Red Team / Tenth Man

Overview

Consensus is a blind-spot amplifier: Janis's groupthink studies (1972) showed cohesive groups suppress dissent precisely when stakes are highest. The fix is not "be more open-minded" — it's structural: assign someone the job of attacking the position. Origins: the Vatican's advocatus diaboli (1587), military red teams, and the Israeli intelligence "tenth man" doctrine post-Yom Kippur 1973 — if nine agree, the tenth is obligated to argue the contrary, because unanimity itself is evidence of a selection failure somewhere.

Dissent must be a role, not a personality trait — roles survive social pressure; volunteers don't.

When to Use

• Decision reached fast with no serious objections raised
• Plans where everyone stands to benefit from believing it works
• Security, reliability, or adversarial surfaces (the attacker IS a red team; pre-empt them)
• Solo work: you've reviewed your own output and found it good

The Procedure