6: Methodological Control in Experimental Research

Question 1

Why are between-subjects designs used

Answer 1

If the independent variable is a subject variable

used for studies where participating in one level makes it impossible to partake in another level (deception)

Question 2

Prime advantages and disadvantages of between-subjects designs

Answer 2

Advantage: each subject enters the study fresh with a naïve perspective

Disadvantage: requires a lot of people
differences in conditions might be due to the independent variables but also might be due to differences between the individuals in different groups

Question 3

Between subjects designs need

Answer 3

equivalent groups

Question 4

How can equivalent groups be made

Answer 4

random assignment (including blocked random assignment) and matching

Question 5

Describe matching

Answer 5

participants are grouped together on some subject variable such as their characteristic level of anxiety and then distributed randomly to the different groups in the experiment

Question 6

What three conditions must be met for matching to take place

Answer 6

Must have good reason to believe the matching variable will have a predictable effect on the outcome of the study
Must believe it to be correlated with the dependent variable - figure this out from previous research

Must be a reasonable way of measuring or identifying participants on the matching variable

small number of subjects are available

Question 7

Describe a within subjects design

Answer 7

Also called repeated-measures designs

Each participant is exposed to every level of the independent variable

Question 8

Advantages of within subjects designs

Answer 8

Fewer participants are needed

Eliminates possibility that differences between levels of the IV could be due to individual differences

Question 9

Issues with within subject designs

Answer 9

Ordered/sequence effects
- progressive effects
-carry-over effects

Question 10

Describe progressive effects

Answer 10

performance changes steadily from trial to trial

Question 11

Describe carry-over effects

Answer 11

Some sequences might produce effects different from those of other sequences

Question 12

what is the typical way to control for order effects

Answer 12

to use more than one sequence: A strategy known as counterbalancing

Question 13

Describe complete counterbalancing
(Used for testing once per condition)

Answer 13

Every possible sequence is used at least once
X!
X: number of conditions !: factorial

Question 14

Describe partial counterbalancing
(Used for testing once per condition)

Answer 14

A subset of the total number of orders used

Take a random sample of orders from the complete set of possible orders, or by randomizing the order of conditions for each subject
Can use the Latin Square strategy
Important for the number of subjects to be equal to or a multiple of the number of rows in a square

Question 15

Why might we test more than once per condition in a within subjects design

Answer 15

to get more reliable measures

Question 16

Describe block randomization for testing more than once per condition

Answer 16

The basic rule is that every condition must occur once before any condition can be repeated

Within each block, the order of conditions is randomized
Eliminates being able to guess what is coming next (unlike in reverse counterbalancing)

Question 17

Describe reverse counterbalancing
(testing more than once per condition)

Answer 17

Experimenter presents the conditions in one order and then presents them again in the reverse order

Question 18

how to control for experimenter bias

Answer 18

double blind procedure

training and protocols to follow as to not lead participants to act a certain way

Question 19

What is the Hawthorne Effect

Answer 19

when behaviour is affected by the knowledge that one is in an experiment and important to the studies success
want to be the ‘good subject’

evaluation apprehension - want to be evaluated positively and behave a certain way

Question 20

what is the concern with demand characerisitcs

Answer 20

that they will create participant bias as they may reveal aspects of the study that reveal what the hypothesis is

Question 21

how to control for participant bias

Answer 21

manipulation check

deception or placebo control group

field research