Under certain conditions, cohesive decision groups can suppress dissent and pursue a defective consensus while feeling confident about it.
Janis's 1972 cases were the Bay of Pigs and Vietnam escalation, and the symptom he emphasised is the illusion of unanimity: nobody voices doubt, so each doubter concludes they are alone. The model remains influential, though its causal structure has had mixed empirical support and later archival work does not strongly support the original group-cohesion account of those decisions.
In practice
- A leadership team under time pressure produces a unanimous decision in forty minutes and nobody voices the reservation they all hold.
- A project board approves a plan every member privately doubts, having read unanimity in the silence.
- Possible explanations
- One explanation is conformity pressure inside cohesive groups. Another is the illusion of unanimity, in which doubts go unvoiced so each doubter concludes they are alone. A third is structural: a leader who states a preference first sets the range of acceptable answers.
- In its favour
- The symptoms are recognisable, the model gave organisations a vocabulary for dissent, and the remedies it suggests, such as assigning a devil's advocate and having leaders speak last, have support in decision research.
- Against it
- Experimental and archival tests of the causal structure have been mixed, cohesion has not reliably predicted the failures, and the original cases have been re-read as ordinary political decisions under uncertainty.
- Standing
- Influential as a model, with mixed empirical support for its causal structure and weak archival support for the original cases.
- Further reading
- Wikipedia
- Subject
- Organizations & Bureaucracy
- Essay
- Why organisations learn, harden and decline