Experimental Designs (RM P2)

Question 1

Independent Groups (unrelated design)

Answer 1

• Recruit group of participants
  Divide into 2
• Each group has a different condition (e.g. sober condition and drunk condition)
• Measure DV for each group
• Compare results

Question 2

adv independent groups

Answer 2

• Order effects not a problem
• Pps less likely to guess the aims

Question 3

disadv independent groups

Answer 3

Pps who occupy different groups aren’t the same in terms of participant variables (confounding variable)

Question 4

Repeated Measures (related design)

Answer 4

• Recruit groups of pps
• Group does both conditions
• Compare results for the two conditions
• Same pps
• Half group do condition A then B, other half do B then A (counterbalancing) which reduces order effect

Question 5

adv repeated measures

Answer 5

• Pp variables are controlled (higher validity)
• Therefore fewer pps needed

Question 6

disadv repeated measures

Answer 6

Each pp has to do at least tasks and the order of these 2 tasks may be significant (order effect)

Question 7

Matched Pairs

Answer 7

• Recruit group of pps
• Find out what sorts of people they are
• Recruit another group that matches relevant characteristics e.g. intelligence
• Treat experiments as independent measures
• Group A: condition 1
  Group B: condition 2
• Compare results

Question 8

adv matched pairs

Answer 8

• Order effects and demand characteristics less of a problem
• Some attempt to reduce pp variables

Question 9

disadv matched pairs

Answer 9

• Pps can never be matched exactly (not even twins)
• May be time consuming so less economic than other designs

Question 10

What is Counterbalancing?

Answer 10

• Used to reduce order effects in a repeated measures design (e.g. boredom, fatigue or practice affecting results of the condition undertaken second)
• One group does condition A then B, other group does condition B then A (ABBA)
• Results can be collected and compared, balances out the effects of order