Mothers were interviewed periodically over the first six years of their same-sex twins' lives and were asked to contrast them on specific behaviors. Intrapair contrasts were moderately stable across age spans for as long as 18 through 36 months. Genotypic similarity was apparently associated with intrapair similarity in emotionality and…

Examines whether there are sex differences during middle childhood in children's choices to participate in activities differing in level of adult-provided structure; effects of structure on children's compliance, leadership, and recognition seeking directed to adults and to peers; and relation of sex-typed social skills or dispositions and…

Investigates the influence of infant-mother attachment patterns on the development of peer interaction between the toddler and preschool periods. Notes that, in an initial encounter with an unfamiliar peer, attachment patterns appear to be related more to the child's attractiveness as an interactive partner than to the child's own active interest…

Argues that an evolutionary perspective can unite the study of species-typical development and individual variation. Provides examples from the domains of personality, social, and intellectual development. Maintains that understanding the ways in which genes and environments work together helps developmentalists identify children who need…