Acting against our real self interest to preserve our self image

Here is a fascinating bit of game playing from Yamagishi et al. :

In a series of experiments, we demonstrate that certain players of an economic game reject unfair offers even when this behavior increases rather than decreases inequity. A substantial proportion (30–40%, compared with 60–70% in the standard ultimatum game) of those who responded rejected unfair offers even when rejection reduced only their own earnings to 0, while not affecting the earnings of the person who proposed the unfair split (in an impunity game). Furthermore, even when the responders were not able to communicate their anger to the proposers by rejecting unfair offers in a private impunity game, a similar rate of rejection was observed. The rejection of unfair offers that increases inequity cannot be explained by the social preference for inequity aversion or reciprocity; however, it does provide support for the model of emotion as a commitment device. In this view, emotions such as anger or moral disgust lead people to disregard the immediate consequences of their behavior, committing them to behave consistently to preserve integrity and maintain a reputation over time as someone who is reliably committed to this behavior.