English-learning infants attend to lexical stress when learning new words. Attention to lexical stress might be beneficial for word learning by providing an indication of the grammatical class of that word. English disyllabic nouns commonly have trochaic (strong-weak) stress, whereas English disyllabic verbs commonly have iambic (weak-strong)…

An important aspect of perspective-taking ability is the appreciation that mental states such as beliefs, desires, and knowledge change over time. The current study focused specifically on 3-, 4-, and 5-year-olds' understanding that they will have knowledge in the future that they do not currently possess--for example, that when they are…

Moral identity research to date has largely failed to provide evidence for developmental trends in moral identity, presumably because of restrictions in the age range of studies and the use of moral identity measures that are insensitive to age-related change. The present study investigated moral identity motivation across a broad age range (14-65…

The present study examined the effects of socioeconomic status (SES) and sibling differences in birth weight on sibling differences in the receipt of maternal sensitivity (i.e., differential parenting). It was hypothesized that sibling differences in birth weight would predict "absolute" differential parenting across the sibship (i.e.,…

This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner…

Vagal tone is widely believed to be an important physiological aspect of emotion regulation and associated positive behaviors. However, there is inconsistent evidence for relations between children's baseline vagal tone and their helpful or prosocial responses to others (Hastings & Miller, 2014). Recent work in adults suggests a quadratic…

This study investigates whether age-related changes in the structure of 5 complex working memory (WM) tasks (a) reflect a general or domain specific system, (b) follows a similar trajectory across different age spans, and (c) contribute domain general or domain specific resources to achievement measures. The study parsed the sample (N = 2,471)…

Naturalistic dyadic sequences of teaching and learning involving older and younger siblings were investigated in 39 middle-class dyads over a 2-year period in early childhood. Siblings were observed during ongoing interactions in the home setting for 6 90-min sessions at both Time 1 (older sibling "M" age = 4.4 years; younger sibling…

In this study we evaluated whether the sophistication of children's invented spellings in kindergarten was predictive of subsequent reading and spelling in Grade 1, while also considering the influence of well-known precursors. Children in their first year of schooling (mean age = 66 months; N = 171) were assessed on measures of oral vocabulary,…

This study tested 2 related hypotheses. The first holds that high co-rumination anticipates heightened internalizing problems. The second holds that positive relationships with friends exacerbate the risk for internalizing problems arising from co-rumination. A sample of MZ twins followed from birth (194 girls and 170 boys) completed (a)…

Recent studies demonstrate that emerging literacy depends on earlier language achievement. Importantly, most extant work focuses on "parent-reported production" prior to 30 months of age. Of interest is whether and how "directly assessed vocabulary comprehension" in the 2nd year of life supports vocabulary and kindergarten…

This study examined relations of social sensitivity to social, school, and psychological adjustment in rural Chinese, urban Chinese, and Canadian children. Participants were 4th to 6th grade students (M[subscript age] = 11 years) in China (n = 593 and 443 for the rural and urban samples) and Canada (n = 325). A self-report measure of social…

The present study investigated the contribution of morphological and cognate awareness to the development of English and French vocabulary knowledge among young minority and majority language children who were enrolled in a French immersion program. Participating children (n = 75) were assessed in English and French on measures of morphological…

It has been argued that children who possess an advanced theory of mind (ToM) are more likely to act prosocially, yet the empirical findings are mixed. To address this issue definitively, a meta-analytic integration of all prior literature that met appropriate inclusion criteria was conducted. In total, 76 studies including 6,432 children between…

Previous studies have demonstrated that various psychosocial risks are associated with poor cognitive functioning in children, and these risks frequently cluster together. In the current longitudinal study, we tested a model in which it was hypothesized that cumulative psychosocial adversity of mothers would have deleterious effects on children's…