Persons representing the extremes of intelligence cannot be included in the same study unless they are approximately equated on mental age, in which case the relative performances of the extreme groups can provide useful information about the nature of intelligence. (Author/RD)

Reviews controversies over intelligence and intelligence testing, focusing on impacts on Canadian society in the past century. Discusses eugenics movements and related immigration policies. Suggests that both "tails" of "The Bell Curve" (cognitive elite and underclass) are influenced by inaccurate methods, and that the middle…