Machiavellianism is an antisocial interpersonal style involving the use of manipulative, deceptive, and coercive behaviors in the pursuit of self-interest. Although widely studied as a "dark" personality trait in adults, relatively little is known about the developmental correlates of Machiavellian tendencies earlier in life. The present…

Twins regularly score nearly a standard deviation below the population mean on standardized measures of cognitive development in infancy but recover to the population mean by early childhood, making rapid gains through the toddler years. To date, only polynomial growth models have been fit to model cognitive recovery across childhood, limiting the…

Early research that relied on standardized assessments of intelligence reported negative effects of bilingualism for children, but a study by Peal and Lambert (1962) reported better performance by bilingual than monolingual children on verbal and nonverbal intelligence tests. This outcome led to the view that bilingualism was a positive…

How we feel about an outcome often depends on how close an alternative outcome was to occurring. In four experiments, we investigated whether predominantly White, middle-class, Canadian children (N = 425, Experiments 1-3) and American adults (N = 227, Experiment 4) consider close counterfactual alternatives when inferring other people's emotions.…

Individual differences in music traits are heritable and correlated with the development of cognitive and communication skills, but little is known about whether diverse modes of music engagement (e.g., playing instruments vs. singing) reflect similar underlying genetic/environmental influences. Moreover, the biological etiology underlying the…

This study examined the factor structure of executive control throughout elementary school, as well as associations between executive control abilities in preschool and elementary school. Data were drawn from a longitudinal study of executive control development in a community sample of children (N = 294; 53% female, 47% male) oversampled for low…

Computer vision algorithms have made tremendous advances in recent years. We now have algorithms that can detect and recognize objects, faces, and even facial actions in still images and video sequences. This is wonderful news for researchers that need to code facial articulations in large data sets of images and videos, because this task is time…

Considerable recent work suggests that mathematical abilities in children correlate with the ability to estimate numerosity. Does math correlate only with numerosity estimation, or also with other similar tasks? We measured discrimination thresholds of school-age (6- to 12.5-years-old) children in 3 tasks: numerosity of patterns of relatively…

Some previous reviews conclude that breastfeeding is not significantly associated with increased intelligence in children once mother's IQ is statistically controlled. The conclusion may potentially have both theoretical and methodological problems. The National Child Development Study allows the examination of the effect of breastfeeding on…

As a spoken word unfolds over time, similar sounding words ("cap" and "cat") compete until one word "wins". Lexical competition becomes more efficient from infancy through adolescence. We examined one potential mechanism underlying this development: lexical inhibition, by which activated candidates suppress…

Although many studies use feedback learning paradigms to study the process of learning in laboratory settings, little is known about their relevance for real-world learning settings such as school. In a large developmental sample (N = 228, 8-25 years), we investigated whether performance and neural activity during a feedback learning task…

Neurological soft signs (NSSs), minor neurological abnormalities, have been implicated as risk factors for poor cognitive performance in small-scale studies. Here we investigate the associations between NSSs and multiple domains of cognitive performance in a large, population-based cohort and evaluate sex differences in these associations. We…

Given the importance of writing for academic achievement, this study aimed to understand how early oral language contributes to later writing skills. The first objective was to determine if preschool language skills were associated with high school writing, and if so, whether they contributed directly or indirectly through school age language. The…

Throughout childhood and adolescence, humans experience marked changes in cortical structure and cognitive ability. Cortical thickness and surface area, in particular, have been associated with cognitive ability. Here we ask the question: What are the time-related associations between cognitive changes and cortical structure maturation.…

When threatened with ostracism, children attempt to strengthen social relationships by engaging in affiliative behaviors such as imitation. We investigated whether an experience of ostracism influenced the extent to which children imitated a partner's language use. In two experiments, 7- to 12-year-old children either experienced ostracism or did…