We examined the degree to which the conventional notion of g associated with IQ tests and general cognitive ability tests ("COG-g") relate to the general ability that underlies tests of reading, math, and writing achievement ("ACH-g"). Two large, nationally representative data sets and two independent individually-administered…

Executive functions (EF) and intelligence are of critical importance to success in many everyday tasks. Working memory, or updating, which is one latent variable identified in confirmatory factor analytic models of executive functions, predicts intelligence (both fluid and crystallised) in adults, but inhibition and shifting do not (Friedman et…

The general differentiation hypothesis states that the strength of the correlations among a set of IQ subtests varies with a given variable. Instances of the general differentiation hypothesis that have been considered in the literature include age and ability differentiation. Traditionally, the differentiation effect is attributed to the varying…

Mental chronometry (MC) studies cognitive processes measured by time. It provides an absolute, ratio scale. The limitations of instrumentation and statistical analysis caused the early studies in MC to be eclipsed by the "paper-and-pencil" psychometric tests started by Binet. However, they use an age-normed, rather than a ratio scale, which…

Although it is well established that preterms as a group do poorly relative to their full-term peers on tests of global cognitive functioning, the basis for this relative deficiency is less understood. The present paper examines preterm deficits in core cognitive abilities and determines their role in mediating preterm/full-term differences in IQ.…

To understand the extent to which the general-factor loadings of tests are inherent in their characteristics or due to the sampling of tests, the number of tests in the correlation matrix, and the factor-extraction methods used to obtain them, test scores from a large sample of young adults were inserted into independent and overlapping batteries…

The working memory (WM) construct is conceptualized similarly across domains of psychology, yet the methods used to measure WM function vary widely. The present study examined the relationship between WM measures used in the laboratory and those used in applied settings. A large sample of undergraduates completed three laboratory-based WM measures…

National differences in murder, rape, and serious assault were examined in 113 countries in relation to national IQ, income, skin color, birth rate, life expectancy, infant mortality, and HIV/AIDS. Data were collated from the 1993-1996 International Crime Statistics published by INTERPOL. Violent crime was found to be lower in countries with…

Considers P. Schonemann's simulation study in light of the multigroup principal component analysis model and interprets it as a study of the specificity of Spearman correlations, given model violations. Asserts that the Spearman correlation is a suboptimal test of Spearman's hypothesis and contends that an explicit model-based approach should be…

Event-related potentials (ERPs) and reaction time (RT) were recorded concurrently during performance of 6 simple cognitive tasks by 30 right-handed women who varied in mental ability. Results suggest that ERPs and RT may assess stimulus evaluation time and the response-production time components of cognitive information processing. (Author/SLD)

A study was conducted in which 226 participants performed 12 tests, 6 thought to reflect verbal, quantitative, and spatial working memory (WM), and 6 of crystallized (Gc), fluid (Gf), and spatial (Gv) cognitive abilities. Confirmatory factor analyses (CFAs) were computed to test the unitary nature of the WM system. Six primary latent factors were…

A battery of information processing measures and psychometric tests of specific and general cognitive abilities was administered to 34 monozygotic and 13 dizygotic reared apart twin pairs or triplets. Correlations between information processing parameters and psychometric abilities as well as twin resemblances for the information processing…

Mildly retarded young adults were given simple and choice reaction time (RT) tests. Subjects' RTs increased with stimulus complexity. RTs of retarded subjects were slower and evidenced more intraindividual variability than those of nonretarded subjects. Several RT parameters were related to measures of intelligence. (Author/RD)

A hierarchical factor solution was obtained from a psychometrized battery of Piagetian-type tasks individually administered to 660 kindergarten children. The first two levels of factors included Piagetian theoretical entities. A third level factor was identified as a g. The association of Piagetian tasks with academic achievement was through the g…

The stability of psychometric "g," the general factor of intelligence, is investigated in simulated correlation matrices and in typical empirical data from a large battery of mental tests. "G" is robust and almost invariant across methods of analysis. A reasonable strategy for estimating "g" is suggested. (SLD)