RESEARCH METHODS
EXPERIMENTAL METHOD
AIMS
-outline what the study is investigating
-can be phrased either as a research question or a statement
-an aim comes from an initial theory
-aims are general statements that describe the purpose of an investigation
-the aim should refer to the IV and DV
-if several conditions are being compared, both should be referenced
e.g., to assess the effectiveness of a type of therapy called CBT, patients suffering from panic
attacks were allocated to either a 6-week course of CBT sessions or a 12-week course. What
is the aim of the study?
The aim of the study is to compare the effectiveness of CBT in a 6-week course or a 12-week
course on patients suffering from panic attacks.
e.g., 2. Researchers asked AS students to estimate how long they spent studying each week
and, recorded whether each student was male or female. The aim of the study was to
compare how long females spent studying, each week, in comparison to males.
VARIABLES AND HYPOTHESES
Independent variable: what the researcher manipulates in the experiment
Dependent variable: what the researcher measures in the experiment
The researcher is looking at how the IV has caused the effect on the DV.
Hypothesis: prediction about the outcome of the experiment. Written as a precise and
testable statement
LEVEL OF THE IV
-we need different experimental conditions to test the effects of the IV on the DV
-we need a comparison e.g., group 1 and 2
-control condition and experimental condition
- a well written hypothesis allows us to easily see the IV and the DV
OPERATIONALISATION OF VARIABLES
-when conducting an experiment, the psychologist must ensure that the IV and DV are
identified and operationalised within the hypothesis
-operationalising is the process of defining the variables precisely
-for the IV, this means we know precisely how it was manipulated
-for the DV, we know precisely how it will be measured
DIRECTION OF HYPOTHESIS
,Directional (one-tailed: specifically states the direction of the results i.e., what effect the IV
will have on the DV. These are used when previous research has shown a particular
outcome is likely.
Words used in directional hypothesis:
-more/less/fewer
-larger/smaller
-higher/lower
-faster/slower
Non-directional: does not specify the expected direction of the results, just that there will
be a change, difference, or effect. These are used when there is little previous research.
Deciding which type of hypothesis to use:
-psychologists tend to use directional hypothesis when the findings of a previous research
suggest a particular outcome
-if there is no previous research or secure findings, we will use a non-directional hypothesis
CONTROL OF VARIABLES
When conducting experiments, it’s possible that other variables may affect the results, and
these must be controlled or removed.
EXTRANEOUS
Extraneous variable: may affect the DV if it is not controlled. ‘Nuisance variables’ that make
it difficult to detect if the IV has had an effect. Many are easy to control for and often, they
don’t change systematically with the IV, which makes them easy to control. (Can be sub-
divided into participant variables and situational variables)
-Participant variables are any individual differences between participants that may affect the
DV. E.g., age, personality, motivation, intelligence, gender etc.
-Situational variables are any features of the experimental situation that may affect the DV.
E.g., noise, weather, instructions, temperature, time of day
HOW TO CONTROL EXTRANEOUS VARIABLES
Situational = Standardisation
- ensure participants experience the same information/ conditions/ situation. This includes
standardised instructions.
-holding these factors constant in the standardised procedures/ instructions
-this will eliminate/reduce the effect of such variables as there will be minimal/no variation
in the factors
Participant = randomisation
-use of chance to reduce the researchers influence on the design of the investigation
-participants are randomly allocated
-assign ppts. A number, put in a hat, draw numbers from hat; first group of numbers drawn
are in condition A, second group are in condition B.
-the order in which the ppts. Receive the stimuli should not be determined by the
researcher
,-individual differences will be distributed evenly so they do not alter systematically with the
IV.
-using these techniques makes it less likely that extraneous variables will become
confounding
CONFOUNDING
Confounding variable: systematically changes with the IV. It therefore acts as another IV. It
is possible that it has caused the change in the DV.
