WHILE not as infamous as Philip Zimbardo’s Stanford prison simulation or Stanley Milgram’s obedience research, Solomon Asch’s conformity experiments remain among the most celebrated in psychology.

In 1951, Asch’s research showed that our judgments about simple factual matters can be swayed by what people around us say. The finding echoed down the decades. Milgram found in 1961 that people were willing to administer apparently dangerous electric shocks when ordered to do so by an experimenter. In 1971, Zimbardo set up an imitation prison, with subjects given the roles of guards and prisoners, then observed as the guards humiliated the prisoners.

The three academic psychologists taught us that to fit in with others we are willing to do almost anything. That, at least, is what we are told. The truth, as is so often the case, is more interesting.

Asch gave his subjects the following task: identify which of three different lines, A, B or C, was the same length as a "standard" line. The task was easy in its own right but there was a twist. Each individual was in a group of seven to nine people, and everyone else in the group was a confederate of Asch’s. For 12 out of 18 questions they had been told to choose, unanimously, a specific incorrect answer.

Would the experimental subject respond by fitting in with the group or by contradicting them? Many of us know the answer: we are swayed by group pressure. Offered a choice between speaking the truth and saying something socially convenient, we opt for convenience every time.

But wait — "every time"? In popular accounts of Asch’s work, conformity tends to be taken for granted. I often describe his research myself in speeches as an example of how easily groupthink can silence dissent. And this is what students of psychology are told by their own textbooks.

A survey of these textbooks in 1990 by three psychologists, Ronald Friend, Yvonne Rafferty and Dana Bramel, found the texts typically emphasised Asch’s findings of conformity. When Friend recently updated his work, he found today’s textbooks stressed conformity more than ever.

This is odd, because the experiments found something more subtle. It is true that most experimental subjects were somewhat swayed by the group. Fewer than a quarter of experimental subjects resolutely chose the correct line every time. (In a control group, unaffected by social pressure, errors were rare.) However, the experiment found that total conformity was scarcer than total independence. Only six out of 123 subjects conformed on all 12 occasions. More than half of the experimental subjects defied the group and gave the correct answer at least nine times out of 12. A conformity effect certainly existed but it was partial.

This surprised me, and it may surprise others who have read popular accounts of the so-called conformity studies. I doubt that it surprised Asch. Conformity was already a well-established finding by 1951. But he wanted to know if peer pressure would also wield influence when the crowd was unambiguously wrong. He found social pressure is persuasive but, for most people, the facts are more persuasive.

Myths about famous experiments have always grown in the telling. But there seems to be something particularly attractive about these famous psychology experiments that paint us all as sheep — even when the experiments may have been flawed, impossible to replicate or (as with Asch’s work) have found something much more subtle than the myth would have us believe.

The psychologist Christian Jarrett comments, "the resistance to tyranny shown by many participants in Zimbardo’s prison study has largely been ignored, and so, too, has the disobedience shown by many participants in Milgram’s seminal work".

We should also ask questions about what Zimbardo really found. By his own admission he strongly steered the guards towards dehumanising the prisoners. Few textbook accounts mention Zimbardo’s attempt to influence the guards; nor do they point out that two-thirds of the guards refrained from sadism.

Social pressure matters, but it is not the only thing that matters. Asch showed that facts can trump groupthink.

It would be ironic if our own biased recollections of his finding proved him wrong.

© The Financial Times Limited 2015