ANYONE who wishes to understand the controversy over the differences in I.Q. scores among different racial, ethnic, and social groups is faced with three formidable obstacles: the veritable mountains of seemingly contradictory empirical data; the growing body of vitriolic polemical writings, which scarcely facilitate the dispassionate examination of the data; and what might be described as the paradigmatic rut-the fixation on the old intellectual models of the Nature/Nurture debate. Given these obstacles, it may be useful to try out a new model that will offer a fresh perspective on the data and, at the same time, shift the political ground of the controversy.