著者
横田 晋大 中西 大輔
出版者
日本社会心理学会
雑誌
社会心理学研究 (ISSN:09161503)
巻号頁・発行日
vol.27, no.2, pp.75-82, 2012

Previous research has shown that ingroup cooperation tends to flourish in intergroup conflict situations. However, the free-rider problem remains unsolved, even in intergroup conflict situations. In this study, based on multi-group selection theory and cultural-group selection theory, we hypothesized that conformity (frequency-dependent behavior) may contribute to enhancing ingroup cooperation. The results of an evolutionary simulation revealed that ingroup cooperation and conformity can evolve in situations of intergroup conflict. When such conflict is mild, agents who cooperate with ingroup members and adjust their behavior to ingroup cooperation rates facilitate cooperation in their own group. However, no effect of conformity on ingroup cooperation was observed during intense intergroup conflict, even though conformity continued to evolve. We discuss the implications of these results and suggest avenues for future research.
著者
佐倉 統 平石 界 池田 功毅 中西 大輔 横田 晋大 三浦 麻子 小森 政嗣 松村 真宏 林 香里 武田 徹
巻号頁・発行日
2013-10-21 (Released:2013-10-24)

今年度は当プロジェクトが本格的に始動した年度である。最初に全体研究会をおこない(2014年5月)、共通認識を醸成した(「放射能」に対する懸念や恐怖感は地域によらない可能性がある、欠如モデルによるリスクコミュニケーションは逆効果、など)。全体研究会は9月と11月にも行なった。11月は福島大学の研究者との合同研究会をおこない、放射線測定活動を続けている地域の方々と、食品の小売り店を訪問し、生活者から見たときの放射能汚染とそれをめぐる「風評被害」の影響について意見交換をおこなった。行動免疫班は、放射能関連リスクならびに、それ以外のリスク要因に対する認知、感情、ならびに情報源への信頼について、2月(非放射能関連リスク)と3月(放射能関連リスク)の2回に分け1600名に対するWeb調査を実施した。放射能関連リスクについては認知と感情の関連が強く、またいかなる情報源も信頼されていないことが示された。ソーシャルメディア班は震災時に流布したデマツイートを見たユーザのうちどういう人が「RTした(しなかった)」か、その特徴を、ユーザのネットワーク特性によって分析した。分析は今年度はまだ途上であるが、恐怖心を抱いているとRTの回数が多いことが示唆されている。社会実装班は、過去の病気の比較やマスメディアの動向を調査すると同時に、原発震災後の政治的ガバナンスの問題点を論じるシンポジウムをおこなった。演者として事故直後に政権の内部から対処に当たった政治家やアメリカから当時派遣された専門家も含め、日本の危機管理体制の問題点を浮き彫りにする論点が出された。年度繰越し分の研究費によって、これらの成果の一部を国際学会で発表し、また、被災者対象保養キャンプの参加者の放射能汚染の認識を調査した。
著者
中川 裕美 横田 晋大 中西 大輔
出版者
日本社会心理学会
雑誌
社会心理学研究 (ISSN:09161503)
巻号頁・発行日
vol.30, no.3, pp.153-163, 2015-03-20 (Released:2015-06-07)
参考文献数
48

In this study, we tested the theoretical validity of both Social Identity Theory (SIT) and the Bounded Generalized Reciprocity Hypothesis (BGR) for explaining in-group cooperation in real social groups. While most previous investigation on real social groups has found support for SIT, confirmatory evidence for BGR remains limited. We conducted a vignette experiment in which reciprocity was manipulated by controlling knowledge of group membership. The participants were 117 undergraduate students who were baseball fans. To control expectation of reciprocity in the experiment, we asked participants to imagine scenarios where they helped others who wore either the same baseball team T-shirts as they did or plain T-shirts. Consistent with BGR, participants tend to cooperate with in-group members when both they and their partner knew that they might be supporters of the same team. On the other hand, participants showed in-group cooperation even when only they knew their partner’s group membership. This finding coincided with SIT. These results thus further verified the theoretical validity of both SIT and BGR in real social groups.
著者
中西 大輔 横田 晋大
出版者
日本社会心理学会
雑誌
社会心理学研究 (ISSN:09161503)
巻号頁・発行日
vol.31, no.3, pp.193-199, 2016-03-18 (Released:2016-03-28)
参考文献数
23

