Asch Conformity Paradigm

The Asch conformity paradigm, established by Solomon Asch in the 1950s, demonstrates the power of group pressure to make people publicly endorse a manifestly false judgment. A naive participant joins a group of confederates for a simple perceptual task -- matching the length of a standard line to one of three comparison lines, where the correct answer is obvious. On certain critical trials the confederates unanimously give the same wrong answer, and the experimenter measures how often the lone real participant goes along with the majority against the evidence of their own eyes. Asch found that a substantial proportion of participants conformed at least once, even on an unambiguous task, while systematic variations revealed that conformity rises with majority size up to a point and collapses when unanimity is broken. The paradigm became the canonical demonstration of normative social influence.