As Rod Stewart once sang, "Some guys have all the luck. Some guys have all the pain." Sometimes, it seems like the luck goes to the beautiful people and the pain goes to everyone else. He gets a promotion. She gets out of a speeding ticket. All because they are "the pretty people."

That's the power of a pretty face, but before you pout and say, "it isn't fair," think about who decides what beautiful means.

We do.

Our first impressions of a person determine how we treat them. If the host of a party is handsome and gracious, you might forgive a bit easier when he spills beer on your shoes, suggests Psychology Today.

"To speed up processing, your brain tends first to apply very simple labels to the things you encounter minute by minute," said David McRaney in his book, "You Are Not So Smart." "You can thank your ancestors for paying attention to these labels for millions of years, because some of the things you are most likely to encounter in life are now hardwired into your mind as being good or bad, desirable or undesirable.

This is a result of the "halo effect." The assumption our brains make when we assume someone who is good-looking is also funny, kind, compassionate or other positive traits.

"In the last one hundred years of research, beauty seems to be the one thing that most reliably produces the halo effect," McRaney said, according to Psychology Today. "Beauty is shorthand, a placeholder term for an invisible mental process in which you are privy only to the final output. "

Psychologists in 1972 set out to see just how much perception of beauty creates a "halo effect." Karen Dion, Ellen Berscheid, and Elaine Walster told participants that the study was about first impressions. They handed each of the participants three photos that the researchers considered highly attractive, average and less than pretty.

The participants judged the people in the photos on 27 personality traits - altruism and stability, for examples. The people in the photos were rated on perceived happiness, marital status, economic standing and other perceptions, Psychology Today reported.

From only a picture, the study participants divined that the better looking people in the photos were happier, richer, better parents and smarter than their less attractive counterparts.

In 1974, researchers tried again - this time, with essays. Some essays had a photo of an attractive woman attached and some had the photo of an unattractive woman attached. The researchers asked the participants to rate the essay. They never mentioned the photos, according to Psychology Today.

The essays with the more attractive photo were rated higher than the essays attached to the unattractive photo.  Only thing was: they were identical essays.

"When the scientists ran [this same] study with essays purposely written to be awful, the disparity between the ratings was magnified," McRaney said. "As Landy and Sigall wrote, you expect better performances from attractive people, but when they fail, you are also more likely to forgive them."

Are you blinded by a halo?