Introduction

Our central hypothesis is that situations enable people to attain goals, which in turn satisfy drives; all the other features of situations can be explained functionally in terms of their contribution to the attainment of goals and the satisfaction of drives. Our main theoretical antecedent is Lewin, and we shall use ideas from Murray, from the McClelland–Atkinson group and from exchange theory. However we shall be concerned with drives and goals as properties of situations rather than of individuals.

Animals and people have biological needs, for food and water etc., which energise and direct behaviour and whose satisfaction is necessary for survival. There are a number of other motivational systems which can be regarded as drives; like needs they direct and energise behaviour, but they are not based on any biological deficit and the survival of the individual does not depend immediately on their satisfaction, though the survival of group and species may do. Drive-related behaviour results in satiation of the drive in some cases, but not in all.

In groups of monkeys it can be seen how each drive contributes to the survival of the individual or group. Sexual and maternal drives need no explanation; aggression enables groups to defend themselves and their territory; dominance produces a stable leadership hierarchy, which makes it possible to keep order internally and to defend the group in an organised way (DeVore, 1965).