The purposes of the study are to describe characteristics of the voice change in sixth-, seventh-, and eighth-grade choir students using Cooksey's voice-change classification system and to determine if the singing self-efficacy of adolescent males is affected by the voice change, grade level, and experience. Participants (N = 80) consisted of…

Growth mixture models (GMMs; B. O. Muthen & Muthen, 2000; B. O. Muthen & Shedden, 1999) are a combination of latent curve models (LCMs) and finite mixture models to examine the existence of latent classes that follow distinct developmental patterns. GMMs are often fit with linear, latent basis, multiphase, or polynomial change models…

In the current study, based on a sample of 1,873 adolescents between 11.4 and 20.9 years of age from the first 3 waves of the National Longitudinal Study of Adolescent Health, we investigated the longitudinal effects of future orientation on levels of and developmental changes in problem behaviors, while controlling for the effects by impulsivity;…

Beyond the traditional notions of intelligence and academic achievement, the successful development of noncognitive or "soft" skills (e.g., personality factors, motivation, creativity) among school-aged youth represents an important objective for any educational system. Such skills have been shown to be significantly predictive of…

Using longitudinal data on 585 youths (48% female; 17% African American, 2% other ethnic minority), the authors examined the development of social response evaluation and decision (RED) across childhood (Study 1; kindergarten through Grade 3) and adolescence (Study 2; Grades 8 and 11). Participants completed hypothetical-vignette-based RED…

The influence of using substances with friends on future individual use was examined in the context of parental monitoring rules and the ecology of peer activities. A 1-year longitudinal study design included a combined sample of North Italian and French Canadian adolescents (N = 285, 53% girls, M = 14.25 years). Data analyses were conducted using…