Neuroesthetics (or neuroaesthetics) is a relatively recent sub-discipline of empirical aesthetics. Empirical aesthetics takes a scientific approach to the study of aesthetic perceptions of art, music, or any object that can give rise to aesthetic judgments. Neuroesthetics received its formal definition in 2002 as the scientific study of the neural bases for the contemplation and creation of a work of art. Neuroesthetics uses neuroscience to explain and understand the aesthetic experiences at the neurological level. The topic attracts scholars from many disciplines including neuroscientists, art historians, artists, and psychologists.
Overview
Neuroaesthetics
is a field of experimental science that aims to combine
(neuro-)psychological research with aesthetics by investigating the
"perception, production, and response to art, as well as interactions
with objects and scenes that evoke an intense feeling, often of
pleasure.". The recently developed field seeks among other things the neural correlates
of aesthetic judgment and creativity. It is argued that visual
aesthetics, namely the capacity of assigning different degrees of beauty
to certain forms, colors, or movements, is a human trait acquired after
the divergence of human and other ape lineages, rendering the experience of beauty a defining characteristic of humankind.
One core question for the field is whether art or aesthetic
preferences are guided by a set of scientific laws or principles.
Additionally, the evolutionary rationale for the formation and
characteristics of these principles are sought. It is believed that
identification of the brain circuitry involved in aesthetic judgments
(e.g., by using through the use of brain imaging) can help pinpoint the origin of these responses.
Approaches of study
Researchers who have been prominent in the field combine principles from perceptual psychology, evolutionary biology,
neurological deficits, and functional brain anatomy in order to address
the evolutionary meaning of beauty that may be the essence of art. It is felt that neuroscience is a very promising path for the search for the quantified evaluation of art.
With the aim of discovering general rules about aesthetics, one approach
is the observation of subjects viewing art and the exploration of the
mechanics of vision.
It is proposed that pleasing sensations are derived from the repeated
activation of neurons due to primitive visual stimuli such as horizontal
and vertical lines. In addition to the generation of theories to
explain this, such as Ramachandran's set of laws, it is important to use neuroscience to determine and understand the neurological mechanisms involved.
The link between specific brain areas and artistic activity is of great importance to the field of neuroesthetics.
This can be applied both to the ability to create and interpret art. A
common approach to uncover the neural mechanisms is through the study of
individuals, specifically artists, with neural disorders such as savant syndrome or some form of traumatic injury.
The analysis of art created by these patients provides valuable
insights to the brain areas responsible for capturing the essence of
art.
The aesthetic enjoyment of individuals can be investigated using
brain imaging experiments. When subjects are confronted with images of a
particular level of aesthetics, the specific brain areas that are
activated can be identified. It is argued that the sense of beauty and
aesthetic judgment presupposes a change in the activation of the brain's
reward system.
A crucial aspect of research lies in whether aesthetic judgment can be thought of as a bottom-up process
driven by neural primitives or as a top-down process with high level
cognition. Neurologists have had success researching primitives.
However, there is a need to define higher level abstract philosophical
concepts objectively with neural correlates. It is suggested that
aesthetic experience is a function of the interaction between top-down,
intentional orientation of attention and the bottom-up perceptual
facilitation of image construction.
In other words, because untrained persons automatically apply the
object-identification habit to viewing artworks, top-down control to
reduce this habit may be necessary to engage aesthetic perception. This
suggests that artists would show different levels of activation than
non-artists.
Aesthetic responses to different types of art and techniques has
recently been explored. Cubism is the most radical departure from
Western forms of art, with the proposed purpose of forcing the viewer to
discover less unstable elements of the object to be represented. It
eliminates interferences such as lighting and perspective angle to
capture objects as they really are. This may be compared to how the
brain maintains an object's identity despite varying conditions. Modern, representational, and impressionistic art
has also been studied for the purpose of explaining visual processing
systems. Yet aesthetic judgments exists in all domains, not just art.
Theories of pioneers
Semir Zeki's laws of the visual brain
Semir Zeki, professor of neuroesthetics at the University College of London, views art as an example of the variability of the brain. Thus a neurological approach to the source of this variability may explain particular subjective experiences as well as the ranges of abilities to create and experience art. Zeki theorizes that artists unconsciously use techniques to create visual art to study the brain. Zeki suggests that
"...the artist is in a sense, a neuroscientist, exploring the potentials and capacities of the brain, though with different tools. How such creations can arouse aesthetic experiences can only be fully understood in neural terms. Such an understanding is now well within our reach."
