Introduction: Representative Foci in Neuroaesthetics—Subjectivist, Objectivist, and Interactionist Perspectives

Abstract

Welcome to Neuroaesthetics! This exciting, new, interdisciplinary field brings together subjects as seemingly far apart as neurobiology and art history and puts them in dialogue with one another. This Introduction is intended to briefly provide insights into some recent scientific works and methods in neuroaesthetics and to whet your appetite for the lectures and lab work that will follow.

Welcome to Neuroaesthetics! This exciting, new, interdisciplinary field brings together subjects as seemingly far apart as neurobiology and art history and puts them in dialogue with one another. This Introduction is intended to briefly provide insights into some recent scientific works and methods in neuroaesthetics and to whet your appetite for the lectures and lab work that will follow.

The disciplinary field of ‘Neuroaesthetics’ was mapped in 1999 by the neuroscientist Semir Zeki, who is a professor at the Wellcome Centre for Human Neuroimaging, in the Department of Imaging Neuroscience at University College London. Hence, it is a relatively new discipline and one which lies at the intersection between cognitive psychology, neurobiology, and art. Neuroaesthetics uses models derived mostly from cognitive psychology and modern brain scanning techniques in order to study how the brain responds to aesthetic stimuli. Zeki’s main interest is in primates' visual brain systems. From 1994 onwards, his studies also included the neural basis for the aesthetic appreciation of art, and in 2001, he founded the Institute of Neuroaesthetics, the first of its kind in the world, at University College London.

There is also another great neuroscientist who should be regarded as a founder of our discipline, namely Vilayanur S. Ramachandran, who is a professor in neurobiology at the Center for Brain and Cognition, University of California, San Diego. Together with William Hirstein, he formulated what he calls the ‘eight laws of aesthetics’. We will not go through each of these laws but focus instead on only one in more detail, the one that provides a suitable starting point for discussing the intersections of objective and subjective studies of art.

According to Ramachandran and Hirstein (1999), art will always tend to be a sort of exaggeration of reality. As arguments in favour of their thesis, they draw on artefacts as diverse as the 28,000 year-old so-called Venus of Willendorf, Indian female temple sculptures from the ninth century C.E. showing an exaggeration of female beauty, and modern caricatures, such as one of the American ex-president Nixon, which, as pointed out by Ramachandran, is more Nixon-like than the photo of the ex-President. Ramachandran labels this exaggeration of form in art as the peak shift effect. Interestingly, he finds the same mechanism at work in the animal world. There is, for instance, an interesting experiment on seagulls feeding their chicks. The beak of the seagull, which is yellow, has a red stripe on it, on which the chickens peck when they beg for food. If a yellow stick with a red patch on it is placed into the nest, the chicks will peck also at this stimulus. Now, if another stick with, say, three red stripes is placed into the nest, the chicken will peck even more vigorously. The stick with three red stripes appears to be a ‘Picasso in the world of chicks’, says Ramachandran: being trained to respond to one particular stimulus will lead to a preference for an exaggerated or peak shifted-version of the same stimulus. This is, of course, interesting also in an evolutionary perspective on art.

Ramachandran’s point is that art will always tend to exaggerate reality. This leads to a most fundamental question in aesthetics: What is beauty? The question debated for at least 2500 years has been given a wide variety of answers. One can broadly distinguish three main positions:

• The objectivist view, which dates to Plato, maintains that beauty is a property of an object that produces a pleasurable experience in any suitable perceiver.

• The subjectivist view dates to the Greek philosophers known as the Sophists. They maintained that beauty is in the eye of the beholder, which means that taste cannot be debated.

• The interactionist view maintains that beauty is grounded in the processing experiences of the perceiver that emerge from the interaction of stimulus properties and the perceivers’ cognitive and affective processes. Hence, this position appears as a golden middle between the objectivist and subjectivist positions.

The Objectivist View

Objectivist criteria for beauty include balance, contrast and clarity, symmetry, and proportions. Among the first instances of intended symmetry in hominid evolution are the countless hand axes produced within the Acheulean stone industry, appearing about 1.7 million years before the present (BP) and continuously produced until almost 200,000 years BP in a wide range of geographical locations. They differ from the previous Oldovan axes, first documented in Olduvai Gorge, Tanzania, by their conspicuous mirror symmetry along the mid-axis of the teardrop form.

