A longitudinal study was conducted to identify unique sources of individual differences in later understanding of the equal sign as a relational symbol of equivalence (i.e., formal understanding of mathematical equivalence). The sample included 141 children from a mid-sized city in the Midwestern United States (M[subscript age] = 6 years, 2 months…

Research has shown that two different, though related, ways of representing magnitude play foundational roles in the development of numerical and mathematical skills: a nonverbal approximate number system and an exact symbolic number system. While there have been numerous studies suggesting that the two systems are important predictors of math…

Data from 790 older school-age (M[subscript age] = 10.2 years, SD = 1.2 years) girls (N = 427) and boys from Barranquilla, Colombia (N = 449) and Montréal, Canada (N = 331) were used to replicate findings reported by Valdivia et al. (2005). This prior study revealed contextual variations in the association between two measures of social behavior,…

The current study examined the developmental trajectory of same-race friendship preference of racially/ethnically diverse students over the course of middle school. Participants were African American, Asian, Latinx, and White youth recruited at the start of middle school in 6th grade (N = 4,361; M[subscript age] = 11.33 years) and followed across…

Achievement goal theory has long been a dominant model in the study of student motivation. However, a relatively small number of researchers have investigated gender differences in achievement goals or have considered the possible role that social and extrinsic goals may play in student academic motivation. Adopting a person-centered multiple…

Drawing on a 2-wave longitudinal sample spanning 40 years from childhood (age 12) to middle adulthood (age 52), the present study was designed to examine how student characteristics and behaviors in late childhood (assessed in Wave 1 in 1968) predict career success in adulthood (assessed in Wave 2 in 2008). We examined the influence of parental…

Much of child care research has focused on the effects of the quality of care in early childhood settings on children's school readiness skills. Although researchers increased the statistical rigor of their approaches over the past 15 years, researchers' ability to draw causal inferences has been limited because the studies are based on…

Despite extensive research on sleep and psychosocial functioning, an important gap within the literature is the lack of inquiry into the direction of effects between these 2 constructs. The purpose of the present 3-year longitudinal study was to examine bidirectional associations between sleep (quality and duration) and 3 indices of psychosocial…

Many child care centers temporarily move children and teachers in and out of their assigned classrooms throughout the day. Such practices create frequent discontinuity in children's experiences in child care, including discontinuity in their peer and teacher relationships. This study examined the prevalence and patterns of teacher and child…

On the basis of a large-scale survey of high-school youth, the authors compared adolescents reporting exclusively heterosexual, mostly heterosexual, bisexual, and predominately same-sex attraction based on high-risk involvement across a range of risk behaviors. Bisexual and same-sex attracted groups were characterized by heightened high-risk…

A longitudinal study of 80 toddlers, preschoolers, and kindergartners found that children who entered early in low quality care had the most difficulty with peers in preschool. Lives of parents who used low quality care were characterized by complexity and use of less appropriate socialization practices than those used by other parents. (RH)

Examined main and interactive effects of multiple social risk factors and preschool IQ and mental health on students' academic trajectories from first to twelfth grade. Found that high-risk students had lower grades and more absences from first to twelfth grade than low-risk students. Higher IQ and better mental health improved the grade point…