A group of 170 children was observed during their first year of life for the incidence of three autoerotic activities, genital play, rocking and fecal play. The mother-child relations were established as the variable among the environmental factors which could affect this group. Two control groups were used in which the variable was kept as constant as possible: one group of family children with optimal mother-child relations and one group of institutionalized children where mother-child relations were so to say absent.

It was found that autoerotic activities are a function of the object relations prevailing during the first year of life. They are absent when object relations are absent; when object relations are so constantly contradictory that object formation is made impossible, rocking results. When object relations change in an intermittent manner fecal play results. When object relations are "normal", genital play results.