As research on mediation has grown, so too has interest in identifying ways to assess the size of indirect effects in a mediation analysis. One such estimate -- the ratio of the indirect effect to the total effect (P[subscript M]) -- was tested in a sample of 21,297 children from the Early Childhood Developmental Study. Results showed that the two…

Latent change score models (LCS) are conceptually powerful tools for analyzing longitudinal data (McArdle & Hamagami, 2001). However, applications of these models typically include constraints on key parameters over time. Although practically useful, strict invariance over time in these parameters is unlikely in real data. This study…

The current study represents the first longitudinal investigation of the potential effects of breastfeeding duration on maternal sensitivity over the following decade. This study also examined whether infant attachment security at 24 months would mediate longitudinal relations between breastfeeding duration and changes in maternal sensitivity over…

Background: We examined the longitudinal trajectory of substance use (binge drinking, marijuana use, and cocaine use) in relation to self-esteem from adolescence to young adulthood. Methods: Generalized estimating equation models were fit using SAS to investigate changes in the relation between self-esteem and each substance use (binge drinking,…

This study examined the relationship between developmental assets during early and mid-adolescence and early adult sexual behaviors among American Indians using a subsample from the National Longitudinal Study of Adolescent Health (N = 465). Grounded in an assets framework, the authors explored the protective role of personal, family, school, and…

Infants exhibit visual preferences for gender-typed objects (e.g., dolls, toy vehicles) that parallel the gender-typed play preferences of preschool-aged children, but the developmental stability of individual differences in early emerging gender-typed preferences has not yet been characterized. In the present study, we examined the longitudinal…

Understanding patterns of educational attainment among rural youth is a critical concern for our nation as we seek to make postsecondary access and attainment more equitable across our increasingly diverse student population. The current study examines data collected in the Education Longitudinal Study of 2002 to identify contemporary patterns of…

Most researchers on media and aggression have examined the behavioral effects of viewing physical aggression in the media. Conversely, in the current study, I examined longitudinal associations between viewing "relational aggression" on TV and subsequent aggressive behavior. Participants included 467 adolescents who completed a number of…

The study of executive function (EF) has become increasingly popular in multiple areas of research. A wealth of evidence has supported the value of EF in shaping notable outcomes across typical and atypical development; however, little evidence has supported the cognitive contributors to early EF development. The current study used data from a…

This study examines the power of cognitive and noncognitive variables to predict students' performance in algebra. We investigated students' prior year's assessment scores and demographic characteristics to predict eighth-grade algebra scores. Using California statewide assessment data, we explored predictive factors in three regression models.…

The purpose of the present study was to determine whether there are visual-spatial gender differences in two-year-olds, to investigate the environmental and cognitive factors that contribute to two-year-olds' visual-spatial skills, and to explore whether these factors differ for boys and girls. Children (N = 63; M[subscript age] = 28.17 months)…

School-entry math achievement is a strong predictor of math achievement through high school. We asked whether reciprocal relations among math achievement, math anxiety, and entity motivational frameworks (believing that ability is fixed and a focus on performance) can help explain these persistent individual differences. We assessed 1st and 2nd…

Women are underrepresented in many science, technology, engineering, and mathematics (STEM) majors and in some non-STEM majors (e.g., philosophy). Combining newly gathered data on students' perceptions of college major traits with data from the Education Longitudinal Study of 2002 (ELS:2002), we find that perceived gender bias against women…

This article explores the relationship between toddlers' (age: 30-33 months) well-being (WB), play (PL), social-emotional competence (SC) and movement skills (MS). Two hypotheses were put forward for testing: (1) there is a significant positive correlation between WB, PL, SC and MS, and (2) toddlers' WB can be predicted from their PL, SC and MS.…

Research abounds on adolescent poverty and on gifted education, but these fields are seldom considered together. This study explores trajectories of aggressive behavior (i.e., weapon carrying) of impoverished, gifted youth. Results indicate that gifted students engage in lower levels of weapon carrying than non-gifted students. Gifted and…