国際誌論文データベース

Yamamoto, H.(山本仁志), Okada, I., Uchida, S., & Sasaki, T. (2017).
A norm knockout method on indirect reciprocity to reveal indispensable norms.
規範ノックアウト手法による協力の進化のための必須規範の解明
Scientific Reports, 7, 44146.
doi: 10.1038/srep44146

Although various norms for reciprocity-based cooperation have been suggested that are evolutionarily stable against invasion from free riders, the process of alternation of norms and the role of diversified norms remain unclear in the evolution of cooperation. We clarify the co-evolutionary dynamics of norms and cooperation in indirect reciprocity and also identify the indispensable norms for the evolution of cooperation. Inspired by the gene knockout method, a genetic engineering technique, we developed the norm knockout method and clarified the norms necessary for the establishment of cooperation. The results of numerical investigations revealed that the majority of norms gradually transitioned to tolerant norms after defectors are eliminated by strict norms. Furthermore, no cooperation emerges when specific norms that are intolerant to defectors are knocked out. プレスリリース：https://www.u-presscenter.jp/modules/bulletin/index.php?page=article&storyid=11071

Toyokawa, W. （豊川航）(2017). 
Scrounging by foragers can resolve the paradox of enrichment.
捕食者による略奪行動が生物群集における富栄養化のパラドクスを解消する
Royal Society Open Science, 4: 160830. 
doi:10.1098/rsos.160830 

Intuition and experimental evidence suggests that increases in prey availability lead to increases in predator populations. However, theoretical models paradoxically suggest that increased prey can lead to instability in the predator-prey ecosystem and possible extinction. To resolve this paradox, I considered social interactions between predators. Some predators produce (find their own prey) and others scrounge (join in on their companions’ prey). I showed mathematically that when scrounging is prevalent, the ecosystem becomes stable and hence, the paradox disappears. My results highlight the importance of social interactions within group-living animals in maintaining stability of ecological communities. 

Ishii, K. (石井敬子), Matsunaga, M., Noguchi, Y., Yamasue, H. Ochi, M. (越智美早), & Ohtsubo, Y. (大坪庸介) (2017) . 
A polymorphism of serotonin 2A receptor (5-HT2AR) influences delay discounting. 
セロトニン2A受容体が遅延割引に影響する
Personality and Individual Differences. 
doi: 10.1016/j.paid.2017.03.011

The present study investigated the association between a polymorphism of the serotonin 2A receptor (5-HT2AR) gene and the form of impulsive choice known as delay discounting. Using a hypothetical situation, we asked Japanese participants to choose between receiving (or paying) a different amount of money immediately or with a specified delay (one week, two weeks, one month, six months, one year, five years, or 25 years), and estimated the parameters of intertemporal choice models (exponential, hyperbolic, hyperbolic with exponent, and quasi-hyperbolic). Regardless of the genotypes, the hyperbolic with exponent model, which always indicated minimum AICc (Akaike Information Criterion with small sample correction), fitted better the observed data than the other models. Future gains were discounted more steeply than future losses. Moreover, as expected, individuals with the AA genotype of the 5-HT2AR A-1438G polymorphism discounted the future more steeply than did individuals with the GG genotype, although this effect was limited to only gains. The findings implied individual differences based on the A-1438G polymorphism in the modulation of serotonin in the reward valuation underlying delay discounting. 

Johnson, B., & Nakayachi, K. (中谷内 一也) (2017). 
Examining Associations Between Citizens' Beliefs and Attitudes about Uncertainty and Their Earthquake Risk Judgments, Preparedness Intentions, and Mitigation Policy Support in Japan and the United States. 
日米における地震についての不確実性とリスク判断、準備意図、被害軽減政策支持などについての市民の信念と態度の関連性
International Journal of Disaster Risk Reduction, 22, 37–45. 
doi: 10.1016/j.ijdrr.2017.02.019 

Although hazards are inherently uncertain, research on citizens’ judgments of risk, hazard preparedness, and support for mitigation policies has rarely accounted for citizens’ beliefs about the uncertainty of fields estimating hazard risk or in science as providing accurate, unbiased knowledge, nor citizens’ need to achieve quick, certain answers. Parallel online surveys of residents of earthquake-prone areas of Japan and the United States revealed that belief in scientific positivism increased policy support in both countries (as did need for closure among Americans), and belief in seismological uncertainty reduced judged earthquake risk in Japan, with small effect sizes. Preparedness was unaffected by these predictors. Associations of other factors (quake experience; trust in experts; demographics) with dependent variables were consistent with other studies, and Japanese-American differences were small on dependent variables and in most predictors. Motivation (i.e., high involvement with the topic, relevance of the fictional earthquake rupture forecast in a quasi-experiment embedded in the survey, and judged ability to use its information) strongly affected judged risk, preparedness and policy support. Low-motivation Japanese and high-motivation Americans exhibited associations most similar to overall findings for their nations. Implications of these findings for hazards research and risk communication are discussed. 

