Research methods - Experimental design Flashcards
What is experimental design?
How researchers allocate the participants to the experimental condition and the control condition. This technique is used to control participants variables.
What are the three types of experimental design?
Repeated measures (one group of
participants who experience both conditions)
Independent group design (2 different groups of participants)
Matched pairs design (2 different groups of participants but matched on key variables)
What is a repeated measures design?
When the same group of participants takes part in both conditions.
What are the pros of repeated measures design?
+ As the same participants are used in each condition, the effects of individual differences are controlled, so any changes in the DV are due to the IV and not participant variables.
+ Fewer participants are needed to conduct the experiment
What are the cons of a repeated measures design?
- The second condition can be affected by order effects such as practice effect, fatigue, or boredom.
What are the pros of an independent group design?
+ Only do one condition so are less likely to experience order effects such as boredom, fatigue and practice effects.
+ The same materials are used for both conditions, so for example harder or easier word lists would not become a confounding variable in this design.
What are the cons of an independent group design?
- Individual differences between the two groups will be a problem in this design.
For example, if one group was more alert than the other this would systematically distort results on a quick response test.
What does a matched pairs design involve?
This is the same as the independent group design, except that the participants have been matched in terms of key characteristics i.e IQ, height, gender, ge, ethnic origin etc.
What are the pros of a matched pairs design?
+ As the participants only take part in one condition they are less likely to experience order effects such as boredom, fatigue, and practice effect.
+ The same materials are used for both conditions, so for example, harder or easier word lists would not become a confounding variable in this design.
+ Individual differences are minimised as participants are matched on important variables.
What is the con of a matched pairs design?
- It is a difficult and time consuming process to find participants who match on a number of key variables. A large pool of participants is needed making it less practical than the other designs.
What is an independent group design?
Where participants take part in only one of the two conditions.