He proposes two supreme laws of the visual brain:
Constancy
Despite the changes that occur when processing visual stimuli (distance, viewing angle,
illumination, etc.), the brain has the unique ability to retain
knowledge of constant and essential properties of an object and discard
irrelevant dynamic properties. This applies not only to the ability to,
for example, always see a banana as the color yellow but also the recognition of faces at varying angles.
Comparatively, a work of art captures the essence of an object.
The creation of art itself may be modeled off of this primitive neural
function. The process of painting for example involves distilling an
object down to represent it as it really is, which differs from the way
the eyes see it. Zeki also tried to represent the Platonic Ideal and the Hegelian Concept
through the statement: forms do not have an existence without a brain
and the ability for stored memory, referring to how artists such as Monet could paint without knowing what the objects are in order to capture their true form.
Abstraction
This
process refers to the hierarchical coordination where a general
representation can be applied to many particulars, allowing the brain to
efficiently process visual stimuli. The ability to abstract may have
evolved as a necessity due to the limitations of memory. In a way, art
externalizes the functions of abstraction in the brain. The process of abstraction is unknown to cognitive neurobiology.
However, Zeki proposes an interesting question of whether there is a
significant difference in the pattern of brain activity when viewing
abstract art as opposed to representational art.
Ramachandran's eight laws of artistic experience
Vilayanur S. Ramachandran and his fellow researchers including William Hirstein, developed a highly speculative theory of human artistic experience and the neural mechanisms that mediate it.
These "laws" combine to develop underlying high order concepts of the
human artistic experience. Although not all encompassing as there are
undoubtedly many other principles of artistic experience, the theorists
claim that they provide a framework for understanding aspects of visual art, aesthetics and design.
Although testing of these principles quantitatively may provide future
evidence for specific areas of the brain responsible for one kind of
aesthetic appeal, the theory faces substantial philosophical and historical objections.
Peak shift principle
This psychological phenomenon is typically known for its application in animal discrimination learning.
In the peak shift effect, animals sometimes respond more strongly to
exaggerated versions of the training stimuli. For instance, a rat
is trained to discriminate a square from a rectangle by being rewarded
for recognizing the rectangle. The rat will respond more frequently to
the object for which it is being rewarded to the point that a rat will
respond to a rectangle that is longer and more narrow with a higher
frequency than the original with which it was trained. This is called a supernormal stimulus. The fact that the rat is responding more to a 'super' rectangle implies that it is learning a rule.
This effect can be applied to human pattern recognition and aesthetic preference. Some artists attempt to capture the very essence of something in order to evoke a direct emotional response.
In other words, they try to make a 'super' rectangle to get the viewer
to have an enhanced response. To capture the essence of something, an
artist amplifies the differences of that object, or what makes it
unique, to highlight the essential features and reduce redundant
information. This process mimics what the visual areas of the brain have
evolved to do and more powerfully activates the same neural mechanisms
that were originally activated by the original object.
Some artists deliberately exaggerate creative components such as shading, highlights, and illumination to an extent that would never occur in a real image to produce a caricature.
These artists may be unconsciously producing heightened activity in the
specific areas of the brain in a manner that is not obvious to the
conscious mind. A significant portion of the experience of art is not
self-consciously reflected upon by audiences, so it is not clear whether
the peak-shift thesis has any special explanatory power in
understanding the creation and reception of art.
Isolation
Isolating
a single visual cue helps the organism allocate attention to the output
of a single module, thereby allowing it to more effectively enjoy the
peak shift along the dimensions represented in that module. In other words, there is a need to isolate the desired visual form before that aspect is amplified. This is why an outline drawing or sketch is sometimes more effective as art than an original color photograph. For example, a cartoonist may exaggerate certain facial features which are unique to the character and remove other forms which it shares such as skin tones.
This efficiency prevents non-unique features from detracting from the
image. This is why one can predict that an outline drawing would be more
aesthetically pleasing than a color photograph.
The viewers attention is drawn towards this single area allowing
one's attention to be focused on this source of information.
Enhancements introduced by the artist more carefully noted resulting in
the amplification of limbic system activation and reinforcement.
Grouping
Perceptual
grouping to delineate a figure from the background may be enjoyable.
The source of the pleasure may have come about because of the
evolutionary necessity to give organisms an incentive to uncover
objects, such as predators, from noisy environments. For example, when viewing ink blots, the visual system segments the scene to defeat camouflage and link a subset of splotches together. This may be accomplished most effectively if limbic reinforcement is fed back
to early vision at every stage of visual processing leading up to the
discovery of the object. The key idea is that due to the limited
attentional resources, constant feedback facilitates processing of
features at earlier stages due to the discovery of a clue which produces
limbic activation to draw one's attention to important features.
