formfeed writes "A lot has been written lately on the crowd effect and the wisdom of crowds. But for those of us who are doubtful, the Proceedings of the National Academy of Science has published a study showing how masses can become dumber: social influence. While previous studies show how groups of people can come up with remarkably accurate results, it seems 'even mild social influence can undermine the wisdom of crowd effect in simple estimation tasks.' Social influence 'diminishes the diversity of the crowd without improvements of its collective error.' In short, crowd intelligence only works in cases where the opinion of others is hidden."