Examines the interplay between genes and environment and argues that the development of much individual variation can be explained in terms of relatively simple forms of underlying regulation. Looks at "sensitive periods," during which variation is produced by experience received at a particular age. Includes a discussion of the…

Genetic and environmental influences on heart rate were studied in samples of twin pairs in middle childhood. Heart rate was measured in resting situation and under two task conditions. Heart rate was related to parental ratings of shyness, emotionality, and selective attention measure. Multivariate analysis suggested that covariance between heart…

Examines reactions to menarche and the subsequent effects of this experience as a function of preparation for and timing of menarche. A questionnaire including measures of responses about first menstruation, current symptoms, and self-image was completed by 639 girls in fifth through twelfth grades. (Author/MP)

Reports two studies in which 12- to 13-year-old girls, half of whom were premenarcheal and half postmenarcheal, responded to pictures of infants. Concurrent assessments of interest in motherhood, cognitive sophistication about the relationship between menarche and childbearing, attitudes toward menarche, and sex-role self-image did not…

To study whether individual differences in general cognitive ability differ in males and females, full-scale IQ data from 426 child twin pairs were fitted to a structural equation model of sex limitation. Individual differences in general cognitive ability appear to be substantially due to common genetic influences in males and females. (SLD)

Used steady-state probe topography to investigate the cortical activity of 12 average and 12 high IQ Australian college students during a spatial working memory task. Results, in terms of changes in visual evoked potentials, suggest that the areas of the brain involved in working memory are influenced by individual differences in intelligence.…

Findings of a series of studies on individual differences and maturational changes in expressivity at the neonatal stage and during early infancy are reported. Research results indicate that newborns are able to discriminate and imitate the basic emotional expressions: happy, sad, and surprised. Results show widened infant lips when the happy…

The authors propose a matrix for a comprehensive approach to cognition and aging. The dimensions of the matrix are (1) biological, psychological, and social factors; and (2) the information processing variables of input, processing, and output. (Journal availability: Department of Adult Education, Kansas State University, Manhattan, KS 66506.) (SK)

The development of 58 preterm low-risk infants was compared over their first 7 years with 100 full-term infants. The study found "catch up" phenomena at certain ages and periods of reversal. Results also indicated that advantaged family circumstances may reduce or compensate for preterm birth whereas a disadvantaged environment may amplify adverse…

Sibling differences in family processes, such as parental monitoring, and in individual adjustment were examined for 133 pairs of 10- to 18-year-old siblings in divorced families. Found that siblings who lived apart after their parents' divorce differed more than siblings who lived together. (MDM)

Examined the impact of 2 environmental factors--social class and family risk levels--and 2 biological factors--intraventricular hemorrhage (IVH) and medical risk--on the cognitive and motor development of 175 preterm infants. Family risk, early medical risk, and the interaction of family risk and IVH were found to be significant predictors of…

This report offers a broad overview of the three major categories of explanations of gender patterns in cognitive functioning. Two of the major categories are biological and psychosocial. The third category, explanations that have been attributed to differences in the educational experiences of men and women, is treated separately because while…

The course of study of time-of-day effects on human performance has not been an easy one to chart, with many findings that seem to be in opposition. This review examines the difference between group and individual differences with regard to time-of-day effects; time-of-day effects in individuals; morningness-eveningness as an individual…