Research Methods
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The main research methods used by psychologists are :

Experiments

Non-experimental methods
-Observation
-Correlation method
-Self report method
-Case Study
EXPERIMENTAL METHOD

The method used by researchers to
study cause-and-effect relationships.

Manipulates an independent variable (IV) in order to
investigate the change in dependent variable.

All other variables which might influence the results

(called extraneous variables) are controlled.
Participants are randomly allocated to the
experimental and control conditions.
Independent variable (IV):
Experimental group: exposed to
the variable that is
the manipulation of the IV
manipulated.
Dependent variable (DV):
Control group. Responses of the
control group are compared with
the variable that is
the responses of the
measured.
experimental group.
LABORATORY EXPERIMENT
 The experiment is carried out in a controlled
environment.
Disadvantages
Advantages
• Variables are easier to
control
• High internal validity
• Procedures can be easily
replicated.
• High levels of control may
lead to artificiality of the
setting
• Ecological validity of the
study may be a concern
•Increased risk of demand
characteristics and
experimenter effects
FIELD EXPERIMENT


Experimental investigations carried out in natural
settings (e.g. homes, school).
Involve direct control of the IV and allocation of
participants to groups.
Advantages
Disadvantages
• Improved ecological
validity. Behaviour studied
is more realistic.
• More difficult to control
extraneous variables.
• Decreased risk of demand
characteristics
• Internal validity of the
study may be affected.
• More difficult to
replicate
NATURAL EXPERIMENT

The researcher neither directly controls the IV nor
allocates participants to conditions.

Makes use of naturally occurring differences in the IV
in the pre-existing groups.
Advantages
Disadvantages
• Reduced demand
characteristics.
• Degree of control over the
IV is less.
• Difficult to make causal
conclusions .
NON-EXPERIMENTAL METHODS

Variables are not deliberately manipulated by the
researcher.

Allows psychologists to study behaviour in more
natural settings.

However reduced level of control over the
variables make it harder to draw any conclusion
concerning cause-effect relationships.

Observational techniques

Correlation analysis


Self-report techniques including
questionnaires and interviews
Case studies
OBSERVATION

A basic research method; behaviour is observed and
recorded

No deliberate manipulation of variables

Observational research can be laboratory or
naturalistic.

Observes behaviour through behaviour categories

Open to subjective bias.
DESIGNING CATEGORIES




Researcher must define the behaviour he/she observes.
Psychologists use behavioural categories to record particular
instances of behaviour.
For example, observers may use check lists or tally chart for
recording observations.
Sampling techniques used for observation can be time sampling
and event sampling.
For example:
Deep sleep
Active sleep
Quiet awake
Active awake
Crying , fussing
STATE OF A BABY DURING A
30-SECOND TIME PERIOD
CORRELATION METHOD

Concerned with the extent of relationships between
variables that covary (varies in the same time period)

Correlational analysis do not establish causal links.

Other variables may influence any measured
relationship.

As a result, the internal/external validity of the study
can be affected.
SELF-REPORT MEASURES


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In this technique, the participants themselves provide
information about specific things relating to themselves.
(e.g. What they think, believe or do)
Questionnaires and interviews- Open or close
Interviews can be:
Structured interviews can be easily repeated.
Unstructured interviews- questions that evolve are
dependent on answers given.
Main disadvantage of self-report measures:
Social desirability bias.
Designing questions
When designing a questionnaire, there are some important
things to be considered.
1. Type of data. Open ended questions will give qualitative
data and close ended questions will give quantitative data.
2. Ambiguity
Items and responses should be simple and clearly defined.
3. Double-barrelled questions.
Avoid two parts in a single question.
4. Leading questions
Avoid questions that lead the participant towards a particular
answer.
CASE STUDY
A detailed study of a particular individual,
institution or event.
 Uses information from a range of sources.
 Techniques involved to collect data include
interview, psychological tests, observations etc.
 Are generally longitudinal.
 Difficult to generalise from specific cases.

RESEARCH DESIGNS
Aims and hypotheses

An aim is a statement of the purpose of a study.

Hypothesis is a statement that is testable. A research hypothesis is a general prediction
made at the beginning of an investigation , about what the researcher expects to happen.

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Types of hypotheses
Experimental hypothesis/alternative hypothesis predicts that something other
than chance alone has played a part in producing the results obtained.
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Null hypothesis predicts that the results obtained from an investigation are due to
chance alone.
Alternate hypothesis can be directional or non-directional.
(the direction of a difference or relationship is or is not stated).


