Experimental Research Vocabulary Psychology Chapter 2 Experimental Research Vocabulary

Theories Formulations that account for the relationships among observed events or experimental findings in ways that make them more understandable and predictable. Example: Theory: Low self esteem feeds depression.

Hypothesis A prediction about the outcomes of an experiment, often implied by a theory. A theory must imply testable hypotheses. Example: People with low self esteem score higher on a depression scale.

Variable Any factor that is capable of change.

Operational Definition A statement of the procedures (operations) used to define research variables. For example, depression may be operationally defined as a low score on a mood scale or a high score on a depression scale.

Independent Variable Is the one that experimenters change or alter so they can observe its effects.

Dependent Variable Is the one that changes in relation to the independent variable. Example: The number of hours you study (the independent variable) affects your performance on an exam (the dependent variable).

Experimental Group The group to which an independent variable is applied. Example: if a new drug is being tested on a group of people, the experimental group is the group that gets the drug.

Control Group The group that is treated in the same way as the experimental group except that the experimental treatment (the independent variable) is not applied. This group would not actually get the drug.

Self-fulfilling Prophecy A situation in which a researcher’s expectations influence that person’s own behavior, and thereby influence the participant’s behavior.

Single-blind Experiment An experiment in which the participants are unaware of which participants received the treatment. (But the researcher knows).

Double-blind Experiment An experiment in which neither the experimenter nor the participants know which participants received the treatment. Helps control researcher bias and self-fulfilling prophesy.

Placebo Anything that seems to be a "real" medical treatment -- but isn't. It could be a pill, a shot, or some other type of "fake" treatment. What all placebos have in common is that they do not contain an active substance meant to affect health. Often given to a control group in experiments involving medications

Placebo Effect A change in a participant’s behavior that results from a belief that the treatment will have an effect, rather than the actual treatment.

Replication The attempt to duplicate research findings.