Darwin's evolutionary social psychology

While reading the chapter 5 of Darwin's The Descent of Man, I noticed that Darwin reconstruct Human evolutionary history as--forgive the anachronism--a gene-culture co-evolution. Of course, there was no concept of gene in Darwin's time, so the correct label would be "nature-culture co-evolution", but I was amazed to see how his intuitions are closed to current theories. Basically, he described our evolution as an evolutionary arms race (another anachronism) between social life and intelligence. The process goes trough 3 phases: social instinct, social intelligence, and social reasoning:

1. Social instincts: learning and sympathy

General intelligence

• It deserves notice that, as soon as the progenitors of man became social (and this probably occurred at a very early period), the principle of imitation, and reason, and experience would have increased, and much modified the intellectual powers in a way, of which we see only traces in the lower animals.

Social instincts: sympathy, fidelity, and courage

• In order that primeval men, or the apelike progenitors of man, should become social, they must have acquired the same instinctive feelings, which impel other animals to live in a body; and they no doubt exhibited the same general disposition. They would have felt uneasy when separated from their comrades, for whom they would have felt some degree of love; they would have warned each other of danger, and have given mutual aid in attack or defence. All this implies some degree of sympathy, fidelity, and courage.

2. Social intelligence--reciprocity and approbation

Reciprocity:

• as the reasoning powers and foresight of the members became improved, each man would soon learn that if he aided his fellow-men, he would commonly receive aid in return. From this low motive he might acquire the habit of aiding his fellows; and the habit of performing benevolent actions certainly strengthens the feeling of sympathy which gives the first impulse to benevolent actions. Habits, moreover, followed during many generations probably tend to be inherited.

Approbation

• [a] powerful stimulus to the development of the social virtues, is afforded by the praise and the blame of our fellow-men. primeval man, at a very remote period, was influenced by the praise and blame of his fellows. It is obvious, that the members of the same tribe would approve of conduct which appeared to them to be for the general good, and would reprobate that which appeared evil.

3. Social reasoning--norms, rules and morality

• With increased experience and reason, man perceives the more remote consequences of his actions, and the self-regarding virtues, such as temperance, chastity, &c., which during early times are, as we have before seen, utterly disregarded, come to be highly esteemed or even held sacred.