In this study, we tested the parasite-stress hypothesis for the distribution of intelligence among the USA states: the hypothesis proposes that intelligence emerges from a developmental trade-off between maximizing brain vs. immune function. From this we predicted that among the USA states where infectious disease stress was high, average…

The level of self-employment varies significantly among immigrants from different countries of origin. The objective of this research is to examine the relationship between home-country national intelligence and self-employment rates among first generation immigrants in Norway. Empirical secondary data on self-employment among immigrants from 117…

We have previously demonstrated that training on a dual n-back task results in improvements in fluid intelligence ("Gf") as measured by matrix reasoning tasks. Here, we explored the underlying mechanisms of this transfer effect in two studies, and we evaluated the transfer potential of a single n-back task. In the first study, we demonstrated that…

A link between pre-morbid intelligence and all cause mortality is becoming well established, but the aetiology of the association is not understood. Less is known about links with cause specific mortality and with morbidity. The aim of this study is to examine the association between intelligence measured in adolescence and a broad range of health…

This paper examines the distribution of national IQ in geographical space. When the heritability of IQ and its dependence on eco-social factors are considered from a global perspective, they suggest that the IQs of neighboring countries should be similar. Using previously published IQ data for 113 nations (Lynn, R., & Vanhanen, T., (2006). IQ and…

Derived changes in genes associated with primary microcephaly (MCPH) have been suggested to be "currently sweeping to fixation" i.e., increasing in frequency in most populations, with the likely outcome that the derived allele will completely displace the ancestral allele over time. Possible causes for this sweep include effects on human reasoning…

Spearman's hypothesis states that racial differences in IQ between Blacks (B) and Whites (W) are due primarily to differences in the "g" factor. This hypothesis is often confirmed, but it is less certain whether it generalizes to other races. We therefore tested its cross-racial generality by comparing American subjects of European…

IQ scores provide the best general predictor of success in education, job training, and work. However, there are many ways in which IQ scores can be increased, for instance by means of retesting or participation in learning potential training programs. What is the nature of these score gains? Jensen [Jensen, A. R. (1998a). "The g factor: The…

Using 49 undergraduates, short-term memory (STM) spans, STM probe-recall tasks, and complex working memory (WM) spans were studied to assess the relationships among STM, WM, and verbal ability. Results indicate that STM and WM are separate cognitive constructs, and that both STM and WM are important to verbal abilities. (SLD)

Eighty-one university students were given a battery of reaction time tests and a group test of intelligence which yielded timed and untimed scores. Multiple regression analyses indicated that speed of information-processing was an equally good predictor of timed and untimed intelligence test performance. (Author/LMO)

The impetus for our study was the contention of both Lynn [Lynn, R. (1991) "Race differences in intelligence: A global perspective." "Mankind Quarterly," 31, 255-296] and Rushton [Rushton, J. P. (1995). "Race, evolution and behavior: A life history perspective." New Brunswick, NJ: "Transaction"; Rushton, J.…

A large number of national and geographic population samples were used to test the hypothesis that the variation in mean values of skin color in the diverse populations are consistently correlated with the mean measured or estimated IQs of the various groups, as are some other physical variables, known as an ecological correlation. Straightforward…

Field dependence and spatial ability are examined as different labels for a common underlying dimension. Sixty college students completed two tests of field dependence and two tests of spatial ability. Results of an analysis of covariance found no evidence to view the two traits as distinct from each other. (Author/LMO)

The degree to which reading ability and intelligence, as measured by the Raven Progressive Matrices Test, were related was studied for 486 students in grades 2 through 12 in a small town, rural school system. Results indicate the strong and consistent relationship between general intelligence and reading ability. (SLD)

Meta-analysis of 225 hypothesis tests of measures of memory for order (MFO) and the relationship of MFO and measures of general ability demonstrate a significant relationship between MFO and standardized test scores. Fifty-one independent samples were tested. MFO task quality was a significant predictor of effect size. (SLD)