As the symmetry of late Acheulean tools goes far beyond functional requirements, it has been assumed that an increased cognitive sophistication of hominines must have taken place during this period (Hodgson, 2009). An ‘awareness toward symmetry itself tended to now come to the fore’ (Hodgson, 2011, p. 39). Throughout the history of art, we find that symmetry is one of the leading principles. A surprising example is portrait painting: in 3/4 profile portraits, the symmetry line, in the majority of cases, passes through one of the eyes. This holds even for Picasso’s cubist paintings. Talking about portraits, it is also remarkable that almost all fifteenth c. portraits are in profile, for example, the self-portrait of Albrecht Dürer, while all depictions of Christ, as the Holy Face, are en face. In portraits of The Holy Face, the gaze is frontally directed towards the beholder; hence, the face has an almost perfect symmetry. This strongly indicates that en face and symmetry were the only acceptable ways to represent Christ in this period of art history.

The question can be raised, as indeed we do in a research project on ‘Symmetry in Art and Science’, in which I cooperate: Is a symmetric face associated with divinity, and is it so because of qualities that lie in the symmetric form itself? Hence, does our biologically determined preference for symmetry imply that holiness must be represented en face, i.e. in the most symmetric manner? Or is it just a convention that determines that Christ shall be represented en face? Our research is based on a survey questionnaire where subjects look at faces with different orientations and with different gaze directions. Faces here presented are from the busts of generals who took part in the manoeuvres of Garibaldi (photographs by Lasse Hodne, Figs. 1, 2, 3 and 4). Each photo illustrates an experimental condition.

Fig. 1

(Source Lasse Hodne, 2023)

One of Garibaldi’s generals en face with gaze directed at the viewer

Fig. 2

(Source Lasse Hodne, 2023)

One of Garibaldi’s generals en face with gaze to one side

Fig. 3

(Source Lasse Hodne, 2023)

One of Garibaldi’s generals 3/4 profile looking in same direction as head orientation

Fig. 4

(Source © Lasse Hodne)

One of Garibaldi’s generals 3/4 profile gazing at you

Subjects are asked to read a list of adjectival allegations in a questionnaire, five positive and five negative, and rate them from 0 to 10 according to how much they agree with them (Fig. 5). Examples of adjectival statements used are given in Fig. 6.

Fig. 5

(Source Lasse Hodne, 2023)

Adjectival statements rated by participants who looked at Figs. 1, 2, 3, and 4

Fig. 6

(Source Lasse Hodne, 2023)

Faces gazing at you

So far, our results seem to indicate that:

• 1. The en face gazing at you is more authoritarian, but also more credible, more caring, more trustworthy, more harmonic, and more including (Fig. 6).

• 2. The profile looking at you is more intimidating and monitoring, not so when looking away (Fig. 7).

  Fig. 7

  

  (Source Lasse Hodne, 2023)

  Faces looking away from you

Our results, in fact, indicate that the frontal Holy Face is more than a convention. That is, it seems reasonable to suggest that there exist deeper biological and evolutionary reasons for such a convention and preference for facial symmetry.

Following the objectivist view, we can ask: what about the golden ratio?

Modern research, such as Di Dio et al.’s fMRI study (2007), has significantly improved our knowledge on whether golden beauty has a real and objective impact on the beholder. But let us start with a brief review of the first studies related to this topic in the late nineteenth century, those of the German physiologist Gustav Theodor Fechner, published in the year 1876. Fechner demonstrated that subjects rated geometrical figures with golden proportions as more beautiful than other figures. The golden rectangle form has been given the highest rating: 35% of the subjects, which were Fechner’s students, rated the rectangle with golden proportions as the most beautiful. The ratio between the width and the length of the rectangle was 0.618, which is the golden ratio.

However, it has been strongly questioned whether a biological and inherited mechanism alone can explain these features, or whether they are the result of the frequent appearance in our culture of forms with golden proportions, ranging from huge aesthetic monuments, to those of art and architecture, to the golden rectangle form of the credit cards of modern daily life.

In a brain scanning study on responses to Classical and Renaissance sculptures Di Dio et al. (2007) demonstrated that subjects rated sculptures following the Greek canon of beauty higher than those that were digitally manipulated. Those manipulated generally scored with a negative rating (Fig. 6). Moreover, the canonical sculptures increased activation in distinct areas of the cerebral cortex. As the abstract of Di Dio et al. indicates, the question is whether there are objective criteria for beauty, and whether the golden mean is such a criterion.

