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,...

To discuss experimental results without discussing how they came about makes sense when the results are robust to the way experiments are conducted. Experimental results, however, are - arguably more often than not - sensitive to numerous design and implementation characteristics such as the use...