The evolution of groups with different beliefs, behaviors and preferences

What is it about?

We use evolutionary game theory to study when populations will fracture into groups that differ in their beliefs, behaviors and preferences. Why are so many democratic societies fractured and polarized? Some cite social pressures, such as social media algorithms that stoke outrage and spread misinformation. This account treats hate as something like the temperature, and imagines Mark Zuckerberg and Elon Musk control the thermostat. Some cite economic and material factors, such as lack of housing and affordability, or a sort of generalized economic anxiety. Usually when people try to model loss of social cohesion or polarization they use opinion dynamics, which account for social pressures but not material factors. In order to try and bridge this disconnect in our new work we model the co-evolutionary dynamics of belief, behavior and social preferences simultaneously. Our results are framed in terms of cultural tightness and social cohesion, and our model captures the interplay between peoples’ willingness to materially help one another (i.e. cooperate), and their beliefs about the value of helping one another.

Featured Image

Photo by Kamil Kalkan on Unsplash

Photo by Kamil Kalkan on Unsplash

Why is it important?

It turns out that this interplay is really quite complicated. Lots of things can happen and what exactly will happen depends on the details of the environment – what in modelling terms we describe as the “initial conditions”. But I want to draw out one lesson. When the material benefits of cooperation are high, something like the rules of classical game theory apply. People act more or less rationally, and will act pro-socially, as long as it is in their individual material interest to do so (which it often is – cooperation is not a mystery). When material benefits are very low, on the other hand, the rules of social conformity apply. People care about “fitting in” and “keeping their head down” and so tend to adopt the same beliefs and behaviors as those around them, whatever those may be. In between these two extremes though, something interesting happens – we see the emergence of groups who both behave and believe in fundamentally different ways. Specifically, we see one group emerge that cares only about their own material benefits, while another group emerges that cares only about social conformity, often at the expense of their material circumstance. It is in this middle ground, when material circumstances are pretty good, but not as good as they could be, where we see the conditions for factionalism and loss of social cohesion take hold, because this is when the desire for material gain comes into sharpest conflict with the desire for social conformity. If maintaining social cohesion is your goal, our work suggests, a good approach is working to improve the material circumstances for everybody.