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Race Differences In Intelligence




''Race Differences in Intelligence: An Evolutionary Analysis'' is a 2006 book by Dr. Richard Lynn , Professor Emeritus of Psychology at the University Of Ulster , Northern Ireland . Lynn describes his book as "...the first fully comprehensive review that has ever been made of the evidence on race differences in intelligence worldwide". Lynn reviews 620 published IQ studies from around the world, surveying a total of 813,778 tested individuals. The book concludes the average human IQ is presently 90, which is equivalent to the mental age of a white 14 year old. (Standardized IQ tests are normed to 100, the mental age of the average white 16-year-old.) The book devotes a chapter to the data on each of the nine genetic clusters or population groups identified in previous genetic cluster analysis (Cavalli-Sforza et al. 1994, p. 79), which Lynn regards as races. Following these 10 chapters, Lynn devotes a chapter to discussing the reliability and validity of the measures. He concludes that, though additional evidence may be required to confirm some of the racial IQ estimates, many have very high reliability in the sense that different studies give very similar results, and that they correlate highly with performance in international studies of achievement in mathematics and science and with national economic development.


CLIMATE AND BRAIN SIZE


Both Lynn and Rushton have previously suggested that high IQ is associated with colder climates. Lynn examines this hypothesis in chapter 16 of ''Race Differences in Intelligence''.

Table 16.2. Race differences in winter temperatures (degrees centigrade) and brain size
Race Winter Temp Wurm Temp Brain Size IQ
Arctic Peoples -15 -20 1,443 91
East Asians -7 -12 1,416 105
Europeans 0 -5 1,369 99
Native Americans 7 5 1,366 86
S. Asian & N. Africans 12 7 1,293 84
Bushmen 15 15 1,270 54
Africans 17 17 1,280 67
Australians 17 17 1,225 62
Southeast Asians 24 24 1,332 87
Pacific Islanders 24 24 1,317 85

In a separate analysis Templer and Arikawa (2006; see discussion examined this question by comparing the national IQ data from Lynn and Vanhanen (2002) with data sets that describe national average skin color and average winter and summer temperatures. They find that the strongest correlations to national IQ were −0.92 for skin color and −0.76 for average high winter temperature. They interpret this finding as strong support for IQ-climate association. Other studies using different data sets find no correlation [http://www.pnas.org/cgi/content/full/101/35/12824 [http://dienekes.angeltowns.net/articles/greekiq/].


REFERENCES

  • Cavalli-Sforza , L. L., Menozzi, P., & Piazza, A. (1994). ''The history and geography of human genes''. Princeton, NJ: Princeton University Press.