Children at play: the role of peers in understanding the effects of child care.

Although the studies of the National Institute of Child Health and Human Development (NICHD) Early Child Care Research Network (this issue) and of Watamura, Donzella, Alwin, and Gunnar (this issue) identify the potential of child care to affect children's adjustment, how these effects are produced remains unclear. In this commentary, it is argued that there is a need to expand child care research by considering one of the most important, but unrecognized, contributors to child care effects-peers. Research is reviewed that suggests that children's interactions in same-sex peer groups at child care affect their short- and long-term adjustment. We consider how research on early peer influences can inform the findings of the NICHD Early Child Care Research Network and Watamura et al. studies, aswell as contribute to the next generation of child care research.