The formation of human society is not mainly a biological process of the evolution of human physiological organization and mechanism, but a process of the formation of social relations such as human activities and communication based on labor. The direct ancestor of human beings used to be a gregarious animal. Facing the harsh nature, we have to make up for the lack of individual ability with the joint efforts and collective activities of the group.
Engels once called gregarious apes "social animals" and their group relationship "social instinct". He pointed out: "Our ape ancestors were socialized animals, and man, the animal with the highest degree of socialization among all animals, obviously could not have developed from a non-socialized recent ancestor" (Selected Works of Marx and Engels, Volume 3, page 5 10). The social instinct of the relationship between human ancestors is one of the most important levers for the evolution from apes to humans. With the development of labor, this kind of group relationship becomes more and more extensive and close, and finally becomes a real social relationship with the appearance of human beings.