This is why we can't have nice things.

Beauty Evades the Clutches of Materialism

Evolution News & Views March 27, 2013 5:02 AM

Evolutionary materialists must believe, at some level, that the experience of beauty can be reduced to actions of neurons in the brain. This would bring beauty into the purview of neuroscience -- a subtopic known as neuroaesthetics -- that could be probed and explained with the tools of science. If the materialists are right, the Prince doesn't really love Cinderella because she is beautiful. She is beautiful to him because he loves her, and he loves her because certain neurons fire in response to a stimulus. Beauty is "merely" an experience in the physical brain, not an external reality.

Bevil R. Conway, a neurobiologist associated with Wellesley College and Harvard, and his colleague from Harvard's Department of Music, Alexander Rehding, evaluated the pretensions of neuroaesthetics to bring beauty under scientific analysis. Their conclusions were published in PLoS Biology in an open-access paper, "Neuroaesthetics and the Trouble with Beauty." They wrote as proponents of neuroaesthetics, not critics of it; but in the end, they found materialism wanting.

As with any good paper, they began with definitions and distinctions.

Here we consider what questions this new field is poised to answer. We underscore the importance of distinguishing between beauty, art, and perception -- terms often conflated by "aesthetics" -- and identify adjacent fields of neuroscience such as sensation, perception, attention, reward, learning, memory, emotions, and decision making, where discoveries will likely be informative. (Emphasis added.)

Conway and Rehding attempted to further clarify what is meant by beauty by providing a historical survey of attempts by various artists, poets and philosophers, beginning with Kant, to define beauty in its relation to the brain or mind. Gustav Fechner, an 18th-century psychophysicist, was one of the first to attempt building a science of beauty from the ground up by locating universal principles pleasure or displeasure elicited from art. "He would doubtless be interested by technological developments in neuroscience that have revealed the operations of neurons at cellular resolution and have enabled us to peer almost unnoticed into each other's working brains," the authors write. Whether those tools would lead to an understanding of beauty is another question.

The upshot of their historical survey, ending with modern neuroscience, is that no consensus exists for the definition of beauty:

While each of these theories is respected, not one is universally accepted. Partly this diversity of opinions is connected to the different functions that beauty holds within various philosophical systems, being sometimes viewed in connection with epistemology or with ethics. One goal of neuroaesthetics is to get to the bottom of the problem of artistic beauty. How can this be accomplished?

It would seem neuroscientists can't approach a subject they cannot define. Beauty is not just a "deeply moving" experience:

Experiences of beauty are often deeply moving, and their importance to the human condition invites a neuroscientific explanation. But while deep emotional reactions are often associated with beauty, being moved does not always indicate an instance of beauty. Consider hearing about a disaster, celebrating a sports victory, or smelling a long-forgotten scent. These experiences are better described as "sympathy," "elation," and "memory," rather than experiences of beauty. If neuroaesthetics is to be concerned specifically with beauty, it must draw distinctions between mechanisms for such disparate reactions.

Note the materialistic bias in that first sentence. They say that beauty, because of its importance, "invites a neuroscientific explanation." Why should that be, unless science has become scientism? What if science is incapable in principle of approaching matters of the inner mind?

Conway and Rehding emphasize that art does not equal beauty, pointing to a particularly grotesque example. Yet many neuroaesthetic studies assume they are one and the same. "Zeki, for instance, argues that the power of Alexander Calder's sculptures derives from the black-and-white moving parts, potent activators of the brain's motion-processing center." One cannot assume, though, that activating motion sensors in the brain equates with an experience of beauty. "An Alexander Calder sculpture may consist of optimal stimuli for the brain's motion center, but this aspect of the work does not make it beautiful," they admit. Furthermore, beauty varies across cultures, and even within cultures over time. One cannot universalize one's own experiences of beauty to the rest of mankind.

Nevertheless, since neuroscience can identify areas of the brain involved with pain, pleasure, identification of external phenomena, evaluation of options, memory, emotions, and decision-making, the authors feel that scientific findings along these lines can provide a heuristic guide for neuroaesthetics.

Below we argue that a successful neuroaesthetics will include the study of each of these stages of processing as they relate to handling, encoding, and generating aesthetic experiences, rather than an attempt to derive a single universal neural underpinning of what constitutes beauty.

Even so, the play's the thing -- not the activity of the stagehands. Let's see how far their hopeful heuristic takes them. It isn't long before Darwin enters, stage right:

One approach commonly included under the umbrella of neuroaesthetics involves examining art objects in museums. Here the complication of establishing "beauty" is obviated by treating artworks as products of a massive empirical experiment. By analogy with evolutionary theory, the assumption is that the tiny number of works that survive the selective pressures exerted by collectors, cultural institutions, and fads are enriched for the strength of their effects on the nervous system. Using this approach, studies have uncovered various artistic strategies reflecting fundamental operations of the neural mechanisms for sensation and perception.

That analogy with natural selection was poised to fail. Art critics use intelligent design, not unguided, mindless processes, to make their selections. The authors admit as much: "It is an open question whether an analysis of artworks, no matter how celebrated, will yield universal principles of beauty." They point to researchers who tried to identify universal principles of attraction with the Golden Ratio, or with locations of eyes in paintings, or female body ratios. Nothing there, either: "Depictions of reproductive fitness can be sexually appealing and contribute to aesthetic appeal, but such depictions are, again, neither necessary nor sufficient for beauty." In short, they find studies of responses to art too subjective for a science of neuroaesthetics.

Having cleared the field of unproductive pathways, Conway and Rehding looked to the tools of modern neuroscience, such as functional MRI (fMRI). What lights up in the medial orbitofrontal cortex (mOFC) during an experience of beauty? Can that help construct a science of beauty from the ground up? Before "brandishing" fMRI as science's skeleton key, researchers need to overcome several experimental challenges.

