Why do responders reject unequal offers in the Ultimatum Game? An experimental study on the role of perceiving interdependence

"Social preferences" have repeatedly been shown to be sensitive to subtle cues of interdependence in many social exchange type-situations. The Ultimatum Game is one such exchange which is assumed to measure preferences for "fairness." The current experiment tests if cueing interdependence triggers an exchange heuristic prompting proposers to give more equal offers, and responders to reject more unequal offers from a particular (yet anonymous) partner. Contrary to expectations, interdependence did not affect proposer behavior, while it spurred responders to be more rational. Responders who were told that they would be matched with one of the other participants after making their decision, rejected an unequal offer more frequently than those who were told they had already been matched prior to making the decision, and for whom the interdependent nature of the exchange was made salient. Based on post-experimental questionnaire data, a plausible explanation for the observed result is that unmatched responders, fostering the illusion of control, reject more in order to signal that they are tough bargainers.