The Scottish Mental Survey of 1932 (SMS1932) provides a record of intelligence test scores for almost a complete year-of-birth group of children born in 1921. By linking UK Army personnel records, the Scottish National War Memorial data, and the SMS1932 dataset it was possible to examine the effect of childhood intelligence scores on wartime…

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…

D. K. Detterman and M. H. Daniel's recognition (1989) that intertest correlations for intelligence quotient (IQ) might not be uniform across the range of ability (and age) was anticipated by C. E. Spearman (1904). Detterman and Daniel appear to have rediscovered Spearman's suggested law of diminishing returns. (SLD)

Explored the relationship of both simple and four-choice reaction time to scores for the Alice Heim 4 (AH4) test to assess whether correlations previously reported adequately represented the strength of the relationship and to test for departures from linearity. Findings for 900 adolescents and adult show the correlation to be a good summary for…

There is a significant association between birth weight and cognitive test scores in childhood, even among individuals born at term and with normal birth weight. The association is not explained by the child's social background. Here we examine whether mother's cognitive ability accounts for the birth weight-cognitive ability association. We…

Eight-seven adult outpatients in Edinburgh (Scotland) were tested with the Wechsler Adult Intelligence Scale--Revised (WAIS-R) and a test of visual inspection time (IT). Factor analysis confirms that IT correlates more strongly with performance than with verbal intelligence quotient (IQ) scores. Implications for the study of IT and mental tests…

Introduces the inspection-time (IT) measure in psychology, and argues that its much-replicated correlation with intelligence quotient (IQ) and its potential for theoretical tractability has more potential for the understanding of individual differences in cognitive ability than other indices of human information processing. It summarizes studies…