A directional hypothesis predicts the direction in which results are
expected to occur.
A non-directional hypothesis does not predict the expected direction of
outcome.

E.g. of a directional hypothesis. More words are recalled from a list
when using rehearsal as mnemonic technique than when no mnemonic
technique is used.

E.g. of a non-directional hypothesis. There is a difference in the number
of words recalled from word lists presented with or without the presence
of background music.
EXPERIMENTAL DESIGNS
Independent group
design
Repeated group design
Matched pairs
design
There are different
participants in each
•Each participant is involved
There are different
participants in each
group of the experiment
in all conditions.
condition. But there are
matched on relevant
 Each participant is
involved in only one
condition of the
experiment
i.e. The same participants are
variables (e.g., age,
intelligence etc.).
used in both the experimental
and control conditions.
condition.
CONTROL OF VARIABLES

All the variables other than the independent variable that might
affect the dependent variable are called extraneous variables.

If a variable other than the IV, produces a change in a DV, the
results of the study are said to have been confounded.

Variables can be controlled by
•
Counterbalancing
•
Random allocation
•
Extraneous variables can be controlled by
keeping them constant or eliminating them
altogether.
PILOT STUDIES
A small scale trial run of a research study to test any aspects of the
design, with a view to making improvements.


This should establish whether the design works.
Based on the feedback from the pilot study, researcher can make
necessary changes.

Saves time, effort and money.
SAMPLING TECHNIQUES

Opportunity sample- uses easily available participants....Biased

Volunteer sample-uses volunteers.......Biased

Random sample-uses random number technique.....Unbiased

Stratified and quota sample – use subgroups within a population and
a proportionate number of participants selected. In stratified sampling,
random selection of participants leads to more representative sample.

In quota sampling, opportunity sampling is used...biased

Snowball sample- Uses personal contacts of participants....biased
ISSUES OF RELIABILITY
Reliability in different research methods.

In the context of an experimental research it refers to consistency of
results.

In observation method, the extent of agreement between observers is
called inter-rater or inter-observer reliability. Reliability can be improved
through training.

In self report methods, the two types of reliabilities are
Internal reliability : the extent to which a test is consistent within itself.
External reliability: consistency over several different occasions.
Inter-interviewer reliability- is the consistency of the outcome of
interviews by different interviewers.

Two assessment methods of reliability: Split-half method and test-retest
method.
ISSUES OF VALIDITY
 Validity –whether the results obtained in a study are true/genuine.
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Kinds of validity :
Internal: Whether the study did test, what it intended to measure.
External: the extent to which the results of the study can be
generalised to other situations ( ecological validity) and people.
Laboratory experiments are not necessarily low in external validity. If
low in mundane realism, reduces generalisability of the findings.
In observation method, internal validity is affected by observer bias.
In self-report techniques, two ways to assess internal validity are
Face validity: the extent to which the test looks as if it is measuring
what it should measure.
Concurrent validity: assessed by comparing the outcome of a test
with an already established test on the same topic.
ETHICAL CONSIDERATIONS IN PSYCHOLOGICAL RESEARCH
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Ethical issues: Informed consent and deception.
And Psychological Harm
BPS code of conduct identifies four ethical principles
1. Respect -for the dignity and worth of all persons. This includes: Right to
privacy, confidentiality, informed consent, and right to withdraw. Intentional
deception is acceptable only in some circumstances.
2. Competence- maintaining high standards in research.
3. Responsibility- Protection from harm (physical and psychological) and
debriefing.
4. Integrity- being honest and accurate in reporting.
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Ethical guidelines in conjunction with ethical committees used o assess research
proposals.
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Socially sensitive research-potential social consequences for participants.
Ethical issues with Non-humans

Reasons for use of animals in research
 Offers greater opportunity for greater control and objectivity;
 When it is not possible to use humans;
 Physiological similarities.
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Moral issues- Whether ‘science at any cost is justifiable’?
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Sentience :Do animals experience pain and emotions?
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Specieism – Form of discrimination against non-human species.
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Animal rights- According to Singer, if animal research can alleviate pain and
suffering, animal research is justifiable. But Regan (1984) argues that no animal
research is acceptable.

Do animals have rights if they have no responsibilities?
 Animal research subject to strict legislation (animal acts; BPS guidelines) ----text
page 285
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Russell and Birch (1959) proposed the three Rs to be followed in animal
research – Reduction (use fewer animals), Replacement (whenever possible
use alternative methods, Refinement (used improved techniques to reduce
stress.