The effects of crowding under different rearing conditions on emotionality and transfer of perceptual learning

Abstract

To examine the effects of population density on emotionality and transfer of perceptual learning, albino rats were either preexposed to circles and triangles in a visually sparse environment or received no early experience with the to-be-discriminated shapes. Within each early experience condition, the animals were initially placed in either a crowded or uncrowded environment. Approximately 1 mo later, half of the rats under each population condition were shifted to the opposite population density condition, while the other half remained under their original condition. Analysis of the data indicated that (1) the animals uncrowded for the entire experiment were less emotional than animals crowded for the same length of time; (2) there was no difference in emotionality produced by 1 mo versus 2 mo of crowding; (3) animals uncrowded for 1 or more mo immediately after weaning were less emotional than animals crowded during this interval; (4) in general, animals preexposed to the to-be-discriminated forms learned the discrimination task in significantly fewer trials than did animals not receiving early stimulus preexposure; (5) animals that were crowded 1 mo immediately after weaning were poorer performers on the discrimination learning problem than were animals uncrowded during this same time period. Thus, the effects of population density on emotionality and transfer of perceptual learning were determined by population rearing conditions existing during the month immediately following weaning.