Research methods- Experimental designs Flashcards
What is an experimental design?
The process by which the researcher decides whether to use different participants in each condition or the same participants in each condition.
What are the three types of experimental design?
-Repeated measures
-Independent groups
-Matched pairs
What is the definition of a repeated measures design?
-Uses the same participants in each condition.
-Every participant experiences both condition.
-e.g. Giving the participants a memory test with a loud noise (A) then at a later date giving the participants the same test without the noise (B).
What is the definition of an independent groups design?
-Uses different participants in each condition.
-Participants only experience one condition.
-Can be randomly allocated.
-e.g. Giving one group of participants a memory test whilst playing loud noise (A) and another group of participants the same memory test without the noise (B).
What is the definition of a matched pairs design?
-Used different but similar participants in each condition.
-Effort is used to match the participants in each condition based on variables, e.g. age,sex,ability.
-e.g. Would involve matching the participants in condition A with the participants in condition B based on age.
What is a strength and limitation for repeated measures?
S- no participant variables. The person in both conditions has the same characteristics. This controls an important CV.
L- Order effects are a problem. Participants may do better or worse when doing a similar task twice, also practice/ fatigue effects. Reduces the validity of the results.
What is a strength and limitation for independent groups?
S- No order effects. Participants are only tested once so can’t participate or become bored/tired. This controls an important CV.
L- Lots of participants variables. The participants in the two groups are different, acting as EV/CV. May reduce the validity of the study.
What is a strength and limitation of matched pairs?
S- No order effects. Participants are only tested once so no practice or fatigue effects. This enhances the validity of the results.
L- Matching is difficult. Matching is time consuming and can’t control all relevant variables. Cannot address all participant variables.
What is the definition of order effects?
The results is effected by the fact that participants are doing the study more than once (take part in both/ all conditions). The results are either effected due to practice, boredom or timeless.
What is the definition of counter balancing?
An attempt to control the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order (ABBA technique).
Fewer participants are needed?
Repeated measures
Time consuming?
Matched pairs
More participants are needed?
Independent groups/ Matched pairs
Reduced effect of participant variables ?
Repeated measures
Decreased risk of demand characteristics?
Independent groups/ Matched pairs
