From the Book, THE AGE OF INSIGHT by Eric R. Kandel. Copyright © 2012 by Eric R. Kandel. Reprinted by arrangement with Random House, an imprint of The Random House Publishing Group, a division of Random House, Inc. All rights reserved.
Our attraction to faces, and particularly to eyes, appears to be innately determined. Infants as well as adults prefer to look at eyes rather than other features of a person’s face, and both infants and adults are sensitive to gaze. The direction of a person’s gaze is very important in our processing of the emotions displayed by that person’s face, because the brain combines information from gaze with information from facial expressions.
Reginald Adams from Pennsylvania State University and Robert Kleck from Dartmouth College have found that a direct gaze and an expression of happy emotion facilitate the communication and processing of joy, friendliness, and approach-oriented emotions presumably because, as Uta Frith has found, only direct gaze recruits the dopaminergic reward system. In contrast, an averted, sad, or fearful gaze communicates the avoidance-oriented emotions of fear and sadness. Although gaze and facial expression are processed together, other aspects of beauty, such as gender and age, are processed independently.
In a biological experiment designed to examine the neural correlates of beauty—that is, the mechanisms in our brain that account for our sense of beauty—John O’Doherty and his colleagues explored the role of the smile. They found that the orbitofrontal (ventrolateral) region of the prefrontal cortex, the region that is activated by reward and thought to be the apex of the representation of pleasure in the brain, is also activated by attractive faces. Moreover, the response of this region is enhanced by the presence of a smile.
Semir Zeki of University College London found that the orbitofrontal region is also activated in response to other, subtly pleasurable images that we interpret as beautiful. Zeki conducted a study in which he first asked volunteers to examine a large number of portraits, landscapes, and still lifes. He then had the volunteers classify the art, irrespective of category, on the basis of whether they found the painting beautiful or ugly. Zeki imaged the volunteers’ brains as they looked at the paintings and found that all of the portraits, landscapes, and still lifes, regardless of whether the viewer saw them as beautiful or ugly, lit up the orbitofrontal, prefrontal, and motor regions of the cortex. Interestingly, however, the pictures ranked most beautiful activated the orbitofrontal region most and the motor region least, whereas the pictures ranked ugliest activated the orbitofrontal region least and the motor region most. The activation of the motor region of the cortex suggests to Zeki that emotionally charged stimuli mobilize the motor system to be prepared to take action to get away from the stimulus in the case of ugliness or threat and toward the stimulus in the case of beauty or pleasure. Indeed, as we know, fearful faces also activate the motor region of the cortex.
Beauty does not occupy a different area of the brain than ugliness. Both are part of a continuum representing the values the brain attributes to them, and both are encoded by relative changes in activity in the same areas of the brain. This is consistent with the idea that positive and negative emotions lie on a continuum and call on the same neural circuitry. Thus, the amygdala, commonly associated with fear, is also a regulator of happiness.
For every evaluation of emotion, from happiness to misery, we use the same fundamental neural circuitry. In the case of art, we evaluate a portrait’s potential for providing new insights into another person’s psychological state. This discovery, by Ray Dolan and his colleagues at University College London, was based on a set of studies in which volunteers viewed faces whose expression of sadness, fear, disgust, or happiness was gradually changed from low to high intensity.
Dolan and his colleagues set out to explore how the amygdala, the brain’s orchestrator of emotions, responds to happy or sad faces; specifically, they studied how the amygdala responds to emotionally charged faces that are presented briefly and can therefore only be perceived unconsciously, and how it responds to such faces presented more slowly, allowing conscious perception. Dolan found that the amygdala and the fusiform face area of the temporal lobe respond to the image of a face regardless of the emotion being displayed and regardless of whether the image is perceived consciously or unconsciously. In a similar vein, Dolan found, using PET imaging studies, that when people view faces that express either fear or happiness, seeing progressively more fearful faces increases activity in the amygdala, whereas seeing increasingly happy faces decreases activity.
How can it be that the amygdala is recruited for different emotions, including different facial expressions of emotion? Do the same cells in the amygdala respond in opposite ways, or are different populations of nerve cells recruited for different emotions? Advances in modern biology have underscored Darwin’s insight that we can learn about the foundations of human mental life by studying simpler animals. Not only are genes conserved through evolution, but bodily form, brain structures, and behavior are conserved as well. It is therefore likely that we share with other animals some of the basic neural mechanisms of fear and pleasure.
This has proven to be true. Working with monkeys, Daniel Salzman at Columbia University examined individual cells in the amygdala and found that specific groups of neurons respond more strongly when visual stimuli are paired with rewards than when they are paired with punishment. Thus, they indicate that changes in both the positive and negative value of an image affect the activity of the amygdala and that they do so by recruiting different groups of neurons.
The beholder may go beyond processing emotions and experiences in response to art and actually try to infer what someone else is thinking. This skill derives from the brain’s ability to generate a theory of mind—that is, to form the idea that another person has his or her own ideas, intentions, plans, and aspirations that are independent of our own. Failure to read another person’s intention correctly is central to fiction and was pioneered by Jane Austen, whose novels often involve misperceiving romantic intention. Arthur Schnitzler’s use of the interior monologue enables his readers to inhabit two or more mental worlds at the same time.
Our response to art stems from an irrepressible urge to recreate in our own brains the creative process—cognitive, emotional, and empathic—through which the artist produced the work. This creative urge of the artist and of the beholder presumably explains why essentially every group of human beings in every age and in every place throughout the world has created images, despite the fact that art is not a physical necessity for survival. Art is an inherently pleasurable and instructive attempt by the artist and the beholder to communicate and share with each other the creative process that characterizes every human brain—a process that leads to an Aha! moment, the sudden recognition that we have seen into another person’s mind, and that allows us to see the truth underlying both the beauty and the ugliness depicted by the artist.