Groupthink
The drive for consensus and harmony overrides realistic appraisal.
What it means
Groupthink is a mode of decision-making in cohesive groups in which the pursuit of unanimity and the avoidance of conflict suppress critical evaluation of alternatives, producing overconfident and often disastrous choices. Janis proposed that it arises under specific antecedents — high cohesion, insulation from outside input, directive leadership, and stress from an external threat — which together breed symptoms such as illusions of invulnerability, collective rationalization, belief in the group's inherent morality, stereotyping of opponents, self-censorship, an illusion of unanimity, and direct pressure on dissenters. The mechanism is that members, valuing belonging and consensus, withhold doubts and 'mindguards' shield the group from disconfirming information, so the group converges prematurely on a course no individual may fully endorse. Janis's theory is influential but contested: experimental tests have struggled to confirm the precise antecedent–symptom links, and historians question some of his case studies, so it is now read more as a rich descriptive checklist than a tightly validated causal model. It matters because the proposed remedies — assigning a devil's advocate, inviting outside critique, leaders withholding their own views, and structured dissent — are widely used to protect high-stakes group decisions in government, medicine, and business.
Examples
Advisory groups behind several foreign-policy and corporate fiascos discounted clear warnings and silenced doubters in order to preserve a confident, united front.
A ward team, confident in its own diagnosis, stops mentioning the symptoms that don't fit, and the junior doctor who doubts it says nothing rather than break the room's united mood.
A close-knit startup team, insulated from outside review, talks itself into launching on time; the one engineer with reservations reads the silence around the table as agreement and keeps quiet.
First described in Irving Janis (1972).