This complex argument about the development of moral and social understanding in children has the exemplary features of Dunn's earlier works (Distress and Comfort, 1977; Sisters and Brothers, 1985) and demonstrates again her ability to pursue hard-to-research ideas with professional vigor and commonsense. Dunn finds a rich source of evidence in the social relationships of preschool children, particularly in exchanges with their mothers and older siblings. Referring to her own studies in Cambridge, Mass., to writings about children in family settings, and to the works of other developmental psychologists, she shows how children use their intelligence on what matters to them emotionally; experiencing distress or anger over conflict, for example, can contribute to learning, and a developing self-interest may act as motivation. Unlike much traditional research, Dunn's avoids the usual focus on stress factors (anxiety, guilt, fear) when examining the growth of understanding. Instead, she relies on everyday interactions, jokes, and make-believe games as equally valid indicators--think how siblings share a similar sense of the absurd--and she suggests that Stem's concept of ""affect attunement"" (that special alignment between mother and child) may extend to some sibling relationships. (She also knows that some preschoolers share better with friends than with siblings.) This book follows up on ideas introduced in Sisters and Brothers (e.g., the powerful socializing influence of older siblings) and includes support from a variety of relevant sources. Readers will value Dunn's subtle and penetrating discriminations and see this work as a corrective to theories like Piaget's, which tend to neglect affective dynamics and see learning as independent of emotional and maturational processes.