The Asch Conformity Experiments
During the 1950s, Solomon Asch conducted and published a series of laboratory experiments that demonstrated the degree to which an individual’s own opinions are influenced by those of a majority group. Together, these experiments are recognized as the Asch conformity experiments or the Asch Paradigm. The methodology developed by Asch has been utilised by many researchers and the paradigm is in use in present day social psychology. The paradigm has been used to investigate the relationship between conformity and task importance, age, gender, and culture. (Source: Wiki)
Asch (1951) set up a situation in which usually about seven people all sat looking at a display. They were given the task of saying out loud which one of three lines (A, B, or C) was the same length as a given stimulus line, with the experimenter working his way around the group members in turn. All but one of the participants were confederates of the experimenter, and had been told to give the same wrong answer on some of the trials. The one genuine participant was the last (or the last but one) to offer his/her opinion on each trial. The performance of participants exposed to such group pressure was compared to performance in a control condition with no confederates.
Asch’s findings were dramatic. On the crucial trials on which the confederates all gave the same wrong answer, the genuine participants also gave the weong answer on between 33% and 37% of these trials in different studies. This figure should be compared against an error rate of under 1% in the control condition. Thus, the correct answers were obvious, and it might have been expected that nearly all the experiments would have given them. However, only about 25% of the confederates avoided error during the course of the study, compared to 95% in the controlled condition.
Asch (1956) manipulated various aspects of the situation to understand more fully the factors underlying conformity behaviour. The conformity effect incresed as the number of confederates went up from one to three, but there was no incresse between three and sixteen confederates. However, a small increase in conformity as the number of confederates gows up above three has sometimes been found (see van Avermaet, 2001).
Another important factor is whether the genuine participant has a supporter in the form of a confederate giving the correct answer on all trials, and who gives his or her answer ahead of the genuine participant. Asch (1956) found that the presence of such a supporter reduced conformity to only 5% of the trials. More surprisingly, a confederate whose answers were even more incorrect than those of the other confederate also produced a substantial reduction in conformity. Thus, any kind of disagreement among other group members was sufficient to reduce conformity. (Source: The Unbound Spirit)
The actual studies that he published, beginning in 1951, are not available online because they are all behind the paywall. Therefore the studies are bp;dr but the following diagram and videos are quite informative.
With commentary from a BBC series:
An explanation from HowtheWorldWorks:
With an introduction from Philip Zimbardo:
A later experiment using the same methodology with elevators: