Designs

Question 1

What is an independent groups design?

Answer 1

Using different participants for each condition of the experiment. Participants only take part in one condition.

Question 2

What is repeated measures design?

Answer 2

Using the same participants for each condition of the experiment. Participants take part in both conditions.

Question 3

What is matched pairs design?

Answer 3

Using different but matched participants for each condition of the experiment. Participants take part in one condition, matched on similar characteristics that may affect the DV.

Question 4

What are demand characteristics?

Answer 4

Participants being aware of what the aim or expected results are, and what this implies for how participants are expected to behave. This may make them change their behaviour, which affects the validity of the results.

Question 5

What are investigator effects?

Answer 5

Any behaviour of the researcher including interaction with participants eg. selection of participants, leading questions and bias in interpretation of results that could affect the results.

Question 6

How can investigator effects be reduced?

Answer 6

Randomisation

Participants to groups, tasks A or B and order of questions.

Question 7

How can order effects be reduced?

Answer 7

Counterbalancing - for repeated measures design only.

Half of each group take part in condition 1 first and the other half do condition 2 first.

Question 8

What are the strengths of independent measures design?

Answer 8

• No order effects

- Less chance of demand characteristics

Question 9

What are the weaknesses of independent measures design?

Answer 9

Participant variables - differ between participants

Number of participants - need more

Question 10

What are the strengths of repeated measures design?

Answer 10

Participant variables - fully controlled

Number of participants - fewer needed

Question 11

What are the weaknesses of repeated measures design?

Answer 11

Possible order effects (boredom, practice)

More chance of demand characteristics

Question 12

What are the strengths of matched pairs design?

Answer 12

No order effects
Less chance of demand characteristics
Participant variables - some are controlled

Question 13

What are the weaknesses of matched pairs design?

Answer 13

Participant variables - some won’t be controlled

Number of participants - may be difficult to match them