"We discovered a new vein of research — the relation between physical and social or psychological concepts — that we came to by taking evolutionary principles seriously and applying them to psychology. We weren't using evolutionary psychology, which has largely been focused on mating and reproduction. Our focus, rather, was in terms of evolutionary biology and the basic principles of natural selection: and that field makes clear that humans must have had these kinds of mechanisms or these processes to guide our behavior prior to evolution or emergence of consciousness."