We examined the effects of early life stress (ELS) on intellectual ability in 2,725 20-year-old male participants, of whom 321 were separated temporarily (mean 1.7 years) from both their parents during World War II, at an average age of 4.3 years. Intellectual ability was tested when entering compulsory military service. The separated men had…

Neuro-imaging studies of intelligence implicate the importance of a parietal-frontal network. One unresolved issue is whether this network underlies a general factor of intelligence ("g") or other specific cognitive factors. A second unresolved issue is whether males and females use different parts of this network. Here we obtained intelligence…

The purpose of the present study is to explain variation in academic achievement with general cognitive ability and specific cognitive abilities. Grade point average, Wide Range Achievement Test III scores, and SAT scores represented academic achievement. The specific cognitive abilities of interest were: working memory, processing speed, and…

Based on stimulating findings suggesting that prenatal levels of steroids may influence cognitive functions, a study with N=40 healthy volunteers of both sexes was conducted. Prenatal levels of testosterone (T) were estimated by use of the second-to-fourth digit ratio (2D:4D) which is supposed to be controlled by the same genes involved in…

Scores on Raven's Progressive Matrices correlated positively with electroencephalogram-recorded alpha rhythm frequency (AF) in 101 healthy male adults, as did one test of verbal ability and one of mental performance. However, AF did not show significant relationships with general intelligence or spatial and arithmetic abilities. (SLD)

Shows changes in the distribution of scores on a set of tests used by the Danish draft board since the late 1950s to the present. The marked gains in cognitive abilities seen in the earlier years have been replaced by very modest gains in the last 10 years. These recent gains appear primarily in a test of visuo-spatial abilities. (Author/SLD)

Sex differences in spatial ability were examined in 410 Israeli college students using standard tests of mental rotation. On related abilities tests, males performed better than females on a numerical skills test, and females performed better on an associative memory test. No significant sex differences were found on other ability tests. (SLD)

Confirmatory factor analysis was used to test first- and second-order factor models on cognitive abilities and their invariance across samples of 234 male and 225 female secondary school students. Factor models suggest that males and females may use different problem-solving strategies for spatial analogies, matrices, and numerical problems. (SLD)