Experimental Design

Question 1

What is the experimental design?

Answer 1

The different ways in which participants can be organised in relation to the experimental conditions

Question 2

Independent groups design

Answer 2

Participants are allocated to different groups where each group represents one experimental condition only

Question 3

Repeated measures design

Answer 3

All participants take part in all conditions of the experiment

Question 4

Matched pairs design

Answer 4

Pairs of participants are first matched on a variable that may affect the DV. Then one member of the pair is assigned to condition A and the other to condition B

Question 5

Random allocation

Answer 5

An attempt to control for participant variables in an independent groups design, ensuring each participant has the same chance of being in one condition as another

Question 6

Counterbalancing

Answer 6

An attempt to control for order effects in a repeated measures design, ensuring half the participants experience the conditions in one order and the other half in the opposite order

Question 7

Evaluation of independent groups design

Answer 7

• Order effects are not an issue
• Random allocation can be used to reduce the effects of participant variables
• Still participant variables
• Less economical (twice as many needed as each p contributes a single result only)

Question 8

Evaluation of repeated measures design

Answer 8

• Participant variables are controlled (higher validity)
• More ecological (fewer participants needed)
• Counterbalancing can be used to reduce order effects
• Order effects (due to getting used to it, fatigue or boredom)
• Demand characteristics

Question 9

Evaluation of matched pairs design

Answer 9

• Order effects and demand characteristics reduced
• Less economical (matching time may be time consuming and expensive)
• Participants can never be matched exactly