divulgatum está dedicado a la difusión de conocimiento científico en español e inglés, mediante artículos que tratan en detalle toda clase de temas fascinantes pero poco conocidos.
divulgatum is devoted to the dissemination of scientific knowledge in Spanish and English, through articles that go into the details of all sorts of fascinating, if not
widely known, subjects.

Thursday, February 11, 2016

A beautiful world

Science and philosophy suggest that the cult of beauty is much more than a simple cultural norm.

The identification of aesthetic beauty and moral beauty has accompanied mankind throughout history. (Credit: Kaho Mitsuki/Wikipedia.)

IT IS NOT something easy to define, and yet all of us recognise beauty when we see it before us. Humankind’s obsession with beauty, especially with human beauty itself, spans millennia. Poets were already writing about it three thousand years ago; today, their works are an insinuation of the boundless character of beauty, and suggest that its roots are deeper than could be expected from a mere cultural concept.

Although the standards of what we consider ‘attractive’ have seen themselves undeniably altered with the passage of centuries, due to a certain cultural influence, the truth is that physical beauty is something real beyond any subjectivity, and possesses an unquestionable biological function. Physical attractiveness plays an important role in every animal species when it comes down to finding a mate; in contrast to what is often said, it is not merely a superficial attribute, but an indicator that reveals, at a glance, crucial information about the state of youth, health and fertility of a potential mate — which are, in turn, signs of that indefinable but indispensable ‘genetic quality’ that every organism wishes for its progeny. It is not a coincidence that most facial make-up products are based on reddish or pinkish pigments, selected to imitate the colour provided by a generous blood flow in the skin, which is an undeniable indicator of good health.

Numerous studies, for their part, have proved facts that can seem disquieting, or even offensive, in the context of modern society, such as that more attractive people tend to enjoy better health and greater fertility than less attractive people, or that considering certain facial features as attractive is more than a cultural construct. In one particular study, both African and European people found the same Asian women attractive. This suggests that physical beauty is more a biological quality than a cultural one. Although the cult of beauty is considered today as superficial, and perhaps pernicious, it is not difficult to imagine the utility that it probably had for our distant ancestors.

More than 150 years ago, Charles Darwin himself was already perplexed by the role of beauty in the natural world, which was not easily explained. The bright forms and colours displayed by animals with the aim of finding a mate not only imply most valuable energy expenditure, but also make the animal an easy prey, as illustrated by the extravagant plumage of many tropical birds. In order to explain the evolutionary importance of beauty, Darwin conceived the concept of ‘sexual selection’. As opposed to the well-known natural selection, by which only those individuals that are fit enough to reach maturity are able to pass their genes on to the next generation, sexual selection implies that certain individuals — the more attractive ones — have the chance to mate more often than others.

Although Darwin was right, sexual selection was neither proven nor understood in depth until the beginning of this century. This is due, in part, to the fact that understanding the aesthetic preferences of each animal requires an exhaustive study of its sensory capabilities. In fact, the incredibly varied peculiarities of sight, smell, touch, taste and hearing of each species are fundamental factors in its perception of sexual attractiveness. A clear example are the cichlids that live in the waters of Lake Victoria, in Africa. These bony fish gather in two distinct populations that, despite belonging to the same species, have stopped mating with each other due to discrepancies in the selection of reproductive mates — that is, in what individuals of each population consider ‘attractive’. The divergence between both groups is such that it even affects the type of proteins that their eyes employ for perceiving different colours, called photoreceptors. One of the cichlid populations lives in shallow waters, where the sunlight penetrates in a large variety of colours. These fish can perceive a wide range of tonalities, and males — the sex that usually puts all its charm on display to attract a mate — exhibit designs of bluish hues in their scales; it is possible that this constitutes a strategy for hiding from the birds that forage near the surface, while remaining visible to the females, who have no problem distinguishing their adornments. The second cichlid population resides in deeper waters, safe from the birds’ sight. Here, light acquires a reddish hue, which fish perceive thanks to specific photoreceptors; in consequence, the males’ scales present scarlet designs, which are readily spotted by the females. Despite living at a few meters’ distance from each other, these populations do not intermix, because the females in each one prefer — and select — the males they can see more easily. If these two fish groups continue to diverge, the accumulation of differences between them will give rise to two different species. The cichlids’ case invites us to consider that adaptations in animal sensory systems, sparked by environmental needs, could exert a selective pressure capable of causing the inception of new species in short periods of time.

