Whereas some evidence suggests that toddlers consider targets' deservingness when deciding whom to help, other research demonstrates that toddlers help indiscriminately. The present findings shed light on this discrepancy by demonstrating that although toddlers do exhibit selectivity in giving behaviors, their emotional responses are comparatively…

Longitudinal data from a large sample of twins participating in the Netherlands Twin Register (n = 42,827, age range 3-16) were analyzed to investigate the genetic and environmental contributions to childhood aggression. Genetic auto-regressive (simplex) models were used to assess whether the same genes are involved or whether new genes come into…

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…

Two studies examined when and why children (10-13 years) help ethnic in-group and out-group peers. In Study 1 (n = 163) children could help an out-group or in-group peer with a word-guessing game by entering codes into a computer. While children evaluated the out-group more negatively than the in-group, they helped out-group peers "more"…

To investigate children's inclusion of language-outgroup members, English-speaking children (8-9 years and 10-11 years of age, N = 57) made inclusion decisions while playing a simulated ball-tossing game, Cyberball, and while evaluating hypothetical scenarios involving language-outgroup members who wanted to play with their group. In the Cyberball…

Adopted persons face special challenges in the development of identity, as aspects of their histories may be unknown, making it difficult to construct a coherent narrative linking past, present, and future. Extensive literature on adjustment outcomes for adopted persons indicates an elevated risk for adjustment problems. In this study, a low-risk…

Parent- and lab-based observer ratings were employed to examine genetic and environmental influences on continuity and change in inhibitory control (IC) in over 300 twin-pairs assessed longitudinally at 2 and 3 years of age. Genetic influences accounted for approximately 60% of the variance in parent-rated IC at both ages. Although many of the…

The developmental significance of youths' racial identities during adolescence is well established. It is less clear how puberty, a normative process, influences the relationship between racial identity and adjustment outcomes during adolescence. This study examined whether puberty moderates the relationship between racial identity dimensions and…

Infants' motor skill development triggers changes in parent-infant interactions, exploration, and play behaviors, particularly during periods of locomotor transitions. We investigated how these transitions reorganized infants' and mothers' explorations of spatial layouts. Thirteen infants and their mothers were followed biweekly from the age of 6…

A community sample of 192 parents reported on their children's restricted and repetitive behaviors (RRBs) at mean ages 15 months (N = 138), 26 months (N = 191), and 77 months (N = 125) using the Repetitive Behavior Questionnaire-2 (RBQ-2). Consistent with previous factor analytic research, 2 factors were found at each age: 1 comprising repetitive…

We examined the prediction that the interaction between Glucocorticoid Receptor Gene ("NR3C1") methylation, stress, and experienced maternal support predicts anxious and avoidant attachment development. This was tested in a general population sample of 487 children and adolescents (44% boys, M[subscript age] = 11.84, SD[subscript age] =…

Given that maternal support promotes healthy social and emotional development in early childhood, it is important to understand the predictors of such support, especially during emotional challenges. In this study, mothers' dispositional distress reactivity (i.e., the tendency toward experiencing distress in response to children's negative…

Recent research with Western populations has demonstrated that children use imitation flexibly to engage in both instrumental and conventional learning. Evidence for children's imitative flexibility in non-Western populations is limited, however, and has only assessed imitation of instrumental tasks. This study (N = 142, 6- to 8-year-olds)…

In view of the theory that the attachment relationship provides a foundation for the development of emotion regulation, here, we evaluated (a) whether change in attachment security from 4 to 6 years predicts change in emotion regulation from 6 to 8 years and (b) whether "5-HTTLPR" moderates this relation in a Norwegian community sample…

Parental induction of empathy-related guilt plays an important role in children's moral development. However, guilt induction can also be psychologically controlling and detrimental for youth adjustment. This study provided a more nuanced view of parental guilt induction by examining how the nature of a child's misdeed and the structure and…