8 symptoms of groupthink from Little Book of Behavioural Investing
1. An illusion of invulnerability - This creates excessive optimism that encourages taking extreme risks.
2. Collective rationalization - Members of group discount warnings and do not reconsider their assumptions.
3. Belief in inherent morality - Members believe in the rightness of their cause and therefore ignore the ethical or moral consequences of their decisions.
4. Stereotyped views of out-groups - Negative views of "enemy" make effective responses to conflict seem unnecessary.
5. Direct pressure on dissenters - Members are under pressure not to express arguments against the group's views.
6. Self censorship - Doubts and deviations from the perceived group consensus are not expressed.
7. Illusion of unanimity - The majority view and judgements are assumed to be unanimous.
8. "Mind guards" are appointed . Members protect the group and their leader from information that is problematic or contradictory to the group's cohesiveness, view and/or decisions.
