The effects of post-weaning environment, biological dam, and nursing dam on feeding neophobia, open field activity, and learning

Using rats in a cross-fostering design, we examined the effects of pre- and post-weaning rearing environments on feeding neophobia, open field activity, runway training, and visual discrimination learning. Fostering had no effect on the offspring behaviors. The animals reared, post-weaning, in an enriched environment consumed more food in a novel situation, were less active in the open field, and learned the first of two discrimination tasks faster than did the animals reared in the standard condition. Inter-correlations among these measures were nonsignificant, suggesting that the effect of environment on learning cannot be reduced to temperamental factors. The deficit in learning resulting from rearing in standard environment does not, however, appear to be irreversible; animals reared in the standard condition reached performance levels on the second discrimination task characteristic of those reared in the enriched environment.