Unfortunately, I am reading yet another book which claims that religion was specifically targeted by natural selection because it makes groups more prosocial and cohesive, thus giving them an advantage in warfare, etc. over other groups. The author claims, of course, that this explains the evolutionary origin of religion. Just so.
As is always the case with these types of books, the author does not mention a single group that might provide historical proof to support this hypothesis. Obviously, we do not have any histories of Paleolithic hunter-gatherers, so we are not aware of any that identified themselves as a religious group. Among historically known hunter-gatherers, I am not aware of any that identify themselves in terms of their “religious” beliefs. In fact, I am not aware of any hunter-gatherer groups that identify themselves primarily or even secondarily in terms of their spiritual affiliations. These are kinship based societies, and usually identify themselves simply as “the people.” Because we can find no such groups among hunter-gatherers, it is highly unlikely that religion evolved — through group level selection — during the Paleolithic.
Turning from the Paleolithic to the Neolithic, we are still hard pressed to find any groups that define or identify themselves primarily in religious terms. The first urban societies that appeared in Mesopotamia identified themselves with the city-state and the rulers of those city-states. There were some recognized ethnic and linguistic divisions between them. Because these city-states shared many of the same gods, they did not compete or war against one another on the basis of different religious beliefs. The same is true of early city-states in the Levant and India.
Truly, we do not find self-identified “religious” groups until fairly recently in history. The Jews were one of the first. No one contends that the Jews were the first to have “religion” or that the origins of religion are Jewish.
Given these facts, it is abundantly clear that religion did not evolve during the Paleolithic to bind groups together and give them advantages over other groups. Until group level selectionists start citing specific historical examples of the groups necessary for their hypothesis, their arguments will remain speculative and unsupported.
If the groups they cite in support of their argument are recent — i.e., post Neolithic Revolution or historic — then their entire argument falls apart. Religion obviously did not evolve over the past 5,000 years. While there have been self-identified religious groups over the past 5,000 years that have used their religious identity to bind them together and compete against other groups, this has nothing to do with the evolution or origins of religion.