Many explanations have been proposed for the evolution of our anomalously large brains, including social, ecological, and epiphenomenal hypotheses. Recently, an additional hypothesis has emerged, suggesting that advanced cognition and, by inference, increases in brain size, have been driven over evolutionary time by the need to deal with…

A high-quality estimate of the mean IQ of a country requires giving a well-validated test to a nationally representative sample, which usually is not feasible in developing countries. So, we used a convenience sample and four corrections based on theory and empirical findings to arrive at a good-quality estimate of the mean IQ in Bali. Our study…

The ranking of Wechsler subtests in terms of their "g" loadings is equivalent to ranking them in terms of the cognitive complexity of the tasks measured. Lower performing groups do not always fall behind higher performing groups the more complex the task. But that is the general rule, no matter whether the cause of the lower performance…

On the basis of several reviews of the literature, Lynn [Lynn, R., (2006). Race differences in intelligence: An evolutionary analysis. Augusta, GA: Washington Summit Publishers.] and Lynn and Vanhanen [Lynn, R., & Vanhanen, T., (2006). IQ and global inequality. Augusta, GA: Washington Summit Publishers.] concluded that the average IQ of the…

Although a negative relationship between fertility and education has been described consistently in most countries of the world, less is known about the relationship between intelligence and reproductive outcomes. Also the paths through which intelligence influences reproductive outcomes are uncertain. The present study uses the NLSY79 to analyze…

How did human intelligence evolve to be so high? Lynn [Lynn, R. (1991). The evolution of race differences in intelligence. Mankind Quarterly, 32, 99-173] and Rushton [Rushton, J.P. (1995). Race, evolution, and behavior: A life history perspective. New Brunswick: Transaction] suggest that the main forces behind the evolution of human intelligence…

Measures of broad fluid abilities including verbal, quantitative, and figural reasoning are commonly used in the K-12 school context for a variety of purposes. However, differentiation of these domains is difficult for young children (grades K-2) who lack basic linguistic and mathematical literacy. This study examined the latent factor structure…

This paper reviews the studies of socioeconomic and ethnic and racial differences in intelligence carried out in Russia/USSR during the late 1920s and early 1930s. In these studies the IQs of social classes and of ethnic minorities were tested. These included Tatars (a Caucasoid people), Chuvash and Altai (mixed Caucasoid-Mongoloid peoples), Evenk…

African-Americans and Whites were asked to solve problems typical of those administered on standard tests of intelligence. Half of the problems were solvable on the basis of information generally available to either race and/or on the basis of information newly learned. Such knowledge did not vary with race. Other problems were only solvable on…

The black-white difference in test scores for the three standardizations of the Woodcock-Johnson battery of cognitive tests is analyzed in terms of birth cohorts covering the years from 1920 through 1991. Among persons tested at ages 6-65, a narrowing of the difference occurred in overall IQ and in the two most highly "g"-loaded clusters…

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…

We argue that the report by Templer and Arikawa contains misleading conclusions and is based upon faulty collection and analysis of data. The report fails to hold up for quality of data, statistical analysis, and the logic of science.

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.…

The current study examines the views of experts in the science of mental abilities about the primacy and uniqueness of "g" and the social implications of ability testing, and compares their responses to the views of a group of non-expert psychologists. Results indicate expert consensus that "g" is an important, non-trivial determinant (or at least…

Administered Raven's Standard Progressive Matrices to 342 young adult engineering students in South Africa (198 Africans; 86 Whites). Data confirm the magnitude of the African-White IQ gap and that the differences on various items are positively correlated with the "g" loading for those items. (SLD)