However, this does not clarify the apparent relationship between physical appearance and ‘genetic quality’. It is frequently difficult or impossible to link beauty traits to an evident selective advantage; in fact, in many cases the sumptuous decoration of the suitors should be a disadvantage in the presence of more discreet organisms, which are harder to spot for their predators. The so-called ‘handicap hypothesis’ tries to explain this incongruity by suggesting that the presence of flashy adornments may act as a sign that the bearer has enough strength or health to bear up under the negative effects of these traits — which, ironically, makes it more attractive for the opposite sex. On the other hand, some scientists believe that the traits associated with beauty are also related to other signs of health and resistance. One illustration of this is given by the common yellowthroat warbler, a little North American bird whose females show preference for those males having either large, bright yellow pectoral feathers, or a large black mask around the eyes, depending on the region in which they live. Curiously, both traits are linked to the same genetic characteristic: a greater variation in the genes of the major histocompatibility complex, a key component of the immune system. Greater diversity in these genes enhances resistance against various infection types. This suggests that both the yellow feathers and the black masks, although they do not confer greater resistance to the male, offer information about it to the females, which explains why the latter pay attention to one or other trait in a rather indiscriminate way. It is the information encoded by them that matters in the eyes of sexual selection.

The male yellowthroat warbler displays yellow feathers and a black mask as a lure to females. (Credit: Distant Hill Gardens/Flickr.)

In this regard, human beings are not very different from the rest of animals. Beauty exerts huge power over our civilisation, a power with an indubitable biological — besides cultural — basis. Psychologists have demonstrated how our conscience and our subconscious react to beauty: a study revealed that, if people are given a button that allows them to see a beautiful face for a longer time, they will push it unceasingly, just as a laboratory mouse would do to obtain food or narcotic substances. That moment when we cannot look away from a beautiful face or body, no matter how long we had seen it already, does not sound unfamiliar in the least. Not even babies can help looking more frequently at more attractive faces. The vision of beauty triggers a response in the brain’s self-reward system, fuelled by dopamine and associated also with stimuli such as sex or drugs. If our species is obsessed with beauty it is because this is, from a biological point of view, pleasant and addictive. A negative consequence of this effect is positive discrimination towards nicer-looking people; it has been proven, for instance, that more attractive students receive better grades, and more attractive defendants, milder sentences. Besides feeling the need to protect those people who attract us, we subconsciously tend to presuppose that they are good people, as well as to stress their positive virtues above the negative. Our sympathy for beauty, through our own subconscious, affects our world in an imperceptible but omnipresent manner. Everything seems to indicate that, at some point in our evolution, physical and moral beauty were irremediably intermixed — or maybe the latter was born from the former. Hence thinkers like the writer Oscar Wilde have toyed with the idea that beauty might be even beyond all moral judgement, might be worthy of existing just by itself, requiring no justification and no purpose other than that of being admired.

Some scientists and philosophers, on the other hand, have proposed that beauty is not only something that transcends cultures due to a biological foundation, but that there exists a so-called ‘objective beauty’. For them, this is the reason that humans can find pleasure in appreciating a flower, a sunset or a symphony. Flowers, for example, despite having evolved to attract insects, have always fascinated man. The images of galaxies and nebulae captured by space telescopes, unseen by anyone before, radiate a beauty that transcends any taste or instinct, a universal beauty that does not correspond to any fad or sexual desire, and which, however, only a human being is capable of noticing. For those who defend objective beauty, there are aesthetic truths that are as certain and objective as any physical law. This abstract beauty may be responsible for our deep love of art, which stretches back to the dawn of humanity, and which today generates more than fifty billion dollars annually.

With a closer look, it becomes evident how deeply embedded beauty is in our world. Everything around us has qualities that we can appreciate as attractive or beautiful, from other people to natural landscapes, to man-made objects and structures designed to couple elegance and utility or, simply, as a pure receptacle for beauty. Beauty surrounds us from so early on in life that we barely notice it, but the obsession that it provokes in us shape us as living beings and as civilisations, both for better and for worse. We are, inevitably, unconscious and conscious slaves, consumers and creators of beauty, and this is, in itself, part of what makes us humans. Maybe Oscar Wilde was right in saying that beauty need no reason for existing other than itself. What would have become of this world, of us, without it?

Special thanks are due to Isobelle Bolton for her invaluable help with translation.

Wald, C. The aesthetic brain. Nature (2015).
Maxmen, A. Come mate with me. Nature (2015).
Q&A Karl Grammer: Innate attractions. Nature (2015).
Q&A David Deutsch: Objective beauty. Nature (2015).
Wald, C. Beauty: 4 big questions. Nature (2015).