The “wisdom of the crowd” has become a bit of a pop cliché, but it’s backed up by real-world evidence. When groups of people are asked to provide estimates of obscure information, the median value of their answers will often be remarkably close to the right one, even though many of their answers are laughably wrong. But crowds rarely act in the absence of social influences, and some researchers in Zurich have now shown that providing individuals information about what their fellow crowd-members are thinking is enough to wipe out the crowd’s wisdom. […]

Compared to the control setup, the additional information changed the crowd’s collective behavior dramatically. In what the authors term the “social influence effect,” the panels that were provided with information about their peers quickly narrowed their focus onto a fairly limited set of values, meaning the diversity of their answers decreased. In contrast, the control group retained its initial diversity throughout the repeated rounds of questioning.

Worse still, the panels that were provided with social information narrowed in on answers that were more likely to be wrong.

Ars Technica: Social influences kill the wisdom of the crowd