Groupthink
A psychological phenomenon that occurs within a group of people in which the desire for harmony or conformity results in an irrational or dysfunctional decision-making outcome.
Origin
Social psychologist Irving Janis introduced the term in his 1972 book Victims of Groupthink: A Psychological Study of Foreign-Policy Decisions and Fiascoes, analyzing how cohesive groups make irrational decisions when the desire for unanimity overrides realistic appraisal of alternatives. Janis's interest began after reading about the Kennedy Administration's 1961 Bay of Pigs invasion, which became his primary case study alongside the Pearl Harbor bombing and the Vietnam War. He identified eight symptoms including illusion of invulnerability, collective rationalization, unquestioned belief in the group's morality, stereotyping opponents, self-censorship, "mindguards" who barrier alternative information, and illusion of unanimity.