Effects of Postweaning Tactual Stimulation on Emotionality and Social Dominance in the Rat

Abstract

10 male rats were systematically handled for 30 days after weaning and compared with 10 controls. Experimental Ss were less timid (cage-emergence latency) and less fearful (reluctance to eat). When each experimental S was paired permanently with a control S and permitted to compete for food over 12 encounters, the experimental Ss won all 10 bouts of the first session. In the remaining 11 sessions, however, the frequencies of wins and losses fell close to chance expectation. Two interpretations of the transitory differences in dominance were posited in terms of (a) the decay of the effects of manipulation over long periods of time and (b) the temporary competition of greater social curiosity-timidity arousal and food-consummatory responses in the control Ss. It was suggested that the greater permanence of differences found when rotated-pair comparisons are used results from continual curiosity-timidity rearousal in control Ss. This rearousal is associated with the introduction of unfamiliar opponents on every trial.