Are irrational reactions to unfairness truly emotionally-driven? Dissociated behavioural and emotional responses in the Ultimatum Game task

The “irrational” rejections of unfair offers by people playing the Ultimatum Game (UG), a widely used laboratory model of economical decision-making, have traditionally been associated with negative emotions, such as frustration, elicited by unfairness ( Sanfey, Rilling, Aronson, Nystrom, & Cohen, 2003; van’t Wout, Kahn, Sanfey, & Aleman, 2006). We recorded skin conductance responses as a measure of emotional activation while participants performed a modified version of the UG, in which they were asked to play both for themselves and on behalf of a third-party. Our findings show that even unfair offers are rejected when participants’ payoff is not affected ( third-party condition); however, they show an increase in the emotional activation specifically when they are rejecting offers directed towards themselves ( myself condition). These results suggest that theories emphasizing negative emotions as the critical factor of “irrational” rejections ( Pillutla & Murninghan, 1996) should be re-discussed. Psychological mechanisms other than emotions might be better candidates for explaining this behaviour.