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 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…

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…

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…

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)…

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 experiments involving 178 and 190 military recruits, spatial, quantitative, and verbal inspection time (IT) and visual search (VS) tasks and an intelligence test were administered. Results indicate that IT performance has a component related to intelligence tests and an independent component related to processing speed tests such as VS. (SLD)

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…

The verbal overshadowing paradigm was used with 167 undergraduates to determine whether performance across all items on Raven's Advanced Progressive Matrices was dependent on the same cognitive processes. Results clearly indicated that a subset of items was dependent on visuospatial processes, while another subset required verbal-analytic…

Two experiments with 172 undergraduate students (70 males and 102 females) examined the relationship among spatial, imagery, and verbal ability and the multitrial free recall of brief prose passages. Results suggest that the psychological mechanisms underlying prose learning performance clearly differ depending on the ability being examined. (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…

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)

Responses of 241 convicts on 18 primary mental abilities were factored to explore the idea that there are organizations among visual and auditory functions that operate independently from the relation-perceiving and correlate-educing functions of fluid and crystallized intelligence. The suggested reliable common-factor functions are discussed.…

Examined critical features of tactile and kinesthetic processes by administering 8 traditional psychometric instruments and 14 measures of tactile and kinesthetic perceptual processes to 116 female college students in Australia. Results show, as is consistent with earlier findings, that visual-spatial processes are difficult to separate from…