Experimental Design Flashcards
What are the 3 types of experimental design?
- Independent groups
- Matched participants
- Repeated measures
Describe the independent groups design.
- There are 2/ more separate groups participants can be allocated to.
- One group does condition (A), the other does condition (B).
- Participants are randomly allocated.
- Participants take part in one condition of the IV only.
Describe the matched pairs design.
- Pairs of participants are created by matching them closely on specific criteria (eg gender, age, personality, genetics…).
- One person participates in condition (A), the other participates in condition (B).
- Criteria the participants are matched on should be relevant to the study.
Describe the repeated measures design.
- All participants will complete both conditions of the IV.
- The participant, in effect, will act as their own control.
What is meant by ‘participant variables’?
The ways in which each participant varies from the other and how this could affect the results.
How do we overcome the problem of participant variables?
- Random allocation to conditions.
- Use repeated measures/ matched participants.
What is meant by ‘order effects’?
- Participants performance in the condition may be affected by the fact that they have already completed the first condition.
- They are more practiced the second time, so perform better.
- They are tired of doing it the second time, so are worse at it.
How do we overcome order effects?
By using counterbalancing.
Define counterbalancing.
- Alternating the order in which participants experience the different conditions in a repeated measures design.
- If there are order effects, they cancel each other out with the use of counterbalancing.
What are some advantages of the repeated measures design?
Results may be more reliable.
Eliminates participant variables.
Fewer participants are required.
What are some disadvantages of the repeated measures design?
May not be able to complete the second condition immediately.
Order effects.
Increase chance of demand characteristics occurring.
Cannot use the same stimulus material in both conditions.
What are some advantages of the independent groups design?
No order effects.
It is possible to use the same stimulus materials for both/ all conditions.
What are some disadvantages of the independent groups design?
Least effective design for controlling participant variables.
Some participant variables are still present because diff participants are performing under diff conditions.
What are some advantages of the matched pairs design?
There are no order effects.
Reduced chance of demand characteristics.
What are some disadvantages of the matched pairs design?
Difficult to match participants exactly.
More participants required for this design.
