Myers' Psychology for AP (Module 6)

placebo effect

(Latin for "I shall please") experimental results caused by expectations alone; any effect on behavior caused by administration of an inert substance or condition, which the recipient assumes is an active agent.

scatterplot

A graphed cluster of dots, each of which represents the value of two variables. The slope of the points suggests the direction of the relationships between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates higher correlation)

confounding variable

a factor other than the independent variable that might produce an effect in an experiment

correlation

a measure of the extent to which two variables change together, and thus of how well either variable predicts the other

experiment

a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the defendant variable). By random assignment of participants, the experimenter aims to control other relevant variables.

correlation coefficient

a statistical index of the relationship between two variables (from -1.0 to +1.0)

double-blind procedure

an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.

random assignment

assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups.

experimental group

in an experiment, the group exposed to the treatment, that is, to one version of the independent variable

control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves a comparison for evaluating the effect of the treatment

independent variable

the experimental factor that is manipulated; the variable whose affect is being studied

validity

the extent to which a test or experiment measures or predicts what it is supposed to do

dependent variable

the outcome factor; the variable that may change in response to manipulations of the independent variable

illusory correlation

the perception of a relationship where none exists