Lynn and Vanhanen (2012) have convincingly established that national IQs correlate positively with GDP, education, and many other social and economic factors. The direction of causality remains debatable. The present study re-examines data from military psychological assessments of the German federal army that show strong IQ gains of 0.5 IQ point…

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…

The present study investigates the impact of changing fertility patterns on the Flynn effect. Intelligence test data comprised scores of army conscripts on an arithmetic, language and a Raven-similar test, and a composite score (General Ability). Family data of the conscripts enabled a decomposition of the population mean into effects of sibship…

Correlated brain size differences with 37 musculoskeletal variables shown in evolutionary textbooks to change with brain size. Findings from a sample of more than 6,000 U.S. military personnel indicate that racial differences in brain size are securely established and are the most likely biological mediators of race differences in intelligence.…

Studied whether a change of test item sequencing, intended to increase test complexity, would cause increased involvement of general intelligence using a sample of Swedish military recruits who received heterogeneous (n=1,778) or homogeneous (n=363) tests. Items presented homogeneously showed higher general intelligence ("G") loadings.…

A sample of 9173 noninstitutionalized youth who took the 1980 Armed Services Vocational Aptitude Battery (ASVAB) was divided into five ability levels. Analysis supports the assertion that cognitive abilities are less correlated in higher ability groups and implies that greater classification effects can be associated with more intelligent groups.…

Two studies involving 26 undergraduates and 126 military recruits investigated the presence of a coordination factor in a task with compensatory tracking and anticipatory timing components. Results suggest that the ability to integrate separate components of a complex task draws on a coordination ability but one that is domain specific. (SLD)

The impact of general control processing and working memory capacity on a measure of abstract intelligence was examined with 577 military recruits. A new multicomponent latent trait model for covert response was applied to item response data for matrix problems. General control processing has a stronger impact. (SLD)

The relationship between reasoning ability, as indicated by performance on conventional reasoning tests, and working memory capacity was investigated in 4 studies involving 723, 412, 414, and 595 military recruits, respectively. The results demonstrate a consistently high correlation between general reasoning ability and general working-memory…

Cranial capacities were calculated from external head measurements reported for a stratified random sample of 6,325 Army personnel measured in 1988. Data suggest that human populations differ in brain size by race and sex. The major source of variation in data was sex; race was second and rank last. (Author/SLD)

Three experiments involving 111 college students and 248 military recruits investigated information coordination abilities using confirmatory factor analysis. Results, discussed in the contexts of the Yee, Hunt, and Pellegrino theory and a model of working memory, support the argument that coordination tasks are useful in research on working…

The hypothesis that quantitative reasoning performance is a function of specific processing components as well as general cognitive abilities (working memory capacity, reasoning, and verbal comprehension) was tested with 240 military recruits. Results suggest that specific processing components are at least as important as general cognitive…

The possibility that the ability measure activation savings is related to practiced skill, not because of cognitive overlap, but because of the proximity of savings' measurement to measurement of practiced skill was assessed with 404 military trainees. Implications for individual difference research of test-proximity effects are discussed. (SLD)

Individual differences in retention, with an emphasis on their relationship with learning speed and other cognitive factors, were studied in 685 military recruits. In all of the forgetting conditions, the fastest learners remembered more and relearned faster. Results support the existence of individual differences in retention. (SLD)

Validity differences for a "g" (general factor of intelligence) score calculated on the Armed Services Vocational Aptitude Battery (ASVAB) alone versus the ASVAB plus 9 experimental tests were determined for 3,922 military recruits. A validity gain of potential utility was observed for hands-on performance measures. (SLD)