In 1985, Garold Stasser and William Titus handed small groups a decision they were set up to get right. Each group collectively held every fact needed to identify the best candidate; the facts were just distributed, a different piece to each member. Most groups chose the wrong candidate anyway.

The finding has replicated for four decades under the name “hidden profiles.” Groups spend their airtime on what everyone already knows. Shared information gets confirmed and built on; a piece only you hold lands in silence, with nobody to back it, so it tends to stay unsaid. Discussion drifts to the intersection of what people know. The value was in the union.

It’s the pattern behind a sentence every leader has heard after a bad outcome: “we knew about that.” The knowledge existed, in pieces, each too small for its holder to defend alone. And the silence trains itself. Every decision that proceeds without your fragment teaches you that meetings aren’t for fragments. The shared pool gets rehearsed and grows; agreement arrives faster; the team feels most aligned exactly when it’s drawing on the least of what it knows.

When I interview a team one person at a time, the same unraised risk often surfaces in three separate conversations, each person having concluded, alone, that it was too small to mention.

So before your next significant decision, add one round: “What do you know about this that the rest of us might not?” If you’re the senior person, answer last.

Then revisit your team’s last bad call. Was the information missing, or never assembled?