Economic decisionmaking in the ultimatum game by smokers. http://www.ncbi.nlm.nih.gov/pubmed/17984946

OBJECTIVE: No study to date compared degrees of inequity aversion in economic decision-making in the ultimatum game between non-addictive and addictive reinforcers. The comparison is potentially important in neuroeconomics and reinforcement learning theory of addiction. METHODS: We compared the degrees of inequity aversion in the ultimatum game between money and cigarettes in habitual smokers. RESULTS Smokers avoided inequity in the ultimatum game more dramatically for money than for cigarettes; i.e., there was a "domain effect" in decision-making in the ultimatum game. CONCLUSIONS: Reward-processing neural activities in the brain for non-addictive and addictive reinforcers may be distinct and the insula activation due to cue-induced craving may conflict with unfair offer-induced insula activation. Future studies in neuroeconomics of addiction should employ game-theoretic decision tasks for elucidating reinforcement learning processes in dopaminergic neural circuits.