Experimental research

Question 1

what is an experiment?

Answer 1

when one or more variables are manipulated to test a cause-effect relationship

Question 2

what is an experimental/alternative hypothesis?

Answer 2

treatment leads to an effect

Question 3

what is a null hypothesis?

Answer 3

treatment does not lead to an effect

Question 4

what is a nuisance variable?

Answer 4

an additional factor that affects the dependent variable

Question 5

how can nuisance variables be dealt with?

Answer 5

they can be turned into control variables

Question 6

how can nuisance variables become confounding variables?

Answer 6

if they change across conditions

Question 7

if the nuisance variable varies across all levels of the independent variable…

Answer 7

hold the variable constant for all participants

Question 8

if nuisance variable varies across participants…

Answer 8

randomly assign participants to treatment across

Question 9

counterbalancing

Answer 9

vice versa for the other half of participants

Question 10

what is an experiment group?

Answer 10

they receive the important level of the independent variable

Question 11

what is a control?

Answer 11

they serve as the untreated comparison group

Question 12

if you have more than one IV, what should you do?

Answer 12

include them in the same experiment

Question 13

why is it better to test IVs in the same experiment?

Answer 13

• more efficient
• better control of nuisance variables
• results will be more representative of real behaviour

Question 14

benefits of measuring more than one DV

Answer 14

it is usually more informative

Question 15

limitations of measuring more than one DV

Answer 15

these variables might not measure the same thing, e.g., the speed-accuracy trade off

Question 16

advantages of experimental research

Answer 16

• relative strong test of causality
• can manipulate a variety of controls, making it easier to eliminate nuisance variables

Question 17

disadvantages of experimental research

Answer 17

• unnatural settings and tasks reduce ecological validity
• some phenomena cannot be studied under controlled conditions, e.g., social interaction
• ethical limitations

Question 18

within-subjects design

Answer 18

repeated measures design

where all participants receive all levels of the IV

Question 19

advantages of within-subjects design

Answer 19

• fewer participants needed
• reduced individual differences

Question 20

disadvantages of within-subjects design

Answer 20

• carryover effects
• effect of one carries over between conditions

Question 21

how can disadvantages of within-subject design be dealt with

Answer 21

• randomly allocating participants to groups
• using matched participants design

Question 22

between-subjects design

Answer 22

independent measures design

where different groups of participants receive different levels of the IV

Question 23

advantages of between-subjects design

Answer 23

• no order effects
• some experiments can only be between-subjects, e.g, health or clinical interventions, or learning a skill
• naive participants

Question 24

disadvantages of between-subjects design

Answer 24

• lots of participants
• more expensive
• individual differences

Question 25

how can disadvantages of between-subject design be dealt with

Answer 25

randomising or counterbalancing the order of conditions

Question 26

what is counterbalancing?

Answer 26

a way to negate carryover effects

Question 27

problem with counterbalancing

Answer 27

it is too complicated to carry out when there are a high number of conditions

Question 28

what is the latin square design?

Answer 28

where each condition occurs equally at each stage of the experiment, e.g., ABCD each appear in all orders

Question 29

problem with latin square design

Answer 29

carryover effects are still possible

Question 30

what are quasi-experiments?

Answer 30

one (or more) IVs are selected, but not manipulated

Question 31

advantages of quasi-experiments

Answer 31

ability to examine variables that would be unethical to manipulate

Question 32

disadvantages of quasi-experiments

Answer 32

• participants are not randomly assigned to IV levels, which can lead to confounding variables
• impossible to make strong conclusions about cause-and-effect

Question 33

random sample

Answer 33

everyone has an equal chance of being chosen

Question 34

limitations of random sample

Answer 34

practically difficult to carry out, and often likely to be opportunity sampling

Question 35

stratified sample

Answer 35

random selection of each subgroup of the population

Question 36

quota sample

Answer 36

representative sample that meets quotas and targets

Question 37

what is EEG?

Answer 37

measures brain activity by placing electrodes on the scalp

Question 38

advantages of EEG

Answer 38

• excellent temporal resolution
• relatively inexpensive

Question 39

disadvantages of EEG

Answer 39

• poor spatial resolution
• artifacts (something else can cause an effect)
• only surface activity information

Question 40

what is fMRI?

Answer 40

gives 2d and 3d views of the brain and measures activity through blood oxygen

Question 41

advantages of fMRI

Answer 41

• excellent spatial resolution
• access to all areas of the brain

Question 42

disadvantages of fMRI

Answer 42

• poor temporal resolution
• movement is restricted
• expensive
• claustraphobic