One of the most famous experiments in social psychology took place in the early 1950s. Solomon Asch, a professor at Swarthmore College, gathered together groups of young men for what he told them was an experiment in “visual judgment”. It was no such thing.
What happened is often known as the “conformity experiment”, but that is a misleading label for an oft-misunderstood study. Asch ran many variations on his experiment, and the most surprising and powerful lesson is not about the power of conformity, but about the power of disagreement.
Asch’s basic approach was to show two cards to a group of about eight people. One card had a single line on it: the reference line. The other card displayed three lines of different length. The task was a straightforward multiple choice, picking the line that was the same length as the reference line. This wasn’t hard; when people were asked to do this task on their own, they almost never made a mistake.
However, Asch was not asking people to do this task in isolation, but as a member of a group. Participants would be asked, one by one, to tell the rest of the group their answer. This made space for the possibility that experimental subjects would be guided not by their own eyes, but by the opinions of others.
The groups were asked to do this 18 times, but Solomon Asch had a trick to play. Everyone in each group was a confederate working for Asch, except a single unsuspecting experimental subject. This poor dupe would be sitting near the end of the line. The confederates had instructions to get the first two questions right and then unanimously agree on the wrong answer for most of the rest.
Imagine the jolt of surprise and anxiety as the experimental subject saw one person after another contradict the evidence of his own eyes. People felt real pressure to conform, with more than one-third of the answers matching the group’s delusion rather than the obvious truth.
Why? When debriefed, some people said they had changed their minds, figuring the group must be right. Others said they didn’t change their minds, but did change their answers, not wanting to spoil the experiment. Still others were staunchly independent, saying that they presumed the group was right and they were wrong, but felt a duty to call them as they saw them.
What fascinates me about Asch’s experiment is what happened when one of the confederates had been instructed to disagree with the group and give the correct answer instead. The answer: the spell of conformity was broken. People made only a quarter as many errors, with the error rate falling below 10 per cent. The pressure from the group had lost much of its power.
Even more brilliant was another variation in which Asch again instructed a confederate to disagree with the group. This time, however, the confederate was an “extremist dissenter”, giving an answer that was even more wrong than the majority consensus. The result? The experimental subjects generally gave the correct answer; their error rate was still below 10 per cent.
Asch had demonstrated three things. First, people will go against the evidence of their own eyes if contradicted by a unanimous group. Second, group pressure is much weaker if even a single person dares to disagree with the group. Third, and most remarkable: it does not matter if the dissenter is mistaken; dissent punctures group pressure either way. People are liberated to say what they believe, not because the dissenter speaks the truth but because the dissenter demonstrates that disagreement is possible.
I thought of Solomon Asch when I heard about a cookbook by Julia Child and Jacques Pepin, Julia and Jacques Cooking at Home. It’s full of the classics, but there are two very different recipes for each dish — one by Julia and one by Jacques. In the margins, each offers a jovial explanation of what the other cook has done wrong, why they made different decisions and what effect those decisions have on the final meal. It is, writes philosopher C Thi Nguyen, “the record of an argument — a rowdy conversation between friends”.
This matters because, as with Solomon Asch’s duplicitous experiment, it shows us that disagreement is possible. The two cases seem very different, not least because while there is only one correct answer to Asch’s visual perception test, there is more than one way to sauté a fish. Yet the disagreement is valuable either way, because it gives us permission to think for ourselves.
Many years ago I was involved in scenario planning for the oil company Shell. It was always a fascinating exercise, but I now realise that one of the most important strengths of the process was rarely discussed: there were always at least two scenarios, and all the scenarios were given equal status. This was Cooking at Home meets corporate strategy: the fundamental assumption was that there was more than one plausible future, and a rowdy conversation about the different possibilities unlocked a treasure chest of fresh thinking.
Charlan Nemeth is a psychologist and the author of No! The Power of Disagreement in a World that Wants to Get Along. She cautions against “contrived” dissent — for example, the Catholic tradition of having a “devil’s advocate” to argue against the canonisation of a putative saint. This sort of thing sounds good in principle, she argues, but in practice there is a limited benefit in a rote play-acting of disagreement. For one thing, everyone knows the devil’s advocate is just pretending, so nobody feels much pressure to persuade them to change their mind. “Role-playing,” writes Nemeth, “does not have the stimulating effects of authentic dissent.”
Yet some contrivances are better than others. Nemeth writes approvingly of an investment firm only making decisions after considering serious arguments both for and against a position. What makes this different from playing devil’s advocate? Perhaps the sense that the contrary arguments are not a game, but made in all seriousness.
Another contrivance is the idea of “red teaming” an idea — giving a group the task of trying to rip a new idea apart before that idea is adopted. Is this an empty ritual, or a serious practice? Depending on people’s intent, it could be either.
Contrived dissent is better than nothing, especially if the contrivance itself is taken seriously. But the most valuable form of dissent is authentic, even stubborn and brave. There is no substitute for finding one of those people who feel a duty to call things as they see them.
Written for and first published in the Financial Times on 25 Feb 2026.
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