Dutch research: why we act like sheep

    Group Spirit

    An art gallery. A painting that arouses everyone’s admiration. Except yours. Nonetheless, when the assembly starts to acclaim the author of this horror, you surprise yourself by applauding and even acknowledging the painter’s merit when someone asks your opinion. Sheep behavior, some will note ironically. A human reflex, psychologists will answer. A reflex from a cerebral mechanism “that normally serves to detect errors in judgment,” a Dutch team* has just shown.

    For – even though it’s difficult to accept – under certain conditions, our sacrosanct personal judgment is altered by that of the group. A Polish pioneer in social psychology, Solomon Asch, demonstrated that as early as 1951.

    In his experiment, Asch seated an individual in the middle of an assembly set up in a circular arc in front of a screen. He projected two images: the first showed an eight-inch-long line; the second, three lines of, respectively, 6, 10, and 8 inches. Then Asch asked each participant to show him which line of the three was the same length as that in the first image. Easy. Except that the members of the assembly – all Asch’s accomplices – asked first, all chose the wrong line, all of them choosing the same one. The result: in 75 percent of cases, the tested individual rallied to group opinion and picked the wrong line – in spite of the evidence he had right before his own eyes.

    The Origins of Conformity

    So this propensity to melt into the mass is very real. Nonetheless, its source remained mysterious. In an attempt to resolve the question, a Dutch team sought to observe, thanks to a functional MRI, those cerebral regions that are activated while such dilemmas of conformity arise. “But to obtain such images, we needed hundreds of observations for each individual. Now, while it’s possible to fool a guinea pig once or twice in a row, it becomes more difficult to do it hundreds of times …” explains Vasily Klucharev, a researcher at Nijmegen’s Radboud University in the Netherlands and co-author of the study. “So we had to set up a variant of Asch’s protocol.”

    Using this procedure, the team asked about twenty young women to rate the beauty of 222 European faces on a scale of one to eight. Each photo was presented twice: the first time, without any indications; the second time, accompanied by a note supposedly representing the consensus of a feminine population on the same question. The first result: between the two presentations of the photos, group opinion effectively influenced individual judgment. Even more interestingly, each readjustment of opinion was preceded by the activation of two highly specific cerebral regions (the rostral part of the cingulate region and the ventral striatum), regions that ordinarily serve to verify the validity of something learned in the past and to confirm its acquisition – or not. (This mechanism is called acquisition reinforcement.) Moreover, these regions of the brain were activated far less whenever there was conformity between the group’s indicative grade and that of the individual.

    The Mistake of Being Different?

    So, when a disagreement arises between personal and group opinion, everything happens as though the brain were trying to evaluate the possibility it was in the process of making an error of judgment. “Even though such a link had been hypothesized in the past, this is the first time it’s been so clearly demonstrated,” Vasily Klucharev asserts. “Ultimately, it seems that we cling to group opinion because our brain ends up deciding that the greatest mistake that could be made in this context is to appear different from everyone else!”

    An assertion that makes Blandine Bril, director of research at the l’école des hautes études en sciences sociales (EHESS) [School for Advanced Studies in the Social Sciences] pounce: “It’s impossible to draw such conclusions from this type of study. The functional MRI allows us to follow blood flow, and consequently to observe the operation of the cerebral mechanism. But in no case, does it inform us on the origins of the behavior studied. Cognitive processes are very complex and there are not necessarily causal relationships between the activation of a cerebral site and the source of a behavior. To allow it to be understood that social conformity results from a neurological process is not only inappropriate, but also dangerous. And how do we then explain that between 25 and 30 percent of the population does not submit to the rules of social conformity? Must we deduce from that that their brains operate in a different way?”

    Such shortcuts in thinking are ever more current in neuropsychology, the researcher deplores … An artifact of trendiness, she believes. A suggestion to remind some people that, as Asch’s pioneering experiment specifically demonstrated, just because the majority asserts something, that doesn’t mean the majority is right.

    * V. Klucharev et al., Neuron, January 13, 2009.

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    To view all images for this story, click here. The captions for these images are translated by Leslie Thatcher, below.

    (1) The Lines in Solomon Asch’s Experiment

    (2) The Experiment Protocol Established by the Dutch Team

    (3) Blandine Bril, Director of Research at the l’École des hautes études en sciences sociales (EHESS) [School for Advanced Studies in the Social Sciences]: Look out for shortcuts in the study of social conformity!

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