Studies show attractive students get more attention and higher evaluations from their teachers, good-looking patients get more personalized care from their doctors, and handsome criminals receive lighter sentences than less attractive convicts. But how much do looks matter at work?

The ugly truth, according to economics professors Daniel Hamermesh of the University of Texas and Jeff Biddle of Michigan State University, is that plain people earn 5 to 10 percent less than people of average looks, who in turn earn 3 to 8 percent less than those deemed good-looking.

These findings concur with other research that shows the penalty for being homely exceeds the premium for beauty and that across all occupations, the effects are greater for men than women.

A London Guildhall University survey of 11,000 33-year-olds found that unattractive men earned 15 percent less than those deemed attractive, while plain women earned 11 percent less than their prettier counterparts. In their report "Beauty, Productivity and Discrimination: Lawyers', Looks and Lucre," Hamermesh and Biddle found that the probability of a male attorney attaining early partnership directly correlates with how handsome he is.

Size matters, too. A study released last year by two professors at the University of Florida and the University of North Carolina found that tall people earn considerably more money throughout their careers than their shorter coworkers, with each inch adding about $789 a year in pay.

A survey of male graduates of the University of Pittsburgh found that the tallest students? average starting salary was 12 percent higher than their shorter colleagues?. The London Guildhall study showed that overweight women are more likely to be unemployed, and that those who are working earn on average five percent less than their trimmer peers.

According to Dr. Gordon Patzer, who has spent over three decades studying and writing about physical attractiveness, human beings are hard-wired to respond more favorably to attractive people. Even studies of babies show they will look more intently and longer at prettier faces.

"Good-looking men and women are generally judged to be more talented, kind, honest and intelligent than their less attractive counterparts," says Patzer. "Controlled studies show people go out of their way to help attractive people - of the same and opposite sex - because they want to be liked and accepted by good-looking people."

This may not sound too pretty to those of us who were dealt a bad hand in the looks department. But don?t rush off to try out for the next round of Extreme Makeover just yet.

Despite what the research tells us, some of the world?s most successful people have been ordinary looking at best, and you would never mistake the faces in Fortune for the faces in Esquire or Entertainment Weekly. Business legends are often of average height (Bill Gates at 5'9½") or even diminutive (Jack Welch, 5'8", and Ross Perot at 5'7"). What?s more, many folks who are lovely to look at complain that they lose out on jobs because people assume they are vacuous or "lightweights."

How does this reconcile with all the research? Hiring managers say it is the appearance of confidence they find attractive, not the presence of physical beauty. And they contend that attractiveness has more to do with how you carry yourself and the energy you exude ? rather than having perfect features or a great physique.

According to Gordon Wainright author of Teach Yourself Body Language, anyone can increase their attractiveness to others if they maintain good eye contact, act upbeat, dress well (with a dash of color to their wardrobe), and listen well. Wainright also stresses the importance of posture and bearing and suggests that for one week you stand straight, tuck in your stomach, hold your head high, and smile at those you meet. Based on many such experiments, Wainwright predicts you will begin to be treated with more warmth and respect and start attracting more people to you.