Of course the allegations of “racism” arise, as usual when in discussions of racial differences in intelligence and level of civilizational achievement. Rushton also says:

Racial differences in brain size and IQ map very closely to the same cultural histories Diamond explains. Although Diamond dismisses such research as "loathsome", he fails to tell his readers what, if anything, might be scientifically wrong with any of it. One hundred years of research has established that East Asians and Europeans average higher IQs than do Africans. East Asians, measured in North America and in Pacific Rim countries, typically average IQs in the range of 101 to 111. Caucasoid populations in North America, Europe, and Australasia typically average IQs from 85 to 115 with an overall mean of 100. African populations living south of the Sahara, in North America, in the Caribbean, and in Britain typically have mean IQs from 70 to 90.Racial differences in brain size and IQ map very closely to the same cultural histories Diamond explains. Although Diamond dismisses such research as "loathsome", he fails to tell his readers what, if anything, might be scientifically wrong with any of it. One hundred years of research has established that East Asians and Europeans average higher IQs than do Africans. East Asians, measured in North America and in Pacific Rim countries, typically average IQs in the range of 101 to 111. Caucasoid populations in North America, Europe, and Australasia typically average IQs from 85 to 115 with an overall mean of 100. African populations living south of the Sahara, in North America, in the Caribbean, and in Britain typically have mean IQs from 70 to 90.