Abstract: Four experiments examined the effects of rearing in isolation on rats performance on discrimination-based and social learning tasks. After demonstrating that the rearing procedures produced similar results in an open field task to those previously established (Experiment 1), rats were subjected to two discrimination tasks: an instrumental occasion setting procedure (Experiment 3) and a nonspatial win-stay/lose-shift versus win-shift/lose-stay procedure (Experiment 4). Deficits in acquisition of the necessary discriminations were noted in the rats raised in isolation, but there were no differences between isolation-reared and socially reared subjects in response acquisition per se. In Experiment 2, rats were presented with an observational learning task using the bidirectional control procedure. Socially reared rats had a tendency to imitate the behavior they had observed, but rats raised in isolation performed the opposite behavior to that observed, indicating a failure to use a conspecific as a reference point in the task. The presence of a mirror during rearing in isolation was also investigated, but was found to have little effect in attenuating the above deficits in behavior.