Receiving a gift can create an impulse to reciprocate, even when doing so may be inefficient and potentially harmful to a third party. For instance, after receiving bribes, people may exhibit impulses to reciprocate. This paper provides a theoretical framework for a pure gift effect on...

Development of human societies requires cooperation among unrelated individuals and obedience to social norms. Although punishment is widely agreed to be potentially useful in fostering cooperation, many recent results in psychology and economics highlight punishments' failures in this regard....