The Science of Beauty

Since time immemorial, physical beauty has inspired and enthralled. It has launched a thousand ships, inspired a million sonnets, and sent 36,482 Brits to a cosmetic surgeon in 2009 alone. Undoubtedly, our collective fixation on beauty has its ugly side. And yet it seems unlikely that the promise of beauty will ever lose its lustre.

Here is a rundown of the science that underpins this ever-alluring trait.

Beauty & Evolution

What is beauty, and why have we evolved our particular set of aesthetic preferences? It seems clear that both aesthetic sensitivity, and beauty itself, are subject to the pressures of selection.

Our love of beauty is not so much a superficial foible as it is a genetic endowment. We are wired to respond to the markers of health, youth, parasite resistance and reproductive ability. This most obviously applies to traits like a symmetrical face and glossy hair.

What may seem more perplexing is how there can be so many cultural variations in beauty ideals. When it comes to the neck rings worn by certain tribes, or the ancient Chinese practice of foot binding, it is hard to see the evolutionary incentive – elongated necks and stunted feet don’t scream out ‘low parasite load’.

It is clear, however, that fashions in beauty are linked to social cachet. If you want to propagate your genes, it is wise to seek out high status mates, and thus, sensitivity to high status markers is beneficial. This may help explain some of the wackier beauty trends over the ages, including the modern veneration of thinness. Although thinness does not necessarily equate to the healthiest or most fertile shape, its scarcity value makes it a desirable commodity.

The mathematics of beauty

The idea that beauty can be mathematically analysed has been in circulation at least since Pythagoras. Over the ages, there have been various attempts to describe ‘ideal’ human proportions in mathematical terms.

Just take Leonardo Da Vinci, who, echoing the Ancient Roman architect Vetruvius, claimed ‘the distance from the hairline to the bottom of the chin is one-tenth of a man’s height’ and that the ‘the length of the ear is one-third of the length of the face’.

More recently, Stephen Marquadt became notorious for his ‘phi mask’, which maps out facial features in terms of the golden ratio. The mask can be superimposed on photographs, revealing how well the subject’s beauty corresponds to a supposedly universal standard.

Although there are various, well documented, problems with the ‘phi mask’ – not least its bias towards Caucasoid features – the premise remains an intriguing proposition. Might beauty be dependent on mathematical constants? And might this apply not just to humans, but represent an underlying truth about the structure of beauty in the arts and the natural world?

Koinophilia

Koinophilia – which has disappointingly little to do with gold-diggers – describes the tendency to seek out mates with average features. If facial features are very big, very small, very close together or very far apart, this can indicate poor genetic quality. Most animals, therefore, take a Goldilocks approach to sexual selection: copulating with mates whose proportions are just right.

Koinophilia in humans has been borne out by a wealth of research. When you blend together several faces using morphing software, the resulting facial composite will almost always be rated as more attractive than any of the faces taken alone. In part, this is due to factors such as the smoothing out of blemishes, but the ‘averaging out’ of facial proportions plays a substantial role.

This paradoxical-sounding finding – that attractiveness hinges on averageness – makes more sense when we bear in mind the soothing effects of familiarity. What it fails to explain is the beauty inherent in imperfection. Sometimes, it can be the extreme features which make a striking individual anything but average.

Beauty in the future

There are several theories about what may be happening to beauty on a larger timescale. One study, for instance, suggests that women are becoming steadily more beautiful over time. Beautiful women have more children than their plainer counterparts, and a higher proportion of these children are daughters.

Another, more apocalyptic theory, suggests that humanity may be on the verge of splitting off into two subspecies: an underclass and an elite. This somewhat alarmist hypothesis ties in to long-standing speculation about genetic technologies, and the extent to which they may enable the emergence of a ‘super-race’. Fortunately for the human race, there is no real scientific evidence to support the idea. It seems likely to remain in the realm of science fiction.

In sum

So, is beauty really in the eye of the beholder? The answer is a resounding ‘yes and no’. While there is certainly a subjective element to beauty, there is also a great deal of consensus among the beholders. It is illuminating to consider how and why this consensus evolved, and of what precisely it consists.

Note, however, that “amazing parasite resistance!” is unlikely to work as a chat-up line.

Jokela, M. (2009). Physical attractiveness and reproductive success in humans: evidence from the late 20th century United States☆ Evolution and Human Behavior, 30 (5), 342-350 DOI: 10.1016/j.evolhumbehav.2009.03.006

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1. The Science of Beauty