Spearman's hypothesis states that the differences between Blacks and Whites in psychometric IQ are attributable to a fundamental difference in general intelligence ("g"). To investigate this hypothesis, Jensen devised the method of correlated vectors. This method involves calculating the correlation between the factor loadings of the…

Relationships between intelligence test scores and measures derived from reaction time and perceptual speed procedures were investigated. Only three reaction time measures produced correlations greater than .25 with a general intelligence factor. Test-retest reliability of reaction time measures was low. The reaction time-intelligence relationship…

We aimed to design alternative estimates of pre-morbid/prior intelligence to the National Adult Reading Test (NART) and the Spot-the-Word (STW) in order to tap non-vocabulary based knowledge stores. The rationale for the development of the new tests was that more cognitively able individuals acquire and retain more "singular facts" from their…

The author refutes Humphrey's test of the Spearman hypothesis. A fair test requires that Black and White samples not be selected on any g-correlated variable, including socioeconomic status. Humphrey's factor analysis on test-score means of demographic groups, rather than on individuals, inflates g loadings and biases results. (LMO)

This study examines cultural bias in the Wechsler Intelligence Scale for Children. Results indicated no evidence of specific factors peculiar to Blacks v Whites, and rank order of item difficulties was similar in both groups. Race differences were due to differences in mental maturity rather than to test bias. (Author/RD)

This author reviews published data and presents new data relevant to the Spearman hypothesis concerning racial differences on cognitive tests. He concludes that across-the-board difference between SES groups occurs primarily on the general factor, and that there are major determinants of race differences independent of the general factor.…

The author responds to criticisms made by Jensen pertaining to tests of the Spearman hypothesis. The near-zero correlation between Blacks and low socio-economic status Whites is neither an artifact of methodology nor a sampling fluke. Low and high SES White differences are highly correlated with general factor loadings. (LMO)