experiment designs Flashcards
What are experimental designs?
Ways in which participants are used in experiments.
Name the three types of experimental designs.
- Independent groups
- Repeated measures
- Matched pairs
Describe independent groups design.
Two separate groups of participants experience two different conditions of the experiment.
What is a strength of independent groups design?
There are no order effects.
What is the repeated measures design?
All participants take part in all conditions of the experiment.
What is a strength of repeated measures design?
Less participants are needed as they complete the same measures. Participant variables are also controlled, meaning higher validity and no participant has one advantage over the other as they are the same person.
What is the matched pairs design?
Participants are paired based on a matched variable affecting the DV and separated into different conditions. One member of the pair is assigned to Condition A and the other to Condition B.
What is a strength of matched pairs design?
Participants only take part in one condition, meaning tha order effects and demand characteristics are less likely to impact the outcome of the study.
What is random allocation?
Each participant has the same chance of being in one condition as the other. It is an attempt to control participant variables when using independent groups.
What is counterbalancing?
Half of the participants experience conditions in one order and the other half in the opposite order. It is an attempt to control order effects when using repeated measures. For every four trials, one participant may do A B B A.
What is the purpose of counterbalancing?
To control order effects in a repeated measures design.
What is a disadvantage of matched pairs design?
Participants can never be matched exactly.
What is a weakness of random allocation?
Differences may be due to participant variables.
What can demand characteristics lead to in repeated measures design?
Participants can guess the aim of the experiment.
What is the ABBA technique?
Another term for counterbalancing.
What might increase boredom in matched pairs design?
Completely similar tasks.
What is a limitation of independant groups?
Differences between the experiment may be down to participant variables and not the IV.
What is a limitation of the repeated measures design?
Demand characteristics are more likely to occur as participants are taking part in both conditions and may guess the aim. Order effects are also more likely to happen as similar tasks may increase boredom and change the performance on the second condition - order DOES matter. Alternatively, skills may improve on the second condition.
What is a limitation of matched pairs design?
Participants can never be matched exactly, even when identical twins are used as there are still differences impacting the DV. Matching may also be time consuming and expensive, especially if a pre-test is needed, so it is less economical than other designs.
What is the purpose of random allocation?
To control order effects when using an independent groups design.
