Attractive people are not like the rest of us. By nature of their good looks, people treat them differently. And according to decades of psychology research, that can shape many facets of their lives—from their jobs, to their personalities, to how they see the world.

First, it might be helpful to define what "attractive" even means. There are a few things that are universally associated with attractiveness, such as facial symmetry, facial shape, and clear skin, because they may have evolved as a shorthand for the health of a potential mate. Average-looking faces are also usually considered more attractive, studies show.

Attractiveness doesn't rest on the ability to see beauty, but to detect flaws. The fewer the flaws, the more attractive someone appears to be, says Kristin Donnelly, a doctoral student in experimental psychology at the University of California, San Diego. Other elements of attractiveness, such as body shape, weight, and skin color, can be more subjective and influenced by culture. There are less physical things that can make a person seem attractive, too, like a person's confidence, smell, or voice.

For psychological experiments, researchers sometimes show participants a number of faces to establish a baseline of what they consider attractive; other times, they use pre-rated faces from a database, such as the Chicago Face Database (essentially HotOrNot, but for science).

Researchers have been looking into the effects of attractiveness for decades. The results show that being considered attractive generally means that other people treat you better. "We assume attractive people have positive qualities that have nothing to do with their physical attractiveness," says Lauren Human, an assistant professor of psychology at McGill University. This is sometimes called the halo effect. Attractive people are generally assumed to be more intelligent, more trustworthy, and have better social skills. We find them more interesting and pay more attention to attractive people, so we tend to get a better sense of who they are as individuals. Good-looking people are more successful—they are paid more at work and are promoted more quickly. They're often happier, too. Even parents treat cute babies better than ugly ones. It's not that unattractive people are viewed more negatively, Human says, they just aren't viewed as positively as their prettier counterparts.

We often attest these qualities to attractive people based on very little knowledge of their personalities, so it's often incorrect. But sometimes, these assumptions can become self-fulfilling prophesies. "If you're an attractive person going through the world and everyone is opening doors, buying you drinks, you're your boss' favorite, your parents' favorite, then you're going to think the world is a better place," Donnelly says—maybe you will be kinder and more open to talking to people, after all.

There can be downsides to being too attractive. Hot people can sometimes have too many choices in their partners, which can make people less happy in their relationships or even shorten marriages. People who become less attractive as they age can question their perspective on the world, or become obsessed with hanging on to beauty in a way that can cause psychological distress. "If you've gone your whole life with this reward structure, that you're constantly told you're attractive and so much of your self-worth is tied into your appearance, that can be a dangerous thing," Donnelly says.

And not all Plain Janes treat pretty people better. Less attractive people, feeling insecure or fearing rejection, might assume that beautiful people are dumb (though studies show that many attractive people are in fact more intelligent). That could really work against you when applying for jobs, a 2010 study showed—too beautiful and bosses, no matter their gender, assume you're incompetent, too dowdy and you're considered unqualified. "It seems in general the stereotype [about attractive people] is positive, but I think we can all think of times that's not the case," Human says.

In general, biases are a thing we want to get rid of, right? But assuming that positive people have good qualities might actually be making the world a better place. "To the extent we're expecting people to be good, these biases can bring good things out, so not necessarily a bad thing," Human says. Where it gets dicey is if you assume someone isn't interesting or worth talking to because of how they look. Human suggests it would be more helpful to overcome the less positive assumptions about less attractive people. How we actually do that, though, is a different question, and one to which there is not yet an answer. Donnelly suggests we might try expanding the definition of what is considered beautiful, a laborious transformation already starting to happen thanks to body-positive advocates and a greater push towards displaying people of different colors and sizes in media.

Attractiveness can sometimes be difficult to study. "One of the difficulties is that it's an amorphous construct—lots of things that go into it, so researchers have to make choices about how they measure it," Human says. And though scientists have put lots of these questions to rest, there are some aspects of this field that have not yet been explored. One is how attractive people perceive themselves and one another. Human intends to further investigate the accuracy component—why attractive people are seen more accurately by others than are their less attractive peers.