How competent are you, compared with your colleagues? When psychologists approach teams of coworkers with variations of this question, an interesting pattern emerges. If people have a truly realistic perspective of their abilities, then their self-assessments should generally fall around the middle. Instead psychologists have repeatedly found that people’s self-assessments are inflated. In fact, superstars and underperformers alike tend to think they are better than they truly are.

This effect is one example of a positive illusion: a cognitive bias that makes you feel more competent, more blessed, more fortunate and better than you are. Positive illusions seem intuitive and reasonable to many people. Some scholars argue that these illusions are fundamental to our species’ survival. To get by in life, they reason, you must remain optimistic, work hard, succeed, live long and leave offspring behind.

Of course, some people don’t experience positive illusions and have a more realistic self-assessment. Unfortunately, such self-appraisals could make them feel more inadequate when comparing themselves with many others who have a very positive self-assessment. These comparisons may be an important cause of imposter syndrome—the suspicion that one is not deserving of one’s achievements. In other words, imposter syndrome may be the dark side of the societal norm toward positive selves.

But there is an important caveat to this discussion: the available evidence is based almost exclusively on a small fraction of humanity called Westerners. If positive illusions were truly essential to our species, we would expect them to be universal. But my work—and that of other research teams—suggests otherwise.

Read the complete article in Scientific American