To me, Charles Darwin’s discovery of sexual selection rivals that of natural selection. In natural selection, the selecting is done totally by nature and change is rendered through chance mutation of genes. In sexual selection, a portion of the power to select is seized by one of nature’s creations, usually the female of a species, and the result is the construction of a micro-ecology between chooser and chosen with rules that sequester a small portion of evolution from the monopoly of chance.
Sexual selection occurs because virtually all animals (and plants) are sexually dimorphic. There are many hypotheses for the ubiquity of sex a few of which rise to the level of theories. It would seem inevitable, perhaps even a natural Law that, given any dimorphism in which the differences between the two types are determined by their reciprocal interaction, eventually one type would evolve to select traits in the other.
A second such dimorphism indeed does exist in nature and its origin is much more obvious than sex. This other dimorphism exists not in physical characteristics but in the behavioral, emotional, and mental sphere, which is my province as a psychiatrist. It arose from the inhibition of the atavistic fight and flight responses in order to enable the benefits of living in groups. Here I refer to the temperaments of dominance and submission. Dominance and submission exist in most social animals, but for 50 million years primates have become “specialists” in the hierarchies produced by them. The rules within these hierarchies, similar to those in sexual selection, has created an internal ecology.
The central idea in this book is that sexual selection in early hominids created just the right balance between the temperaments of dominance and submission such that the dominance temperaments began selecting the submissive temperaments for traits that were for the good of small, monogamous groups – which I have dubbed selection inclusion. It was in this manner that dominance in the individual Ascended to become the force of authority over the group.