To study effects of the gender-packaging of science, technology, engineering, and mathematics (STEM) toys, mother-child dyads (31 daughters; 30 sons; M = 5.2 years) were randomly assigned to play with a mechanical toy packaged for girls ("GoldieBlox") or boys ("BobbyBlox"). When familiarizing themselves with the toy to prepare…

Adults exhibit strong preferences when framing symmetrical relations. Adults prefer, for example, "A zebra is like a horse" to "A horse is like a zebra," and "The bicycle is near the building" to "The building is near the bicycle." This is because directional syntax requires more typical or prominent items…

Oral language development is a key outcome of elementary school, and it is important to identify factors that predict it most effectively. Commonly researchers use ordinary least squares regression with conclusions restricted to average performance conditional on relevant covariates. Quantile regression offers a more sophisticated alternative.…

Vocabulary knowledge was tested in a native (Cantonese-Chinese) and foreign (English) language in 150 twins and 150 singletons aged 6-11 years, matched on age, gender, grade level, nonverbal intelligence, parents' education, family income, and number of siblings and household members. The singletons clearly outperformed the twins on the native…

Child maltreatment often has a negative impact on the development of social behavior and health. The biobehavioral mechanisms through which these adverse outcomes emerge, however, are not clear. To better understand the ways in which early life adversity affects subsequent social behavior, changes in the neuropeptide oxytocin (OT) in children…

This study leveraged data from the Minnesota Longitudinal Study of Risk and Adaptation (N = 243) to investigate the predictive significance of maternal sensitivity during the first 3 years of life for social and academic competence through age 32 years. Structural model comparisons replicated previous findings that early maternal sensitivity…

This study investigated 282 eight- to twelve-year-old Danish majority children's judgments and justifications of exclusion based on gender and ethnicity (i.e., Danish majority children and ethnic-minority children of a Muslim background). Children's judgments and reasoning varied with the perpetrator of the exclusion and the social identity of the…

This study examined the increase in salivary cortisol from midmorning to midafternoon in 151 children (3.0-4.5 years) in full-time home-based day care. Compared to cortisol levels at home, increases were noted in the majority of children (63%) at day care, with 40% classified as a stress response. Observations at day care revealed that intrusive,…

The study examines group and individual differences in psychological functioning and hypothalamic-pituitary-adrenal and sympathetic nervous system (SNS) activity among adolescents displaced by Hurricane Katrina and living in a U.S. government relocation camp (n = 62, ages 12-19 years) 2 months postdisaster. Levels of salivary cortisol, salivary…

This study examined the effects of prenatal cocaine exposure on infant hypothalamic-pituitary-adrenal axis activity and reactivity at 7 months of infant age. Participants were 168 caregiver-infant dyads (87 cocaine exposed, 81 not cocaine exposed; 47% boys). Maternal behavior, caregiving instability, and infant growth and behavior were assessed,…

Transactional models of problem behavior argue that less effective parenting and adolescent problem behaviors coevolve, exerting bidirectional influences. This article extends such models by analyzing growth trajectories of sexual risk behaviors and parenting processes among 3,206 adolescents (aged 13-18) and their residential parents. Within…

Skin conductance level reactivity (SCLR) was examined as a moderator of the association between harsh parenting and child externalizing behavior. Participants were 251 boys and girls (8-9 years). Mothers and fathers provided reports of harsh parenting and their children's externalizing behavior; children also provided reports of harsh parenting.…