Spatial Memory and Response Strategies in Rats: Age, Sex and Rearing Differences in Performance

Rats reared in social isolation made more errors on a spatial memory task and made errors earlier in each trial than socially reared rats. The difference in performance only occurred when rats were isolated prior to 50 days of age, and it survived IOO days of subsequent social housing. IOO days of isolation after 50 days of age did not influence performance on the spatial memory task. Subsequent experiments suggest that spatial abilities may not differ between groups but that isolates are slower to learn to make a particular response and to locate a particular arm when spatial and response cues are irrelevant. In contrast to previous experiments, clear response strategies were seen in the present experiments. These were prevalent in the young (54-days-old) rats, were less common at 90 days and had completely disappeared by 180 days. Response strategies were more common in male rats and in socially reared rats.