You're in a room with 10 other people who seem to agree on something, but you hold the opposite view. Do you say something? Or do you just go along with the others?Neuroscientists have experimentally confirmed that the brain reacts to disagreements with the larger group in a similar manner to punishment. Groupthink exists, and exists on a massive scale. This makes more and more sense in the mass media age where we consume the same media (NY Times, TechCrunch, and Hacker News for me) and read the same forums and talk about all the same ideas. While the Internet revolution has brought many more voices to the foreground and reduced the role of traditional media (1000 channels on TV instead of 5, 1 million blogs instead of 1 local newspaper), this effect still plays out heavily throughout society. Whenever there is a crowd, there will be group consensus. The CNN article mentions that groupthink will overwhelm even obviously correct thinking: "The most famous experiments in the field were conducted by Solomon Asch in the 1950s. He found that many people gave incorrect answers about matching lines printed on cards, echoing the incorrect answers of the actors in the room." This is significant for entrepreneurs. Apple was absolutely on to something when it said: Think Different. Why think different? Because the masses are wrong. (In fact, the masses are asses. =) ) And this is why many startups and entrepreneurs are perceived to be pursuing inane, crazy or irrelevant ideas. Prevailing wisdom isn't, and it takes a crazy dreamer to ignore the massive and overwhelming tidal wave of group think.