title: Cortical thickness of the dorsolateral prefrontal cortex predicts strategic choices in economic games.
abstract: Human prosociality has been traditionally explained in the social sciences in terms of internalized social norms. Recent neuroscientific studies extended this traditional view of human prosociality by providing evidence that prosocial choices in economic games require cognitive control of the impulsive pursuit of self-interest. However, this view is challenged by an intuitive prosociality view emphasizing the spontaneous and heuristic basis of prosocial choices in economic games. We assessed the brain structure of 411 players of an ultimatum game (UG) and a dictator game (DG) and measured the strategic reasoning ability of 386. According to the reflective norm-enforcement view of prosociality, only those capable of strategically controlling their selfish impulses give a fair share in the UG, but cognitive control capability should not affect behavior in the DG. Conversely, we support the intuitive prosociality view by showing for the first time, to our knowledge, that strategic reasoning and cortical thickness of the dorsolateral prefrontal cortex were not related to giving in the UG but were negatively related to giving in the DG. This implies that the uncontrolled choice in the DG is prosocial rather than selfish, and those who have a thicker dorsolateral prefrontal cortex and are capable of strategic reasoning (goal-directed use of the theory of mind) control this intuitive drive for prosociality as a means to maximize reward when there are no future implications of choices.
authors.affiliation: Graduate School of International Corporate Strategy, Hitotsubashi University, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8439, Japan; Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo 194-8610, Japan; yamagishitoshio@gmail.com.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamagishi
authors.affiliation: Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo 194-8610, Japan;
authors.forename: Haruto
authors.initials: H
authors.lastname: Takagishi
authors.affiliation: Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo 194-8610, Japan;
authors.forename: Alan de Souza Rodrigues
authors.initials: Ade S
authors.lastname: Fermin
authors.affiliation: Department of Neuroinformatics, Araya Brain Imaging, 3-16-16 Daizawa, Setagayaku, Tokyo 155-0032, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Kanai
authors.affiliation: Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo 194-8610, Japan;
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo 194-8610, Japan;
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Matsumoto
mesh_terms: D000328:Adult; D002755:Choice Behavior; D003071:Cognition; D003299:Cooperative Behavior; D005260:Female; D005717:Games, Experimental; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010551:Personality; D017397:Prefrontal Cortex / Q000033:anatomy & histology*
keywords: DLPFC; dictator game; prosocial behavior; strategic reasoning; ultimatum game