1. Edexcel GCSE 9-1 Psychology Topic 11 Research Methods
Variables (pp. 132 – 134)
Learning objectives:
1) To learn how to identify the IV, DV and extraneous variables in an investigation.
2) To learn about the influence of extraneous variables and possible ways to control them.
Key terminology: try to write it in your own words – and without looking at your yellow sheet! Try to draw
a picture or a key word/phrase to help you remember each in the right hand column.
Task 1:
Independent
variable
Dependent variable
Operationalisation
Extraneous variables
Confounding
variables
Task 2:
In each of the following experiments, identify the IV and DV.
1) A study to examine the influence of caffeine on performance.
IV = DV =
2) A study to investigate whether cats or dogs sleep longer.
IV = DV =
3) A study to see if age affects the amount of sleep we need.
IV = DV =
4) An investigation into how the type of praise you receive influences the grades achieved in exams.
IV = DV =

2. Task 3:
Answer the following questions:
1) Why do extraneous variables need to be controlled?
2) What happens if extraneous variables can’t be
controlled?
3) If one group is trying to complete a task in poor light and they can’t see their paper properly, why
would we refer to this as a situational variable? What could this do to the results?
More key terminology:
Complete the definitions and try to draw a picture or key word/phrase to help you remember it.
Task 4:
Situational variables
Order effects
Demand
characteristics
Investigator effect
Participant variables
Standardised
procedure
Task 5:

3. Answer the following questions:
1) Why is it that when participants repeat the test, order effects occur?
2) Why do participants change their behaviour in studies?
3) Give four examples of participant variables and say how each could affect the results of the study.
4) Give three ways in which experimenters could control extraneous variables in their studies.
5) Give three examples of how experimenters could ensure they use a standardised procedure in their
study.
6) Identify the potential situational variables and participant variables that may influence the findings
of the following investigation:
Researchers posted a notice on a social media site to recruit volunteer participants for an
investigation. The investigation wanted to see whether or not people select partners who are similar
to themselves. Once they were recruited, they were invited to a university laboratory and asked to
select their ideal partner from a series of photographs and descriptions. The researchers wanted to
see if males or females were more likely to select people who were more similar to themselves as
ideal partners. The participants came to the laboratory on different days and were tested by a
variety of male and female researchers.
a) Situational variables
b) Participant variables
Stretch and challenge:

4. a) Identify the IV from the above study.
b) Identify the DV from the above study.
c) Can you identify any extraneous variables from the above study?
Key terminology:
Task 6:
Counterbalancing
Randomisation
Single-blind
technique
Double- blind
technique
Random allocation
Task 7:
1) Explain how researchers use counterbalancing to prevent order effects.
2) Explain how randomisation is used to generate the condition order.
3) Give an example of how a single-blind trial could be used in clinical psychology.
4) Give an example of how a double-blind trial could be used in clinical psychology.

5. 5) What is the easiest/best way to control participant variables?
6) Explain what is meant by random allocation. Try to give an example in your answer.
Task 8:
Apply it:
How would you go about controlling extraneous variables in the following investigations?
- A group of researchers were planning to investigate bystander behaviour in a local shopping centre.
They decided to take turns throughout the week to drop their shopping in full view of other
shoppers.
- A psychological study was set up to investigate the influence of music on memory. The researchers
invited one group of maths students to listen to Mozart while learning a list of simple words. A
different group of psychology students listened to rock music while learning a different list of simple
words. The recall of the participants was tested after they had listened to the musical piece.
Stretch and Challenge:
How could you go about improving these studies?

6. 5) What is the easiest/best way to control participant variables?
6) Explain what is meant by random allocation. Try to give an example in your answer.
Task 8:
Apply it:
How would you go about controlling extraneous variables in the following investigations?
- A group of researchers were planning to investigate bystander behaviour in a local shopping centre.
They decided to take turns throughout the week to drop their shopping in full view of other
shoppers.
- A psychological study was set up to investigate the influence of music on memory. The researchers
invited one group of maths students to listen to Mozart while learning a list of simple words. A
different group of psychology students listened to rock music while learning a different list of simple
words. The recall of the participants was tested after they had listened to the musical piece.
Stretch and Challenge:
How could you go about improving these studies?