If you don’t like it, move: how migration impacts cooperative behavior

When faced with a poor environment at home, a time-tested strategy is to search for better options further afield. Leaving for greener pastures is a potentially rewarding endeavor, but it also comes with stress and uncertainty. Sometimes, it is better to remain at home.

Lee et al. employed evolutionary game theory to study the impacts of migration on individuals looking to improve their conditions. Their model reveals the conditions under which migration is advantageous, and how increased migration affects both communities receiving migrants and those left behind.

In their model, individuals can either be cooperators, who work together for the common good, or defectors, who take advantage of the generosity of others for their own selfish gain. Some individuals who find themselves in a community unsuited to their interests can decide to move — for a price.

“Movement has a certain cost, not simply to execute it, but also to ‘think about it’ and search the wider environment permanently,” said author Attila Szolnoki.

The authors found that despite the cost, migration is often beneficial for individuals and society at large. Cooperators who find themselves surrounded by defectors can escape to more welcoming environments, and generous individuals moving into a community can encourage their new neighbors to behave in kind. In fact, societies with frequent migration tend to be more cooperative than those without.

While this study is abstract, the authors hope the general principles behind it can be used to better understand real-world environments.

“Identifying mechanisms or conditions which support cooperative strategies could be an inspiration for how to design our systems to reach that goal,” said Szolnoki.

Source: “When costly migration helps to improve cooperation,” by Hsuan-Wei Lee, Colin Cleveland, and Attila Szolnoki, Chaos (2022). The article can be accessed at https://doi.org/10.1063/5.0100772 .