“What Other People Say May Change What You See”

Sandra Blakeslee, New York Times, Jun 28, 2005.

http://www.nytimes.com/2005/06/28/science/28brai.html?ex=1175400000&en=39e2d97417286c29&ei=5070

            In the 1950’s, social psychologist Dr. Solomon Asch performed a simple experiment that had dramatic results. He took two index cards and on one of them he drew three lines of different lengths and labeled them A, B and C and on the second card, he drew a reference line that was longer than A, shorter than B and the same length as C. He gathered his subject and several actors in the same room to ask whether or not the reference line was shorter, longer, or the same length as the lines A, B and C. When asked this question, the actors intentionally gave incorrect answers. Having the actors give incorrect answers was meant to put the subject in a dilemma: should he go against the group, follow his own instincts and give the correct answer, or should he give in, follow the group, and give the wrong answer? In the end, 75% of his subjects gave the wrong answer, which Asch attributed to social pressure and the appeal of conformity.

            In 2005, Dr. Gregory Berns, a psychiatrist and neuroscientist at Emory University in Atlanta, used an M.R.I machine to find out whether the subjects gave incorrect response because they intentionally wanted to follow the group’s responses or if what other people said actually changed what the subjects perceived. He reasoned that if people consciously tried to conform to the other members of the group, then the area of the brain that controls higher-level thinking should show high activity, and that the area of the brain that controls spatial awareness would be active if the subject’s perception was altered by what the other members of the group answered. The 32 subjects used in the experiment were shown two three-dimensional objects and were instructed to rotate them in their minds to see if the two objects are identical or not. Though it is not possible to instantaneously determine if they are the same, it is fairly easy to see that the two objects are not identical. When asked to determine whether the two objects were identical or not, the subjects declared that the objects were identical when their group members said they were about 41% of the time. When Dr. Berns looked at the M.R.I. results, he saw high activity in the area of the brain that controls spatial awareness, indicating that the subjects’ perceptions were actually altered by the answers that the actors gave.

            When Dr. Asch published the results of his experiment in his 1951 paper called “Effects of group pressure upon the modification and distortion of judgements”, he revealed the power of information cascades and the pressure to conform. What Dr. Berns actually disproves Dr. Asch’s claims: the subjects, for the most part, did not try to conform to give incorrect answers along with the rest of the group, but in fact were made to misperceive the information that was given to them. At the same time though, Dr Berns’ results demonstrates that information cascades can have profound power over what the mind sees and how it interprets it.