Beauty is in the eye of the beholder.
Beauty is only skin deep.
The list of adages goes on and on, but a new book written by an economics professor at the University of Texas-Austin concludes that beauty brings many real benefits.
Daniel S Hamermesh has studied the economics of beauty for about 20 years. In the book, Beauty Pays, he writes that attractive people enjoy many advantages while those who are less attractive often face discrimination.
Hamermesh finds beautiful people are likely to be happier, earn more money, get a bank loan with a lower interest rate and marry a good-looking and highly educated spouse.
So what defines beauty? A symmetrical face generally is considered beautiful, Hamermesh says. Other factors, like expression and "overall gestalt", are in the mix but are difficult to measure, he says.
In his book, Hamermesh concludes that better-looking employees are more productive, leading to higher sales and potentially higher profit.
The book also shows how society generates premium pay for beauty and penalties for ugliness. Hamermesh says beautiful people earn at least $200,000 more in a lifetime than workers with below-average looks. He says that figure is an estimate based on an average salary of $20 an hour in 2010.
The earnings disparity is greater when broken down by gender. Beautiful women earn four per cent more and handsome men earn three per cent more than their average-looking counterparts.
When Hamermesh's early research on this topic circulated in the early 1990s, comedian Jay Leno joked that if the findings were true, why did Dallas businessman Ross Perot earn more than actor Rob Lowe?
"Look, we don't talk about individuals, we talk about the average good-looking person and the average bad-looking person," says Hamermesh, who also teaches at Maastricht University in the Netherlands.
"There are always outliers."
Other factors, such as education and work experience, also affect earnings, he says.
Politics is another area where looks matter tremendously, Hamermesh says.
"(Texas) Governor Rick Perry is someone that is considered good-looking, and I assume he's benefited from that."
Over the years, plenty of research has been done on how beauty and facial structure affects how people act or how they're perceived by others.
One study, which will be published in an upcoming issue of Psychological Science, finds a CEO's facial structure can predict his company's financial performance.
A team of researchers from the University of Wisconsin-Milwaukee, analysed photos of 55 male bosses of large companies and the companies' return on assets.
The study found companies with CEOs who have a higher facial width relative to facial height perform better financially. The group included former CEOs Herb Kelleher of Southwest Airlines (now chairman) and Bob Allen of AT&T Inc.
"Kelleher is an example of a CEO who has a higher facial width, while Allen is an example of a CEO who had a lower facial width as compared to the rest of our sample," lead researcher, Elaine Wong, says.
"And Southwest was performing well at the time."
Earlier research by Wong found the higher the facial width-to-height ratio, the more likely people were to act unethically or lie.
Researchers at the University of Toronto and University of California in San Diego found female faces were deemed most attractive if the vertical distance between the eyes and the mouth was 36 per cent of the face's length and the horizontal distance between the eyes was 46 per cent of the facial width.
And other research has shown that the facial width-to-height ratio correlates with male aggression.
What's the bottom line?
"You're not going to change your looks very much," Hamermesh says.
"So do the best you can with what you've got."