"Prominent economic theories have emphasized the role of commonly held perceptions and expectations for determining macroeconomic outcomes. A key empirical question is how such collectively held beliefs are formed. We use the FIFA World Cup 2006 as a natural experiment. We provide direct...

Experimental evidence has convincingly shown the existence of reciprocal inclinations, i.e., a tendency for people to respond in-kind to hostile or kind actions. Little is known, however, about: (i) the prevalence of reciprocity in the population, (ii) individual determinants of reciprocity,...