2000; Rosenthal, 1994; Vandell and Ramanan, 1992). Of central importance to cognitive and language outcomes is the verbal environment of the child care setting (McCartney, 1984; NICHD Early Child Care Research Network, 2000). As with mother care, child care providers who are both supportive and provide more verbal stimulation have children in their care who show advanced cognitive and language development.
In light of the experimental evidence on center-based early intervention programs, it is interesting that evidence is emerging from nonexperimental studies of more typical child care suggesting that cumulative experience in high-quality, center-based care starting in the second year of life may be particularly beneficial for cognitive development (Broberg et al., 1997; Hartmann, 1995; NICHD Early Child Care Research Network, 2000). Some studies find that center-based care is especially beneficial for children from low-income families (Caughy et al., 1994), but others find that all children benefit regardless of their family background (NICHD Early Child Care Research Network, 2000). What might children be getting in child care centers that they are not getting in other settings? One of the features that distinguishes higher-quality from lower-quality care with regard to early cognition and language is the amount of language stimulation that child care teachers provide (McCartney, 1984; Melhuish et al., 1992; NICHD Early Child Care Research Network, 2000). Center-based teachers, who are more likely to have received specialized training in early development and more education generally than providers in other child care settings (NICHD Early Child Care Research Network, 1996, in press b). As a result, they may talk more with children and respond to their efforts to communicate in precisely the ways that foster early language and cognitive skills, but this speculation requires empirical study.
Efforts to understand how child care affects children's social-emotional development have assessed a vast array of outcomes that tap children's self-regulatory behavior, their cooperation with and attachments to adults, their social skill (or lack of it) with other children, and the developmental level of their social interactions. For virtually every outcome that has been assessed, quality of care shows positive associations with early social and emotional development (see NICHD Early Child Care Research Network, 1998c and reviews by Lamb, 1998; National Research Council, 1990; Scarr and Eisenberg, 1993) after family influences on development are controlled, albeit to varying degrees. The experimental literature on early intervention also has demonstrated significant effects on young children's social skills and, in particular, on reduced conduct problems (Yoshikawa, 1994, 1995). Indeed, it is in the realm of preventing delinquency in adolescence and early