Four experimental-design challenges surface. First, the options are necessarily restricted, and might not include a truly beautiful choice -- the study design tests preferences, not beauty. Second, different subjects likely interpret the instructions in radically different ways. Third, the use of different stimulus sets in different subjects makes it difficult to control for differences in low-level stimulus features, which likely drive different patterns of neural activity. And fourth, the experiment requires that a given object retain a fixed preferred status, and one that is not modulated by context, which we know is unlikely. As Fechner showed, mere exposure changes judgments of preference in favor of the familiar option. Brandishing fMRI does not circumvent these problems.

And that's just for starters. More serious conceptual challenges remain -- some that make fMRI answer different questions than the one of interest:

Moreover, fMRI has cripplingly low spatial and temporal resolution, and the relationship between the measured signal and underlying neural activity is indirect. In addition, fMRI experiments often only report regions that show differential activation between pairs of conditions (e.g., response to beautiful greater than response to ugly); such an analysis is misleading in situations in which all brain regions show significant but slightly different levels of activity for the different conditions, as is likely the case in considerations of beauty. Brain imaging provides a blurry, although seductively glossy, view of brain function. And by finessing a definition of beauty, these sorts of studies sidestep what is at the heart of our interest in beauty: the connection between physical stimuli, specifically those crafted by human hands, and our response.

When considering the medial orbitofrontal cortex (mOFC), more challenges surface. Beauty involves more than the mOFC, and other experiences besides beauty activate the mOFC. Relating the experience of beauty to the mOFC is, therefore, another source of blurriness: "Ascribing responses of the mOFC to experiences of beauty is premature; many experiences depend on these processes without being beautiful." For empirical support, consider that strokes in the mOFC do not necessarily correlate with an inability to experience beauty; in some instances, they even promote it.

Facing challenges on every side, Conway and Rehding seek to identify "What Questions Can Neuroaesthetics Answer?" Here, in one of their most potent paragraphs, they pose cogent questions, asking whether "rational reductionist" science is even capable in principle of explaining the experience of beauty.

Inspired by the power of polling, in 1994 a pair of artists, Komar and Melamid, set out to determine "USA's most wanted painting." The painting was formulated on the basis of a thousand people's responses to questions of their favorite color, favorite setting, and favorite subjects. The resulting painting is absurd, showing that a composition with everything that people find beautiful does not make a beautiful painting. Rational reductionist approaches to the neural basis for beauty run a similar risk of pushing the round block of beauty into the square hole of science and may well distill out the very thing one wants to understand. There is a popular conception of beauty as a fixed attribute of objects, a notion that much of current neuroaesthetics depends upon. But there is a distinction between abstract notions of beauty and our experience of it--consider a specific example in which you have experienced beauty. Beauty is an analog, not binary, condition that varies in complex ways with exposure, context, attention, and rest--as do most perceptual responses. In trying to crack the subjective beauty nut with scientific, objective information, we also run the risk of fueling a normative, possibly dangerous campaign through which science is required to valorize our experience. Should we deny someone's experience of beauty if the mOFC is not activated? Obviously not. But the question underscores the danger of reverse inference, a technique used in brain-imaging studies which posits that activation of a brain region indicates the presence of a stimulus. Reverse inference is almost always invalid because single brain structures almost never regulate single specific experiences.

Wow! That's devastating. Add to it the fact that there is no universal definition of beauty, and all that is left is a series of questions -- not answers.

Insofar as beauty is a product of the brain, correlations between brain activity and experiences of beauty must exist. At what spatial scale, and within what brain regions, do we find these correlations? What functions do the brain regions implicated serve in other behaviors? What signals during development and experience are responsible for wiring up these circuits? And perhaps most critically, how does the activity of these circuits integrate across modalities and time to bring about the dynamic, elusive quality of beauty? To address these questions, the field is thirsty for carefully conducted experiments that distinguish responses to beauty from those involved in more general value-based decision tasks such as self-evaluation or selecting a juice for lunch. But any such experiments are caught on the same stubborn thorn -- the lack of a cogent, universally accepted definition of beauty. One should not always demand a precise definition to make headway, but it might turn out that the philosophers' disagreement is symptomatic: maybe there is no universal concept beyond the human capacity to experience beauty.

In their final two paragraphs, Conway and Behding basically "give up" on the idea that science can explain beauty. All that remains is for neuroscientists to perform the kind of experiments done with monkey brains: use fMRI to study attention, decision-making, and reward. Maybe some of those brain regions correlate with the experience of beauty, but science might never know, the two wishful materialists confess.

There may well be a "beauty instinct" implemented by dedicated neural machinery capable of producing a diversity of beauty reactions, much as there is language circuitry that can support a multitude of languages (and other operations). A need to experience beauty may be universal, but the manifestation of what constitutes beauty certainly is not. On the one hand, a neuroaesthetics that extrapolates from an analysis of a few great works, or one that generalizes from a single specific instance of beauty, runs the risk of missing the mark. On the other, a neuroaesthetics comprising entirely subjectivist accounts may lose sight of what is specific to encounters with art. Neuroaesthetics has a great deal to offer the scientific community and general public. Its progress in uncovering a beauty instinct, if it exists, may be accelerated if the field were to abandon a pursuit of beauty per se and focus instead on uncovering the relevant mechanisms of decision making and reward and the basis for subjective preferences, much as Fechner counseled. This would mark a return to a pursuit of the mechanisms underlying sensory knowledge: the original conception of aesthetics.

C.S. Lewis fans will find strong support for his "argument from joy" in the consternation of these materialists. An experience of joy (or delight in something beautiful) transcends the merely physical and enters the realm of the numinous -- realities that surpass scientific comprehension.