This article describes the average and group-based developmental trajectories of aggression, opposition, property violations, and status violations using parent reports of externalizing behaviors on a longitudinal multiple birth cohort study of 2,076 children aged 4 to 18 years. Trajectories were estimated from multilevel growth curve analyses and…

The behaviors of narcotics-addicted and nonaddicted newborns in the first 2 days of life were assessed and compared. (JMB)

The furnishings and toys of boys' and girls' rooms were canvassed on the assumption that differences, if found, would indicate parental ideas about sex-appropriateness. The children were 48 boys and 48 girls under 6 years of age; each child had his own room. (Author/CS)

Studied a social developmental model of discounting. Experiments showed that discounting increased according to the degree of similarity between the task situation and subjects' earlier experience. Although older children discounted consistently, younger children discounted only after a relevant script-generating experience. (RJC)

Investigates factors associated with outcomes in attachment relationships between 30 well-educated, full-time working mothers and their 18-month-old firstborn sons. Suggests maternal employment effects on mother-son attachment are mediated primarily by a woman's affective state, which becomes manifested in her style of caregiving and child-care…

Examines the ability of six- and eight-year-old children to hide and recover 20 marbles in a large room containing 100 possible sites. Shows that children tend to concentrate activities in sections of the room and are sensitive to clusters of proximal sites. (HOD)

Examines relations between Matthews Youth Test for Health ratings on hyperactive boys and diverse measures obtained from five sources: direct behavior observations; staff evaluations, nonparticipant observer ratings, peer nominations, and self-reports. (HOD)

Using the Ainsworth Strange Situation Procedure, a study examined the interrelations between dimensions of emotion and social interactive behaviors to explore the regulatory role of each in mother-infant interaction and how these roles may change in the second year. (HOD)

Live behavioral and televised behavioral models were the most effective, and live verbal models were the least effective. The effects of the deviant models were more stable over time than the effects of the conforming models. (Authors)

Mothers of 232 pairs of twins were interviewed periodically about the similarities and differences in behavior displayed by their twins during infancy and early childhood. (Authors)

Behaviors observed in 47 families interacting at home were recorded in terms of interactions between a target child and other family members. The types of behaviors emitted by a target child to parents versus siblings were analyzed as were the types of responses that parents versus siblings gave to the target child's behavior. (Author/RH)

Acting on the premise that she was teaching her son a task, each of 30 mothers selected consequences for her child's errors. In actuality, feedback to the mother regarding her son's performance was experimentally manipulated. Results showed that differential conditioning of both high and low maternal punitiveness could be achieved by using the…

Examined three- to five-year-old children's understanding of pretense and deception in folktales in which a villain deceived his victim by pretending to be someone else. Found that the three-year-olds were able to follow the pretense but were not able to grasp the false belief integral to the deception. (MOK)

Investigated sex differences in the motor activity level of 83 children of 5-8 years. Relative maturity was negatively related to activity level. Girls were less motorically active and more mature than boys. (RJC)