Threat and the Evolution of Tribalism

Across the globe, there is a rise of tribalism, yet we have little insight into its evolutionary basis. Here we apply an agent-based model in an evolutionary game theoretic framework and examine the causal effects of societal threat on tribalism at the population level. We find that as threat increases, tribalism tends to increase. Yet when threat becomes very high, tribalism begins to decrease – illustrating a non-monotonic effect of threat on tribalism – a finding which is replicated with data on disease and economic threats. Our study indicates that growing threat faced by human societies may play a causal role in the rise of tribalism, but that mass cooperation, which goes beyond group tags such as race, ethnicity, religious belief, and nationality, is possible when humans face extreme threat.