Abstract
The moral reasoning and cooperative skills of four groups of educable mentally handicapped subjects and their intellectually average counterparts of the same mental age were examined Consistent with the assumptions of cognitive-developmental theory, it was found that both types of subjects showed an increasing tendency to adopt higher levels of moral reasoning as a function of mental ages 5,6,7, and 9 years. In accord with the postulated role of intelligence in producing moral development, there were few differences between handicapped and non-handicapped subjects of the same mental age on the Piagetian test of restitutive reasoning. However, contrary to postulates about the importance of peer cooperation for moral development, handicapped subjects were more cooperative than their non-handicapped counterparts.