Most of the individual difference variance in the population is found "within" families, yet studying the processes causing this variation is difficult due to confounds between genetic and nongenetic influences. Quasi-experiments can be used to test hypotheses regarding environment exposure (e.g., timing, duration) while controlling for…

Available evidence indicates that experience with one face from a specific age group improves face-processing abilities if acquired within the first 3 years of life but not in adulthood. In the current study, we tested whether the effects of early experience endure at age 6 and whether the first 3 years of life are a sensitive period for the…

Examined differences in social and academic competence between Chinese 8- and 10-year olds with and without siblings. Unlike previous studies, results of peer assessment measures and behavior rating scales indicated no significant differences between the only-child subjects and those with siblings in the areas of social behavior, peer…

Reviews the literature in two areas of research concerned with social development of siblings. Compares and contrasts studies of sibling relationships of handicapped children with the wider literature on nonhandicapped siblings. Focus is on methodological and conceptual features. (RWB)