The scientists trained a large group of golden shiners, a small freshwater fish used as bait, to associate the arrival of food with a blue target. They then trained a smaller group to associate food with a yellow target, a color naturally preferred by the fish. Not surprisingly, when all the trained golden shiners were put in one aquarium, most of them swam toward the yellow dot; the stronger desires of the minority, fueled by the shiners’ natural preference, persuaded the majority to follow along.

But when scientists introduced a group of fish without any color training, yellow suddenly lost its appeal. All of a sudden, the fish began following the preferences of the majority, swimming toward the blue target. “A strongly opinionated minority can dictate group choice,” the scientists concluded. “But the presence of uninformed individuals spontaneously inhibits this process, returning control to the numerical majority.”…

Nevertheless, this research helps to explain the importance of indifference in a partisan age. If every voter was well-informed and highly opinionated, then the most passionate minority would dominate decision-making. There would be no democratic consensus—just clusters of stubborn fanatics, attempting to out-shout the other side. Hitler’s rise is the ultimate parable here: Though the Nazi party failed to receive a majority of the votes in the 1933 German election, it was able to quickly intimidate the opposition and pass tyrannical laws.