In the chapters that follow, it is necessary to distinguish ‘environmentalism’ from research on the environment. Environmentalism is the scientifically anomalous attitude that ignores, shuns, or denigrates any hypothesis of genetic causation in specific classes of human individual or group differences. Environmentalists differ among themselves in the kinds of differences from which they exclude the possibility of genetic influences. Thus we see environmentalists who accept the findings on the heritability of individual differences in intelligence but who vehemently argue against the suggestion that genetic factors may be involved in any subpopulation differences, social-class or racialŝ Still others acknowledge the evidence on genetic intelligence differences among social classes within racial groups, but categorically reject without evidence the hypothesis that specific racial groups differ genetically in mental abilities. Some will admit genetic explanations, or at least grant their plausibility, regarding racial differences in physical and sensory capacities, while not allowing the possibility of genetic differences in more complex mental capabilities. The idea that certain small and isolated racial groups, such as the Australian Bushmen, might differ genetically from major racial groups in mental capacities is viewed only with a mild skepticism by some environmentalists, who vociferously denounce those who would question wholly environmental theories of intelligence differences between major racial groups.