It's common knowledge that we humans take our looks very seriously. Just watch an hour of TV and count the commercials for hair, skin, teeth, and nail products; make-up for every conceivable fold of facial skin; the South Beach, Atkins, Cookie, and Cabbage Soup diets; low-fat foods and exercise machines; flattering clothing for every body type … the list goes on and on. The real question is “Is it worth it?” How much does physical beauty actually impact our lives, careers, relationships, and happiness? Multiple studies from forty years ago on have tackled this controversial question, and all have drawn the same conclusion: Although we like to toss around maxims such as “beauty is only skin deep,” humans put much more importance on looks than we care to admit.

First of all, forget about defining beauty. No universal, pan-temporal definition applies to all races, cultures, ethnicities, time periods, or personal preferences. The specifics of what makes a person beautiful vary dramatically and are affected by multiple factors. A sixteenth-century English courtesan would take one look at Halle Berry's tanned, toned abs or Kim Kardashian's voluptuous figure and cringe. In the fifteenth century, a flat stomach was indicative of the lower class, and large breasts were considered “vulgar.” On the other hand, who could picture a dumpy Dark Ages noblewoman with a pasty white stomach and barely-there breasts walking in the annual Victoria's Secret fashion parade? Before World War I, women were supposed to be soft and feminine, as in the case of the oft-referenced Rubens nude paintings. Now our culture worships jutting hipbones, protruding clavicles, and visible rib cages.

Despite beauty's transience, there is no end to the things humankind will do in its name. The Padaung women of Burma wear brass rings to elongate their necks, simultaneously deforming their collar bones and ribs and permanently bruising their throat muscles. The Kikuyu men of Nairobi stretch their earlobes with enormous plugs until the skin snaps, at which point they tie the ends in an attractive – and undoubtedly very masculine – bunny-ears bow.

Modern society marvels at the extremes these allegedly “primitive” groups undergo to achieve their definition of beauty. However, are we any different? We spend hours at the gym tearing and re-tearing our muscles, hoping they will grow back bigger, rounder, smoother, stronger. We submit ourselves to unnecessary surgeries, hacking off unsightly nasal cartilage and flabby love handles. We starve ourselves for days and shove our fingers down our throats to vomit up any extra calories threatening to plump our rib cages.

In her lifetime, the average American woman will spend $13,000 on cosmetics and an astonishing two and a half years bathing, dressing, and grooming herself. In other words, the average woman who lives for 80 years will have frittered away three percent of her life beautifying herself. In comparison, the average American man will spend a year and a half primping, or about two percent of his life (this manly attention to appearance has led to the term “manscaping”). Many scoff at this excessive focus on outward appearance. At least subconsciously, however, humans seem to realize that looks have dramatic implications.

In 1971, The Journal of Personality & Social Psychology published a seminal article titled “What Is Beautiful Is Good.” It extrapolated on the now common “halo effect,” or “the attribution of positive characteristics to attractive people.” Most ­people form a first impression seven seconds after meeting someone. Obviously this brief time doesn't allow for much critical personality analysis. Without intimate knowledge of a person's character, we tend to judge others on shallower factors, i.e., looks. Furthermore, we're inclined to impart positive characteristics to attractive people and negative characteristics to unattractive ones.

One could argue that we are taught to do this from childhood. The improbably good-looking and virtuous Disney princesses exemplify the “beauty is good” stereotype. From our bassinets and high chairs we are led to believe that these attractive women with their hourglass figures and flowing locks are the quintessence of innocence and goodness. But the hunched cronies with the warty skin and hefty schnozzes? The large women with the moles and discolorations? We look on them less kindly. One study published in Developmental Psychology demonstrated that children as young as three prefer attractive playmates, associating pro-social behavior with attractive children and anti-social behavior with unattractive children.

This early conditioning demonstrates itself all too clearly in the workplace. Studies have shown that good-looking people earn significantly more money than their average- or below-average-looking counterparts. One study determined that attractive people earn an average of three to four percent more than “average-looking people.” Over a lifespan, this can add up to hundreds of thousands of dollars in wages.

A 2011 study published in Social Forces further emphasized this beauty bias when it concluded that taller men and thinner women earn more than their shorter or heavier counterparts.

Employers alone can't be blamed for the beauty bias, though. After all, customers prefer attractive employees. We are more likely to buy products from attractive salespeople, more likely to tip pretty waitresses and barmaids. Patients attribute higher-levels of education and responsibility to good-looking doctors. In some countries help-wanted ads stipulate specific physical characteristics for applicants. Hamermesh writes, “In China … a recent study of [help-wanted] advertisements showed a requirement for looks being mentioned nearly 10 percent of the time … Some ads in Mexico even require that job applicants submit photographs to demonstrate that they have a ‘nice appearance.'”

Based on data accumulated over decades of study, researchers have concluded that if two workers with equal productivity, skills, and education were to compete for a job, the more attractive one would most likely be hired. Even those at the top of the corporate food chain are affected by the halo effect. One 1997 study led by a team of economics professors found that “firms with better-looking executives have higher revenues and faster growth than do otherwise identical firms whose executives are not so good-looking.”

Clearly humans put a great deal of stock in beauty, and, despite its constantly evolving definition, people have a markedly biased opinion regarding “beautiful” people. Some claim that our inherent propensity toward the halo effect is simply the next step in evolution: As we move into the future, survival of the prettiest will supplant survival of the fittest. Others argue that we should value qualities such as kindness, compassion, and selflessness – traits that have remained unchanged for millennia – over beauty. Beauty, they argue, changes with the season, transient as the weather. Today's “It” girl is tomorrow's Ugly Betty. Advocates of the personality-over-looks philosophy hope that consistently positive and invariable qualities such as integrity and personality will one day replace shallow and capricious traits as the defining factors of a person's character.

In the end, while looks do play a significant role in our lives and careers, beauty is not the only contributing factor to success. Aristotle may have claimed that “beauty is a greater recommendation than any letter of introduction,” but it's always wise to remember the often-quoted but still-true cliché, “Beauty is only skin deep.”