception
2.Know the values of perception to an individual
3.Be familiar with the acquisition of perception
4.Know the dimensions of perception
5.Understand the constancy of percepts together
with their meanings and finally,
6.Be able to explain the disorders of perception
INTRODUCTION
.Perception and attention are identifiable component of
human cognitive system.
.For the complete understand of them it’s necessary to
appreciate the way that interact and depend on one another
Neuropsychology 2007 elsevier
.In this review examine how perception and attention is
involved in detecting faces
.In this review examine perception are automatic
. They are especially rapid , non conscious ,mandatory and
capacity free
.Perception is a cognitive response to sensory input
DEFINITIONS OF THE TERMS USED
Perception: Is the organization of sensory experiences into a
meaningful, orderly arrangement of object and events in time
and spaceORIs the cognitive response to sensory input.
Percept: Is the organization of sensory information into
cognition.
Attention:a concentration of the mind on a
single object or thought, especially one
preferentially selected from a complex, with
a view to limiting or clarifying receptivity by
narrowing the range of stimuli.
Illusion:Misinterpretation of sensory cues.
•GENERAL OBJECTIVE
1.Perception and Attention
As previously defined, perception is not simply the sum of
integrated sensory experiences as thought by most people
but rather it is the cognitive response to sensory input.
From the definition, it is obvious that perception is an active
process that involves organizing sensory experiences into a
meaningful, orderly arrangement of objects and events in
both time and space.
Characteristics of perceptual process are based on
minimal sensory cues, for instance identical patterns of
sensation may give rise to very different perceptions
from one individual to another or from one occasion to
another for the same individual.
Consider the following figures:
Figures: Reversible images (after Escher)
From the two figures above, it is possible to have more than
one perception depending on what part the observer puts
his/her attention.
2..Values of Perception
Perception as a process is very vital to human being as it
has got Survival value through the ability to organize
sensations into a meaningful percept thus enables
adaptive action to occur. For example, seeing an object
flying rapidly towards you and recognizing it as
dangerous can enable you to duck in time. No wonder,
Sir Sherrington, English Neurophysiologist pointed out
that all the distance receptor were in the head hence
had the shortest nerve pathway to the brain thus
permitting a longer time be available
Furthermore, perception facilitates the orientation of an
individual in space by combining different sensory cues.
Through such means, an individual can protect himself and
take advantage of his external world.
Additionally, perception allows an individual to sustain
himself in the environment when it is combined with
memory. It is true that identical sensory inputs are very
unlikely to occur on subsequent occasions, we never see
things exactly the same way twice, and therefore it is
necessary that images or concepts evolve which will
enable to express the essential qualities of what is sensed.
A good example is that of a primitive hunter who leave the
shelter in search of food and what is more, recognize his
quarry as such when he finds it despite never having seen
this particular animal before.
3.Acquisition of Percepts
Percepts acquisition is influenced by three major factors:
1.ualities of the external world; for example we might
see certain colors during daylight which appear simply as
grey at dusk.
2.The efficiency of our sense receptors. It is well known
that individuals will hearing problems usually
misperceive what may be said in conversation.
3.The nature of the perceiver. Researches have revealed
that some certain noxious stimuli are perceived as
painful by a majority of people, and yet can be erotic or
exciting for others.
In order to acquire perception, we addbits, ignore bits
and fit bits together in an individual manner to produce a
personal meaning. This becomes possible through paying
attention. Conversations take place on noisy buses
because participants are able to tend selectively to part
of total sensory information
4.Dimensions of Perception
The dimensions of sensory experience that are important
in relation to perception include:
1.Intensity,
2.Duration
3.Qualitative differences across modalities
4.Adaptation
It should be noted that it is only a part of sensory
information that is perceived and even this is interpreted in
a highly subjective manner. A good example is that of
medical students inspecting a histological section under a
microscope, they have to be told what might be seen and
stains are used to facilitate this perception. Without being
told what to perceive, many would fail to identify any thing
meaningful
5.Constancy of Percepts
Percepts maintain constancy. This is their major
characteristic; that is to say, they continue to be perceived
in the same manner although the sensory experience may
never be the same on two occasions. For example one
may easily recognize a bus in the street despite the fact
that it is most unlikely to have been sensed in an identical
setting in the past.
An illusion is the misperception of sensory cues. For
example the seemingly moving pictures seen at the
An illusion is the misperception of sensory cues. For
example the seemingly moving pictures seen at the
cinema are in fact a series of still pictures projected at
high speed. Many illusions are created by the
expectancies of the perceiver. An interesting illusion is
déjà vu (a false memory of having been somewhere
before). This is just the recollections from many previous
experiences resulting in an overall composite false
impression of memory for a new situation.
6.Disorders of Perception
Since perception is a very sophisticated process, it is
always subjected to disturbances as a result of illness or
altered consciousness as a result of a blow to the head
or anaesthesia.
Some people deliberately alter their levels of
consciousness by using toxic substances which produce
distorted perception.
Brain damages may produce long lasting or permanent
disorders of perception; and here, the location is more
important than the extent of damage.
Dyspraxia which is difficulty in carrying out coordinated
voluntary movement, often occur with agnosia, a
perceptual disturbance in which objects cannot be
recognized adequately although peripheral sensory is
minations which occupy more and more of their time.
Perceptual disturbances are often observed with
patients suffering from psychiatric illnesses example
auditory hallucination as in Schizophrenics. An
hallucination is a perceptual experience without the
presence of appropriate sensory stimulation.
Apart from that, perceptional disturbances are also
reported in people with psychological disorders even
though it is in a less extent. For example depressed
people complain that they cannot concentrate to
matter in hand and food has no taste. Obsessed people
say they cannot get their mind
SUMMARY
In summary,Perceptionis the organization of sensory
experiences into a meaningful, orderly arrangement of
objects and events in time and space where as
Attentionrefers to concentration of the mind on a
single object or thought, especially one preferentially
selected from a complex, with a view to limiting or
clarifying receptivity by narrowing the range of stimuli .
It is possible for an individual to have more than one
perception depending on what part the observer puts
his/her attention
Perception is thus very important to an individual as
it:
1.has got Survival value,
2.facilitates the orientation of an individual in space
and
3.Allows an individual to sustain himself in the
environment.
Percepts are gained depending on:
a/Qualities of the external world,
b/The efficiency of our sense receptors and
c/The nature of the perceiver.
It should however be noted that percepts are always
constant
REFERENCES
The following materials were used in writing this paper:
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3.Sims A.C.P,Hume.W.I.(1984).Lecture notes on
Behavioral science.(Blackwell scientific publications:
Oxford