Science is like evolution in at least one respect: it has developed as a sort of branching process. Social science, especially, has become ever more specialized. Part of the specialization is the natural result of growth. In social and personality psychology, for example, the publication norm seems to be one or a few experiments of three kinds: clever demonstrations of common sense, equally clever demonstrations congenial to academic fashion, or cute demonstrations showing something strikingly counterintuitive. The media take-away was that stereotype threat alone is responsible for the substantial difference between white and black Scholastic Aptitude Test scores. Some economists regard the diversity as a strength: "The diversity of models in economics is the necessary counterpart to the flexibility of the social world. Instead, the field was structured around some broad questions proposed by the great ethologist Niko Tinbergen.