In the present investigation, we studied the development of 6 physically aggressive behaviors in infancy and toddlerhood, posing 3 questions (a) How do the prevalences of individual physically aggressive behaviors change from 8, 15, and 24 months? (b) Are there groups of children who show distinctive patterns in the way individual physically…

We evaluated the extent to which the externalizing behavior construct is self-organizing in the first 2 years of life. Based on dynamic systems theory, we hypothesized that changes in physical aggression, defiance, activity level, and distress to limitations would each be predicted by earlier manifestations of one another. These hypotheses were…

This study investigated the normative use and developmental course of physical aggression (PA), defined as use of physical force such as hitting, biting, and kicking, from 8 to 26 months and predictors thereof. We used data from the Behavior Outlook Norwegian Developmental Study, comprising 1,159 children (559 girls and 600 boys). Both mothers and…

Investigating heterogeneity in antisocial behavior early in life is essential for understanding the etiology, development, prognosis, and treatment of these problems. Data from the longitudinal National Institute of Child Health and Development (NICHD) study of Early Child Care were used to identify homogeneous groups of young antisocial children…

The link between behavior problems and low academic achievement is well established, but few studies have examined longitudinal relations between early externalizing behaviors before school entry and low academic achievement following transition to formal schooling. Early inattention has been particularly overlooked, despite strong associations…

There has been much controversy over the past decades on the origins of gender differences in children's aggressive behavior. A widely held view is that gender differences emerge sometime after 2 years of age and increase in magnitude thereafter because of gender-differentiated socialization practices. The objective of this study was to test…

Influence of others' emotions on the emotions and aggression of 2-year-olds was examined. Dyads of familiar peers were exposed during play to a sequence of experimental manipulations of background emotions of warmth and anger. Theoretical and practical implications of sensitivity to others' conflicts and interpersonal problems in toddlers are also…

Tests the ability of 43 children, ranging in age from 20 months to 40 months, to discriminate between pictures of boys and girls and male and female adults. Compares children who passed this gender-task with those who failed it on three behaviors most often categorized as sex-typed: toy choice, aggression, and peer playmate selection. (HOD)

Mothers and infants were observed in the laboratory when the infants were 12, 18, and 24 months. Mothers reported their child's behavior at 36 months. Predictors of boys' externalizing behavior at two and three years were maternal unresponsiveness and infant attention seeking, aggression, and noncompliance. For girls, infant noncompliance was…