[Complex form of adaptive behavior in rats].

Two problems have been dealth with: a) are rats able by self-learning to form purposive associations, involving elements of reasoning object activity and b) at what age period are they most capable of purposive tool activity. The experiments were performed on 55 rats aged from two to three, five to six and eight to ten months. It was established that tool activity in rats appeared on the 14th to 34th experimental day in 14.