A failure mode in collective decision-making where the desire for harmony and conformity overrides realistic appraisal of alternatives. Coined by Irving Janis in 1972 after his analysis of the Bay of Pigs invasion and other foreign-policy fiascos, groupthink produces self-censorship, illusion of unanimity, and the suppression of dissenting views.
Its institutional antidote is structurally adversarial roles — devil's advocates, red teams, pre-mortems — that legitimize disagreement and protect dissenters from the social cost of speaking up.