The article contains a short review of approaches to studying the problem of generalization, which serves as a basis for an experimental study. The author investigated the dependence of characteristics being generalized on their role in the structure of the subject's activity. The subjects were two groups of children aged 5 to 6 and 3/4 years, normal and mentally retarded. The results show that generalization only occurs in the characteristics specified by the orienting base for the activity. The latter proves that generalization is not directly determined by the objects, but is mediated by the subject's activity involving those objects.