Using evolutionary simulation, Yokota and Nakanishi (2012) have shown that majority syncing (generalized tit-for-tat strategy) is an adaptive strategy in intergroup conflict situations. When intergroup conflict is mild, agents who cooperate with ingroup members and ensure their behavior conforms to other members’ cooperation rates facilitate cooperation in their own group. This finding is supported by multi-group selection theory and by cultural group selection theory. However, this model addresses only majority-syncing as a social influence strategy. The current study introduced a minority-syncing strategy to Yokota and Nakanishi’s (2012) model. There were four conditions: Majority-syncing (agents conformed to the majority, but not to the minority), no conformity (agents did not conform), minority-syncing (agents conformed to the minority, but not to the majority), and mixed (both majority- and minority-syncing strategies were used). Computer simulation revealed that the cooperation rate decreased when minority-syncing was introduced. The cooperation rate of the no-conformity condition was higher than of both the minority and the mixed conditions. We discuss the implications of minority-syncing.
著者
横田 晋大 結城 雅樹
出版者
北海道心理学会
雑誌
北海道心理学研究 (ISSN:09182756)
巻号頁・発行日
vol.33, pp.11-26, 2010-03-31

近年,適応論に基づく研究において,人が様々な種類の外集団からの脅威に対抗するために,脅威の種類に応じた多様な心理メカニズムと行動傾向を持つ可能性に注目が集まっている。本研究では,外集団脅威への適応心理メカニズムの性差を検討した。男性には,外集団からの資源の強奪や暴力 (“妨害脅威”) に対抗するための心理メカニズムが,女性には,外集団から未知の病原体の感染 (“感染脅威”) に対抗するための心理メカニズムが備わっているという仮説を立て,実験室実験にて検証した。大学生166名が参加し,事前に外集団脅威の状況手がかりの有無と種類(妨害vs. 感染)を操作した後,最小条件集団状況で報酬分配課題を行った。その結果,予測通り,妨害脅威条件では男性でのみ,感染脅威条件では女性のみで差別行動が見られた。しかし,予測と異なり,脅威の手がかりが存在しない統制条件においても,男性の差別行動が見られた。
著者
中川 裕美 横田 晋大 中西 大輔
出版者
The Japanese Society of Social Psychology
雑誌
社会心理学研究 (ISSN:09161503)
巻号頁・発行日
vol.30, no.3, pp.153-163, 2015

In this study, we tested the theoretical validity of both Social Identity Theory (SIT) and the Bounded Generalized Reciprocity Hypothesis (BGR) for explaining in-group cooperation in real social groups. While most previous investigation on real social groups has found support for SIT, confirmatory evidence for BGR remains limited. We conducted a vignette experiment in which reciprocity was manipulated by controlling knowledge of group membership. The participants were 117 undergraduate students who were baseball fans. To control expectation of reciprocity in the experiment, we asked participants to imagine scenarios where they helped others who wore either the same baseball team T-shirts as they did or plain T-shirts. Consistent with BGR, participants tend to cooperate with in-group members when both they and their partner knew that they might be supporters of the same team. On the other hand, participants showed in-group cooperation even when only they knew their partner's group membership. This finding coincided with SIT. These results thus further verified the theoretical validity of both SIT and BGR in real social groups.
著者
横田 晋大
出版者
心理学評論刊行会
雑誌
心理学評論 (ISSN:03861058)
巻号頁・発行日
vol.60, no.1, pp.15-22, 2017 (Released:2018-07-20)
参考文献数
78
被引用文献数
2

In this paper, the evolutionary roots of gender differences in aggressive behavior are presented. Previous studies in the field of social psychology have shown that men are more aggressive than women not only in interpersonal, but also in intergroup relationships. From an evolutionary psychological view, it is predicted that outgroup aggression is triggered by the psychological mechanisms adapted to intergroup conflict specified for males. However, social psychologists demonstrated that ingroup cooperation, but not outgroup aggression, was dominant in intergroup conflict situations in a laboratory experiment. On the other hand, in these days, some evidence in the field of cultural anthropology, ethnography, and bioarcheology have clearly shown that hunter-gatherer and forager males frequently engaged in war. I discuss whether intergroup conflict influences selection pressure on male aggressive behavior as a reproductive strategy to enhance fitness.
著者
横田 晋大 中西 大輔
出版者
日本社会心理学会
雑誌
社会心理学研究 (ISSN:09161503)
巻号頁・発行日
vol.27, no.2, pp.75-82, 2012-01-31 (Released:2017-02-22)

Previous research has shown that ingroup cooperation tends to flourish in intergroup conflict situations. However, the free-rider problem remains unsolved, even in intergroup conflict situations. In this study, based on multi-group selection theory and cultural-group selection theory, we hypothesized that conformity (frequency-dependent behavior) may contribute to enhancing ingroup cooperation. The results of an evolutionary simulation revealed that ingroup cooperation and conformity can evolve in situations of intergroup conflict. When such conflict is mild, agents who cooperate with ingroup members and adjust their behavior to ingroup cooperation rates facilitate cooperation in their own group. However, no effect of conformity on ingroup cooperation was observed during intense intergroup conflict, even though conformity continued to evolve. We discuss the implications of these results and suggest avenues for future research.