Common Language and Integration of Interethnic Networks

In diverse societies, differences in language can create barriers to economic opportunity, trust, and cooperation. While early interventions that improve communication and social skills can foster cross-group cohesion, these efforts may come at the cost of educational efficiency, as learning in one’s native language often requires segregation. How should policymakers balance these trade-offs?

We study this question in North Macedonia, where high schools segregate students by language of instruction. Using a randomised experiment, we pair students from different ethnic backgrounds to play a cooperative video game that requires teamwork and communication. We test how shared language skills and intergroup interactions shape cooperation, measuring changes in economic trust, willingness to work with out-group peers and game performance.

Our results suggest that intergroup contact significantly improves social cohesion. Students in mixed-ethnicity teams become more willing to collaborate across ethnic lines, showing a 14% lower preference for same-ethnicity partners and a 34% reduction in in-group bias when sharing money in a behavioural game. Importantly, these gains come without a loss in productivity—students in mixed teams perform just as well as those in same-ethnicity teams, despite facing communication challenges. However, students in mixed teams report lower satisfaction with the experience, pointing to non-economic costs of integration, such as social discomfort or cognitive effort. However, when students had fluency in a shared language these costs decreased.

Our findings highlight both the promise and challenges of fostering social cohesion in diverse societies. While structured interactions can successfully reduce ethnic divisions, they may require additional support to ensure that participants find the experience positive and rewarding.