Early rearing conditions and within-group behavioral variability

Rats were maintained in enriched or isolated conditions for periods ranging from 10 to 51 days postweaning in four experiments. Animals were subsequently run in a simple maze in acquisition and extinction trials. A measure of variability, the coefficient of variation, showed a tendency for enriched groups to be more homogeneous in their performance, especially after 30 days differential rearing, a finding analogous to some of those in the differential rearing-brain changes literature. Some additional material suggests that these findings may have some generality.