How might conversations between individuals on controversial issues lead to ideological polarization of a society? A recent study explores this question by creating a computer model that simulates interactions between individuals using only two simple rules. The first rule is that people who have similar views tend to interact more frequently. The second rule is that people with similar views tend to move closer together in their views when they interact, while people with dissimilar views can be repulsed by each other’s views and actually move farther apart.


To evaluate the possible outcomes, the authors ran the simulation many times with different levels of tolerance in the simulated society as a whole. In the simulation, individuals with higher levels of tolerance tend not to shift their views, and when they do move, they are more likely to move closer to people with similar views. But individuals with lower levels of tolerance may be repulsed even by interactions with those holding similar but slightly different views. When the simulation is run assuming lower levels of tolerance in the society, the effect of repulsion dominates, and the society tends to split into two extreme camps. When the level of tolerance is high, the society tends to converge at one ideological position. However, at moderate levels of tolerance, extreme camps form but a moderate majority can hold out against polarization of the society as a whole.


The simulation suggests that the best way to fight against polarization in a society where tolerance is low is actually to minimize interactions between those who disagree. When individuals who disagree have fewer opportunities to interact, a low tolerance society may be less likely to be dominated by the effect of repulsion.


If individuals are even marginally motivated to hold on to their original views, for example because of economic self-interest, polarization can be prevented. Even a small scale change in how willing people are to resist shifting their position can lead to a more moderate, stable society with more diversity of opinions.


Finally, the authors used the simulation to explore the impact of a shock to the society that shifts the positions of everyone in the society in one direction. If a shock occurs before extreme groups are formed in the society, it can reduce polarization.


This simulation does not try to explain everything about how polarization works. However, it does suggest paths for future research on how individual actions can lead to trends in polarization and how a society could potentially be more resistant to polarization.


Axelrod, R., Daymude, J. J., & Forrest, S. (2021). Preventing extreme polarization of political attitudes. Proceedings of the National Academy of Sciences, 118(50).