This research examined whether non-"g" residuals of the SAT and ACT subtests, obtained after removing g, predicted specific abilities. Non-"g" residuals of the verbal and math subtests of the SAT and ACT were correlated with academic (verbal and math) and non-academic abilities (speed and shop), both based on the Armed Services…

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…

Empirical studies of high school mathematics typically report small gender differences in favor of boys. The present article challenges this established finding by comparing two competing structural conceptions of mathematical ability. The standard model assumes mathematical ability alone to account for the interindividual differences observed on…

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…

A 2003 paper in this journal reported results from a large sample of twins assessed at 2, 3 and 4 years of age on parent-administered tests and reports of their verbal and nonverbal ability. We found clear evidence for phenotypic general cognitive ability (g) that accounted for about 50% of the variance, for modest genetic influence on g (about…

Lynn [Lynn, R., 2002. Sex differences on the progressive matrices among 15-16 year olds: some data from South Africa. "Personality and Individual Differences 33," 669-673.] proposed that biologically based developmental sex differences produce different IQ trajectories across childhood and adolescence. To test this theory we analyzed the…

The relationship between non-verbal decoding ability and social intelligence, defined as the ability to decode social information accurately, was studied using 40 adults. Results are discussed in the framework of R. J. Sternberg's triarchic theory of human intelligence. Decoding skills appeared to be an important part of social intelligence. (SLD)

The study of genotype-environment interaction (G x E) has been dominated by two competing hypotheses, one that heritability is greater in high-risk environments (diathesis-stress) and the other that heritability is greater in permissive environments. The current study examined relationships between verbal and nonverbal abilities and 10 measured…

Three psychophysical auditory processing tests, varying in emphasis on speed of processing and pitch discrimination, and tests of verbal and nonverbal ability were administered to 108 13-year olds. A structural equation model suggests that information processing speed and pitch discrimination ability are significantly associated with nonverbal and…

Choice reaction time and simple reaction time were measured for 147 young adults for whom significant positive correlation between nerve conduction velocity in a brain nerve pathway and nonverbal intelligence was previously found. Results suggest that two largely independent neurophysiological processes affect intelligence. Differences in choice…

Sex differences in spatial visualization ability accounted for sex differences in mathematical ability for a group of college students. With spatial visualization statistically controlled, no significant sex differences in Quantitative Scholastic Aptitude Test scores were found. Males were more predictable than females due to higher spatial…

An auditory inspection time (AIT) test, pitch discrimination tests, and verbal and non-verbal mental ability tests were administered to 59 undergraduates and 119 12-year-old school children. Results indicate that AIT correlations with intelligence are due to AIT being an index of information intake speeds. (TJH)