A room full of intelligent people can still make a catastrophic decision together, for the single reason that no one in the room wanted to be the one who broke the agreement.

In April nineteen sixty one, a group of experienced advisors sat with the President of the United States and approved a plan to invade Cuba at a location called the Bay of Pigs. The plan failed within days, in a way that seemed, in hindsight, almost obviously flawed to nearly everyone who studied it afterward. What made the failure remarkable wasn't that a mistake was made — mistakes happen. It was that a room full of capable, well-informed people had approved a plan whose weaknesses were visible from the start.

A researcher studying the decision later gave the pattern a name still used today: groupthink. A state where the desire to preserve harmony overrides honest evaluation, even among people fully capable of that evaluation on their own.

The mechanism isn't stupidity. It's closer to social physics. In a room where confidence is rising and no one has voiced doubt yet, the first person to raise a concern risks looking like the outsider, the pessimist, the one slowing everyone down. As more people stay quiet for exactly this reason, the appearance of agreement grows stronger — which makes the next person even less likely to speak.

Trading groups, investment chats, even a friend circle discussing a stock can fall into the same pattern at a smaller scale. Once a few voices express excitement about a position, raising a doubt now costs social standing — not because the doubt is unreasonable, but because voicing it feels like breaking something. The group's confidence rises even as the actual quality of its thinking falls, and the two move in opposite directions without anyone noticing.

The only reliable defence against this is structural, not personal. Assign someone the explicit job of arguing the other side, regardless of what they personally believe, before any decision is finalised. Not because dissent is always right — but because a group that has genuinely heard its own best counterargument makes a fundamentally different decision than one that only hears its own agreement echoed back.