DEMAND CHARACTERISTICS AND INVESTIGATOR EFFECTS
Demand Characteristics: environmental clues to what the investigation is about, causing a
participant to alter their behaviour. Participant reactivity is a significant extraneous variable,
where participants may react differently according to how they think they are expected to
act
-may work out the research aim
-may conform to what they believe the researcher expects
-may attempt to ruin the results by deliberately defying expectations
How these can be controlled: by using single-blind procedures, where the participants are
not informed as to which condition each ppt has been placed in
Investigator effects: the person collecting the data knows the research aim or has
characteristics that affect the data obtained
-researcher may communicate research aims to participants
-may do this consciously or unconsciously
-e.g., non-verbal cues such as smiling or frowning to encourage/ discourage performance
How these can be controlled: by using double-blind procedure, where the ppts. and the
person collecting the data are not informed as to which condition each ppt. has been placed
in
, EXPERIMENTAL DESIGNS
Experimental designs refer to how researchers are going to allocate and organise the
participants to the conditions in an experiment. There are two groups/conditions:
experimental and control
The three main ways in which you can allocate participants in experiments are:
-repeated measures design
-independent groups design
-matched pairs design
REPEATED MEASURES DESIGN
A repeated measures design involves using the same people in each condition and
comparing ‘like for like’.
Every participant does both the conditions
+participant variables are controlled for; there are no individual differences, so the DV is not
affected by participant variables, so the difference between conditions is likely to be down
to the IV.
+it’s cheaper; the same ppts. take part in both conditions so there isn’t the additional cost
for the researcher to recruit another set of participants, which makes this method
economical
-demand characteristics are likely to be experienced because ppts. become aware of what is
being manipulated and this means that the DV is likely to be affected by participants
working out the aim of the study and changing their behaviour, rather than the IV.
-order effects are likely to be experienced because ppts. take part in both conditions so they
may become tired, bored, or more skilled at the task in the second condition, which means
that the DV may be affected by fatigue, boredom, or practise, rather than IV.
When a repeated design is used, psychologists should always use the following procedure:
It is possible to control order effects by using a procedure called counterbalancing, where
half the participants undergo the experimental condition first, followed by the control
condition, whereas the other half of the participants undergo the control condition first,
followed by the experimental. This way, if participants get tired by the time they complete
the second task, this will affect recall for one of the conditions only. Counterbalancing
ensures that any order effects are distributed between the conditions so that the conditions
are equally affected
Independent Groups Design
This design involves using different people in each condition of the experiment and
comparing each group’s performance. Each participant is allocated at a different condition;
half do condition A, half do condition B.
+ there is less chance of demand characteristics occurring because participants only take
part in one condition and so are unaware of what is being manipulated, which means the DV
EXPERIMENTAL METHOD
AIMS
-outline what the study is investigating
-can be phrased either as a research question or a statement
-an aim comes from an initial theory
-aims are general statements that describe the purpose of an investigation
-the aim should refer to the IV and DV
-if several conditions are being compared, both should be referenced
e.g., to assess the effectiveness of a type of therapy called CBT, patients suffering from panic
attacks were allocated to either a 6-week course of CBT sessions or a 12-week course. What
is the aim of the study?
The aim of the study is to compare the effectiveness of CBT in a 6-week course or a 12-week
course on patients suffering from panic attacks.
e.g., 2. Researchers asked AS students to estimate how long they spent studying each week
and, recorded whether each student was male or female. The aim of the study was to
compare how long females spent studying, each week, in comparison to males.
VARIABLES AND HYPOTHESES
Independent variable: what the researcher manipulates in the experiment
Dependent variable: what the researcher measures in the experiment
The researcher is looking at how the IV has caused the effect on the DV.
Hypothesis: prediction about the outcome of the experiment. Written as a precise and
testable statement
LEVEL OF THE IV
-we need different experimental conditions to test the effects of the IV on the DV
-we need a comparison e.g., group 1 and 2
-control condition and experimental condition
- a well written hypothesis allows us to easily see the IV and the DV
OPERATIONALISATION OF VARIABLES
-when conducting an experiment, the psychologist must ensure that the IV and DV are
identified and operationalised within the hypothesis
-operationalising is the process of defining the variables precisely
-for the IV, this means we know precisely how it was manipulated
-for the DV, we know precisely how it will be measured
DIRECTION OF HYPOTHESIS
,Directional (one-tailed: specifically states the direction of the results i.e., what effect the IV
will have on the DV. These are used when previous research has shown a particular
outcome is likely.
Words used in directional hypothesis:
-more/less/fewer
-larger/smaller
-higher/lower
-faster/slower
Non-directional: does not specify the expected direction of the results, just that there will
be a change, difference, or effect. These are used when there is little previous research.
