Chapter 3 Experiments and Experimental Designs

Question 1

Asymmetrical Order Effect

Answer 1

Order effect that has greater strength in one particular order of conditions and where, therefore, counterbalancing would be ineffective

Question 2

Baseline Measure

Answer 2

Measure of what would occur if not experimental level of the independent variable were applied; how ‘untreated’ participants perform

Question 3

Confounding Variable

Answer 3

Variable that is uncontrolled and obscures the effect sought, varying with the independent variable in a systematic manner

Question 4

Control Group

Answer 4

Group used as a baseline measure against which the performance of the experimental group is assessed

Question 5

Counterbalancing

Answer 5

Half of the participants do conditions in a particular order and the other half take the conditions in the opposite order - this is done to balance possible order effects

Question 6

Dependent Variable (DV)

Answer 6

Variable that is assumed to be directly affected by changes in the independent variable in an experiment

Question 7

Experiment

Answer 7

Design in which an independent variable is manipulated, all other variables controlled and a dependent variable is measure for changes caused by the independent variable

Question 8

Factorial Design

Answer 8

Experiment in which more than one independent variable is manipulated

Question 9

Independent Samples Design (independent groups/measures; between groups/subjects)

Answer 9

Each condition of the independent variables is experience by only one group of participants

Question 10

Matched Pairs Design

Answer 10

Each participant in one group/condition is paired on specific variable(s) with a participant in another group/condition

Question 11

Related Design

Answer 11

Design in which individual scores in one condition can be paired with individual scores in other conditions (repeated measures and matched pairs)

Question 12

Repeated Measures Design(within subjects/groups)

Answer 12

Each participant experiences all levels of the independent variable

Question 13

Single Participant Design

Answer 13

Design in which only one participant is tested in several trials at all independent variable levels

Question 14

Small N Design

Answer 14

Design in which there is only a small number of participants, typically in clinical or counselling work but also where participants need substantial training for a highly skilled task

Question 15

Unrelated Design

Answer 15

Design in which individual scores in one condition cannot be paired (or linked) in any way with individual scores in any other condition

Question 16

Extraneous Variable

Answer 16

Anything other than the independent variable that could affect the dependent variable; it may or may not have been allowed for and/or controlled

Question 17

Independent Variable (IV)

Answer 17

Variable which experimenter manipulates in an experiment and which is assumed to have a direct effect on the dependent variable

Question 18

Levels (of the IV)

Answer 18

The different values taken by the independent variable; often, the conditions of an experiment, e.g., levels of caffeine at 50mg, 100mg and 200mg in the investigation of memory recall

Question 19

Non-Equivalent Groups

Answer 19

A possible confounding variable where two or more groups in an independent samples design experiment differ on a skill or characteristic relevant to the dependent variable

Question 20

Order Effect

Answer 20

A confounding effect caused by experiencing one condition, then another, such as practice or fatigue

Question 21

Placebo Group

Answer 21

Group of participants who don’t receive the critical ‘treatment’ but everything else the experimental group receives; used in order to eliminate placebo effects - participants may perform differently simply because they think they have received an effective treatment

Question 22

Pre-Test

Answer 22

Measure of participants before an experiment in order to balance or compare groups, or to assess change by comparison with scores after the experiment

Question 23

Randomisation

Answer 23

Putting stimulus items or trial types into random order for the purpose of elimination of order effects

Question 24

Standardised (procedure)

Answer 24

Testing or measuring behaviour with exactly the same formalised routine for all participants

Question 25

Vignette

Answer 25

A story, scenario, or other description given to all participants but with certain details altered and this difference constitutes the random variable