In experimental research, these are factors that are not part of the intended hypothesis being tested, but that have effects on variables of interest and threaten internal validity

German psychologist who introduced the experimental method. He established a laboratory for experimentation that became a model for social research.

a school of psychology founded in the 1920's that emphasized measuring observable behavior or outcomes of mental life and advocated the experimental method for conducting rigorous empirical tests of hypotheses.

Measuring social phenomena with numbers

Advocated using experiments in factories to increase productivity.

They are known as the participants in experimental research

Participants are randomly assigned to either the experimental or control group

The participants who receive the treatment

The participants who do not receive the treatment

A test that measures the dependent variable of an experiment prior to the treatment

The independent variable in experimental research

The outcome of the experiment.

A test that measures the dependent variable of an experiment after the treatment

A lie by an experimenter to participants about the true nature of an experiment or the creation of a false impression through his or her actions or the setting

A person working for the experimenter who acts as another participant or in a role in front of participants to deceive them with an experimenter’s cover story

A type of deception in which the experimenter tells a false story to participants so that they will act as wanted and do not know the true nature of the study

Participants are divided into groups at the beginning of the study using a random process so the experimenter can treat the groups as equivalent

an alternative to random assignment where research subjects are assigned to the experimental and control groups based on known

Experimental plans that lack random assignment or use shortcuts and are much weaker than the classical design. They are substituted in situations where an experimenter cannot use all of the features of a classical design

Plans that are stronger than pre-experimental designs, but are still variations of the classical design. They are used in situations where the experimenter has limited control over the independent variable.

An experimental plan in which the dependent variable is measured periodically across many time points and the treatment occurs in the midst of such measures, often only once.

An experimental plan in which there are several repeated pretests, posttest, and treatments for one group often over a period of time.

An experimental plan to examine whether the order or sequence in which participants receive versions of the treatment has an effect

An experimental plan in which participants are randomly assigned to two control groups and two experimental groups; only one experimental and control group receive a pre-test; all four groups receive a post-test. This design is used to check for the testing effect.

an experimental plan that considers the impact of several independent variables simultaneously.

an effect of two independent variables operating simultaneously and in combination on a dependent variable. It is a larger effect than occurs from the sum of each independent variable working separately.

Occurs when the independent variable, and nothing else, influences the dependent variable.

the ability to generalize findings beyond a specific study

It is one of the threats to internal validity where that occurs when groups in an experiment are not equivalent at the beginning of the study.

a threat to internal validity which results from an unplanned event occurring which is outside the control of the experimenter.

A threat to internal validity where a natural processes of growth, boredom, or maturity occurs during the experiment and affects the dependent variable.

a threat to internal validity that occurs because the very process of conducting a pre-test can have an effect on the outcome (dependent variable

a threat to internal validity that occurs when the instrument changes during the

A threat to internal validity that occurs when some research participants do not continue throughout the entire experiment.

A threat to internal validity from measurement instruments providing extreme values and a tendency for random errors to move extreme results toward the average.

A threat to internal validity that occurs when the treatment “spills over” from the experimental group and control group and participants modify their behavior because they have learned about the treatment.

A threat to internal validity when participants in the control group modify their behavior to make up for not getting the treatment.

A threat to internal validity where the experimenter indirectly makes participants aware of the hypothesis or desired results

It is a design intended to control experimenter expectancy. In this type of experiment the only people who have direct contact with participants do not know the details of the hypothesis or treatment.

a threat to internal validity that occurs when research participants pick up clues about the hypothesis or an experiment’s purpose and modify their behavior to what they think the research demands of them

A threat to internal validity that occurs when participants do not receive the real treatment but receive a non-active or imitation treatment but respond as though they have received the real treatment.

When researchers can accurately generalize from what they learn in an experiment to a population.

whether or not a researcher can generalize accurately from what was learned in an artificially created controlled laboratory setting to real life natural settings.

asks whether an experiment or a situation is like the real world.

the impact of an experimental treatment or setting on people; it occurs when participants are caught up in theexperiment and are truly influenced by it

asks whether the researcher can accurately generalize from an abstract theory that he or she is testing from a set of measures in the experiment.

A threat to external validity that occurs because participants are aware that they are in the experiment and being studied.

A separate measure of independent or dependent variables to verify their measurement validity and/or experimental realism.

A study that takes place in a natural setting such as a subway car, a liquor store, or a public sidewalk. Participants are usually unaware that they are involved in an experiment and react in a natural way.

This is a type of experiment which tends to have higher internal validity but lower external validity. They are better controlled than field experiments but have less generalizability because they are conducted in labs and participants know that they are part of a study.

This type of experiment tends to have higher external validity (since they are conducted in natural settings) but have lower internal validity because the researcher is unable to control many facets of the experiment.

A process where something happens to activate a particular identity. Once reminded of the identity it moves to the forefront of how we think about ourselves and therefore influences our behavior