Groupthink

Groupthink is the failure mode in which a tightly cohesive group values maintaining consensus so highly that it suppresses dissent, avoids critically testing its own assumptions, and settles on a decision worse than individual members would have reached on their own. Psychologist Irving Janis coined the term in 1972, analyzing foreign-policy fiascos — most notably the 1961 Bay of Pigs invasion — where senior advisors privately harbored doubts they never voiced, each assuming the group's confidence reflected information they personally lacked.

Janis catalogued the symptoms in detail: an illusion of invulnerability that encourages excessive risk-taking, collective rationalization that discounts warnings, an unquestioned belief in the group's own morality, stereotyping of outsiders as too weak or evil to negotiate with, direct pressure on any member who voices doubt, self-censorship of one's own reservations, a shared illusion of unanimity built partly from that self-censorship, and self-appointed "mindguards" who shield the group from dissenting information. The mechanism runs on social cost: dissent in a cohesive group feels like a threat to belonging, not just a disagreement about facts, so the group optimizes for feeling unified over being right.

The standard countermeasure Janis proposed — and the reason the concept gets cited constantly in corporate and military decision design — is structural, not moral: assign a formal devil's advocate, invite outside experts, break into independent subgroups before reconvening, and have the leader withhold their own opinion until subordinates have spoken, so early agreement can't anchor the room. Groupthink is often confused with simple conformity or Social Proof, but it specifically requires cohesion and stress on a decision-making body, not just a crowd tending to imitate itself; the diagnostic tell is a room full of people who each had a private doubt no one said aloud.