Even without being Nazis, most of us know the experience of being part of a crowd wild with excitement, and have an intuitive sense that the way our minds process information might change under such circumstances, even to the point that we might come to do something or begin to believe something different. If to pay attention is to open the mind to information, to do so in an animated crowd is to fling the doors wide open. To be exposed to any information is to be influenced, but in crowds the possibilities go well beyond everyday experience. Gustave Le Bon, the first theorist of crowd psychology, held that it is loss of individual responsibility that makes the individual in the crowd more malleable. Freud would say that the superego was supplanted by the will of the crowd, as unconscious wishes rise to the surface and are shared.

Tim Wu, The Attention Merchants, loc. 399