The necessity is argued to set up a special interdisciplinary field of studies of the ontogenesis and sociogenesis of the personality in childhood: social psychology of childhood. The data pertaining to development of humane attitudes is used to present the following three aspects of manifestation of interpersonal relations in social groups: role-functional, estimating-emotional, and sense-personal. The empirical results obtained by the author show that socialization of humane attitudes in ontogenesis correspond to the general-psychological pattern of development of a higher form of behavior - L.S. Vygotsky and A.N. Leontiev's "parallelogram of mediation". Appearance, functioning, and purposeful development in the child of attitudes to the world, other people, and to oneself mediated by joint goal-directed acting in the social situation of development constitute the subject-matter of the outlined field. The perspectives of the later are seen in studies of development of the personality in a child in different cultures and at different stages of man's social history.