Rats’ performance on repeated tests in the open field as a function of age

Abstract

Sprague-Dawley rats, 50, 90, and 150 days old, received 10 tests in an open field. Younger rats were both significantly more active and showed different trends in activity over tests than older rats. Also, as a function of tests, younger rats became less thigmotaxic and showed less defecation, while the oldest rats showed a relatively constant degree of thigmotaxis and a relatively constant level of defecation over tests. Younger rats spent significantly more time grooming than older rats, and all Ss increased grooming time over tests. It was suggested that level of curiosity in young and old rats might be equal but that younger rats are less fearful than older rats. © 1971, Psychonomic Journals, Inc.. All rights reserved.