We develop a new experiment to study the emergence of welfare-reducing bilateral alliances within larger groups, and … curtailing welfare reducing reciprocity, i.e. 'back-scratching'. …

of the U.S. population, oversampling immigrants, to study trust, positive, and negative reciprocity between first …

report on the results of an experiment designed to evaluate two distinct explanations for this phenomenon, indignation and … group reciprocity. We find evidence in favor of both, with the caveat that the incidence of indignation-driven sanctions is …

altruism. Instead, we posit that social reciprocity is a triggered normative response. Our experiment confirms the existence of …We define social reciprocity as the act of demonstrating one's disapproval, at some personal cost, for the violation of … widely-held norms (e.g., don't free ride). Social reciprocity differs from standard notions of reciprocity because social …

behavior is almost non-existent. We study sabotage in tournaments in a controlled laboratory experiment and are able to confirm …