Cooperation hidden frontiers: The behavioral foundations of the Italian North-South divide

Socio-economic performance differs not only across countries but within countries too and can persist even after religion, language, and formal institutions are long shared. One interpretation of these disparities is that successful regions are characterized by higher levels of trust, and, more generally, of cooperation. Here we study a classic case of within-country disparities, the Italian North-South divide, to find out whether people exhibit geographically distinct abilities to cooperate independently of many other factors and whence these differences emerge. Through an experiment in four Italian cities, we study the behavior of a sample of the general population toward trust and contributions to the common good. We find that trust and contributions vary in unison, and diminish moving from North to South. This regional gap cannot be attributed to payoffs from cooperation or to institutions, formal or informal, that may vary across Italy, as the experimental methodology silences their impact. The gap is also independent of risk and other-regarding preferences which we measure experimentally, suggesting that the lower ability to cooperate we find in the South is not due to individual \moral" flaws. The gap could originate from emergent collective properties, such as different social norms and the expectations they engender. The absence of convergence in behavior during the last 150 years, since Italy was unified, further suggests that these norms can persist overtime. Using a millennium-long dataset, we explore whether the quality of past political institutions and the frequency of wars could explain the emergence of these differences in norms.