The pleasantness or unpleasantness of the sensation one experiences from the stimulus of a given person, object or situation.

The practice of restricting marriage partners to a person from one’s own social or kinship group.

Contrasted with EXOGAMY.

Considered essential by SOCIAL SCIENTISTS in breaking down social prejudices. While a relationship between people of unequal status can breed attitudes consistent with their relationship, so do relationships between those of equal status. Thus, to reduce PREJUDICE, interracial contact should be between persons equal in status.

Named after the German physicist and psychologist Gustav Fechner. Large increases in the intensity of a stimulus produce smaller, proportional increases in the intensity perceived. It is expressed mathematically as S=k log R, where S is the intensity experienced, R is the actual physical intensity and k is a constant. This is one of the first attempts at a mathematical statement of a psychological PHENOMENON. It grew out of the studies in PSYCHOPHYSICS with which PSYCHOLOGY became an experimental science in the 1870s.

A drug, like LSD or mescaline, that induces HALLUCINATION.

The effects on an EXPERIMENT of the CONSCIOUS or UNCONSCIOUS attempts by the experimenter to influence the outcome in the direction predicted. This is an important and pervasive problem, as the outcome of virtually every published experiment is in the predicted direction. The ramifications of this PHENOMENON are much wider than the experimental situation.

See also DEMAND CHARACTERISTICS, DOUBLE-BLIND TECHNIQUE, INTERVIEWER BIAS, ROSENTHAL EFFECT and SELF-FULFILLING PROPHECY.

The branch of PHILOSOPHY that deals with the search for true knowledge: the origins, nature, limits and verifiability of what is known.

Any study of human or animal BEHAVIOUR outside of a laboratory or an EXPERIMENT.

The tendency to regard the group one identifies with, especially one’s ethnic group, as superior to any other. Like EGOCENTRICITY in individuals, it involves the inability to step outside the perceptual framework of one’s own group and see life from the viewpoint of a different group.

A biological theory about the development of the embryo which stresses the influence of the environment. The interaction of embryo and environment produces new properties that were not present in the fertilised egg, or ZYGOTE. In certain psychological theories, especially those of ERIK ERIKSON, epigenesis refers to a sequence of developmental stages that must be followed to attain psychological maturity.