Belief centered on bargains of various kinds with the spirits. Limitations of Paleolithic existence. Because of the need for survival, there was little room for social innovation. Limits on the size of the group. Excess population had to be trimmed.
Cultures tend to be integrated wholes.
On the most basic level, a culture includes techniques found useful for survival. It is, therefore, shaped by the environment. But it also means techniques useful for surviving in the society. On a higher level, they provide a means of group identification. Culture facilitates group interaction.