Do stage-related patterns of early cognitive development reported for normally developing children also characterize at-risk and handicapped children when mental age organization of data is used? Mental age predicted Piagetian-based cognitive levels one to three but did not predict highest-level symbolic functioning in 95 handicapped children.…

Patterns of intellectual ability of Arab children aged 6 to 16 years were examined using the new Arab WISC-R. As in prior work, a distinct profile emerged: relative superiority in Verbal over Performance IQ's which diminished with age as a flat profile emerged in adolescence. An environmental explanation is offered. (Author/RD)

Genetic effects on specific cognitive abilities as distinct from those on general cognitive ability were studied in 302 pairs of twins (some reared together, some apart) from the Swedish Adoption/Twin Study of Aging. Overall, results showed significant genetic influence on specific abilities independent of influence on general ability. (SLD)

Spearman's hypothesis states that the differences between Blacks and Whites in psychometric IQ are attributable to a fundamental difference in general intelligence ("g"). To investigate this hypothesis, Jensen devised the method of correlated vectors. This method involves calculating the correlation between the factor loadings of the…

Two experiments examined whether correlations between IQ and probed serial running memory depend on IQ-related individual differences in the retention of order information in short-term memory. Children's IQ correlated with memory, regardless of whether instructions emphasized serial or free recall; and with recent item but not recent order…

Scarr and Weinberg's results (Intelligence, 1977) are compared to those of similar adoption studies and found to be quite similar, despite the transracial adoption patterns in Scarr and Weinberg's sample. The author also suggests that the major contribution of behavioral genetics to psychology may be our increased understanding of the environment.…

A directed forgetting task was used in an investigation of the conditions under which normal and educable mentally retarded junior high school students would disregard irrelevant information. Results showed that irrelevant information in memory interfered with the performance of only the retarded group, when given a minimal explanation of the…

The relationship between psychometric intelligence and rapid acoustic information processing was explored in two experiments using college students. Group differences occurred in threshold interstimulus intervals required for recognition and in speed. Results were interpreted as indicating better information processing efficiency (higher…

Support for the confluence model of intellectual development has come from analyses of family size-birth order means of large aggregate data sets. Analyses of individual scores do not substantiate the confluence model, as explained variance is markedly reduced. The study of family interaction variables utilizing longitudinal data is recommended.…

Zajonc and Bargh's (EJ 241 537) application of the confluence model to six national data sets is critiqued. Extreme differences in intelligence levels are predicted between nations, including substantial retardation for some populations. Moreover, the parameter values used do not allow mental growth functions which are consistent with previous…

In this response to the critiques by Jensen and McVicker Hunt, we focus on the meaning of g, the permanence of effects produced by early education, and the educational significance of IQ gains produced by early education programs. New longitudinal data from our study presented. (Author/RD)

Explanations of differences in IQs of Northern and Southern Blacks focus on selective migration (hereditarians) or environmental causes such as education, discrimination and cultural deprivation. In this paper the environmentalist position is questioned and certain neglected features of Lee's data are construed as providing strong evidence for…

IQ tests and intelligence were discussed from an evolutionary perspective and implications concerning legal decisions and social policy were presented. It was concluded that disproportionate social and economic benefits need not result from the use of IQ tests in the selection of educational and occupational elites. (RD)

Recent studies are examined for methodological adequacy in establishing dimensions of individual differences in information-processing abilities, and the theoretical problems involved in inferring psychological processes from individual difference dimensions. Methodological inadequacies include use of small samples, questionable procedures in…

Relationships between intelligence test scores and measures derived from reaction time and perceptual speed procedures were investigated. Only three reaction time measures produced correlations greater than .25 with a general intelligence factor. Test-retest reliability of reaction time measures was low. The reaction time-intelligence relationship…