Over confidence

The psychologist Ellen Langer coined the phrase in 1975 to describe “an expectancy of personal success probability inappropriately higher than the objective probability would warrant.” Experimental evidence for the illusion goes back at least to 1965, when one research team found that college-educated employees of AT&T asked to press buttons to illuminate lights had the tendency to believe they had more control than they actually did, even when the lights lit randomly, and even when they used pen and paper to track their results.

In another study, done in 1992, a group of Israeli college students was found to be more willing to bet on dice, and to bet bigger, before they rolled than after, reflecting the belief that they had control over their rolls. Such a preference for prediction over postdiction had been observed before, but this study also found that the preference grew stronger when the students were threatened with an electric shock if they guessed wrong—evidence that stress amplifies the illusion of control.

Langer’s work showed that the illusion is also intensified by “skill cues”: circumstances that make people feel like they’re engaged in acts of skill rather than luck. Such cues include competition, choice, and familiarity with the task at hand. Therefore people will tend to overestimate their prospects in a game of pure chance even more than usual if they face a nervous-looking opponent, or if they pick rather than get assigned a lottery ticket, or if they’re given the chance to familiarize themselves with an apparatus that’s simply spitting out random numbers. Or, I might add, if they’ve toiled over complicated mathematical equations to back up their decisions.

Medicine

A 2014 study by Helena Matute, the director of the experimental psychology lab at the Unversidad de Duesto in Bilbao, Spain, asked 50 pairs of participants to administer fictional medicine to fictional patients suffering from a fictional disease. Half had 30 doses of the medicine to disburse among 100 patients, and the other half had 70. Eighty percent of the patients recovered, regardless of whether or not they were given medicine.

Slightly less than half of the participants giving 30 doses believed that the medicine was effective, but more than two-thirds of the 70-dose crowd believed they’d played a role in patients’ recovery. The experience of repetition, and greater personal involvement, strengthens the illusion of agency even with no causality. Success with some causality, like mine, surely must strengthen it even more.