Miyatake, S.(宮武沙苗), & Higuchi, M.(樋口匡貴) (2017).
Does religious priming increase the prosocial behaviour of a Japanese sample in an anonymous economic game?
宗教プライミングは向社会的行動を増加させるか？匿名の経済ゲームを用いた日本人サンプルによる検討
Asian Journal of Social Psychology.
doi: 10.1111/ajsp.12164

We examined the effect of religious priming on a Japanese sample in an anonymous dictator game whereas previous studies on religious priming on prosociality had mainly been conducted within Western contexts. The current study attempted to examine whether religion increases prosocial behaviour in a Japanese sample through the replication of ‘God is Watching You’ (Shariff & Norenzayan, 2007) where it was found that participants primed with religion-related words and secular justice-related words behaved more prosocially than participants primed with neutral words in an anonymous dictator game. The current experiment was conducted with Japanese students (n = 106) to examine whether the results of the original study could be applied to Japanese people. The results showed that among the three priming conditions (control, religion, secular justice), there was no difference in the amount of money participants allocated to anonymous strangers, although in the secular justice priming condition, theists allocated more money than atheists. The results might be due to the fact that the religious priming words used in the original study did not precisely activate the propositional network of religion that Japanese participants have. More culture-specific studies are necessary to examine how religious priming works for non-Westerners.

Uchida, Y.（内田由紀子）, Savani, K., Hitokoto, H. (一言英文), & Kaino K. (2017).
Do You Always Choose What You Like? Subtle Social Cues Increase Preference-Choice Consistency among Japanese But Not among Americans.
（微細な社会的手がかりが選好選択の一貫性に及ぼす影響の日米比較）
Frontiers in Psychology.
doi: 10.3389/fpsyg.2017.00169

Previous research has suggested that stability of self-concept differs across cultures: in North American cultural contexts, people’s self-concept is stable across social contexts, whereas in Japan, different self-concepts are activated within specific social contexts. We examined the implications of this cultural difference for preference-choice consistency, which is people’s tendency to make choices that are consistent with their preferences. We found that Japanese were less likely than Americans to choose items that they liked the most, showing preference-choice inconsistency. We also investigated the conditions in which Japanese might exhibit greater preference-choice consistency. Consistent with research showing that in Japanese culture, the self is primarily conceptualized and activated by social contexts, we found that subtle social cues (e.g., schematic representations of human faces) increased preference-choice consistency among Japanese, but not among Americans. These findings highlight that choices do not reveal preferences to the same extent in all cultures, and that the extent to which choices reveal preferences depends on the social context.

Yanagisawa, K.（柳澤邦昭）, Kashima. E. S., Moriya. H., Masui, K.（増井啓太）, Furutani, K.（古谷嘉一郎）, Yoshida, H., Ura, M.（浦光博）, & Nomura, M.（野村理朗） (2017).
 Tolerating dissimilar other when primed with death: Neural evidence of self-control engaged by interdependent people in Japan.
 死をプライムされたとき、価値観の異なる他者を受け入れる：
 相互協調的自己観の高い日本人のセルフコントロールに関する神経科学的知見
 Social Cognitive and Affective Neuroscience.
 doi: 10.1093/scan/nsx012

Mortality salience (MS) has been shown to lead to derogation of others with dissimilar worldviews, yet recent research has shown that Asian-Americans who presumably adopt an interdependent self-construal (SC) tend to reveal greater tolerance after MS induction. In the present study, we demonstrated that Japanese individuals who are high on interdependent SC indeed show greater tolerance towards worldview-threatening other in the MS (vs. control) condition, thus replicating the prior research. Extending this research, we also found that interdependent people’s tolerance towards worldview-threatening other was mediated by increased activity in the right ventrolateral prefrontal cortex (rVLPFC) in the MS condition. These data suggested that when exposed to death-related stimuli, highly interdependent individuals may spontaneously activate their neural self-control system which may serve to increase tolerance towards others.

