Obesity is contagious. If your best friends get fat, your risk of gaining weight goes up.
Broadcasters mimic one another, producing otherwise inexplicable fads in programming. (Think reality television, American Idol and its siblings, game shows that come and go, the rise and fall and rise of science fiction, and so forth.)
The academic effort of college students is influenced by their peers, so much so that the random assignments of first-year students to dormitories or roommates can have big consequences for their grades and hence on their future prospects. (Maybe parents should worry less about which college their kids go to and more about which roommate they get.)
In the American judicial system, federal judges on three-judge panels are affected by the votes of their colleagues. The typical Republican appointee shows pretty liberal voting patterns when sitting with two Democratic appointees, and the typical Democratic appointee shows pretty conservative voting patterns when sitting with two Republican appointees. Both sets of appointees show far more moderate voting patterns when they are sitting with at least one judge appointed by a president of the opposing political party.
After my first lecture, Binmore offered a version of the “low stakes” critique. He said that if he were running a supermarket, he would want to consult my research because, for inexpensive purchases, the things I studied might possibly matter. But if he were running an automobile dealership, my research would be of little relevance. At high stakes people would get stuff right.
The next day I presented what I now call the “Binmore continuum” in his honor. I wrote a list of products on the blackboard that varied from left to right based on frequency of purchase. On the left I started with cafeteria lunch (daily), then milk and bread (twice a week), and so forth up to sweaters, cars, and homes, career choices, and spouses (no more than two or three per lifetime for most of us). Notice the trend. We do small stuff often enough to learn to get it right, but when it comes to choosing a home, a mortgage , or a job, we don’t get much practise or opportunities to learn. And when it comes to saving for retirement, barring reincarnations we do that exactly once. So Binmore had it backward. Because learning takes practice, we are more likely to get things right at small stakes than at large stakes. This means critics have to decide which argument they want to apply. If learning is crucial, then as the stakes go up, decision-making quality is likely to go down.
People are unrealistically optimistic even when the stakes are high. About 50 percent of marriages end in divorce, and this is a statistic most people have heard. But around the time of the ceremony, almost all couples believe that there is approximately a zero percent chance that their marriage will end in divorce — even those who have already been divorced! (Second marriage, Samuel Johnson once quipped, ‘is the triumph of hope over experience.’) A similar point applies to entrepreneurs starting new businesses, where the failure rate is at least 50 percent. In one survey of people staring new businesses (typically small businesses, such a contracting firms, restaurants, and salons), respondents were asked two questions: (a) What do you think is the chance of success for a typical business like yours? (b) What is your chance of success? The most common answers to these questions were 50 percent and 90 percent, respectively, and many said 100 percent to to the second question.
Unrealistic optimism can explain a lot of individual risk taking, especially in the domain of risks to life and health.
Why does this matter? There’s solid evidence that experiencing such losses—noticing that our portfolio is losing money—leads to poor choices. In one lab experiment by Richard Thaler, Amos Tversky, Daniel Kahneman, and Alan Schwartz, subjects were far more likely to invest in a bond fund when feedback was given more frequently. Unfortunately, these low-risk bonds also generate lower returns over the long haul. As the scientists noted, “Providing such investors with frequent feedback about their outcomes is likely to encourage their worst tendencies…. More is not always better. The subjects with the most data did the worst in terms of money earned.” Such is the vicious circle of loss aversion, as our strong dislike of losses causes us to lose even more.
Additional experiments, growing out of Asch’s basic method, find large conformity effects for judgments of many different kinds. Consider the following finding. People were asked, ‘Which one of the following do you feel is the most important problem facing our country today?’ Five alternatives were offered: economic recession, educational facilities, subversive activities, mental health, and crime and corruption. Asked privately, a mere 12 percent chose subversive activities. But when exposed to an apparent group consensus unanimously selecting that option, 48 percent of people made the same choice!