Victor Kumar and Richmond Cambell write:

For most of history, human populations were limited to small bands of around 150 members. After exceeding that size, a band would split and drift apart, the descendants forgetting their common ancestry. At some point in human history, however, bands were knit together into tribes—groups of groups—geographically distributed but linked by ethnicity, dialect, and common purpose.

Tribes had an edge over bands because they enabled cooperation at a larger scale. One vital benefit was sharing and minimizing risk. Members of a tribe helped each other out in lean times, during droughts and blights. Another benefit is that tribes were more successful in raiding and warfare—along with defense against other groups’ raiding and warfare. In addition, tribes had more leverage for negotiating peace with their neighbors. Peace was often as important as conquest, since it meant forgoing the risk of injury and death. Peaceful relationships between groups also eliminated demilitarized zones and opened access to the resources available there.

But these benefits were uncertain, since internal conflict and strife are more likely to arise in tribes compared to smaller bands. The keys to stable, functioning tribes were social institutions. [Continue reading…]