Hierarchy. Animalistic instincts. Structure of gender relationship.
As long as our ancestors were (relatively) undeveloped, as long as they lacked effective tools, weapons, hunting strategies, knowledge of agriculture and cattle breeding, their level of satiety and safety was not any different from that of other animals. They were preyed upon by predators, their population size fluctuated with the amount of game and edible plants available. They balanced between life and death, competed with other species for survival in the process of evolution. A pack (or troop) of humans was not (yet) much different from a pack of chimpanzees. Every pack was headed by a single leader — the strongest and the most aggressive male. The leader dominated all the other pack members. The rest of the males took positions below him in a hierarchy, the place in the hierarchy was determined in daily cruel fights and conflicts between them. Due to lack of any strong weaponry, such as claws, hoofs, or horns, these conflicts rarely resulted in death. For the same reason, a single human, a pair or even a small group could not leave the pack — unarmed and slow, a lone human was an easy prey. Birth rates were at about replacement level, and the amount of humans stayed roughly the same throughout the period. And, naturally, this sort of lifestyle made the humans evolve corresponding instincts (firmware) — same instincts other animals that live in packs, packs or herds had to evolve. This firmware is still with us — there wasn’t enough time for it to go away. If, for one reasons or another, low-educated humans form an isolated group where resources are scarce, and are not able to leave the group, they start to live according to these ancient instincts. They form an animalistic herd led by the most aggressive, cunning and audacious male, with harsh competition for place in the hierarchy. Examples of such groups are prisons, foster homes, the army (hazing).
The position of the female in the human pack differed slightly from that of another species. Human female still preferred to mate with the strongest and most aggressive males — these qualities made the males fittest for the environment. These males fathered most of the children in the pack. The difference arose because the female of human species had a lot less survivability and could not feed her children on her own. And since an aggressive, strong and cunning male was a lot more concerned with keeping and advancing his place in the hierarchy than caring for his many females and children, humans came up with the system of sexual favors or rewards. A male in the hierarchy below the leader could, too, earn a female’s grace by sharing his catch with the female. The ability to bring home booty was a additional measurement of success and fitness. There was a market of sorts, a market for sexual favors. The price of sex was determined by the male’s position in the hierarchy. The leader mated for free. A low rank male, even if fortunate enough to come into a possession of something valuable, had no chance (here we see that roots of prostitution are not social, but biological, and all efforts to get rid of it are wasted).
The leader (as well as second, third and fourth male in the hierarchy) is not only efficacious on his own, he can take the catch from a weaker male. Therefore, he is the most prominent source of resources for a female. He can also drive off a weak, low rank male the female does not want to mate with. Every female wanted to get an exclusive feeding and protection from that valuable male, drive off other females from him, attach him using sex and ritualistic feeding with especially sweet fruits she found when gathering food, and other methods. To excel at her role and to overcome her physical weakness, the female became more cunning than the most cunning male. Every one of us knows the erotic female tricks, when a woman, kissing a man, puts some sweet berry into his mouth. This is an ancient erotic ritual, known to many primates. This is how pair structure formed. In the stone age, however, the pair only existed until children achieved a certain degree of self-sufficiency. This is why today the peak of all divorces is four years after marriage — at age three, a child can eat and move on his own.
There were no old people in the pack to speak of. As soon as an adult grew weak, he or she fell to the bottom of the hierarchy and was eaten by the predators. The old and the low rank males were the buffer between the dangerous environment and reproductive part of the pack.