The early emergence and developmental implications of externalizing behavior problems in toddlers and preschoolers are discussed with an emphasis on which young children are truly at risk for continuing problems. The extant literature is reviewed with a focus on the stability of early externalizing behavior and the diverse pathways that young children, primarily boys, with early-emerging problems may follow. Findings from a number of studies, both epidemiological and high risk, suggest that the small subgroup of boys with multiple risk factors that include especially high levels of early hyperactivity and aggression, and high levels of negative parenting and family stress, are most likely to evidence continuing problems at school entry. Sociodemographic and neighborhood influences are also discussed, as are implications for future research and policy.

The present study applied a semiparametric mixture model to a sample of 284 low-income boys to model developmental trajectories of overt conduct problems from ages 2 to 8. As in research on older children, 4 developmental trajectories were identified: a persistent problem trajectory, a high-level desister trajectory, a moderate-level desister trajectory, and a persistent low trajectory. Follow-up analyses indicated that initially high and low groups were differentiated in early childhood by high child fearlessness and elevated maternal depressive symptomatology. Persistent problem and high desister trajectories were differentiated by high child fearlessness and maternal rejecting parenting. The implications of the results for early intervention research are discussed, with an emphasis on the identification of at-risk parent-child dyads.

Emotion regulation strategies observed during an age 3 1/2 frustration task were examined in relation to (a) angry affect during the frustration task, (b) child and maternal characteristics at age 1 1/2, and (c) indices of self-control at age 6 in a sample of low-income boys (Ns varied between 189 and 310, depending on the assessment). Shifting attention away from sources of frustration and seeking information about situational constraints were associated with decreased anger. Secure attachment and positive maternal control correlated positively with effective regulatory strategy use. Individual differences in strategy use predicted self-control at school entry, but in specific rather than general ways: Reliance on attention-shifting strategies corresponded with low externalizing problems and high cooperation; reliance on information gathering corresponded with high assertiveness.

Using cross-domain latent growth modeling, we examined trajectories of externalizing and internalizing problems in disadvantaged boys followed from ages 2 to 6 years~N ϭ 303!. On average, externalizing problems gradually decreased and internalizing problems gradually increased. However, we found significant variability in individuallevel trajectories. Higher levels of externalizing problems were associated with higher levels of internalizing problems; rates of change were also positively correlated across domains. In addition, high levels of externalizing problems predicted rapid increases in internalizing problems. In follow-up analyses involving child and parenting factors, the combination of high negative emotionality, low fearfulness, and high negative maternal control preceded high, nondecreasing externalizing trajectories. The combination of high negative emotionality, high fearfulness, and high negative maternal control preceded high, increasing internalizing trajectories. Taken together, the results indicate both general and specific processes in the development of early externalizing and internalizing problems.

This study examined relations among neighborhood disadvantage, parent-child conflict, deviant peer involvement in the neighborhood, and early-starting antisocial trajectories. Antisocial group patterns were identified in 218 low-income boys followed from ages 5 to 11, and neighborhood and family variables were evaluated as predictors in early and middle childhood. Four trajectory groups emerged: one increasing pattern that corresponded with developmental theories of early-starting antisocial behavior; one with initially high and decreasing problems over time; and two low antisocial groups. Parent-child conflict and neighborhood disadvantage were significantly associated with trajectory patterns, with youth in the 2 higher antisocial behavior groups characterized by more neighborhood problems and parent-child conflict than other groups. The results suggest that in early childhood, neighborhood disadvantage and family conflict place children at risk for early-starting trajectories, and that involvement with deviant peers in the neighborhood takes on an increasingly important role in patterns of antisocial behavior over middle childhood.