advanced design technique

A research design that manipulates more than one independent variable to examine their separate and combined effects on a dependent variable.

Factorial Design

An independent variable in a factorial experiment that has different levels or conditions.

Factor

The different conditions or values of an independent variable that are compared in an experiment.

Levels

The variable that is manipulated by the researcher to determine its effect on behavior or performance.

Independent Variable (IV)

The variable that is measured to determine the effect of the independent variable.

Dependent Variable (DV)

A research design in which only one independent variable is manipulated while other factors are held constant or controlled.

Single-Factor Design

A research design that examines the effects of two or more independent variables on a dependent variable.

Multifactor Design

A shorthand way of showing the number of factors in an experiment and the number of levels each factor contains.

Factorial Notation

The number of numbers in factorial notation indicates this.

Number of Factors

The product of the numbers in factorial notation tells the researcher this.

Total Number of Treatment Combinations

A factorial design with two factors, each having two levels, resulting in four treatment combinations.

2 × 2 Design

A factorial design with two factors, one having two levels and the other having three levels, resulting in six treatment combinations.

2 × 3 Design

A factorial design with three factors, each having two levels, resulting in eight treatment combinations.

2 × 2 × 2 Design

The total number of treatment combinations in a 2 × 3 factorial design.

Six Conditions

The total number of treatment combinations in a 2 × 2 × 3 factorial design.

Twelve Conditions

A result that shows the effect of one independent variable on the dependent variable when the effects of the other independent variables are considered across their levels.

Main Effect

A result that occurs when the effect of one independent variable on the dependent variable changes depending on the level of another independent variable.

Interaction Effect

An effect that describes how the influence of one factor differs across the levels of another factor.

Interaction

The effect of one independent variable at a particular level of another independent variable.

Simple Effect

A pattern in which the effect of one factor is different depending on the condition of another factor.

Factor Interaction

A graph used to display the relationship between factors and their effects; nonparallel lines can suggest that an interaction is present.

Interaction Plot

A factorial experiment in which the researcher examines the separate effects of each factor and whether the factors work together.

Factorial Experiment

A factorial design involving more than two independent variables or factors.

Complex Factorial Design

The process of determining whether an observed result is unlikely to have occurred by chance under a specified statistical model.

Statistical Significance

A numerical value used to assess how compatible the observed data are with a null hypothesis.

p-value

The hypothesis that states there is no effect or relationship of the kind being tested.

Null Hypothesis

A finding that does not meet the chosen statistical criterion for significance.

Nonsignificant Result

A research finding that meets the chosen statistical criterion for significance.

Significant Result

A statistical result that indicates whether the evidence meets a predefined threshold for rejecting the null hypothesis.

Significance Test

A research design used when researchers cannot fully manipulate the independent variable or randomly assign participants to conditions, but still want to examine possible cause-and-effect relationships.

Quasi-Experimental Design

A setting in which researchers have substantial control over the conditions and stimuli being studied.

Closed System

An environment in which researchers have little or no control over the conditions, such as the real world.

Open System

A possible explanation for a result other than the treatment being studied, such as changes in weather, road conditions, or driver education.

Alternative Explanation

A research approach that examines an intervention or event in a real-world setting when a fully controlled laboratory experiment is not practical.

Quasi-Experimental Research

A research strategy that examines changes in an outcome over time, particularly before and after an intervention.

Time-Series Approach

A comparison approach that evaluates the outcome in a group or location receiving an intervention against outcomes in similar groups or locations that did not receive it.

Comparison-Group Approach

A quasi-experimental example in which researchers examined whether stricter treatment of speeding drivers was related to changes in Connecticut traffic fatalities.

Connecticut Traffic Fatalities Study

The researcher associated with the study of Connecticut traffic fatalities and the effects of the 1955 crackdown on speeders.

Donald Campbell

A type of research design that uses functional definitions and systematically investigates the conditions that control behavior.

Functional Design

A research area associated with B. F. Skinner that studies how environmental conditions influence behavior.

Experimental Analysis of Behavior

A definition that specifies the relationship between measurable determining conditions and their effects on behavior.

Functional Definition

A researcher who focuses on identifying variables that control behavior and allows theoretical explanations to emerge from findings rather than primarily testing an existing theory.

Atheoretical Research Approach

The process of developing general principles or theories from observations and research findings.

