The reason a group is persuaded differently than a person

One-to-one, she concedes the point in four minutes. In the meeting where she has already said the opposite in front of nine colleagues, the same argument produces a defence of the original view and a request for more data.

What everyone sees

A group is treated as several individuals receiving the same argument, so persuading it should be the individual case repeated. It is a different task. Each person in a group has a second constraint the private listener lacks — a record of what they have said, held by an audience that will be present when they say the next thing.

What is actually happening

Deutsch and Gerard separated informational from normative influence, showing that judgements made publicly were substantially more resistant to change than the same judgements made in private, with the difference driven by the presence of an audience rather than by any difference in evidence. Tetlock examined accountability and found that people who had publicly committed to a position before being made accountable defended it rather than revising it, while those made accountable before committing engaged in more even-handed reasoning — so the sequence of commitment and scrutiny determines whether accountability improves or entrenches judgement. The practical implication is uncomfortable for meetings: asking people to state a view early, which feels like efficient information-gathering, is the step that makes later updating expensive.

Why it stays hidden

The constraint hides because it is never stated as one. Nobody says they cannot change their position because they said something last week. The resistance surfaces as methodological objection, requests for more evidence and concern about implementation — all legitimate, all available, and all indistinguishable from genuine disagreement.