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,...

In the past decades, behavioural economics has become an influential and important field of economics. Interest in behavioural economics derives from unease with standard economic models that are based on restrictive assumptions, which confine the nature of human motivation. Although Adam Smith,...