社会行動 1 Social Behavior 1
O2-8-1-1 腹側線条体における報酬感受性は不正直な行動を予測する Reward sensitivity in the ventral striatum predicts dishonest behavior ○阿部修士1 ○Nobuhito Abe1, Joshua Greene2 京大・こころの未来1, ハーバード大・心理2 Kokoro Research Center, Kyoto Univ, Kyoto1, Dept of Psychol, Harvard Univ, Cambridge, U.S.A.2 Previous research indicates that consistently honest behavior in response to opportunities for dishonest gain is a matter of "Grace" rather than "Will". That is, such behavior depends on automatic dispositions to behave honestly rather than the active deployment of cognitive control. The nature of these automatic dispositions remains unknown. Here we test the hypothesis that reward sensitivity plays a critical role in determining whether an individual behaves honestly or dishonestly when confronted with opportunities for dishonest gain. Subjects underwent functional magnetic resonance imaging (fMRI) while completing a monetary incentive delay (MID) task in which they anticipated a monetary reward, no reward, or the avoidance of monetary punishment. Individual differences in reward sensitivity were indexed by the level of fMRI BOLD signal in the ventral striatum during the anticipation of reward. Subjects also performed an incentivized prediction task that gave subjects repeated opportunities to gain money dishonestly by lying. Subjects attempted to predict the outcomes of random computerized coin-flips and were financially rewarded for accuracy. In some trials, subjects recorded their predictions in advance. In other trials, subjects were rewarded based on self-reported accuracy, allowing them to gain money dishonestly by lying about the accuracy of their predictions. Dishonest behavior was indexed by improbably high levels of self-reported accuracy. We found that reward sensitivity in the ventral striatum, as measured using the MID task, predicted the frequency of dishonest behavior across individuals in the coin-flip prediction task. These results suggest that reward sensitivity is an important determinant of honest and dishonest behavior.	O2-8-1-2 説得による社会規範の変容の神経基盤 The neural basis of changes in social norms by persuasion ○蓬田幸人1, 松元まどか1, 青木隆太1,2, 杉浦綾香3, 松元健二1 ○Yukihito Yomogida1, Madoka Matsumoto1, Ryuta Aoki1,2, Ayaka Sugiura3, Kenji Matsumoto1 玉川大学脳科学研究所1, 日本学術振興会2, 東京大学 大学院 総合文化研究科 広域科学専攻 生命環境科学系 認知行動科学大講座3 Tamagawa University Brain Science Institute, Tokyo, Japan1, Japan Society for the Promotion of Science, Tokyo, Japan2, Department of Life Sciences, GSAS, University of Tokyo, Tokyo, Japan3 Objective: Social norms are the rules that are shared and determine acceptable behaviors within a group. These norms are internalized as beliefs, and play a substantial role in shaping individuals' social behavior. Further, dynamic changes in social norms within a society occur through persuasive communication at both the interpersonal and mass media levels. Here, we aimed to clarify the neural basis of persuasion-induced changes in social norms by using functional magnetic resonance imaging.Methods: Twenty-seven subjects participated in this study. Brain activity was recorded while subjects read four types of persuasive messages presented on a screen. Two types of messages either countered or reinforced social norms (Norm Countering: NC and Norm Reinforcing: NR, respectively). The other two types served as controls, and either countered or reinforced a non-social belief (Belief Countering: BC and Belief Reinforcing: BR, respectively). Attitude changes resulting from persuasion was assessed for each subject.Results: By using subtraction analysis (contrast [NC+NR]-[BC+BR]), we found that regardless of the direction of persuasion, engaging social norms activated social-cognition related regions including the medial prefrontal cortex, temporal pole, and medial and lateral parietal cortices. By using interaction-effect analysis (contrast [NC-BC]-[NR-BR]), we found that persuasion that countered social norms activated the left middle temporal gyrus (MTG). Moreover, the amount of left MTG activity during persuasion was positively correlated with the degree of subsequent attitude changes.Conclusions: These results suggest that persuasion of social norms is processed through multiple brain regions thought to be involved in social cognition, and that left MTG plays a crucial role in persuasion-induced attitude changes regarding social norms.
