Genetic and environmental factors account for variability in a range of developmental outcomes, including socioeconomic status (SES). The challenge is to find ways to incorporate genetic information based on studies using biologically related family members (i.e., studies not involving twins). To address this issue, we computed polygenic scores…

Prior nonexperimental studies have been used to conclude that children's reading and mathematics achievement bidirectionally influence each other over time, with strong paths from (a) early reading to later mathematics and (b) early mathematics to later reading. In the most influential study on the topic, the early math-to-later-reading path was…

The goal of this article was to examine gender-typed behavior longitudinally and to consider its relationship with sexual orientation in adulthood. Data were from 10,624 respondents who completed Wave 1 (adolescence), Wave 3 (emerging adulthood), and Wave 4 (early adulthood) of the National Longitudinal Study of Adolescent to Adult Health. First,…

Guided by evolutionary-developmental models, this study tested the hypothesis that children's exposure to parental relationship instability, defined by initiation and dissolution of caregiver intimate relationships, has both costs in cognitive impairments and benefits in enhanced learning skills. Participants included 243 mothers and their…

Behavioral research has shown that 12- but not 9-month-olds imitate an unusual and inefficient action (turning on a lamp with one's forehead) more when the model's hands are free. Rational-imitation accounts suggest that infants evaluate actions based on the rationality principle, that is, they expect people to choose efficient means to achieve a…

In recent years, an increased interest in the importance of children's ability to regulate emotions in socially adaptive ways has driven considerable research on the development of emotion regulation. A widely studied emotion regulation strategy known as "expressive suppression" (ES), in which a person attempts to conceal…

The association between academic self-concept and achievement is assumed to be reciprocal. Typically, the association is analyzed by variants of the classical cross-lagged panel model. Results with more recently developed methodological approaches, for example, the random intercept cross-lagged panel model, its continuous-time implementation, and…

Nordic welfare states have been very successful at reducing poverty and inequality among their citizens. However, the presence of a strong social safety net in these countries has not solved the problem of "socioeconomic exclusion", manifesting in such outcomes as chronic unemployment and welfare dependency. In an effort to understand…

The aim of this longitudinal study is to evaluate 3 views on the relationship between nonword repetition and vocabulary: (i) the storage-based view that considers nonword repetition, a measure of phonological storage, as the driving force behind vocabulary development, (ii) the lexical restructuring view that considers improvements in nonword…

Loneliness is a stressful experience that appears to interfere with health and social integration (SI). Recently, researchers proposed that both antecedents and consequences of loneliness may change across the life span. To fully understand the processes related to loneliness it may thus be crucial to adopt an age-differentiated perspective. This…

How can individuals regulate their own development to live happy, healthy, and productive lives? Major theories of developmental regulation across the life span have been proposed (e.g., dual-process model of assimilation and accommodation; motivational theory of life-span development; model of selection, optimization, and compensation), but they…

We propose a model linking the early parent-child mutually responsive orientation (MRO), children's temperament trait of effortful control, and their internalization of conduct rules. In a developmental chain, effortful control was posited as a mediator of the links between MRO and children's internalization. MRO was further posited as a moderator…

Ever since the classic research of Nicholls (1976) and others, effort has been recognized as a double-edged sword: while it might enhance achievement, it undermines academic self-concept (ASC). However, there has not been a thorough evaluation of the longitudinal reciprocal effects of effort, ASC, and achievement, in the context of modern…

The vast majority of studies on theory of mind (ToM) have focused on the preschool years. Extending the developmental scope of ToM research presents opportunities to both reassess theoretical accounts of ToM and test its predictive utility. The twin aims of this longitudinal study were to examine developmental relations between ToM, executive…

A wealth of literature has examined the association between breastfeeding and the development of cognitive abilities in childhood. In particular, at least some evidence exists suggesting that breastfed children perform better on measures of intelligence later in life. Although a correlation appears to be present, fewer observational studies have…