We investigated time-related patterns in levels of cognitive performance during the period from 1970 to 1993 based on data from Swedish draft boards. The conscripts, including more than a million 18-19-year old men, had taken one of two versions of the Swedish enlistment battery (SEB67; 1970-1979 or SEB80; 1980-1993), each composed of four…

This study explored the controversy surrounding working memory: whether it is a unitary system providing general purpose resources or a more differentiated system with domain-specific sub-components. A total of 348 participants completed a set of 6 working memory tasks that systematically varied in storage target contents and type of information…

This study investigated intellectual development in 4-7 years old Greek and Chinese children. They were examined on speeded performance, working memory, reasoning, and self-awareness tasks in order to investigate possible effects of learning the Chinese logographic system on possible differences in intellectual development between these ethnic…

Mean gain scores for cognitive ability tests between two sessions in a selection setting are now a robust finding, yet not fully understood. Many authors do not attribute such gain scores to an increase in the target abilities. Our approach consists of testing a longitudinal SEM model suitable to this view. We propose to model the scores' changes…

In two recent papers, Johnson & Bouchard [Johnson, W., & Bouchard, T. J., Jr. (2005a). The structure of human intelligence: It is verbal, perceptual, and image rotation (VPR) , not fluid and crystallized. "Intelligence," 33, 393-416, Johnson W., & Bouchard, T. J., Jr. (2005b). Constructive replication of the visual…

We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear age-related trends towards more efficient visual information processing in older participants. There…

A previous explanation of the sex difference on so-called perceptual speed tests was in terms of a female advantage in accessing and using phonological name codes in making item comparisons. That explanation was extended to a task involving alphabetical transformations without the requirement for comparison of perceptually available items. A…

The relationship between working memory, intelligence and problem-solving is explored. Wittmann and Suss [Wittmann, W.W., & Suss, H.M. (1999). Investigating the paths between working memory, intelligence, knowledge, and complex problem-solving performances via Brunswik symmetry. In P.L. Ackerman, R.D. Roberts (Ed.), "Learning and individual…

Young adults, originally tested as infants for their ability to process information as measured by selective attention to novelty (an operational definition of visual recognition memory), were revisited. A current estimate of IQ was obtained as well as a measure of academic achievement. Information processing ability at 6-12 months was predictive…

A study involving 90 children (50 preterm and 40 full-term) found continuity in visual recognition memory from early infancy (7 months) to later childhood (11 years), even when other measures of memory at 11 years were controlled. Implications for the study of other types of infant memory are discussed. (SLD)

Studied whether a primary imagery (IM) factor can be identified as a separate dimension of individual differences in the spatial ability domain. Findings for 213 adults suggest the existence of three first-order IM factors, and a second-order confirmatory factor analysis suggests that the visual imagery dimensions can be located within the spatial…

Empirical data suggest that there is at most a very small sex difference in general mental ability, but men clearly perform better on visuospatial tasks while women clearly perform better on tests of verbal usage and perceptual speed. In this study, we integrated these overall findings with predictions based on the Verbal-Perceptual-Rotation (VPR)…

The predictability of individual differences in the ability to reason about dynamic displays from tests using static displays was studied in 170 adults given paper-and-pencil and computer controlled tests. Several multivariate analyses indicated that the ability to reason about dynamic motion was distinct from the ability to reason about static…

When adult versions of tests of spatial ability were modified and administered to 94 boys and 99 girls in Norway, results indicated that spatial ability is a more unified trait in boys than in girls, in whom spatial abilities are more heterogeneously organized. (SLD)

Results from a study in which 25 deaf children and 25 hearing children completed a vocabulary test and a compound stimulus visual information task support the hypothesis that performance on cognitive tasks is dependent on compatibility of task demands with a coding orientation. (SLD)