In this article, we contrast evolutionary and psychobiological models of individual development to address the idea that individual development occurring in prototypically risky and unsupportive environments can be understood as adaptation. We question traditional evolutionary explanations of individual development, calling on the principle of…

The current study investigated the influence of rewards on very young children's helping behavior. After 20-month-old infants received a material reward during a treatment phase, they subsequently were less likely to engage in further helping during a test phase as compared with infants who had previously received social praise or no reward at…

It has been hypothesized that sensation seeking and impulsivity, which are often conflated, in fact develop along different timetables and have different neural underpinnings, and that the difference in their timetables helps account for heightened risk taking during adolescence. In order to test these propositions, the authors examined age…

This study used data from the National Institute of Child Health and Human Development's Study of Early Child Care and Youth Development to examine relations between parenting, self-control, and externalizing behavior from infancy through 5th grade. Results indicate that self-control measured during middle childhood mediates relations between…

Maternal ratings on internalizing (INT) and externalizing (EXT) behaviors were collected in a large, population-based longitudinal sample. The numbers of participating twin pairs at ages 3, 7, 10, and 12 were 5,602, 5,115, 2,956, and 1,481, respectively. Stability in both behaviors was accounted for by genetic and shared environmental influences.…