Calamities, Common Interests, Shared Identity: What Shapes Social Cohesion in Europe?

We conduct a large-scale incentivized survey experiment in nine EU countries to study how priming common economic interests (EU trade), a shared identity (EU common values), and a major health crisis (COVID-19), influences altruism, reciprocity and trust of EU citizens. We find that the COVID-19 treatment increases altruism and reciprocity towards compatriots, as well as altruism towards citizens of other EU countries. The EU common values treatment has similar effects and in addition also boosts reciprocity towards fellow Europeans. The EU trade treatment has no tangible impact on behavior. Trust in others is not affected by any treatment. Our results suggest that both a shared identity and a shared crisis can have a unifying effect among EU citizens, while shared economic interests (alone) do not significantly affect European cohesion.