“Don’t hate me because I’m beautiful.” So says the classic shampoo commercial, but a new study indicates a lot of people believe they’re beautiful when they are, in fact, average in appearance. Researchers from the universities of Chicago and Virginia have shown that subjects see themselves as better-looking than they actually are, while rating others based on their actual appearance. Scientists Nicholas Epley and Erin Whitchurch took photos of study participants and, using computers, created more-attractive and less-attractive versions. When asked to choose unmodified image, subjects were most likely to select the attractively-enhanced version.

The results are contrary to a recent promotion from Dove in which women were asked to describe their own faces to a sketch artist. Later, a briefly-acquainted stranger was also asked to describe the women’s faces. When the two drawings were later shown to the women, they were generally surprised to find the stranger’s description produced a sketch of a more-beautiful person.

Dove’s experiment is a great concept, but Epley and Whitchurch don’t believe its results. They describe a general phenomenon psychologists call “self-enhancement.” Research has shown that people not only over-estimate their appearance, but also their likelihood to engage in desirable behaviors. For example, people overestimate their likelihood to vote and the amount of money they donate to charity. Meanwhile, they more accurately estimate positive behaviors displayed by others.

Obviously, not everyone can be above average. But 93 percent of drivers rate their skills as above average. Likewise, 94 percent of college professors believe they do above average work, most people believe they are less likely to fall ill than others, and investors think their stock picks are more likely to be successful than others.

At the same time, most people also predict they provide more accurate self-assessments than others. So are they confident or delusional? Probably a little of both. Scientists believe the phenomenon occurs because of the adaptive nature of self-enhancement. Basically, people tend to show strong negative emotional responses toward deceivers. But through self-enhancement, they truly believe their own desirable characteristics, so they can promote themselves without lying, which boosts their confidence.

Extra confidence drives people to perform better, and there’s nothing wrong with that. Go ahead and delude away.