The studies were carried out using a functional magnetic resonance imagining (fMRI) scanner. The most striking finding is the activation of the right insula in those cases when the subjects in the scanner viewed sculptures following Polycleitus’ mathematical canon. This is important because the insula is a central structure in the emotional neural network of the brain, also called the limbic system. Observation of canonical sculptures will thus activate the emotional pathways, and these mechanisms seem to be biologically determined. Di Dio et al.’s results suggest that golden beauty may be an objective and biological parameter that elicits activity in particular regions of the brain. Therefore, their results can be taken to illustrate what is meant by the objectivist view. However, this is not to say that this Italian group of researchers are pure objectivists when it comes to the question of beauty. It simply means that they have demonstrated how the golden mean affects beholders, and that the golden mean seems to be universally and biologically determined.

The Subjectivist View

As we have already seen, the subjectivist view maintains that beauty is in the eye of the beholder, which means that taste cannot be debated. In 2011, Semir Zeki’s group in London documented that music and visual artworks, considered to be beautiful by subjects in a test group, where what is beautiful for one person may be ugly for another, nevertheless will activate the same area in the brain, the medial orbitofrontal cortex (mOFC). This has led the researchers to formulate a brain-based theory of beauty: ‘Almost anything can be considered to be art, but only creations whose experience has, as a correlate, activity in mOFC would fall into the classification of beautiful art’ (http://www.youtube.com/watch?v=NlzanAw0RP4). According to this definition of aesthetics, then, beauty is in the beholder’s eye, which here actually means the brain of the beholder, within the structure of mOFC, localized frontally, towards the midline, right above the eyes, and the orbits. Ishizu and Zeki (2011) found an overlap between the activation of mOFC as a response to beautiful musical and visual stimuli: subjective beauty activates mOFC. Moreover, this universal response to beauty is a physiological objective truth. The OFC is part of our neurological reward network, and it is ‘perhaps primarily a higher order cortex for smell and taste’ (Brown & Dissanayake, 2009). This part of the brain is phylogenetically old, hence significant also for lower animals.

The Interactionist View

In addition to the objectivist and subjectivist views of beauty, we have the so-called interactionist view, according to which beauty is grounded in the processing experiences of the perceiver that emerge from the interaction of stimulus properties and perceivers’ cognitive and affective processes, in accordance with models deriving from gestalt psychology.

The interactionist view: beauty is grounded in the processing experiences of the perceiver that emerge from the interaction of stimulus properties and perceivers’ cognitive and affective processes.

Research has documented that the feeling of pleasure in response to a stimulus is greater if the stimulus is easily processed, a process called fluent processing. Processing fluency is defined as the subjective experience of ease with which an incoming stimulus can be processed.

Processing fluency is defined as the subjective experience of ease with which an incoming stimulus can be processed.

What increases the processing speed?

• 1. The processing fluency increases if the stimulus is symmetrical and if it has a high degree of contrast and clarity.

• 2. Likewise, processing fluency increases when we recognize the stimulus, i.e. if we have seen it before. We call it the mere exposure effect.

• 3. The processing fluency will also be increased if the stimulus has been so frequently seen that it can be considered to be prototypical (cf. the seminal article by Reber et al., 2004).

An article by Piotr Winkielman et al. (2006) stresses precisely that prototypes are attractive because they are easy on the mind; they are easily processed by our nervous system. Let us, for the sake of simplicity, take an example from everyday life: our preference for a familiar car model, the Volkswagen Beetle with its classical round forms. In a comparison between one of the newest models and an older one; the two forms demonstrate well what is meant by prototypicality. So, one of the reasons why Volkswagen, Fiat, or other successful car industries present their retro models is because we all prefer the prototypical, we want a car that resembles our beloved prototype.

We will now leave this discussion about objectivist, subjectivist, and interactionist positions, to face another question, which has been hotly debated in modern art history: Is art foremost a stimulus for our cognitive processes, a position dominating in the art theory of the twentieth century? For instance, the modernist art theoretician Clement Greenberg stressed the cognitive and analytical content of the pure picture plain. We hereby ask whether art has also a strong emotional impact? This question is among the subjects of the paper, ‘Motion, emotion and empathy in esthetic experience’, written by the art historian David Freedberg and the neuroscientist Vittorio Gallese.

