Data are presented from families of monozygotic twin pairs which give evidence of genetic variance on the Block Design Test, a nonverbal measure of intelligence. Analyses of genetic and environmental effects on behavior are possible with this kind of information. (SA)

Summarizes Arthur Jensen's theories on IQ, heritability, and Black intelligence and reviews some responses to Jensen. (JLF)

Findings from a study reported in this paper indicate that the differences in family background that affect IQ are largely the result of genetic differences among parents, which affect the parents' own status attainment and which are passed on genetically to their offspring, whose status attainments are subsequently affected. (Author/EB)

"The Bell Curve" declares that studies of separated identical twins--the "purest" of "direct" methods for estimating IQ heritability--indicate a value of +.75-+.80. But, the main study cited suggests a heritability of "two-thirds" for the middle class, and Herrnstein and Murray neglect to mention numerous…

Milkman (TM 504 643) accuses Arthur Jensen of misapplying heritability data in speculating on the causes of racial differences in intelligence test scores, and offers a method for illuminating Jensen's alleged error. It is contended in this article that Milkman has misconstrued Jensen's argument and that his method is without point. (Author/CTM)

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)

Criticizes claims in "The Bell Curve" that a high value for heritability of intelligence constrains the extent to which environmental changes can increase intelligence. Cites adoption studies and the increasing intelligence of successive cohorts of U.S. children as evidence that intelligence can increase substantially without heroic…

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)

Presents social scientists' claim that IQ scores can determine a person's social, educational, and occupational future at an early age. Echoes the Platonic idea that each individual should be put to the use for which nature intended, and that IQ, which is thought to be hereditary, can effectively predict this use. (58 citations) (EMH)

Sets of randomly generated numbers are used to produce simulated data sets to illustrate that high heritability of a property within each of two populations may be consistent with a vanishingly small heritability in the combined population. (A response by Jensen appears in the next issue of Journal of Educational Statistics, p.385). (CTM)

A Canadian study compared the rate of cognitive disabilities in 156 relatives of 49 individuals with autism to that found in 55 relatives of 18 individuals with mental retardation. No differences were found; however, female and low IQ individuals were found to have higher family histories of cognitive disabilities. (Author/CR)

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)

Commentary on "The Bell Curve." Points out that Herrnstein and Murray do not acknowledge their politically conservative funding sources. Discusses bias and inadequacies of IQ tests, lack of evidence of intergenerational reproduction of occupational classes, current underemployment of highly educated people, and the authors'…

Platelet serotonin (5HT) levels of 5 autistic subjects (ages 16-37) who had siblings with either autism or pervasive developmental disorder were significantly higher than levels of 23 autistic subjects without affected siblings. Autistic subjects without affected siblings had 5HT levels significantly higher than 10 normal controls. Sex, age, and…

Word recognition data from identical and fraternal twins and siblings (N=172) indicated that the phonological coding deficit of children with reading disabilities was highly heritable. Orthographic coding was not significantly heritable. Poor readers with low IQs were superior to similar reading but average IQ readers in phonological coding.…