Symptoms of groupthink:
Type I: Overestimations of the group — its power and morality
- Illusions of invulnerability creating excessive optimism and encouraging risk taking.
- Unquestioned belief in the morality of the group, causing members to ignore the consequences of their actions.
Type II: Closed-mindedness
- Rationalizing warnings that might challenge the group’s assumptions.
- Stereotyping those who are opposed to the group as weak, evil, biased, spiteful, impotent, or stupid.
Type III: Pressures toward uniformity
- Self-censorship of ideas that deviate from the apparent group consensus.
- Illusions of unanimity among group members, silence is viewed as agreement.
- Direct pressure to conform placed on any member who questions the group, couched in terms of “disloyalty”
- Mindguards— self-appointed members who shield the group from dissenting information.
Groupthink
Wikipedia
https://en.wikipedia.org/wiki/Groupthink
Groupthink is a psychological phenomenon that occurs within a group of people in which the desire for harmony or conformity in the group results in an irrational or dysfunctional decision-making outcome. Cohesiveness, or the desire for cohesiveness, in a group may produce a tendency among its members to agree at all costs. This causes the group to minimize conflict and reach a consensus decision without critical evaluation.
Groupthink is a construct of social psychology but has an extensive reach and influences literature in the fields of communication studies, political science, management, and organizational theory, as well as important aspects of deviant religious cult behaviour.
集団思考
ウィキペディア
https://ja.wikipedia.org/wiki/集団思考
集団思考（集団浅慮、groupthink）とは、集団で合議を行う場合に不合理あるいは危険な意思決定が容認されること、あるいはそれにつながる意思決定パターン。デマや流言、インターネットから発生する幼稚な自己表現などがここから発生すると見る向きもある。政治的な意思決定のような場面では、集団思考は致命的である。
過度の結束はチームをダメにする！チームリーダーなら知っておくべき「集団思考（グループシンク）」という落とし穴
「チームの教科書」編集部
https://atlassian-teambook.jp/_ct/17541117
「結束」は、見方を変えれば「結託」だ。
「結束しなければ、それぞれ破滅する」というのは、結束を促す人たちの脅し文句だ。