In one of the most famous definitions of beauty, the 18th century Anglo-Irish philosopher Edmund Burke wrote that “Beauty is, for the greater part, some quality in bodies acting mechanically upon the human mind by the intervention of the senses”. There are interesting aspects of this definition that the relatively new field of neuroesthetics is well suited to address.
It is best to begin by describing what neuroesthetics is not. It is not, as some have imagined, a discipline that is trying to explain beauty or works of art. Rather, it is an 
experimental discipline which finds inspiration in works of art, as well as in humanistic debates, to gain insight into brain mechanisms that are the basis of some of the most profound human experiences. The experience of beauty is but one of these, and as any reading of one of the most influential texts in Western culture – The Symposium by Plato – shows, it is intimately linked to that of desire and love, and also to the impulse to create, making these also areas of enquiry for neuroesthetics. It is not “reductionist”, as some accuse it of being, or at least not any more so than other areas of science, which try to study the parts to understand the whole. Nor is it any more “reductionist” than some artistic schools, for example the Neo-Plasticism of Piet Mondrian and his followers, who wanted to establish what was the common constituent of all forms by “reducing” (Mondrian’s terms) all forms in the world to their basic constituents (the vertical and horizontal straight line) or than the efforts of Cézanne to reduce the naturalistic world into the cube, the sphere and the cone.
Neuroesthetics has been aided in its quest by the development of powerful new techniques to study the brain activity that correlates with particular experiences, especially that of brain imaging. These methods not only locate the activity in the brain when we have particular experiences or undertake particular tasks, but can also quantify the activity there. This is not to say that the brain areas so localized act in isolation, unconnected with what the rest of the brain does. It simply emphasizes that there are areas of the brain which are especially important for certain experiences and that, in their absence, such experience are compromised or become impossible.
Perhaps one of the most exciting discoveries in this area relates to the brain activity that correlates with our experience of beauty. One will notice from the definition of Burke that he speaks of beauty in the abstract sense, without reference to its source, that is to say whether it is musical or visual or any other kind of beauty. And it is very interesting to note that, reflecting this, neuroesthetic studies have shown that the experience of beauty correlates with activity in an area of the emotional brain, located in the medial (inner) part of the frontal lobe, above the orbits of the eye, and hence known as the medial orbito-frontal cortex, or mOFC for short. The area is active whenever an individual experiences something, regardless of whether it is a painting or a musical excerpt, as beautiful, implying that beauty is abstracted in the brain, just as Burke implied in his definition.
The mOFC is the site of heavy dopaminergic activity, dopamine being the so-called “feel good” neurotransmitter, which has in general been found to be an important constituent of brain areas whose activity correlates with the experience of pleasure and reward. Perhaps future neurobiological studies will be better able to tease apart the brain sites whose activity correlates with these obviously linked but also different experiences. They may also be able to give a more detailed account of the neurochemistry that correlates with these experiences. For dopamine is neurochemically intimately linked to other neurotransmitters, such as serotonin, oxytocin and vasopressin and how they act in concert during these experiences remains unknown. Of course, there are some who are skeptical that emotions such as those of love and desire and beauty can be reduced to what they call “chemical” events. The term “reduced” is theirs, not ours. We rest with the belief that there are very important chemical bases to these experiences, and it is very interesting for us to describe these in quantitative and qualitative terms. Indeed, current work in America has shown that, at least in voles, bonding between individuals is strongly regulated by neurotransmitters and it is entirely plausible to suppose that the experience of love in humans, as well as the experience of beauty, is also regulated by brain chemistry, which is not the same as saying that brain chemistry can explain every aspect of the experience of love and beauty.
The next point to emphasize is that the experience of beauty of is not uniform between individuals. Some may prefer a given painting, which others may not like and some may have a strong preference for a musical experience which others may dislike. But whenever an individual experiences a work of art as beautiful, the neural correlate is an increase of activity in the mOFC. This means that at an elemental, biological, level the experience of beauty is not tied to any particular culture or education. It is, instead, an experience that we are all capable of. In these studies, of course, neuroesthetics has separated the experience of art from the experience of beauty and concentrated on beauty alone. After all, ever since Marcel Duchamp sent a urinal, which he euphemistically called The Fountain, as an exhibit to an art exhibition, it has been traditional to separate the two.
It is also critical to emphasize that the activity in the mOFC which correlates with the experience of beauty can be quantified. In other words, the activity is greater for works which are declared to have been experienced as more beautiful than for works which have been declared as being experienced as less beautiful. This, for the first time, answers a dominant theme in the history of art – can aesthetic judgments ever be quantified? They can, but in terms of brain activity. At the same time, one of the requirements of science – quantification – is also satisfied.
Centuries of debates in the humanities have addressed the question of whether there is a single characteristic or a single set of characteristics that qualify an object as beautiful, without any conclusion. Neurobiology also addresses this questions, but in neural terms. Its answer is that there is indeed a single characteristic to all that is apprehended as beautiful, and that is that the experience correlates with activity in a well defined part of the emotional brain, the mOFC. That is the only characteristic that so many diverse works of art and music seem to have in common. Hence, somewhat surprisingly, an age old question in the humanities finds an answer through neurobiology, though perhaps an unexpected one.
But in addition, neuroesthetics can address the question of why there cannot be a single attribute or set of attributes that can characterize an object as beautiful. It lies in a description of the “intervention of the senses” which is a cardinal part of Burke’s definition. For intervening between the objects we view or music that we hear are the sensory areas of the brain. Research over the past 40 years have charted the organization of these areas in unprecedented detail and shown that the visual brain, for example, consists of many different areas which process different attributes of the visual world in parallel and more or less independently. Hence, colour is processed in separate areas from visual motion, which is processed in separate areas from those processing faces or human bodies. All of this adds to a functional specialization of the visual brain. Current neurobiological research tends to show that each one of these areas has specific visual configurations that are preferred. From which it follows that there cannot be a single configuration that will satisfy all of the visual areas. The nearest way of approximating to a single characteristic to qualify an object as beautiful is to have a work which emphasizes heavily a single attribute – for example faces or visual motion – and de-emphasizes all else.
There are some who dread the approach of learning more about the neural correlates of some of our most profound experiences, indeed the experiences that are so well developed in humans that they almost become characteristic of the human race. I know of professors in the humanities who have written that they just do not want to know what happens in their brain when they are moved by music or by sight. It reminds me very much of the two Aristotelian professors of philosophy, one at Padua and the other at Pisa, who refused to look through Galieleo’s telescope when invited to do so, or who looked but did not see what Galileo had seen. The verdict of history has not been in their favour. And I suppose that the verdict of history will always be against those who favour ignorance over knowledge. More than that, the combination of modern technology with one of the great human characteristics – curiosity – will ensure that the experiences that I write of here will continue to be explored by neuroesthetics.
But I do have some words of comfort for those who fear neuroesthetics. They come from Pope John Paul II who, when beatifying the Danish anatomist Niels Stensen, spoke warmly of the wonders of what research reveals, saying, “All that we know is beautiful, but more beautiful still is that which we do not know”.
Semir Zeki is Professor of Neuroesthetics at University College London. He pioneered the study of the higher visual areas of the brain. More recently, he has expanded his work to enquire into the neural correlates of aesthetic and artistic experience. In addition to his published scientific papers, he is author of A Vision of the Brain, Inner Vision: an exploration of art and the brain, and Splendours and Miseries of the Brain. He is a Fellow of the Royal Society and a Foreign Member of the American Philosophical Society. He was awarded the King Faisal International Prize in Biology in 2004 for his work on the brain, and founded the Institute for Neuroesthetics in London and California.
