The theory-of-mind abilities of twins, children with nontwin siblings, and only children were compared to investigate further the link between number and type of siblings and theory-of-mind abilities. Three- to 5-year-old children with nontwin siblings outperformed both only children and twins with no other siblings, twins who also had other…

Young children's beliefs about the relationship between gender and aggression were examined across 3 studies (N121). In Study 1, preschoolers (ages 3 to 5) described relational aggression as the most common form of aggression among girls and physical aggression as the most common form among boys. In Study 2, preschoolers and a comparison group of…

Eight- to 12-month-olds might make A-not-B errors, knowing the object is in B but searching at A because of ancillary (attention, inhibitory, or motor memory) deficits, or they might genuinely believe the object is in A (conceptual deficit). This study examined how diligently infants searched for a hidden object they never found. An object was…

This paper examined associations between mothers' work schedules and children's cognitive outcomes in the first 3 years of life for approximately 900 children from the National Institute of Child Health and Human Development Study of Early Child Care. Both the timing and duration of maternal nonstandard work schedules were examined. Although…

Behavioral responses of 3- to 4-day-old newborns to the odors of various human milk (HM) and formula milk (FM) were examined in paired-choice tests. When both stimuli were nonfamiliar, breast-fed, as well as bottle-fed, infants oriented their head and mouthed more vigorously to HM than to FM. When breast-fed infants were exposed to nonfamiliar HM…

Adults use both first-order, or categorical, relations among features (e.g., the nose is above the mouth), and second-order, or fine spatial relations (e.g., the space between eyes), to process faces. Adults' expertise in face processing is thought to be based on the use of second-order relations. In the current study, 5-month-olds detected…

This study examined, in 3 cohorts (1990, 1998, and 2002) of elementary school children (M age10 years), relations between social functioning and adjustment in different phases of the societal transition in China. Data were obtained from multiple sources. The results indicate that sociability-cooperation was associated with peer acceptance and…

The links between single mothers' employment patterns and change over time in the well-being of the mothers' adolescent children were investigated using the National Longitudinal Survey of Youth. Adolescents were ages 14 to 16 at baseline, and they and their mothers were followed for 2 years. Relative to being continuously employed in a good job,…

In this study, 126 children were observed at 6 months, 12 months, and 2 years. During infancy, latencies to reach for novel objects were measured. At 2 years, positive and negative affect, and behavioral approach-inhibition to low- and high-intensity situations were coded, and mothers assessed behavior problems. Confirmatory factor analysis…

Cross-situational continuity and change in anxious solitary girls' behavior and peer relations were examined in interactions with familiar versus unfamiliar playmates. Fourth-grade girls (N=209, M age 9.77 years, half African American, half European American) were identified as anxious solitary or behaviorally normative using observed and…

The current study examined how individual differences in children's temperament and motivation relate to attention skills in children from economically disadvantaged families. A total of 73 motherchild dyads participated in this study. Children were between the ages of 3 and 5, and all attended a Head Start program. Using multiple hierarchical…

Toy choices of 3- to 10-year-old children with congenital adrenal hyperplasia (CAH) and of their unaffected siblings were assessed. Also assessed was parental encouragement of sex-typed toy play. Girls with CAH displayed more male-typical toy choices than did their unaffected sisters, whereas boys with and without CAH did not differ. Mothers and…

Two experiments explored how infants learn to form an abstract categorical representation of support (i.e., on) when habituated to few (i.e., 2) or many (i.e., 6) examples of the relation. When habituated to 2 pairs of objects in a support relation, 14-month-olds, but not 10-month-olds, formed the abstract spatial category (i.e., generalized the…

In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana…

This research examined the hypothesis that a tendency to base one's self-worth on peer approval is associated with positive and negative aspects of children's well-being. A sample of 153 fourth through eighth graders (9.0 to 14.8 years) reported on need for approval, global self-worth, social-evaluative concerns, anxiety and depression, and…