group polarisation

Meaning: Group polarization is the tendency for discussion within a group to strengthen the leaning most members already had, so the group's position ends up more extreme than the members' average beforehand. A cautious-leaning group becomes more cautious, and a risk-leaning group becomes riskier. Two accounts explain it. Social comparison (normative influence): members want to look favorable to the group, so they move to a somewhat stronger version of the favored view. Persuasive arguments (informational influence): discussion exposes members to more arguments for the favored side than they had alone.

On the MCAT: A passage has people rate an attitude privately, discuss it in a group, then rate again. Predict that the average moves further in the direction of the initial majority. Questions ask which account fits: hearing new supporting arguments points to informational influence, while shifting to fit in points to normative influence. Early "risky shift" findings showed groups taking more risk, but the shift can go either way.

Common confusion: Do not confuse it with groupthink, a pattern of flawed decision making in a cohesive group that suppresses dissent to preserve harmony. Polarization is about attitudes becoming more extreme, not about compromise at the midpoint, and it does not require a pressured, cohesive group.