Group Polarization and Groupthink

Put people who lean the same way in a room and talk, and the group does not settle toward the middle. It moves further out. Two things drive this. First, people hear new arguments for their side they had not thought of, which gives them more reasons to believe it strongly. Second, people compare themselves to others and want to seem at least as committed as the group norm, so each person nudges their stated opinion a little further out to avoid looking wishy-washy. Average those nudges across the group and the whole thing drifts toward a more extreme version of where it started. That is group polarization.

Groupthink is a related but separate failure, driven by cohesion rather than by comparison. When a group feels unified, confident, and eager to preserve that harmony, members start editing themselves. Someone notices a flaw or holds contrary information, but speaking up feels like threatening the group's good feeling, so they stay quiet. No one challenges the plan, not because the evidence is solid but because nobody tested it. The decision proceeds unexamined, and it can fail for a reason the group had the information to catch.

Both effects show how being in a group changes judgment, which is why they sit together in this unit alongside conformity and obedience. The fix for groupthink is structural: assign someone the explicit job of arguing the opposite case, a devil's advocate. That person's role is not to actually believe the contrary view but to force the group to defend its reasoning out loud, which interrupts the slide toward unexamined consensus and can also slow polarization by surfacing arguments the group would not generate on its own.