Deciding which type of hypothesis to use:
-psychologists tend to use directional hypothesis when the findings of a previous research
suggest a particular outcome
-if there is no previous research or secure findings, we will use a non-directional hypothesis
CONTROL OF VARIABLES
When conducting experiments, it’s possible that other variables may affect the results, and
these must be controlled or removed.
EXTRANEOUS
Extraneous variable: may affect the DV if it is not controlled. ‘Nuisance variables’ that make
it difficult to detect if the IV has had an effect. Many are easy to control for and often, they
don’t change systematically with the IV, which makes them easy to control. (Can be sub-
divided into participant variables and situational variables)
-Participant variables are any individual differences between participants that may affect the
DV. E.g., age, personality, motivation, intelligence, gender etc.
-Situational variables are any features of the experimental situation that may affect the DV.
E.g., noise, weather, instructions, temperature, time of day
HOW TO CONTROL EXTRANEOUS VARIABLES
Situational = Standardisation
- ensure participants experience the same information/ conditions/ situation. This includes
standardised instructions.
-holding these factors constant in the standardised procedures/ instructions
-this will eliminate/reduce the effect of such variables as there will be minimal/no variation
in the factors
Participant = randomisation
-use of chance to reduce the researchers influence on the design of the investigation
-participants are randomly allocated
-assign ppts. A number, put in a hat, draw numbers from hat; first group of numbers drawn
are in condition A, second group are in condition B.
-the order in which the ppts. Receive the stimuli should not be determined by the
researcher
,-individual differences will be distributed evenly so they do not alter systematically with the
IV.
-using these techniques makes it less likely that extraneous variables will become
confounding
CONFOUNDING
Confounding variable: systematically changes with the IV. It therefore acts as another IV. It
is possible that it has caused the change in the DV.
DEMAND CHARACTERISTICS AND INVESTIGATOR EFFECTS
Demand Characteristics: environmental clues to what the investigation is about, causing a
participant to alter their behaviour. Participant reactivity is a significant extraneous variable,
where participants may react differently according to how they think they are expected to
act
-may work out the research aim
-may conform to what they believe the researcher expects
-may attempt to ruin the results by deliberately defying expectations
How these can be controlled: by using single-blind procedures, where the participants are
not informed as to which condition each ppt has been placed in
Investigator effects: the person collecting the data knows the research aim or has
characteristics that affect the data obtained
-researcher may communicate research aims to participants
-may do this consciously or unconsciously
-e.g., non-verbal cues such as smiling or frowning to encourage/ discourage performance
How these can be controlled: by using double-blind procedure, where the ppts. and the
person collecting the data are not informed as to which condition each ppt. has been placed
in
, EXPERIMENTAL DESIGNS
Experimental designs refer to how researchers are going to allocate and organise the
participants to the conditions in an experiment. There are two groups/conditions:
experimental and control
The three main ways in which you can allocate participants in experiments are:
-repeated measures design
-independent groups design
-matched pairs design
REPEATED MEASURES DESIGN
A repeated measures design involves using the same people in each condition and
comparing ‘like for like’.
Every participant does both the conditions
+participant variables are controlled for; there are no individual differences, so the DV is not
affected by participant variables, so the difference between conditions is likely to be down
to the IV.
+it’s cheaper; the same ppts. take part in both conditions so there isn’t the additional cost
for the researcher to recruit another set of participants, which makes this method
economical
-demand characteristics are likely to be experienced because ppts. become aware of what is
being manipulated and this means that the DV is likely to be affected by participants
working out the aim of the study and changing their behaviour, rather than the IV.
-order effects are likely to be experienced because ppts. take part in both conditions so they
may become tired, bored, or more skilled at the task in the second condition, which means
that the DV may be affected by fatigue, boredom, or practise, rather than IV.
When a repeated design is used, psychologists should always use the following procedure:
It is possible to control order effects by using a procedure called counterbalancing, where
half the participants undergo the experimental condition first, followed by the control
condition, whereas the other half of the participants undergo the control condition first,
followed by the experimental. This way, if participants get tired by the time they complete
the second task, this will affect recall for one of the conditions only. Counterbalancing
ensures that any order effects are distributed between the conditions so that the conditions
are equally affected
Independent Groups Design
This design involves using different people in each condition of the experiment and
comparing each group’s performance. Each participant is allocated at a different condition;
half do condition A, half do condition B.
+ there is less chance of demand characteristics occurring because participants only take
part in one condition and so are unaware of what is being manipulated, which means the DV
