Studies investigating evolutionary theories on the origins of national differences in intelligence have been criticized on the basis that both national cognitive ability measures and supposedly evolutionarily informative proxies (such as latitude and climate) are confounded with general developmental status. In this study 14 Y chromosomal…

Many aspects of cognition decline from middle to late adulthood, but the dimensionality and generality of this decline have rarely been examined. We analyzed 20-year longitudinal data of 6203 middle-aged to very old adults from Greater Manchester and Newcastle-upon-Tyne, UK. Participants were assessed up to eight times on 20 tasks of fluid…

The concept of general intelligence ("g") summarizes the well established finding that scores on separate cognitive tasks are positively correlated, indicating a trait common to many aspects of information processing. Inspection time is a well-established correlate of IQ, where those of a higher IQ can correctly identify a briefly…

Self-perceived abilities (SPA), which play an important role in academic achievement, have been recently reported to be fully attributable to genetic and non-shared environmental influences. To replicate and extend this finding, 732 Croatian twins (15-22 years old) were assessed on cognitive ability, self-assessed intelligence (SAI), and Five…

General cognitive ability ("g") does not explain sex differences in academic test performance by the end of compulsory education. Instead, individual differences in specific reasoning abilities, after removing the effects of "g," may contribute to the observed gender gaps. Associations between general or specific cognitive…

This study explores whether or not intelligence tests' scores predict individual differences in scholastic achievement irrespective of SES factors such parents' income and education. The variables of interest are analyzed considering three independent samples of participants comprising a total of 641 children. The participants belonged to a…

A theoretical overview of the relationship between nonacademic aspects of intelligence and success in immigrating is presented, and an empirical study involving 65 scientists who immigrated to Israel is reported. Findings suggest that the individual intelligence of the immigrant is a major determinant of immigration success. (SLD)

Studied the associations between scores on a test of general mental ability and reaction time, measured with a "Hick"-style device, using a sample of 900 adults (aged 56 years) in Scotland. Results agree with literature reviews suggesting that reaction times and their variabilities are stronger correlates of mental test scores than are…

Tested 101 adults, aged 77, who had completed psychometric intelligence testing in 1932, with the same test of mental ability. Results of this study, the longest follow-up study reported to date, show substantial stability in mental ability differences from childhood to late life. (SLD)

The relationship between general intelligence and the ability to ignore irrelevant stimuli appearing in the same visual field as an attended target was studied for 167 college students. Results indicate that psychometric intelligence does not tap visual focused attention. (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.…

Studied individual differences in the ability to allocate processing resources among competing tasks and its relationship with general cognitive ability for 50 Israeli undergraduates performing single and dual tasks. Results suggest that the unique ability to perform dual tasks may become more automatic and less controlled with practice so that…

Data from the national standardization of the French version of the WISC-III were analyzed to determine when during childhood the IQ-related process of differentiation appears and how the strength of the relationships among subtests evolves with age in low- and high-IQ groups. Indeed, some recent studies suggest that age might moderate the effect…

A large sample of 11-year-olds were observed on a perceptual maze task. Three ability level groups were formed and compared as to overall response paths and specific binary decision configurations. Explanations for observed qualitative differences and discussion of the viability of the experimental approach adopted are presented. (Author/RD)

The hypothesis that a task that increases in complexity (increasing its correlation with a central measure of intelligence) does so by increasing its dimensionality by tapping individual differences or another variable was supported by findings from 46 adults aged 20-70 years performing a mental counting task. (SLD)