Psychology - Research
methods
Introduction to research methods
Aim - A statement of what the researcher(s) intends to find out in a research
study.
Independent variable - The variable that changes across conditions.
Dependent variable - The variable that is measured in response to this.
Operationalise - How you define and measure a specific variable in an
experiment.
Hypothesis - A precise and testable statement about the assumed relationship
between variables.
● Directional - States the direction of the predicted difference between 2
conditions or 2 groups of participants.
● Non-directional -Predicts that there is a difference between 2
conditions/groups of participants, without stating the direction.
Standardised procedures - A set of procedures that are the same for all
participants in order to be able to repeat the study.
, 2
Control variables
Confounding variables - A variable under study that is not the IV but varies
systematically with the IV. Changes in the DV may be due to the confounding variable
rather than the IV, and therefore the outcome is meaningless.
Extraneous variable - Do not vary systematically with the IV and therefore do not act as
an alternative IV but may have an effect on the DV. They are ‘extra’ variables that make it
more difficult to detect a significant effect.
More issues that may act as a confounding/extraneous variable:
● Demand characteristics - A aspect of the research situation that makes
participants unconsciously aware of the aims of a study. Participants may then
change their behaviour to fit in with these expectations.
● Investigator effects - A cue from the investigator that encourages certain
behaviours in participants which may lead to a fulfilment of the investigators
expectations.
Dealing with these problems:
● Single blind design - The participant is not aware of the research aims
and/or which condition of the experiment they are receiving. This reduces
demand characteristics.
● Double blind design - Both the participant and the person conducting the
experiment are ‘blind’ to the aims and/or hypothesis. Reduces the influence of
both demand characteristics and investigator effects.
● Randomisation - The use of chance in order to reduce the influence of the
experimenter on the design of the investigation.
● Standardisation - Using the same procedures and instructions for each
participant. Reduces the influence of extraneous and confounding variables.
, 3
Realism
The aim of a psychological study is to provide information about how people behave in
‘real life’. If the setting of the study is to artificial the participants won’t act as they
normally would.
Mundane realism - Refers to how an experiment mirrors the real world.
★ If a study has high mundane realism it is representative of real life.
★ If a study isn’t representative of real life it has low mundane realism.
The point of realism in psychological research is to be able to generalise the results in
order to understand behaviour in everyday life.
Types of experiment
Experiment Advantages Disadvantages
Laboratory experiment ✔️
✔️ High internal validity ❌
❌ Low external validity
An experiment conducted
in a special environment
✔️
Establish cause and
effect ❌ Low ecological validity
Can’t generalise to the
where variables can be
carefully controlled. ✔️ Objective
✔️Replicable
Controlled ❌Demand characteristics
population
Field experiment ✔️
✔️ High external validity ❌
❌ Low internal validity
An experiment conducted
in a more natural ✔️
✔️
High ecological validity
Can generalise to others
❌
Can’t establish cause
and effect
environment. The IV is
deliberately manipulated
by the researchers.
Less demand
characteristics ❌ Not controlled
❌Less likely to replicate
Not objective
Natural experiment ✔️
✔️ High ecological validity ❌ More expensive and
Experimenters cannot
manipulate the IV directly
✔️
Low demand
characteristics ❌
time consuming
No control over
but where if varies
naturally.The effect of the
IV was then observed on
Can be used in unethical
situations ❌
extraneous variables
❌May cause bias
Difficult to replicate
the DV.
methods
Introduction to research methods
Aim - A statement of what the researcher(s) intends to find out in a research
study.
Independent variable - The variable that changes across conditions.
Dependent variable - The variable that is measured in response to this.
Operationalise - How you define and measure a specific variable in an
experiment.
Hypothesis - A precise and testable statement about the assumed relationship
between variables.
● Directional - States the direction of the predicted difference between 2
conditions or 2 groups of participants.
● Non-directional -Predicts that there is a difference between 2
conditions/groups of participants, without stating the direction.
Standardised procedures - A set of procedures that are the same for all
participants in order to be able to repeat the study.
, 2
Control variables
Confounding variables - A variable under study that is not the IV but varies
systematically with the IV. Changes in the DV may be due to the confounding variable
rather than the IV, and therefore the outcome is meaningless.
Extraneous variable - Do not vary systematically with the IV and therefore do not act as
an alternative IV but may have an effect on the DV. They are ‘extra’ variables that make it
more difficult to detect a significant effect.
More issues that may act as a confounding/extraneous variable:
● Demand characteristics - A aspect of the research situation that makes
participants unconsciously aware of the aims of a study. Participants may then
change their behaviour to fit in with these expectations.
● Investigator effects - A cue from the investigator that encourages certain
behaviours in participants which may lead to a fulfilment of the investigators
expectations.
Dealing with these problems:
● Single blind design - The participant is not aware of the research aims
and/or which condition of the experiment they are receiving. This reduces
demand characteristics.
● Double blind design - Both the participant and the person conducting the
experiment are ‘blind’ to the aims and/or hypothesis. Reduces the influence of
both demand characteristics and investigator effects.
● Randomisation - The use of chance in order to reduce the influence of the
experimenter on the design of the investigation.
● Standardisation - Using the same procedures and instructions for each
participant. Reduces the influence of extraneous and confounding variables.
, 3
Realism
The aim of a psychological study is to provide information about how people behave in
‘real life’. If the setting of the study is to artificial the participants won’t act as they
normally would.
Mundane realism - Refers to how an experiment mirrors the real world.
★ If a study has high mundane realism it is representative of real life.
★ If a study isn’t representative of real life it has low mundane realism.
The point of realism in psychological research is to be able to generalise the results in
order to understand behaviour in everyday life.
Types of experiment
Experiment Advantages Disadvantages
Laboratory experiment ✔️
✔️ High internal validity ❌
❌ Low external validity
An experiment conducted
in a special environment
✔️
Establish cause and
effect ❌ Low ecological validity
Can’t generalise to the
where variables can be
carefully controlled. ✔️ Objective
✔️Replicable
Controlled ❌Demand characteristics
population
Field experiment ✔️
✔️ High external validity ❌
❌ Low internal validity
An experiment conducted
in a more natural ✔️
✔️
High ecological validity
Can generalise to others
❌
Can’t establish cause
and effect
environment. The IV is
deliberately manipulated
by the researchers.
Less demand
characteristics ❌ Not controlled
❌Less likely to replicate
Not objective
Natural experiment ✔️
✔️ High ecological validity ❌ More expensive and
Experimenters cannot
manipulate the IV directly
✔️
Low demand
characteristics ❌
time consuming
No control over
but where if varies
naturally.The effect of the
IV was then observed on
Can be used in unethical
situations ❌
extraneous variables
❌May cause bias
Difficult to replicate
the DV.
