We overestimate how much we can influence outcomes that actually depend on chance.
Choosing your own lottery numbers feels different from being assigned random numbers, even though the odds of winning are exactly the same either way. The illusion of control is the tendency to overestimate how much we can influence an outcome that, in reality, depends entirely or partly on chance.
In a study with lottery tickets, one group of people was assigned a ticket with random numbers, and another group was allowed to choose their own numbers. Before the drawing, both groups were offered the chance to sell their ticket back. Those who had chosen their own numbers asked, on average, a much higher price than those who received an assigned one, even though the real odds of winning were identical for both.
Any cue that resembles a skill-based situation (choosing, actively participating, practicing) activates the same sense of control we feel in tasks where effort really does determine the outcome, even when the actual result depends solely on chance.
Source: Langer, E. J. (1975). The Illusion of Control. Journal of Personality and Social Psychology, 32(2), 311-328.
Giving a user a sense of active participation (choosing, customizing, configuring) increases their commitment to an outcome, even in processes where that choice doesn't objectively change the final probability.
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