Evolution.

Society for Experimental Biology (Great Britain)

Date:: 1953

Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Evolution. Source: Wellcome Collection.

429/484 (page 397)

SOCIAL BEHAVIOUR AND PRIMATE EVOLUTION 399 be bome in mind that the circumstances employed in the study of a form of behaviour in one mammal may not be directly applicable to the study of the same form in another mammal. We must be careful to ensure that the same element of behaviour is studied in each animal, and this may entail the ultilization of the stimulus situation normally evoking the response in its natural environment. Not all naturally occurring stimulus situations will have selective conse¬ quences, but there are some in which these consequences are very great. Where an animal is in such a relation to its environment that slight changes in its behaviour bring about a relatively high degree of inappropriateness, this is a situation of behaviour stress. This behaviour may have evolutionary consequences, in proportion to the influence it has on the breeding performance. The stress in the life of subhuman primates arises out of an element of conflict, to which they are continuously subjected by the nature of their social relations. It is now necessary to consider the terms in which this can be defined. III. THEORETICAL FRAMEWORK FOR ANALYSIS OF MAM¬ MALIAN BEHAVIOUR IN FREE RANGING CONDITIONS We are here concerned with the formulation of a general statement governing the relationship of the organism (in this instance a mammal) to the environment, therefore the variation of structure which allows one animal to perform movements, wholly or partly different from those performed by others, is not relevant. The diagram (Text-fig. i) is an attempt to illustrate the role conflict plays in normal, as well as in abnormal, behaviour, so that it can be interpreted within a single framework of ideas. Conflict occurs in situations in which a repellent influence affects the behaviour of an animal, which is subject to a single persistent drive, orienting its behaviour with respect to a single spatially identifiable goal. Conflict at this stage can, therefore, be defined as the state of simultaneous opposition of attractive and repellent stimuli operating on an animal. Abnormal behaviour resulting from such situa¬ tions arises when the resolution of the conflict is without reference to the positive or negative goal. Conversely, normal conflict resolution involves an orientation component derived from the relevant environmental stimuli. The most elementary type of conflict resolution takes the form of stimulus- ranking behaviour, in which the intensity of the prevailing external stimu¬ lation determines the path of the behaviour. When opposition between two animals engenders conflict, however, the overt effort of the animals may exert a predominant influence in the form of the resolutions, by virtue both