An organized set of concepts that explains a phenomenon or set of

phenomena.

The doctrine that all events—physical, behavioural, and

mental—are determined by specific causal factors that are potentially

knowable.

A tentative and testable explanation of the relationship

between two (or more) events or variables; often stated as a prediction

that a certain outcome will result from specific conditions.

The distortion of evidence because of the personal motives

and expectations of the viewer.

A set of uniform procedures for treating each participant

in a test, interview, or experiment, or for recording data.

A definition of a variable or condition in terms of

the specific operation or procedure used to determine its presence.

In an experimental setting, a factor that varies in amount and

kind.

In an experimental setting, a variable that the

researcher manipulates with the expectation of having an impact on

the value of the dependent variable.

In an experimental setting, a variable that the

researcher measures to assess the impact of a variation in an

independent variable.

Research methodologies that involve the

manipulation of independent variables in order to determine their

effects on the dependent variables.

A stimulus other than the variable an experimenter

explicitly introduces into a research setting that affects a participant’s

behaviour.

Results that occur when a researcher or observer subtly

communicates to participants the kind of behaviour he or she expects

to find, thereby creating that expected reaction.

A change in behaviour in the absence of an experimental

manipulation.

Consistent procedures for giving instructions, scoring

responses, and holding all other variables constant except those being

systematically varied.

An experimental technique in which biased

expectations of experimenters are eliminated by keeping both

participants and experimental assistants unaware of which participants

have received which treatment.

An experimental condition in which treatment is not

administered, used in cases where a placebo effect might occur.

A research design in which different groups of

participants are randomly assigned to experimental conditions or to

control conditions.

A procedure by which participants have an equal

likelihood of being assigned to any condition within an experiment.

A group in an experiment that is exposed to a

treatment or experiences a manipulation of the independent variable.

A group in an experiment that is not exposed to a

treatment or does not experience a manipulation of the independent

variable.

The entire set of individuals about which generalizations will

be made based on an experimental sample.

A subset of a population that closely matches the

overall characteristics of the population with respect to the distribution

of males and females, racial and ethnic groups, and so on.

A research design that uses each participant as his

or her own control; for example, the behaviour of an experimental

participant before receiving treatment might be compared to his or her

behaviour after receiving treatment.

Research methodologies that determine to what

extent two variables, traits, or attributes are related.

A statistic that indicates the degree of

relationship between two variables.

The degree to which a test produces similar scores each time

it is used; stability or consistency of the scores produced by an

instrument.

The extent to which a test measures what it was intended to

measure.

The behaviours that are identified through a

participant’s own observations and reports.

Overt actions and reactions that are observed and

recorded, exclusive of self-reported behaviour.

Intensive observation of a particular individual or small group

of individuals.

A procedure conducted at the end of an experiment in which

the researcher provides the participant with as much information

about the study as possible and makes sure that no participant leaves

feeling confused, upset, or embarrassed.