O2-8-1-3 内側前頭前野で表象される評判に対する親密度の影響 Reputation representation in medial prefrontal cortex is modulated by familiarity ○川道拓東1, 佐々木章宏1, 松永昌宏1, 吉原一文1, 高橋陽香1, 田邊宏樹2, 定藤規弘1 ○Hiroaki Kawamichi1, Akihiro T Sasaki1, Masahiro Matsunaga1, Kazufumi Yoshihara1, Haruka K Takahashi1, Hiroki C Tanabe2, Norihiro Sadato1 生理学研究所　大脳皮質機能研究系1, 名古屋大学　環境学研究科2 Div Cerebral Integration, Natl Inst Physiol Sci, Okazaki1, Dept Social and Human Environment, Nagoya Univ, Nagoya2 In human society, reputation formed by other members plays key role. Especially in cooperative behaviors, human selects cooperation partners based on reputation toward others. In this sense, representation of others' reputation serves as pivotal functions in social behaviors. In spite of the importance of reputation representation toward others, there remains still unclear in terms of neural correlates underlying reputation representation of others.Neural processing of praise to self is known to include the representation of one's own reputation in the mPFC and the valuation process in striatal regions. In reputation representation, humans primarily depend on own evaluation. As motivation for interaction promotes forming more nuanced, individualized impressions to target, human tends to imagine reputation representation for familiar persons through utilizing own evaluation in a daily life. This raised the possibility that reputation representation to other might also be mediated by the mPFC and be modulated by familiarity in the context of attributions made by a third party. To test this hypothesis, we conducted fMRI experiments of 11 romantic partners viewing reputation toward target person (self, partner, and stranger) ostensibly rated by other evaluators. During the task, subjects were required to judge social desirability of the presented words. We analyzed brain activation related to reputation effects for average social desirability by including social desirability rating data as effect of no interest.As a result, reputations of self and partner commonly activated mPFC in comparison with strangers' reputation effects. These two activations were overlapped. Self specific activation was found in precuneus, which represents self-related processing. Thus, we found that midline structures represent self reputation. In addition, familiarity modulated activation in mPFC suggests that we represent reputation towards familiar others similar to our own reputation.	O2-8-1-4 Developmental imprinting of female preference of male songs and its' roles on reproduction in mice. ○浅場明莉1, 岡部祥太1, 永澤美保1, 茂木一孝1, 菊水健史1 ○Akari Asaba1, Shota Okabe1, Miho Nagasawa1, Kazutaka Mogi1, Takefumi Kikusui1 Asaba1, 麻布大学大学院　獣医学研究科　動物応用科学専攻3, 14, 神奈川県5, 042-769-18536, a.asaba.03@carazabu.com8 School of Veterinary Medicine, Azabu University, Sagamihara1, 229-85014, 相模原市渕野辺１－１７－７１5, a.asaba.03@carazabu.com7 Male mice emit ultrasonic vocalizations when encountering females, the features of which are similar to songbird communications. We previously reported that male song characteristics, such as syllable compositions or temporal sequence of syllables, differ across strains in mice. However, whether female mice prefer specific traits in male songs, and male songs activate reproductive function of female is yet unknown. First, we examined the song preference of female C57BL/6 (B6) and BALB/c (BALB) mice, and found that among female mice subjected to male sexual cues, such as the male pheromone ESP1, B6 females spent more time on searching behavior for BALB male songs, whereas BALB females spent more time on searching behavior for B6 male songs. To establish the degrees of genetic and environmental influences on the song preference, female pups from these two strains were cross-fostered, which ensured that pups had auditory exposure to their foster parents. We found that female song preference was completely reversed by cross-fostering. This demonstrated that female mice can discriminate song characteristics and prefer the songs from strains other than their foster parents based on their early auditory experience. Thus, male songs may contribute to kin recognition by females, and avoiding inbreeding and facilitating offspring heterozygosity. Secondly, we counted the number of delivery in B6 pairs for 4 months and syllable emission during 3 minutes of sexual encounter by male, and a positive correlation between these two indices was found to be significant. In a sexual behavior test, female approached more to the singing male than to the devocalized male. These suggest that male songs contribute female's fertility. This study uncovers new possibilities for studying the biological significance of song variation and the molecular and neural mechanisms of song perception in an established genetic model organism.

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