Inductive Approach

A research design that may use only one or two participants instead of large groups assigned to experimental conditions.

Small-n Design

A design often used in clinical psychology and behavioral analysis when the treatment and outcomes of an individual are the focus.

Small-n Design

A graph showing a segment of a participant's behavior that is considered typical under particular experimental conditions.

Typical Response Curve

A method of examining patterns in behavior by visually inspecting response curves instead of relying only on group averages and statistical tests.

Visual Inspection

A measure calculated by combining the scores of participants in a group to represent their average performance.

Mean

A measure describing how much scores vary around the mean.

Variance

A research strategy that examines an individual's behavior under different conditions, often by introducing and withdrawing a treatment.

Single-Subject Design

A design in which a baseline is measured, a treatment is introduced, and the treatment is then withdrawn to observe whether behavior changes again.

ABA Design

The first phase of an ABA design, in which the behavior is measured before the treatment is introduced.

A Phase (Baseline)

The second phase of an ABA design, in which the treatment or intervention is introduced.

B Phase (Treatment)

The final phase of an ABA design, in which the treatment is withdrawn and behavior is observed again.

Return to A Phase

The phase of a single-subject design that provides a reference for comparing behavior before or without the intervention.

Baseline

A change in behavior that occurs after an intervention is introduced and may reverse when the intervention is withdrawn.

Treatment Effect

A limitation of an ABA design that can arise when behavior does not return to its original baseline level after treatment is withdrawn.

Failure to Reverse

A consequence or event that changes the likelihood of a behavior occurring again.

Reinforcement

A consequence that increases the future likelihood of the behavior it follows.

Positive Reinforcement

The removal or avoidance of an unpleasant stimulus that increases the future likelihood of a behavior.

Negative Reinforcement

A consequence that decreases the future likelihood of the behavior it follows.

Punishment

A procedure that specifies the conditions under which reinforcement is delivered for a behavior.

Reinforcement Schedule

A schedule in which every instance of the target behavior is reinforced.

Continuous Reinforcement

A schedule in which reinforcement is delivered only for some instances of the target behavior.

Intermittent Reinforcement

A reinforcement schedule in which reinforcement is delivered after a set number of responses.

Fixed-Ratio Schedule

A reinforcement schedule in which the number of responses required for reinforcement changes around an average.

Variable-Ratio Schedule

A reinforcement schedule in which reinforcement is delivered for the first response after a fixed amount of time has passed.

Fixed-Interval Schedule

A reinforcement schedule in which the time that must pass before reinforcement becomes available changes around an average.

Variable-Interval Schedule

A reinforcement schedule based on the number of responses made.

Ratio Schedule

A reinforcement schedule based on the passage of time.

Interval Schedule

A schedule in which the requirement for reinforcement remains consistent.

Fixed Schedule

A schedule in which the requirement for reinforcement changes unpredictably around an average.

Variable Schedule

The process by which a behavior learned under one set of conditions also occurs in other settings, with other people, or in response to similar stimuli.

Generalization

The occurrence of a learned behavior in situations or settings different from those in which it was originally learned.

Stimulus Generalization

The transfer of a learned behavior or treatment effect to people, settings, or circumstances beyond the original situation.

Generalization of Treatment Effects

The extent to which a research finding can apply to situations, people, or conditions beyond those directly studied.

Generalizability

A study approach that describes or examines an individual or situation in its natural context rather than necessarily manipulating variables to establish cause and effect.

Case Study

An example in which researchers examine how behavior changes after an intervention and whether the change extends to other situations.

Behavioral Intervention Study

A research strategy in which the researcher systematically changes environmental conditions and observes the resulting changes in behavior.

Experimental Analysis of Behavior

A major reason researchers use advanced designs: psychological phenomena often have several causes, and each cause may influence behavior in multiple ways.

Complexity of Behavior

A relationship in which a change in one variable produces a change in another variable.

Cause-and-Effect Relationship

A factor other than the independent variable that may influence the dependent variable and affect the interpretation of results.

Extraneous Variable

A research goal of identifying whether an outcome is attributable to the treatment rather than to other possible influences.

Control of Alternative Explanations

A design strategy that examines several independent variables at once to better reflect the multiple factors that may influence behavior.

Multifactorial Approach