Antisocial peer behavior and low parental knowledge of adolescents' activities are key interpersonal risk factors for adolescent substance use. However, how the magnitude of associations between these risk factors and substance use may vary across adolescence remains less well understood. The present study examined the age-varying associations of…

This study examines developmental change across adolescence in the similarity of friends versus nonfriends. This differential in similarity is a key aspect of the organization of the peer context of development: The stronger the correlation between friends for an attribute, the more the attribute delineates clustering and divisions of friendships.…

Many students' knowledge of fractions is adversely affected by whole number bias, the tendency to focus on the separate whole number components (numerator and denominator) of a fraction rather than on the fraction's integrated magnitude (ratio of numerator to denominator). Although whole number bias appears early in the fraction learning process…

Numerical understanding and arithmetic skills are easier to acquire for whole numbers than fractions. The "integrated theory of numerical development" posits that, in addition to these differences, whole numbers and fractions also have important commonalities. In both, students need to learn how to interpret number symbols in terms of…

Background: "NEEDs for Bones" (NFB), based on the Health Belief Model, is a 4-lesson osteoporosis-prevention curriculum for 11- to 14-year-olds. This study examined the relationship between enjoyment of food tastings and interest in NFB. Methods:NFB was administered by teachers as part of standard practice and evaluated after the fourth…

We examined developmental and individual differences in 6th and 8th graders' fraction arithmetic and overall mathematics achievement and related them to differences in understanding of fraction magnitudes, whole number division, executive functioning, and metacognitive judgments within a crosssectional design. Results indicated that the difference…

We tested 2 hypotheses derived from Moffitt's (1993) taxonomic theory of antisocial behavior, both of which are central to her explanation for the rise in delinquency during adolescence. We tested whether persistently delinquent individuals become more accepted by their peers during adolescence and whether individuals who abstain from delinquent…

Prospective longitudinal data from over 14,000 youth residing in 28 communities in the rural United States were analyzed to examine the emergence of mixed-sex friendship groups in early adolescence. Youth were surveyed on 5 occasions between fall of 6th grade and spring of 9th grade. At each assessment, youth reported the names of up to 7…

Background: Insufficient physical activity among urban youth increases risk of chronic disease.Purpose:This study assessed reported physical activity to determine when disparities in participation emerge and what ecologically guided factors are linked with high activity. Methods:We administered a cross-sectional survey to a diverse sample of 321…

We examined developmental and individual differences in 6th and 8th graders' fraction arithmetic and overall mathematics achievement and related them to differences in understanding of fraction magnitudes, whole number division, executive functioning, and metacognitive judgments within a cross-sectional design. Results indicated that the…

Research conclusions concerning predictors of academic success have been, at best, less than convincing. In fact, these conclusions are more conflicting or mixed when emotional constructs are used. As a result, modern curriculum developers as well as classroom instructors seem to deemphasize, if not ignore, the role of the affective domain in…

This study examined the motivation to read of children in grades two through six. All children in the study were strong in their literal comprehension of narrative text. Some were equally strong in their ability to respond thoughtfully to the text (Blue Group); others struggled to respond to questions requiring them to think about the implications…

Given the strong relationship between number line estimation accuracy and math achievement, might a computer-based number line game help improve math achievement? In one study by Rittle-Johnson, Siegler and Alibali (2001), a simple digital game called "Catch the Monster" provided practice in estimating the location of decimals on a…

This article reports on analyses examining contextual influences on parenting with an ethnically and geographically diverse sample of parents (predominantly mothers) raising 387 children (49% ethnic minority; 51% male) in high-risk communities. Parents and children were followed longitudinally from first through tenth grades. Contextual influences…