Effects of post-weaning environment on learning in the rat

Abstract

Rats were reared in three different kinds of post-weaning environment: (1) with litter-mates and a variety of playthings (objects/social), (2) without either litter-mates or playthings (no-objects/isolates), (3) with litter-mates, but without playthings (no-objects/social). The animals were subsequently tested on a variety of learning tasks. In one task, the rats had to remove an obstacle from an alley in order to enter a food compartment; subsequently they were required to remove the obstacle in a different way from the one they had learned. Another task was to open a door leading to a food compartment; when the rats and learned this, the floor of the apparatus was lowered so they had to reach the door by climbing a ladder. Object-deprived/isolates were slower than the objects/social group in the transfer phase of the above tasks, though not in original acquisition. Object-deprived/social animals were not inferior to an objects/social group. Isolates had a higher free feeding weight than social animals, were more active in an open field, and ran faster for food reward when deprived.