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Journal Article 2014; 35(6): 510-517 PubMed PMID: 25433845 Citation  Keywords:  Adolescent, Adult, Antisocial Personality Disorder:diagnosis, Choice Behavior, Female, Gambling:psychology, Games, Experimental, Humans, Impulsive Behavior, Male, Models, Psychological, Predictive Value of Tests, Probability, Risk-Taking, Young Adult,.   

BACKGROUND: This study investigated the relationships between psychopathy and impulsive and risky decision making, by utilizing intertemporal and probabilistic choices for both gain and loss, in addition to the Iowa gambling task.

METHODS: The Psychopathic Personality Inventory-Revised - a 154-item measure that assesses psychopathic traits by self-report - was used with a 4-point response scale to assess 113 undergraduate students from three Japanese universities. Participants' performance on the Iowa Gambling Task and four behavioral neuroeconomic tasks of discounting - delayed gain, delayed loss, uncertain gain, and uncertain loss - were estimated.

RESULTS: Risky decisions in probability discounting of gain and loss were associated with psychopathy. Psychopathic traits had no relationship with performance on the Iowa Gambling and were not significantly related to delay discounting.

CONCLUSIONS: Psychopathy is predicted by risky decision in probability discounting of gain and loss, but not strongly associated with future myopia. Implications of the present findings for neuroeconomics and neurolaw are discussed....

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Journal Article 2013; 34(1): 47-51 PubMed PMID: 23524623 Citation  Keywords:  Adolescent, Decision Making:physiology, Depression:blood, Economics, Behavioral, Emotions:physiology, Games, Experimental, Happiness, Humans, Interleukin-6:blood, Male, Neuroimmunomodulation:physiology, Predictive Value of Tests, Young Adult,.   

OBJECTIVES: This study aimed to examine one of biological correlates, pro-inflammatory cytokine, in rejection of unfair financial offers in the Ultimatum Game (UG), where the division of a sum of money is proposed and the player can accept or reject this offer.

METHODS: Nineteen participants played 20 trials of the UG as responders, and they were proposed unfair offers in a half of the trials. Baseline levels of several pro-inflammatory and anti-inflammatory cytokines, subjective happiness, and depression of them were measured.

RESULTS: Participants with higher levels of the pro-inflammatory cytokine, interleukin (IL)-6 rejected fewer unfair offers. This effect of IL-6 levels on decision-making was independent from other pro-inflammatory cytokines, anti-inflammatory cytokines, subjective happiness, and depression.

CONCLUSIONS: These results suggested that chronic higher levels of IL-6 might affect functions of neural regions related to decision making, and thus can modulate rejection of unfair offers....

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Journal Article 2009; 30(5): 643-646 PubMed PMID: 20035253 Citation  Keywords:  Adolescent, Choice Behavior:physiology, Decision Making:physiology, Emotions:physiology, Female, Games, Experimental, Humans, Neuropsychological Tests, Saliva:enzymology, Salivary alpha-Amylases:metabolism, Young Adult,.   

OBJECTIVES: This study aimed to examine the role of emotions in rejection of unfair offers in an ultimatum game, which is of interest in neuroeconomics of fairness.

METHODS: Thirty-seven participants played a one-shot ultimatum game as responders and decided whether to accept or reject the unfair offers by the proposers. Salivary alpha-amylase (sAA) was assessed before and after the ultimatum game.

RESULTS: Forty-four percent of the participants rejected the unfair offers. While sAA levels of the participants who rejected the unfair offers increased between pre- and post-experiment, sAA levels of the participants who accepted the unfair offers remain unchanged.

CONCLUSIONS: Emotional stress response was observed when participants rejected the unfair offers. Our results indicated that rejection of the unfair offers is a reflection of emotional arousal associated with adrenergic activations....

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Journal Article 2009; 30(4): 496-500 PubMed PMID: 20010492 Citation  Keywords:  Cerebral Cortex:physiology, Decision Making:physiology, Emotions:physiology, Female, Game Theory, Games, Experimental, Gyrus Cinguli:physiology, Humans, Magnetic Resonance Imaging, Male, Social Behavior, Young Adult,.   

OBJECTIVES: This study examined the roles of the insula and the anterior cingulate activations in the rejection of unfair offers in the impunity game.

METHODS: Fifteen participants played the impunity game in ten trials as responders during neuroimaging.

RESULTS: About 45% of the unfair offers were rejected by the responders even when responders could not restore a fair outcome, which cannot be accounted for by social preference of inequity aversion. Imaging data showed that the right anterior insula was activated when participants faced and rejected unfair offers.

CONCLUSIONS: The insula activation during a rejection of the unfair offers is the reflection of an emotional response, rather than social preference of inequity aversion. The role of emotion in the neuroeconomics of fairness was demonstrated....

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Journal Article 2007; 28(5): 659-661 PubMed PMID: 17984946 Citation  Keywords:  Adult, Behavior, Addictive:psychology, Cerebral Cortex:physiology, Choice Behavior, Conflict (Psychology), Decision Making, Games, Experimental, Humans, Male, Reinforcement (Psychology), Smoking:psychology, Socioeconomic Factors,.   

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....

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Journal Article 2007; 28(5): 662-665 PubMed PMID: 17984929 Citation  Keywords:  Adolescent, Adult, Altruism, Amylases:metabolism, Decision Making:physiology, Games, Experimental, Humans, Male, Reference Values, Reward, Saliva:metabolism, Self Concept, Social Perception,.   

OBJECTIVE: Little is known regarding the relationship between social evaluation-induced neuroendocrine responses and generosity in game-theoretic situations. Previous studies demonstrated that reputation formation plays a pivotal role in prosocial behavior. This study aimed to examine the relationships between a social evaluation-induced salivary alpha-amylase (sAA) response and generosity in the dictator game. The relationship is potentially important in neuroeconomics of altruism and game theory.

METHODS: We assessed sAA and allocated money in the dictator game in male students with and without social evaluation. RESULTS Social evaluation-responders allocated significantly more money than controls; while there was no significant correlation between social evaluation-induced sAA elevation and the allocated money.

CONCLUSIONS: Social evaluation significantly increases generosity in the dictator game, and individual differences in trait characteristics such as altruism and reward sensitivity may be important determinants of generosity in the dictator game task....

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