Vittorio Gallese and David Freedberg address this issue and challenge the primacy of cognition in responses to art. They propose that a crucial element of aesthetic response consists of the activation of embodied mechanisms encompassing the simulation of actions, emotions and corporeal sensation, and that these mechanisms are universal.

An amazing discovery in neuroscience is the existence of the so-called mirror neurons. These nerve cells link sensory and motoric parts of the brain in a very particular manner, and they are found in monkeys as well as in humans. They respond to the visual input by activation. When a Macaque monkey looks at a man executing a grasping movement:

• a. In the brain of the monkey the mirror neurons are activated. The same neurons will also be activated ahead of a grasping movement done by the (grasping) monkey itself (https://www.youtube.com/watch?v=yacL60710hg).

• b. The activation of the mirror neurons during pure observation of a movement will, however, not result in a real movement of the limb. What they do is react ‘as if’ in movement.

• c. A most significant implication of the discovery of mirroring mechanisms is that the simulation of action by the mirror neurons, the embodied activation, leads to our understanding of a movement executed by others.

The mirror neurons can even interpret the final intention behind a movement, even when the concluding stages of the movement are hidden from vision. Significantly, this motoric understanding also leads to an activation of our emotional nerve networks, leading to empathetic responses to what we see, whether it is an action taking place here and now, in a photo, or in a work of art. Vittorio Gallese and David Freedberg propose that a crucial element of aesthetic response consists of the activation of embodied mechanisms within the brain that simulate actions, leading to corporeal sensations as well as emotions and that these mechanisms are universal.

Embodied simulation in aesthetic experience will explain our empathy for pain. As one of their examples, Freedberg and Gallese point to Goya’s etching from Los Desastres de la Guerra (Disasters of War: Biblioteque Nationale, Paris, France). The viewing of images of punctured or damaged body parts activates part of the same neural network of the brain that is normally activated by our own sensation of pain. This accounts for the feeling of physical sensation and corresponding shock upon observation of pressure or damage to the skin and limbs of others. But they will also be activated when a ballerina watches the movements of another ballerina. The mirror mechanisms are mostly localized in the prefrontal cortex and in the inferior parietal cortex.

Can we mirror the movements of others also when we simply see traces of these movements, as, for instance, in the paintings of Jackson Pollock that reflect the painter’s dancing movements as he simulated Indian dance during the very act of painting? Or, to put it in another way: Does one feel the movement of brushstrokes when looking at the completed work? Vittorio Gallese proposes ‘that even the artist’s gestures in producing the artwork induce the empathetic engagement of the observer, by activating simulation of the motor program that corresponds to the gesture implied by the trace.’ Gallese stresses that ‘despite the absence of published experiments on this issue, the mirror-neuron research offers sufficient empirical evidence to suggest that this is indeed the case’ (Freedberg & Gallese, 2007, p. 202).

What about the pierced canvases of Lucio Fontana? According to the mirror neuron data collected from other experiments, and in line with Freedberg and Gallese’s (2007) arguments, it seems reasonable to suppose that neurons in the mirror system will activate, as if they were part of the motor act of cutting the canvas, although the beholder stands still, merely looking at the artwork, not moving as little as a finger. In fact, this is now proved experimentally.

Moreover, how does our brain react to the finger of Thomas piercing the breast of Christ in Caravaggio’s famous painting? The discovery of the mirror mechanisms in the brain tells us that we react physically, the mirror neurons mirror the movements, those of Thomas, as well as the imagined sensory reaction of Christ; moreover, the mirror mechanisms are not isolated. In the dynamics of the brain, the activation of the mirror neurons will also lead to the activation of emotional centres. Hence, observed motion will lead to emotion, and empathy (Freedberg & Gallese, 2007).

In this introductory lecture, we have focused on different ways to define what beauty is, and discussed the objectivist view, the subjectivist view, and the in-between standpoint—the so-called interactionist view. Whether we prefer one of these views above the others, or adopt an intermediate position, we will ultimately have to deal with the fact that the sense of beauty involves our neurons, neuron networks, rewarding mechanisms, mirroring mechanisms, etc. Moreover, each region communicates with other regions by means of neural connections, for instance, those complex interactions linking the cognitive, affective, and emotional neural mechanisms of the brain. Let us close by welcoming you to this new and fascinating discipline, neuroaesthetics, in the hope that you will find the journey ahead as exciting as we do!