Chapter 3 Experiments and Experimental Designs Flashcards
Asymmetrical Order Effect
Order effect that has greater strength in one particular order of conditions and where, therefore, counterbalancing would be ineffective
Baseline Measure
Measure of what would occur if not experimental level of the independent variable were applied; how ‘untreated’ participants perform
Confounding Variable
Variable that is uncontrolled and obscures the effect sought, varying with the independent variable in a systematic manner
Control Group
Group used as a baseline measure against which the performance of the experimental group is assessed
Counterbalancing
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
Dependent Variable (DV)
Variable that is assumed to be directly affected by changes in the independent variable in an experiment
Experiment
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
Factorial Design
Experiment in which more than one independent variable is manipulated
Independent Samples Design (independent groups/measures; between groups/subjects)
Each condition of the independent variables is experience by only one group of participants
Matched Pairs Design
Each participant in one group/condition is paired on specific variable(s) with a participant in another group/condition
Related Design
Design in which individual scores in one condition can be paired with individual scores in other conditions (repeated measures and matched pairs)
Repeated Measures Design(within subjects/groups)
Each participant experiences all levels of the independent variable
Single Participant Design
Design in which only one participant is tested in several trials at all independent variable levels
Small N Design
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
Unrelated Design
Design in which individual scores in one condition cannot be paired (or linked) in any way with individual scores in any other condition
Extraneous Variable
Anything other than the independent variable that could affect the dependent variable; it may or may not have been allowed for and/or controlled
Independent Variable (IV)
Variable which experimenter manipulates in an experiment and which is assumed to have a direct effect on the dependent variable
Levels (of the IV)
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
Non-Equivalent Groups
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
Order Effect
A confounding effect caused by experiencing one condition, then another, such as practice or fatigue
Placebo Group
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
Pre-Test
Measure of participants before an experiment in order to balance or compare groups, or to assess change by comparison with scores after the experiment
Randomisation
Putting stimulus items or trial types into random order for the purpose of elimination of order effects
Standardised (procedure)
Testing or measuring behaviour with exactly the same formalised routine for all participants
Vignette
A story, scenario, or other description given to all participants but with certain details altered and this difference constitutes the random variable
