Asch believed that the main problem with Sherif's (1935) experiment was that there was no correct answer to the ambiguous autokinetic experiment. How could we be sure that a person conformed when there was no correct answer? Asch (1951) devised an experiment whereby there was an obvious answer to a line judgement task. If the participant gave an incorrect answer it would be clear that this was due to group pressure.
Aim: Asch (1951) conducted an experiment to investigate the extent to which social pressure from a majority group could affect a person to conform.
Procedure: Asch (1951) used a lab experiment to study conformity. Using the line judgement task (see above), Asch put a naive participant in a room with seven confederates. The confederates had agreed in advance what their responses would be when presented with the line task. The real participant did not know this and was led to believe that the other seven participants were also real participants like themselves. Each person in the room had to state aloud which comparison line (A, B or C) was most like the target line. The answer was always obvious. The real participant sat at the end of the row and gave his or her answer last. In some trials, the seven confederates gave the wrong answer. There were 18 trials in total and the confederates gave the wrong answer on 12 trails. Asch was interested to see if the real participant would conform to the majority view.


Results: Asch measured the number of times each participant conformed to the majority view. On average, about one third (32%) of the subjects who were placed in this situation went along with the clearly incorrect majority.
Conclusion: Why did the participants conform so readily? When they were interviewed after the experiment, most of them said that they did not really believe their conforming answers, but had gone along with the group for fear of being ridiculed or thought "peculiar". A few of them said that they really did believe the group's answers were correct.
Apparently, people conform for two main reasons: because they want to fit in with the group (normative influence) and because they believe the group is better informed than they are (informational influence).
Evaluation: All participants were male students who all belonged to the same age group (biased sample). The task (judging line lengths) was artificial (low in ecological validity) as it is unlikely to happen in everyday life. Therefore, it is not similar to a real life situation demonstrating conformity. The Asch (1951) study has also been called a child of its time (as conformity was the social norm in 1950’s America).
Finally, there are ethical issues: participants were deceived and not protected from psychological stress which may occur if they disagreed with the majority.