A critique arguing: (1) that the assumptions underlying the use of intelligence tests are invalid; (2) that findings regarding individual differences can not be generalized to differences between populations; and, (3) that the studies cited as evidence were both incorrectly designed and improperly executed. (JM)

Analyzes and refutes two propositions of H.J. Eysenck: (a) that intellectual differences in our culture are overwhelmingly determined by genetic factors, and (b) that the 15-point mean I.Q. gap between black and white Americans is largely determined by genetic factors. (JM)

This article reviews sex studies of children of cousin marriages and three studies of children of incestuous matings. It is argued that these studies, taken as a whole, provide no substantial evidence for an inbreeding depression effect within the polygenic system commonly asserted to determine IQ. (Author/DB)

The question as to whether males and females have different kinds of intellectual abilities is addressed. The evidence that there are some differences in cognition and perception between men and women is reviewed. (KR)

The author reexamines the controversy surrounding his genetic hypothesis in an attempt to clarify his contention that differences in IQ scores between blacks and whites may be attributable as much to heredity as environment. (EH)

Ronald C. Johnson argued that if early environmental stimulation or deprivation has a significant effect on intellectual ability, then individuals who are genetically identical and who are exposed to a common early environment should resemble one another more closely in IQ than similar individuals who have not shared a common environment. Johnson…

Genetic effects on specific cognitive abilities as distinct from those on general cognitive ability were studied in 302 pairs of twins (some reared together, some apart) from the Swedish Adoption/Twin Study of Aging. Overall, results showed significant genetic influence on specific abilities independent of influence on general ability. (SLD)

Argues against the presence of dysgenic trends for IQ on the basis of absence of change in the differences between various groups. Illustrates this with an example of the numbers of children born to Black and to White women at different educational levels. Discusses the effects, mechanisms, and implications of dysgenesis for IQ. (MMU)

Evidence on the poorer spatial visualization ability in various Negro populations compared to the White populations and on the direction and magnitude of sex differences in spatial ability relative to other abilities suggests the genetic hypothesis that spatial ability is enhanced by a sex-linked recessive gene and that, since the 20-30 percent…

The controversy over the causes of intelligence--genetic or environmental--is reviewed. More specifically, the subject of the consistently lower intelligence scores for blacks is analyzed. Much attention is devoted to Jensen and his monograph published in the "Harvard Educational Review," entitled "How much can we boost IQ and scholastic…

Heritability is defined as the proportion of a manifested trait's varience that is due to genetic variation. Sixty-five pairs of twins were employed to investigate the heritability of: (1) short term memory (Jensen's Level 1), operationalized using of modified "digit span" test; (2) the general intellective factor (Jensen's Level II),…