In 1950 Solomon Asch conducted some experiments designed to measure the effects of peer pressure. Groups of students were shown a line and asked to select the line of the same length from another set of three lines and say their answer out loud.

Only one of the students in each group was really taking the test. The rest were actors intentionally giving the wrong answer. The real participant would be placed at the end of the line, and after hearing the incorrect consensus view, 3/4 of them answered incorrectly at least once, and 1/3 of them answered incorrectly consistently. Asch checked to see if they were answering wrong intentionally by conducting the same test with written answers. When they didn’t hear the other student’s answers, they gave the correct answer. This video shows how it was done.

4 minutes. Link to Video

Asch wondered why they gave the wrong answer, but without a way to see inside their heads he had to take the student’s word for what was going on in there. They said things like “it was easier to go along” indicating that the answer was based on some social calculation. When their brain decided it was in it’s best interest to not rock the boat, they would tell a white lie. It seemed logical.

A couple years ago neuroscientists at Emory University repeated the experiment, but this time the subject was scanned with an fMRI during the test. This time the researchers could see which parts of their brains were active while the subject thought about their answer. Again, 41% of the subjects gave wrong answers in an effort to conform to the group, but the real shocker: the area of the brain associated with visual perception was active. The areas that deal with conscious decision making were not. Instead of choosing to conform based on some kind of social calculation, we seem to conform because what we think we are seeing is changed by the opinions of others. They also found that the emotional area of the brain was active in students that went against the crowd.

Here’s an article about the second experiment reprinted from the New York Times.
Sandra Blakeslee | What Other People Say May Change What You See

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