Longitudinal data analysis has been widely employed to examine between-individual differences in within-individual changes. One challenge of such analyses is that the rate-of-change is only available indirectly when change patterns are nonlinear with respect to time. Latent change score models (LCSMs), which can be employed to investigate the…

In light of the growing interest in the cognitive approach to task in second language (L2) research, comparatively little has been done to examine such effect over time and the role of individual differences (IDs). The present study was designed to verify some longitudinal evidence for the role of tasks in L2 production and whether IDs, in the…

The context of this study is the Danish upper secondary school, which has undergone remarkable changes during the past ten years. Cross-disciplinary activities have been introduced as a teaching principle in order to create new skills for future generations in the knowledge society, while team organization among teachers has become obligatory in…

In this article a continuous-time stochastic model (the Ornstein-Uhlenbeck process) is presented to model the perpetually altering states of the core affect, which is a 2-dimensional concept underlying all our affective experiences. The process model that we propose can account for the temporal changes in core affect on the latent level. The key…

Latino adolescents often are less likely to participate in extracurricular activities compared to youth from other ethnic groups. This descriptive study examined the differences in activity participation by family resources and markers of cultural orientation for the four largest Latino ethnic groups in the U.S. Findings were based on secondary…

Obesity and high body fat percentages are a major public health issue. The percentage of obese and overweight Americans has increased over the past 30 years. On average, overweight individuals with higher percent body fat than normal weight individuals are at increased risk for numerous negative outcomes both physically and mentally. A prime time…

In 2004, the pattern in academic pathways for high school students in the USA showed that students were completing more demanding mathematics courses. Despite the upward pattern in advanced-level mathematics course-taking, disparities among racial/ethnic groups persisted between 1982 and 2004. Using data from the Education Longitudinal Study of…

The author examined enrollment differences at postsecondary institutions between students with and without disabilities in science, technology, engineering, and mathematics (STEM) majors to investigate the extent to which students with disabilities, compared with their counterparts, pursue highly demanded STEM careers that require postsecondary…

Growth mixture modeling (GMM) is a method for identifying multiple unobserved sub-populations, describing longitudinal change within each unobserved sub-population, and examining differences in change among unobserved sub-populations. We provide a practical primer that may be useful for researchers beginning to incorporate GMM analysis into their…

Discussed are limitations of studies focused on group data and some alternative conventions that might be used in reporting data so that it accurately represents individual subjects' patterns of language development. Evidence is presented from (1) a study of mothers' attempts to elicit verbal behavior from their normally developing or moderately…

Study investigated whether the observed individual differences in visual pursuit endure beyond the neonatal period. (Authors/MB)

Researchers in the fields of cognitive and language development have made less use of large-scale longitudinal designs and of person-centered approaches to data analysis than have researchers in the fields of social and personality development. It is argued that differences among domains of developmental psychology in the research methods employed…

Many educational questions of research interest focus on individual differences in attitudes and behaviors related to academic achievement, changes in such attitudes and behaviors over time, and the types of academic environments that facilitate or prevent development of achievement attitudes and behaviors at school. This paper, the first in a…

Does nutritional deficiency retard psychological development? The Tulane Nutrition Study reports the first segment of its research based on extensive analysis of psychological and nutritional data gathered predominately on children who attended five, 6-week Head Start programs. Scores on a battery of eight psychological tests and two hematological…

Data from the National Longitudinal Surveys of Labor Market Experience were analyzed to determine the unemployment experiences of four groups of workers from the labor force during a recent decade. The subjects were men who at the end of the decade were 26-34 and 55-69 and women who were 26-34 and 40-54 years of age. Information on unemployment…