2.3.3 Experimental designs

Question 1

what is the experimental group?

Answer 1

the group getting the experimental treatment - IV manipulated

Question 2

what is the control group?

Answer 2

the group receiving non experimental treatment e.g. placebo group

Question 3

what do the placebo group provide?

Answer 3

baseline for comparison

Question 4

what does the term experimental design refer to?

Answer 4

how psychologists allocate their participants to groups

Question 5

when do you have an experimental design?

Answer 5

when carrying out experiments - lab, field, quasi

Question 6

what is an independent measures design?

Answer 6

participant takes part in one condition of the experiment (either experimental or control)

Question 7

in an independent measures design how are participants allocated to groups?

Answer 7

randomly allocated

Question 8

what are the 2 strengths of independent measures designs?

Answer 8

reduces risk of demand characteristics

reduces order effects

Question 9

(strength) independent measures reduces risks of demand characteristics. What are demand characteristics?

Answer 9

where participants try to figure out the aim of the study and change their behaviour accordingly (Hawthorne effect, Screw you effect)

Question 10

how does an independent measures design reduce the risk of demand characteristics?

Answer 10

less opportunity for participants to work out the aim of the study - they only do it once, this increases validity

Question 11

(strength) independent measure reduces order effects. What are order effects, what are the 2 types?

Answer 11

effects from previously having completed the research
practice effects - participant does better as they’ve already done it
fatigue effects - participant do worse due to being bored or tired

Question 12

how does an independent measures design reduce the chance of order effects?

Answer 12

person only does the research once

Question 13

what are two weaknesses of independent measures designs?

Answer 13

individual differences - accidental bias

expensive and time consuming

Question 14

(weakness of independent measures) what does it mean that results may be affected by individual differences? what could it influence?

Answer 14

groups may not be identical

differences could influence validity of results

Question 15

(weakness) why can independent measures designs be expensive and time consuming?

Answer 15

need to find more participants

e.g. want to test 100 people, you need 200 as 100 will be needed for the control group

Question 16

what does a repeated measures design involve?

Answer 16

participants participate in both conditions

Question 17

what are strengths of repeated measures designs?

Answer 17

quick and cheap

not affected by individual differences

Question 18

(strength) why are repeated measures quick and cheap?

Answer 18

you don’t have to find more participants - the same ones participate in both conditions

Question 19

(strength) why are repeated measures not affected by individual differences?

Answer 19

the same people participant in each condition - no differences between groups, no effect on validity

Question 20

what are two weaknesses of repeated measures designs?

Answer 20

demand characteristics

order effects

Question 21

(weakness) why do repeated measures have the risk of demand characteristics?

Answer 21

participants participate twice - can try to figure out the aim of the study and change their behaviour accordingly

Question 22

(weakness) why do repeated measures have the risk of order effects?

Answer 22

participants are repeating the same task (practice/fatigue)

Question 23

what technique can be used to overcome order effects?

Answer 23

counterbalancing

Question 24

what does counterbalancing involve?

Answer 24

half the participants do the experimental condition followed by the control
half the participants do the control condition followed by the experimental

Question 25

what does a matched pairs design involve?

Answer 25

participants only participate in one condition but are matched according to characteristics and one is placed in the experimental condition and the other the control

Question 26

who are the best matched pairs carried out on and why?

Answer 26

identical twins | because they grow up in similar environments with similar characteristics

Question 27

what are two strengths of matched pairs designs?

Answer 27

reduce order effects | not affected by individual differences

Question 28

(strength) how do matched pairs reduce order effects?

Answer 28

each participant participates in each condition once so they wont show fatigue or practice effects

Question 29

(strength) why are matched pairs not affected by individual differences?

Answer 29

participants are matched according to characteristics - groups are as identical as possible

Question 30

what is a weakness of matched pairs?

Answer 30

expensive and time consuming

Question 31

why are matched pairs expensive or time consuming?

Answer 31

you have to match participants or take the time looking for identical twins willing to participate