Tsuboya, T., Aida, J., Hikichi, H.（引地博之）, Subramanian S., Kondo K., Osaka, K., & Kawachi, I. (2017).
Predictors of decline in IADL functioning among older survivors following the Great East Japan earthquake: A prospective study.
東日本大震災被災高齢者の手段的日常生活動作低下の予測要因：前向き研究の結果から
Social Science & Medicine, 176, 34–41. 
doi: 10.1016/j.socscimed.2016.05.026 

Introduction We described associations between the type of disaster experience and change in instrumental activities of daily living among older adult survivors before-after a terrible disaster. Methods The study took advantage of a “natural experiment” afforded by the Japan Gerontological Evaluation Study (JAGES), a nationwide cohort study established in 2010, seven months prior to the earthquake and tsunami. A follow-up survey was conducted in 2013. This study was conducted in Iwanuma, which was directly struck by tsunami. Our sample comprised community-dwelling aged survivors in Iwanuma who responded to questions about personal circumstances and functional status both before and after the disaster (N = 3547). Personal experiences of earthquake and tsunami damage was used as an exposure variable. The outcome was changes in self-reported 13-item instrumental activities of daily living (IADL), which was assessed both before and after the disaster. Results Among the participants, 931 reported losing family member(s) to the disaster, while a further 549 reported losing friend(s). More than half of the participants reported any damage to their houses while approximately 1 in 8 lost their car(s). The multivariable OLS regression revealed that complete house loss and disruption of internal medicine were associated with significantly worse IADL: −0.67 points (95%CI: −0.99, −0.34) for entirely destroyed homes; −0.40 points (95% CI: −0.71, −0.092) for disruption of internal medicine. By contrast, loss of family/friends/pets/cars and disruption to the other medical service were not associated with decline in IADL. Conclusion Complete house loss and disruption of access to internal medicine after a disaster were associated with significant adverse impact on decline in physical and cognitive functions 2.5 years after the disaster, while loss of family/friends was not.

Hikichi, H.（引地博之）, Kondo, K., Takeda, T., & Kawachi, I. (2016).
Social interaction and cognitive decline: Results of a 7-year community intervention
社会的交流と認知機能の関連：７年間のコミュニティ介入研究の結果から
Alzheimer's & Dementia: Translational Research & Clinical Interventions. 
doi: 10.1016/j.trci.2016.11.003

Introduction There are few intervention studies that demonstrated linking social participation to lower risk of cognitive decline. We examined prospectively the protective effect of a community intervention program promoting social participation on the incidence of cognitive disability. Methods The baseline was established in a survey of community-dwelling older people aged 65 years old or more in July 2006 (2793 respondents, response rate 48.5%). The setting was Taketoyo town in Japan, where municipal authorities launched an intervention that was based on the establishment of community-based centers called “salons,” where the town’s senior residents could congregate and participate in social activities, ranging from arts and crafts, games, and interactive activities with preschool children. Three salons were established in May 2010, and a total of 10 salons were in operation by 2013. We recorded the frequency of salon participation among survey respondents till 2013 and conducted two follow-up surveys (in 2010 and 2013) to collect information about health status and behaviors. The onset of cognitive disability was followed from May 2007 to January 2014. We used the marginal structural models to evaluate the effect of program. Results The range of prevalence of cognitive disability was from 0.2% to 2.5% during the observation period. The proportion of respondents who participates to salons increased over time to about 11.7%. The frequency of salon participation was protectively associated with cognitive decline, even after adjusting for time-dependent covariates and attrition (odds ratio = 0.73, 95% confidence interval: 0.54–0.99). Discussion Our study suggests that operating community salons that encourage social interactions, light physical activity, and cognitive activities among older participants may be effective for preventing cognitive decline. In future studies, we need to understand what sorts of activities (e.g., those involving light physical activity vs. purely intellectual activities) are most effective in maintaining cognitive function.

Mifune, N.(三船恒裕), Simunovic, D., & Yamagishi, T.(山岸俊男) (2017).
Intergroup Biases in Fear-induced Aggression.
恐怖性攻撃行動における集団間バイアス
Frontiers in Psychology.
doi: 10.3389/fpsyg.2017.00049

Using a recently created preemptive strike game (PSG) with 176 participants, we investigated if the motivations of spite and/or fear promotes aggression that requires a small cost to the aggressor and imposes a larger cost on the opponent, and confirmed the earlier finding that fear does but spite does not promote intergroup aggression when the groups are characterized as minimal groups; additionally, the rate of intergroup aggression did not vary according to the group membership of the opponent. The PSG represents a situation in which both the motivations of spite and of fear can logically drive players to choose an option of aggression against an opponent. Participants decide whether or not to attack another participant, who also has the same capability. The decision is made in real time, using a computer. We discuss theoretical implications of our findings on the evolutionary foundations of intragroup cooperation and intergroup aggression. The evolutionary model of intergroup aggression, or the parochial altruism model, posits that intragroup cooperation and intergroup aggression have co-evolved, and thus it predicts both intragroup cooperation and intergroup aggression to emerge even in a minimal group devoid of a history of intergroup relationships. The finding that only intragroup cooperation but not intergroup aggression emerged in the minimal group experiments strongly suggests that intergroup aggression involves a psychological mechanism that is independent from that of intragroup cooperation. We further discuss the implications of these findings on real-world politics and military strategy.