Intelligence is an important indicator of physical, mental and social well-being. In old age, intelligence is also associated with a higher quality of life and better health. Heritability studies have shown that there are strong genetic influences, yet unknown, on intelligence, including in old age. Other approaches may be useful to investigate…

Discusses how viewing intelligence as a learned skill and not a genetic gift may make the standard IQ test a thing of the pedagogical past. (GB/Editor)

Studies by the late English psychologist Cyril Burt of IQ scores of separated twins strongly suggested that intelligence was inherited. A summary of recent research costs doubt upon the validity of Burt's work. (SL)

An analysis, supported by recently published data, which suggests that IQ differences between groups may be explained by environmental factors. (Author/FF)

A critical review of Jensen's book which contains a reprint of the original controversial 1969 "Harvard Educational Review" article, 5 related articles by Jensen, and a bibliography of related articles. (EH)

Comparison of the mental status of 30 subjects with Down's Syndrome mosaicism and 30 matched subjects with trisomy 21 Down's Syndrome found that the mean intelligent quotient of the mosaic Down's Syndrome group was significantly higher and that this group showed better verbal abilities and more normal visual-perceptual skills. (Author/DB)

Data from the General Social Survey (GSS) collected in the years 1990-1996 are examined for the relationship between fertility and intelligence as measured by vocabulary. The results show that the relation between fertility and intelligence has been consistently negative for successive birth cohorts from to 1900 to 1979, indicating the presence of…

A classification of natal influences is proposed with a model of their operation. Natal influences affect maternal capacity, maternal load, and maternal efficiency. Since maternal load is increased in twin pregnancy, results of twin studies must be generalized with caution. The method of co-twin control is exemplified by examination of a small…

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 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),…

Explanations of differences in IQs of Northern and Southern Blacks focus on selective migration (hereditarians) or environmental causes such as education, discrimination and cultural deprivation. In this paper the environmentalist position is questioned and certain neglected features of Lee's data are construed as providing strong evidence for…