The new-object and new-place reactions of Rattus rattus L.

Abstract

The behaviour of the wild “black” or “house” rat, Rattus rattus L., was studied in an artificial environment, a plus-maze. The maze consisted of a central nest box and four arms. Food and water were placed at the ends of different arms, and movements of the rats were recorded automatically. A detailed analysis was made of habituation to the artificial environment and of the patterns of activity displayed there. Rats were most active during the dark phase of ‘he light cycle; they displayed a bimodal pattern of visits to and time spent in the arms, with peaks around three hours after lights off and four hours before lights on. Reaction to new objects and places was measured in several ways. The rats usually avoided new objects placed in a familiar area, but showed little hesitation to explore a previously inaccessible area. Rats generally stopped avoiding new objects in the feeding area within one to two days, even when an alternative source of food was available elsewhere. There was, however, much variation. The methods used allow study of two distinct initial responses to novelty, each clearly displayed: (a) withdrawal from a strange object in a familiar place (“fear”), and (b) approach to a newly accessible area (“curiosity”). Behaviour often depends on the interaction between these two processes.