Around The World, People Co-operate More Willingly With Others From Their Own Country

By Matthew Warren

Many of the world’s most pressing problems require global co-operation. If we are to combat climate change or contain the spread of devastating diseases, for instance, we need to work across borders and share resources.

So a new study in Nature Communications doesn’t make for encouraging reading. Using a common paradigm for studying co-operation, Angelo Romano from the Max Planck Institute for Research on Collective Goods and colleagues look at how more than 18,000 participants from 42 different countries co-operate with people from their own nation and elsewhere. They find that in every single country, participants show national parochialism: they co-operate more readily with people from their own country than with others.

Participants completed 12 trials of a prisoner’s dilemma task, each with a different partner who either came from their own country or another country (there were also some trials in which participants weren’t given any information about their partner’s nationality). In each trial, participants were given 10 “monetary units”, and had to decide how many to keep for themselves and how many to give to their partner. Any money they gave away was doubled — and any they received from their partner were doubled too — so in theory the optimal result would be for both parties to co-operate by giving away all of their money. Additionally, on some trials participants were told their decisions would be private, while on others they were told they would be published online.

The team found that people co-operated more (i.e. sent more money to their partner) when their partner came from the same country compared to when they came from a different country. This effect was statistically significant for 39 of the 42 countries, and the remaining three showed a non-significant trend in the same direction. It also didn’t matter whether or not their decisions were going to be made public: participants displayed this “national parochialism” either way. And although the decisions were all about a hypothetical pool of money, a sub-study in which participants actually received a monetary reward produced the same results.

Interestingly, the extent to which participants favoured co-operating with their compatriots over people from other nations was similar across the different countries, and the team didn’t find any evidence that this was related to cultural or political factors. By contrast, they did find that overall levels of co-operation varied by country and were related to particular factors. For instance, co-operation was generally greater in countries with more egalitarian values and those where there are more opportunities to establish new relationships with others.

The results suggest that national parochialism occurs around the world with surprisingly little variation. This is consistent with theories that our tendency to favour the in-group is a universal human behaviour, the authors write. However, they also note that past studies using different methodologies have found cultural differences in in-group favouritism, so further work is needed to understand the exact scenarios in which national parochialism emerges in different countries.

Still, the study shows that at least when it comes to making decisions about sharing goods with others, people are less keen to co-operate with those outside of their own country. While the paper focuses on decisions made at an individual level rather than those made by governments and institutions, the work has clear implications when it comes to understanding the obstacles to co-operating across borders. In fact, we’re in the middle of a pandemic that requires a co-ordinated, global response, yet in most low-income countries the vast majority of people haven’t received a single dose. The barriers to global co-operation are obviously multi-faceted, but national parochialism surely doesn’t help.  

National parochialism is ubiquitous across 42 nations around the world

Matthew Warren (@MattBWarren) is Editor of BPS Research Digest