Study offers insights into why inequality and economic decline drive polarisation

Visiting Professor Joanna Bryson has co-authored a study showing why rebuilding trust in societies can be so challenging.

  • Last updated on Friday 8 January 2021

Polarisation, such as the emergence of extreme right or left movements, can create conflict and keep individuals and even governments from working toward a common good. Social and political polarisation has occurred recently in a number of countries - the United States, the United Kingdom, Hungary and Brazil, among others. What causes a population to split into rival camps - and how can people come together again?

New research by Joanna Bryson, Hertie School Professor of Ethics and Technology and Visiting Professor at the University of Bath, Alexander J. Stewart of the University of Houston, and Nolan McCarty of Princeton University offers an explanation of why individuals might become more polarised when they experience economic inequality, and what this implies. Their article, "Polarization under rising inequality and economic decline", was published in Science Advances on 11 December 2020. Bryson began this research while at Princeton on sabbatical from the University of Bath.

Together, Stewart, McCarty and Bryson created a model based on game theory and cultural evolution. The model shows that in times of economic hardship, individuals do well to seek interactions with groups that are economically and socially similar to them - so-called in-groups - as they develop an aversion to risk and reject collaboration with non-like-minded "out group" individuals. This is the case, despite the fact that overall they would be better off working with the out-group. But when times are hard, the risks of collaboration may outweigh the benefits.

Their model shows that polarisation toward in-groups "can spread rapidly to the whole population and persist even when the conditions that produce it have reversed." This kind of us-vs-them perspective breeds populism, which in recent years has led to movements like Brexit, the authors note.

In another significant finding, Bryson and her co-authors found a reason why it is so hard to re-establish trust once people are divided. If we assume that cooperation requires both sides to be willing to overcome their fears, individuals may remain polarised even after the economy has recovered and inequalities have subsided. It might even take an external shock - like a pandemic - to remind people that they have common interests and give individuals an incentive to work toward a common good.


This site uses cookies and analysis tools to improve the usability of the site. More information. |