Teeth, Beauty, Biology, and Health

I. A Universal Human Preoccupation

Looking good is a universal human preoccupation. We acknowledge that our perception of beauty in people is culturally derived when we say that 'beauty is in the eye of the beholder.' Ornamentation seems to matter in the animal kingdom where it is usually the male who is colorful; a biological fact especially evident in birds. Decoration and body shape matters in many human societies; tattooing, body piercing, and dental mutilation has both a long history and a world wide distribution. Every culture--at every time in history--is/has been preoccupied with good looks.

Figure One. Culturally modified teeth

Are there cultural universals? When British researchers asked women from England, China, and India to rate pictures of various Greek men, their choices were identical. When asked to select a 'good looking' face from a diverse collection, whites, Asians and Latinos from 13 countries shared the same choices. Even infants have a sense of what is attractive: 3- and 6-month-old infants will gaze longer at an attractive face that one the is not attractive. Regardless of nationality, age, or ethnic background, people universally share a sense of what is attractive

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II. What is Attractive?

What, then, is beauty made of? We seem wired to find robust health prettier than infirmity. All animals are attracted to other animals that are healthy. Attractiveness seems to certify biological quality. To my knowledge, for example, no culture considers rotting teeth and body lesions as beauty aids. Having an attractive smile signals biological health. Teeth make a crucial difference in how we look and what hidden messages we convey

 

 

The single feature that matters time and again in animal studies is symmetry. Insects, birds, and mammals prefer a mate with symmetry and balance. The biological cost of displaying that symmetry can be enormous: consider the diagram of the Irish elk shown here.

Those antlers, shed annually, are a burden to carry and consume enormous resources. Moose and elk illustrate that symmetry is important, and in some situations, animals engage in a sort of runaway arms race to display it. The first feature of human attractiveness is symmetry.

Figure Two. The Irish Elk (Megaceros hibernicus)

A second feature in human attractiveness is averageness. A century ago, Charles Galton, the eccentric cousin of Charles Darwin superimposed the faces of many criminals seeking to find the 'criminal face type'. The result was something confirmed in many subsequent studies: many faces assembled into a composite produce a face better looking than those individuals.

Let me add one qualification: the faces we find most beautiful have some exaggerated features. The most ideal female has a higher forehead, fuller lips, an shorter jaw and a narrower chin. Men particularly favor a waist-to-hips ratio of 7:10 The ideal male has a big jaw, a broad chin and an imposing brow. Square-jawed males are more likely to attain higher rank in the military. These choices seem to apply cross-culturally: New Mexico, British, and Japanese students express similar preferences.

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III. Benefits and Risks of Good Looks

Most symmetrical males have sex earlier (by three to four years) and more often than their lopsided brethren. Greater symmetry also predicted a larger number of past sex partners. Women with highly symmetrical partners were more than twice as likely to climax during sexual intercourse. Men with symmetrical bodies are typically larger than their peers, more muscular, athletic and dominant in personality.

Women are more sexually responsive to symmetrical men. Men who have it exploit that advantage. Extremely symmetrical men are less attentive to their partners and more likely to cheat on them. Women show no such tendency. Our innate tendency to prefer symmetry unfortunately doesn't prepare us to prefer integrity, personal worth, or life in complex technological societies. Our beauty lust is better suited to the Stone Age than an era of freeways and computers where commitment matters more than ever before.

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IV. Beauty and Health; What Does Symmetry Tell About Biology?

One genetic characteristic that symmetry reveals is genetic diversity. Follow this closely: The more heterozygous the individual, the more facial symmetry is observed. The ability to successfully resist or withstand various environmental traumas or parasitic infection. A heterozygous individual has a wider range of genetic potential to resist parasitic invaders--to produce proteins that are unfamiliar to infectious organisms. Pathogens are least resistant to rare alleles.

A specific type of asymmetry called fluctuating asymmetry is observed in teeth. It just means that teeth are larger on one side than the other. Animal studies have shown that Selye stress produces teeth of different sizes right and left (directional asymmetry) when exposed to intense stress (such as immersion in ice water). A biologically strong individual, whether a rat or human can better withstand stress than a weak one. Fluctuating asymmetry correlates with lower survival and growth rates, and fewer offspring.

One final observation: facial asymmetry may provide more information when displayed by men than women.

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V. Mathematics, Proportion, and Esthetics 

Can beauty be reduced to mathematics? Yes and no. Mostly no. In art and architecture is a legendary old proportion known variously as the golden proportion, golden section, or as Fibonnaci Numbers. It is the proportion 1 to .618. The proportion is considered pleasing to the eye and appears in classical architecture and even in Khufu's tomb chamber within the Great Pyramid, Giza, Egypt. In the diagram below, Side A is to B as B is to the sum of A and B. Fibonacci Numbers date from recreational mathematical games developed in the 12th century.

Figure 3. The Golden Section

The golden proportion applies to the widths of upper incisor teeth and to the lengths of the metacarpals in the fingers.

Footnote on Fibonnaci numbers: They date from recreational mathematical games devised in the 12th Century. If a golden section is drawn as in figure three above is drawn and a perfect square is removed from it, the remaining rectangle is also a golden section. If this process is continued and circular arcs are drawn in each perfect square so that they are continuous with one aonther (as in figure three), a logarithmic spiral is created. This form is found in nature as the whorls on a pineapple or a pinecone. In botany, this phenomenon is known as phyllotaxis.

Figure Four

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VI. Marquardt's Face Template

 

 

A California oral surgeon has devised a geometric face template based on Fibonnaci Numbers to assess facial symmetry and proportion. It has received publicity on Hard Copy and the Discovery Channel, but has gained little respect from the academic community. It is shown here as something interesting and creative. The drawing of the face of actress Audrey Hepburn is shown with an adaptation of Marquardt's template superimposed to reveal facial symmetry and proportion.

Figure Five.

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Resources:

Alhadlaq, A. Facial Asymmetry and Health. term paper submitted for OSCI 590 summer, 1998 UIC.

Cowley, G. "The Biology of Beauty" Newsweek, June 3rd, 1996 pp 61-66

Colwley, G. "What Makes Us Attractive" Readers Digest

Diamond, J. Why is Sex Fun? New York: HarperCollins Publishers, 1997.

Ricketts, R. "The biologic significance of the diving proportion and Fibonacci series" Am. J. Orthod. Vol 81, No 5 May, 1982 pp 351-370.

Thornhill, R. and Gangestad, S. "Human Facial Beauty" Human Nature Vol 4, No. 3, pp 237-269.

Unsworth, T. "Beauty that lies behind the mask" Hong Kong: The Guardian: December 28th, 1996.

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Also see fibonacci numbers in Encyclopedia Britannica.