Experimental Methods

Question 1

what is an experiment?

Answer 1

manipulation of one or more variables

determine the effect of the manipulation

test cause effect between variables

Question 2

what are the two types of hypotheses

Answer 2

1. alternative / experimental
2. null

Question 3

what is alternative hypothesis?

Answer 3

treatment leads to effect

Question 4

what is a null hypothesis

Answer 4

treatment does not lead to effect

Question 5

what is the relationship between a dependant variable and independent variable?

Answer 5

manipulating the independent variable changes the value of the dependant variable

Question 6

what is a nuisance variable?

Answer 6

additional factor that affects the dependant variable

Question 7

how do you deal with a nuisance variable?

Answer 7

turn it into a control variable
randomly assign ppt to groups
counterbalancing
include a control group

Question 8

what is an experimental group?

Answer 8

group receiving the important level of the independent variable

Question 9

what is a control group?

Answer 9

untreated comparison group

Question 10

what to do if you have more than one independent variable?

Answer 10

change a nuisance variable into an IV
and include in one experiment

Question 11

advantages of experiments

Answer 11

relative strong test of causality
possibility of a variant of manipulative controls

Question 12

disadvantages of experiments

Answer 12

unnatural settings & tasks
reactivity
some phenomena cannot be studied under controlled conditions
ethical limitations

Question 13

what does within subjects design mean

Answer 13

repeated measures - all ppt recieve all levels of independent variable

Question 14

what does between subjects design mean?

Answer 14

independent groups - different groups receive different levels of the IV

Question 15

what to do if nuisance variable varies across all levels of the independant variable?

Answer 15

hold the variable constant for all ppt

Question 16

what to do if the nuisance variable varies across the ppt?

Answer 16

randomly assign ppt to conditions

Question 17

give 2 other ways to deal with nuisance variables?

Answer 17

1. counterbalancing
2. include a control group

Question 18

why is testing more than one IV in one experiment better than several experiments (3)

Answer 18

1. more efficient
2. better control of nuisance variables
3. results often more representative of behaviour

Question 19

whats the difference between nuisance and confounding variables?

Answer 19

nusiance variables BECOME confounding variables when their effects differ between the conditions

Question 20

3 advantages of between subject design

Answer 20

1. no order effects
2. some experiments can only be between
3. naive participants

Question 21

2 disadvantages of between subject design?

Answer 21

1. lots of ppt needed
2. individual differences

Question 22

how to counteract disadvanatges (2)

on between subject

Answer 22

1. random assignment
2. match ppt on characteristics

Question 23

2 advantages of within subject design?

Answer 23

1. fewer ppt needed
2. reduced individual differences

Question 24

disadvantages of within subject design

Answer 24

1. carryover effects - effect over one carries on to next session

Question 25

how to counteract within subject design disadvantages?

Answer 25

counterbalancing random order latin square design

Question 26

what is a quasi experiment?

Answer 26

one or more independant variable selected but not manipulated

Question 27

advantage of quasi experiments?

Answer 27

can examine variables that would be unethical to manipulate

Question 28

disadvantage of quasi experiments

Answer 28

no strong conclusion about cause and effect

Question 29

how to improve quasi experiments? (2)

Answer 29

1. match ppt 2. if treatment study - test before and after

Question 30

what are the 3 sampling types?

Answer 30

1. random 2. stratified 3. quota

Question 31

what is random sampling?

Answer 31

everybody has a equal chance of being selected

Question 32

what is stratified sampling?

Answer 32

random selection of each subgroup of the population

Question 33

what is quota sampling?

Answer 33

representative sample that meets targets

Question 34

what are psycho physiological measurements?

Answer 34

testing the effect of psychological variables on physiological processes

Question 35

whats one example of psycho physiological measurements?

Answer 35

brain imaging

Question 36

what does brain imaging do?

Answer 36

look at localisation and timing of brain functions

Question 37

what are three ways to measure the brain?

Answer 37

1. EEG 2. ERP 3. FMRI

Question 38

what is a EEG (electroencephalography)

Answer 38

electrodes placed on scalp detect and measure patterns of electrical activity

Question 39

advantages of EEG (2)

Answer 39

1. excellent temporal resolution 2. relatively inexpensive

Question 40

disadvantages of EEG (3)

Answer 40

1. poor spatial resolution 2. artifacts from eye movements ect 3. surface activity only

Question 41

what is a fmri (functional magnetic resonance imaging)

Answer 41

2D and 3D view of the brain measures the amount of blood oxygen

Question 42

advantages of fmri (2)

Answer 42

1. excellent spatial resolution 2. accesses all areas of the brain

Question 43

disadvantages of fmri (4)

Answer 43

1. poor temporal resolution 2. expensive 3. claustrophobia inside scanner 4. ppt must not move