A new study uses advanced brain-scanning technology to cast light on a topic that psychologists have puzzled over for more than half a century: social conformity.

The study was based on a famous series of laboratory experiments from the 1950's by a social psychologist, Dr. Solomon Asch.

In those early studies, the subjects were shown two cards. On the first was a vertical line. On the second were three lines, one of them the same length as that on the first card.

Then the subjects were asked to say which two lines were alike, something that most 5-year-olds could answer correctly.