The anchoring effect is the tendency for judgments and estimates to be pulled toward a starting number, even when that number has nothing to do with the question. The idea comes from psychophysics, where researchers noticed that people judging a range of stimuli compared the others with the first and last ones they saw. Amos Tversky and Daniel Kahneman formalised it in economics in their 1974 work, describing anchoring as a shortcut people use when they are uncertain. In one famous line of studies, participants who first saw a random number on a wheel then gave noticeably different estimates of African countries in the United Nations. The effect also works without numbers, with people judging length, weight and volume differently depending on a prior reference. It matters in pricing, where a higher-priced model placed next to a cheaper one makes the second seem reasonable, and in negotiations, where the first offer often sets the range. Awareness helps a little, but people still drift toward the anchor.

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.