Question

Which social, cultural, and other environmental factors explain some of the racial differences in intelligence test score? Then discuss research that has attempted to identify genetic determinants of racial differences in intelligence are due to environmental or genetic factors?

Answer 1

• I don’t really personally believe that there could possibly be any real evidence to suggest that race has anything to do with a person’s IQ, but this is what I found in the reading: Social, cultural and other environmental factors might help explain some of the racial differences in intelligence test scores. It has been said that the average black student has a lower SES score that the average white student, and black students tend to come from families with less income, attend worse schools, and have lower birth weights. It seems to be that racial differences in intelligence scores are due to environmental factors.
• Families in high-SES homes have higher levels of intelligence, therefore, the same goes for their children. Children that are exposed to bad environments might not receive good nutrition or medical care, and are at more risk for several illnesses than higher SES children.
• Children who grow up in intellectually stimulating environments tend to have higher intelligence scores than children who have less stimulating environments. Children who grow up being read to by their parents have higher SES, and they are more likely to be exposed to more vocabulary and encouraged to ask more questions.
• Malnutrition during childhood often results in cognitive deficits. A Guatemalan study on undernourished preschoolers showed that those who were given a protein-rich dietary supplement over a ten-year period performed much better on IQ tests than those who did not.(Pollitt, E.; K. S. German; P. L. Engle. R. Martorell, and J. Rivera. 1993. Early supplementary feeding and cognition. Monographs of the Society for Research in ChildDevelopment. 58(235): 1-99.)
• The principal kinds of inadequate nutrition that have been studied are proteinenergy malnutrition, iron deficiency, and iodine deficiency. Protein-energy malnutrition retards growth and in extreme cases causes kwashiorkor and marasmus. Iron deficiency produces anemia, and lack of energy and impairs intelligence. Iodine deficiency produces goiter and in pregnant women impairs the neurological development of the brain of the fetus resulting in cretinism and impaired intelligence.
• The adverse effect of iodine deficiency on intelligence has been synthesized by Bleichrodt and Born (1994) in a meta-analysis of 18 studies that compared intelligence in iodine deficient regions with that in non-deficient regions and the effects of the administration of iodine in iodine deficient populations.They conclude that the effect of severe iodine deficiency is to reduce intelligence by 13.5 IQ points.
•   Fish,(2002, p. 14) explained a lack of formal education of Africans in relation to European comparison groups provides an obvious explanation of their lower test performance. Biesheuvel (1949) has advanced the same view and cites a study in South Africa showing that Africans who had never been to school had IQs about 10 points lower than those who had been to school, and he contends that this shows that lack of schooling impairs intelligence.
• There are race differences in brain size that are associated with differences in intelligence,
  and brain size has a heritability of 90 percent (Baare, Pol et al., 2001).The only reasonable interpretation of this association is that the races with the higher intelligence have evolved larger brains to accommodate their higher IQs.
• When the amount of European ancestry in American blacks is assessed by skin color, dark-skinned blacks have an IQ of 85 and light-skinned blacks have an IQ of 92 (Lynn, 2002a), and there is a statistically significant association between light skin and intelligence.