In SOCIAL PSYCHOLOGY, the idea that the area immediately surrounding a person is felt to be his or her own. The amount of space claimed in this way varies from person to person and fromCULTURE to culture, but any invasion of it is taken as a hostile or threatening act. Not to be confused with TERRITORIALITY.

Work expands to fill the time available.

A research technique in the SOCIAL SCIENCES where an observer becomes an accepted member of the group he wants to study.

A person who expresses anger and hostility by oscillating between extreme DEPENDENCE on, and extreme aggression towards, other people. The term passive- aggressive is also used of BEHAVIOUR which is passively aggressive. For example, a person arriving late for a meeting with someone he knows will become anxious at his lateness.

Producing a greater effort than is needed to overcome a difficulty or resolve a defect. Often used in connection with attempts to overcome anINFERIORITY COMPLEX.

In STATISTICS, a value representative of a whole group of numbers, such as one of the MEASURES OF CENTRAL TENDENCY (MEAN. MEDIAN and MODE ). See also GROUP NORM andSOCIAL NORM.

In PSYCHOANALYSIS, the loss of love from a valued external object.

Statistical methods that may be used when the data do not conform to a NORMAL DISTRIBUTION, i.e. most data in studies of human BEHAVIOUR.

The physiology of the nervous system.

A technique used in studies of learning where words are presented to the subject in pairs and afterwards he is given the first word of each pair and asked to recall the second.