example, are significantly more likely as adults to display a host of behaviors that are destructive to themselves and others, including substance abuse, unemployment, low income, welfare dependency, delinquency, and crime (Haveman and Wolfe, 1984; Hawkins and Lishner, 1987; Hinshaw, 1992; Loeber and Stouthamer-Loeber, 1987; Rutter et al., 1998; Steinberg et al., 1984).
One of the most significant insights about educational attainment in recent years is that educational outcomes in adolescence and even beyond can be traced back to academic skills at school entry (Chen et al., 1996; Cunningham and Stanovich, 1997; Luster and McAdoo, 1996; Weller et al., 1992). Academic skills at school entry can, in turn, be traced to capabilities seen during the preschool years and the experiences in and out of the home that foster their development. Children's cognitive skills before they enter kindergarten show strong associations with achievement in elementary and high school (Hess and Hahn, 1974; Stevenson and Newman, 1986) and during early adulthood (Baydar et al., 1993). Preschool general cognitive ability has also been shown to predict high school completion (Brooks-Gunn et al., 1993). This evidence underpins the national commitment to school readiness and has fueled the proliferation of public prekindergarten programs (Schulman et al., 1999).
It is important to note that children who start school lagging behind their peers in language and cognitive abilities are not doomed to be school failures and dropouts. To the contrary, early interventions can make substantial contributions to the academic skills of young children (see Chapter 13). Moreover, the associations found between early and later achievement leave substantial unexplained variance. This means that there is plenty of room for children to defy the odds, and many do.
Both language development and the emergence of early learning capabilities appear to be relatively resilient processes. This means that they are relatively protected from adverse circumstances, that it may take more to undermine these processes than is the case for other aspects of development, and that they can show surprising recovery if children exhibiting delays are placed in more advantageous environments. Nevertheless, some aspects of language and cognition appear to be less resilient and more open to environmental influence than others, including vocabulary and attentional capacities. These aspects are particularly important to school success, in part because of what they can set in motion once a child enters formal schooling. They are also characterized by striking socioeconomic differences and therefore contribute to inequities in children's life chances. Moreover, the prospects for children with serious delays in language and cognition resulting from developmental disabilities and specific disorders can be seriously constrained and are heavily dependent on early detection and intervention. This chapter illustrates these points first with a discussion