A reciprocal action is an action meant to have a similar influence on another's payoff as another's action has on one's own. One hypothesis asserts that reciprocal action is triggered by the reciprocator's belief that another's action was good or ill intended. The other hypothesis says that the reciprocator is simply acting to implement fixed preferences over payoff allocations. We report on an experiment that allows us to study both positive (reward) and negative (punishment) reciprocal action in a single framework. Knowing the preferences for payoff allocations is sufficient to account for nearly all the reciprocal action we observe in our experiment.
