How Groups Can Change Your Mind

If you’ve read my book Group Genius, you know about the research showing that face-to-face brainstorming groups are almost always less creative than the same number of solitary individuals. I’ve just learned of another body of research, by psychologists who study memory, showing similar group effects.* The phenomenon is called “memory conformity” and what happens is that even when you saw an event, and you remember it pretty well, if everyone around you says they saw something different you’ll often change your mind to conform to the group’s collective opinion.

Researchers have been able to make this happen fairly easily in the lab. In a common research design, researchers bring together a group of subjects and then they tell them a story or show them a short video; then later, they bring back to the lab each person alone, and basically lie to them and tell them everyone else in the group remembered something that wasn’t even in the video. Then, they give them a memory test, and sure enough, you’ve been able to change their memory from an accurate one to an inaccurate one. Not 100% of the people, but usually at least half or even more.

Two different things might be happening with memory conformity. The first is that you might have actually changed your memory to match what the group is saying. Pretty amazing, isn’t it? Are we really that weak and our minds so malleable? But there’s another possibility: If you’re in a group, you might agree with everyone else just to get along, but secretly you’re convinced you’re right and you retain your own memory. That’s called “public conformity.” Your memory doesn’t change, but your behavior changes.

A new study in Science magazine reproduced these effects, while taking an fMRI brain image of the subjects’ brains. Some people changed their own memory when they learned of the group’s memory; others weren’t fooled. And for those people whose memory changed, their brain showed a different pattern of activation just at the moment when they were being exposed to the group’s collective memory. Essentially, they activated all of the brain regions associated with memory. For those people who weren’t fooled and didn’t change their own recollection, the brain regions associated with memory were not activated.

That might not be so surprising; it’s sort of common sense. But there was another more surprising finding. In addition to social conformity, the researchers tried another condition, where subjects were given the same wrong answers to the memory questions, but they were told that the answers had been generated by a computer program. Memory conformity still occurred, but it wasn’t as severe as with social conformity. And with social conformity, there was elevated brain activation in the amygdala, but not with computer conformity. The brain seems to respond in a unique way to social interaction.

I look forward to more neuroscience studies that enlighten us about how people are influenced by groups, and what happens in the brain when people are participating in groups: a new area known as social neuroscience.

*”Following the crowd: Brain substrates of long-term memory conformity.” Micah Edelson, Tali Sharot, Raymond J. Dolan, and Yadin Dudai. Science, 1 July 2011, Vol. 333, pp. 108-111.