In EXPERIMENTAL PSYCHOLOGY, a group of subjects as similar as possible to the EXPERIMENTAL GROUP for purposes of comparison. They share the same conditions as the experimental group except exposure to the EXPERIMENTAL VARIABLE which is the object of the study.

An altered state of CONSCIOUSNESS characterised by DELUSIONS, HALLUCINATIONS and ILLUSIONS.

According to the American psychologist Lawrence Kohlberg, the second of three broad levels of moral development, beyond which most people do not mature. At this level people judge the rightness or wrongness of an action in terms of what other people think and the dictates of authority.

See STAGE THEORY.

See JUST NOTICEABLE DIFFERENCE.

Derived from a Greek term meaning something like ‘steersman’, cybernetics was introduced in 1948 by Norbert Wiener, a computer engineer. It is usually defined briefly as the study of regulatory mechanisms (like thermostats). Out of this field came the analogy of the brain as a computer and the model of psychological processes as systems of messages with their own built-in FEEDBACK.

Supposed response of an animal or human to the effects of being crowded, and often subject to very dubious GENERALISATION across species.

For example, the aggressive behaviour of rats at a certain level of crowding is thought by many to be INSTINCTIVE and this ‘explanation’ may then be offered to account for violence in urban slums. There is little or no hard evidence that any human behaviour is instinctive, and as an explanation for the extremely complex (and sometimes apparently contradictory) relationship between urban violence and crowding, it is so simplistic as to be silly.

The branch of PSYCHOLOGY that deals with the interactions of physical, psychological and social changes that occur as an individual increases in age. For a long time, this meant largely CHILD DEVELOPMENT and perhaps adolescence but increasing attention is now being paid to MIDDLESCENCE and SENESCENCE.

Thinking along conventional lines in an attempt to find the best single answer to a problem. Compare with DIVERGENT THINKING.

Usually used in connection with teenagers and often called ‘juvenile delinquency’ to describe breaches of the law like theft and vandalism. Many factors have been proposed to explain it over the years such as depressing environment, unhappy home life, innate sinfulness and the SELF-FULFILLING PROPHECY engendered by LABELLING.

A technique of learning in which the lessons or periods of practice are spread out as widely as the available time permits. A much more effective method of learning than SPACED PRACTICE, with which it is usually contrasted.