Aim: To investigate normative social influence by examining whether individuals would conform in an unambiguous situation where the correct answer was always obvious.

Method: Asch recruited 123 male students from Swarthmore College in America. To conceal the true aim of the experiment, participants were told they were taking part in a vision test. Each real, or naïve, participant was placed in a room with six to eight confederates (actors) and was seated second from last.

The task involved a line judgement exercise where participants had to state aloud which line (A, B, or C) matched a target line in length.

There were 18 trials in total, 12 of which were critical trials where the confederates all gave the same incorrect answer. The experimenter recorded each response to determine whether the participant would conform to the majority view, even when the correct answer was obvious.

Results: Asch reported the following key findings:

• The naïve participants conformed on 32% of the critical trials

• 75% of the participants conformed at least once; 25% of the participants did not conform

• 5% of the participants conformed on every trial

Conclusion: In post-experiment interviews, many participants admitted that they conformed to fit in with the group, even though they knew the majority was incorrect. This demonstrates that the participants conformed due to normative social influence, as they changed their public behaviour but not their private beliefs.