Wicherts, Dolan, and van der Maas (2009) contend that the average IQ of sub-Saharan Africans is about 80. A critical evaluation of the studies presented by WDM shows that many of these are based on unrepresentative elite samples. We show that studies of 29 acceptably representative samples on tests other than the Progressive Matrices give a…

In his article "In Italy, North-South differences in IQ predict differences in income, education, infant mortality, stature, and literacy," Richard Lynn claims to have found the reason causing the divergence between the Northern and the Southern regions of Italy. This article identifies the four main hypotheses formulated in his paper…

The authors argue that upon publication of a paper, the data should be made available through online archives or repositories. Reasons for not sharing data are discussed and contrasted with advantages of sharing, which include abiding by the scientific principle of openness, keeping the data for posterity, increasing one's impact, facilitation of…

Here we reprint, and provide background and a commentary on, a recently-rediscovered lecture by Godfrey H. Thomson entitled, "Intelligence and civilisation." It was delivered at the University of Manchester, UK, on 23rd October, 1936, printed in 1937 in the short-lived "Journal of the University of Manchester" and as a pamphlet…

Working with data from the PISA study (OECD, 2007), Lynn (2010) has argued that individuals from South Italy average an IQ approximately 10 points lower than individuals from North Italy, and has gone on to put forward a series of conclusions on the relationship between average IQ, latitude, average stature, income, etc. The present paper…

Mackintosh and Bennett [Mackintosh, N. J., Bennett, E. S. (2005). What do Raven's Matrices measure? An analysis in terms of sex differences. "Intelligence, 33," 663-674] reported that male students obtained higher scores than females on Raven's items that required for their solution addition/subtraction or distribution of two rules, but…

The law of diminishing returns suggested by C. Spearman (1904) presents a paradoxical conclusion that groups with the largest amount of "g" (general factor of intelligence) should have the greatest intertest correlation among intelligence tests, but, in fact, they have the least. Implications for intelligence theory are discussed. (SLD)

Psychometric g is by far more highly correlated with all tests conventionally called "IQ," cognitive abilities, and the like, than any other single factor or combination of other factors independent of g. Researchers must now examine the nature of psychometric g, including its causal underpinnings. (LMO)

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)

In an earlier article, Hunt envisions the automation of intelligence testing, but he appears to be overly optimistic. He neglects to mention conceptual and practical difficulties at the interface of measurement and theory that place psychometry not in the dawn of microcomputerization, but rather more nearly in its primordium. (Author)

Six points of view regarding the future of intelligence testing are considered, and a "prototypical" point of view is presented. The past history and present status of intelligence testing and research are considered. Their future is discussed in terms of assessment of various kinds of components of intelligence. (Author/RD)

The major impediment to an understanding of human intelligence is the fragmented way it is studied. An orientation is suggested which integrates various aspects of the study of human intelligence. If this approach is adopted, intelligence tests will be an integral part of a systematic theory of knowledge acquisition. (Author/RD)

The question of how to integrate developmental (Piagetian) and psychometric conceptions and assessments of intelligence is considered. A solution which incorporates the contributions of each position--intelligence as forms and as traits--is offered. Premises and objectives of each tradition are reviewed and compared. Overlaps make synthesis…

Four points are made in regard to the controversial reaction times studies: (1) apparatus used is not the best; (2) practice effects have not been thoroughly accounted for; (3) there is some evidence that simple reactions are different from choice ones; and (4) basic data to be explained are those which show substantial group differences.…

Persons representing the extremes of intelligence cannot be included in the same study unless they are approximately equated on mental age, in which case the relative performances of the extreme groups can provide useful information about the nature of intelligence. (Author/RD)