PAPER 2 PSYCH

Experiment

An investigation seeking a causal relationship by manipulating an independent variable to observe changes in the dependent variable.

Independent variable

The manipulated factor in an experiment expected to cause changes in the dependent variable.

Dependent variable

The measured factor in an experiment expected to change due to the independent variable.

Extraneous variable

A variable that can obscure the effect of the independent variable by affecting the dependent variable.

Experimental condition

Situations in an experiment representing different levels of the independent variable compared to a control condition.

Control condition

A level of the independent variable where it is absent, compared to experimental conditions.

Laboratory experiment

Research method with an independent variable, dependent variable, and strict controls for causal relationships.

Experimental design

The way participants are associated with levels of the independent variable.

Repeated measures design

Each participant performs in every level of the independent variable.

Matched pair design

Participants are paired based on important characteristics, with one member in each level of the independent variable.

Demand characteristics

Features of an experiment that may influence participants to change their behavior.

Random allocation

Participants are assigned to different levels of the independent variable randomly to reduce confounding variables.

Order effects

Changes in performance due to participating in a study more than once.

Practice effect

Improvement in performance due to repeated exposure to the task.

Fatigue effect

Decline in performance due to repeated exposure to the task.

Participant variables

Individual differences that could affect behavior in a study.

Counterbalancing

Overcoming order effects by varying the order of levels of the independent variable.

Standardization

Keeping the procedure consistent for each participant in an experiment.

Reliability

Consistency of a procedure, task, or measure.

Validity

The extent to which a study tests what it claims to test.