Though not spontaneous, this reinforcement is the source of the
pleasant sensation. The discovery of the object itself results in a
pleasant 'aha' revelation causing the organism to hold onto the image.
An artist can make use of this phenomenon by teasing the system.
This allows for temporary binding to be communicated by a signal to the
limbic system for reinforcement which is a source of the aesthetic
experience.
Contrast
Extracting contrast involves eliminating redundant information and focusing attention. Cells in the retina, the lateral geniculate body or relay station in the brain, and in the visual cortex respond predominantly to step changes in luminance rather than homogeneous surface colors. Smooth gradients
are much harder for the visual system to detect rather than segmented
divisions of shades resulting in easily detectable edges. Contrasts due
to the formation of edges may be pleasing to the eye. The importance of
the visual neuron's varying responses to the orientation and presence of
edges has previously been proven by David H. Hubel and Torsten Wiesel.
This may hold evolutionary significance since regions of contrast are
information rich requiring reinforcement and the allocation of
attention. In contrast to the principle of grouping, contrasting
features are typically in close proximity eliminating the need to link
distant, but similar features.
Perceptual problem solving
Tied
to the detection of contrast and grouping is the concept that discovery
of an object after a struggle is more pleasing than one which is
instantaneously obvious. The mechanism ensures that the struggle is
reinforcing so that the viewer continues to look until the discovery.
From a survival point of view, this may be important for the continued
search for predators. Ramachandran suggests for the same reason that a
model whose hips and breasts are about to be revealed is more provocative than one who is already completely naked. A meaning that is implied is more alluring than one that is explicit.
The generic viewpoint
The
visual system dislikes interpretations which rely on a unique vantage
point. Rather it accepts the visual interpretation for which there is an
infinite set of viewpoints that could produce the class of retinal
images. For example, in a landscape
image, it will interpret an object in the foreground as obscuring an
object in the background, rather than assuming that the background
figure has a piece missing.
In theory, if an artist is trying to please the eye, they should avoid such coincidences. However, in certain applications, the violation of this principle can also produce a pleasing effect.
Visual metaphors
Ramachandran
defines a metaphor as a mental tunnel between two concepts that appear
grossly dissimilar on the surface, but instead share a deeper
connection. Similar to the effects of perceptual problem solving,
grasping an analogy
is rewarding. It enables the viewer to highlight crucial aspects that
the two objects share. Although it is uncertain whether the reason for
this mechanism is for effective communication or purely cognitive, the
discovery of similarities between superficially dissimilar events leads
to activation of the limbic system to create a rewarding process.
Support for this view is highlighted by the symptoms of Capgras delusion, where sufferers experience reduced facial recognition due to impairments in the connections from the inferotemporal cortex to the amygdala,
which is responsible for emotions. The result is that a person no
longer experiences the warm fuzzy feeling when presented with a familiar
face. A person's 'glow' is lost through what is suggested as due to the
lack of limbic activation.
Symmetry
The aesthetic appeal of symmetry is easily understandable. Biologically it is important during the detection of a predator, location of prey,
and the choosing of a mate as all of these tend to display symmetry in
nature. It complements other principles relating to the discovering of
information rich objects. Additionally, evolutionary biologists suggest
that the predisposition towards symmetry is because biologically, asymmetry is associated with infection and disease,
which can lead to poor mate selection. However, departures from
symmetry in visual art are also widely considered beautiful, suggesting
that while symmetry may explain the judgment that a particular
individual's face is beautiful, it cannot explain the judgment that a
work of art is beautiful.
Areas of the brain linked to the processing of visual aesthetics
Aesthetic perception relies heavily on the processing by the visual centers in the brain such as the V1 cortex. Signals from V1 are distributed to various specialized areas of the brain.
There is no single area where all specialized visual circuitry connect,
reducing the chances of determining a single neural center responsible
for aesthetics, rather a neural network is more likely.
Therefore, the visual brain consists of several parallel multistage
processing systems, each specialized in a given task such as color or
motion. Functional specializations of the visual brain are already
known.
Physiological phenomenon can explain several aspects of art appreciation. Different extrastriate areas
of the visual cortex may have evolved to extract correlations of
different visual features. The discovery and linking of various visual
stimuli is facilitated and reinforced by direct connections from these
areas to limbic structures.
Additionally, art may be most appealing if it produces heightened
activity in a single dimension rather than redundant activation of
multiple modules, restricted by the allocation of attentional resources.
In experimentation to determine specific areas, many researchers allow
the viewer to decide the aesthetic appeal prior to the use of imaging
techniques to account for the varying perceptions of beauty. When
individuals contemplate the aesthetic appeal, different neural processes
are engaged than when pragmatically viewing an image.
However, processes of object identification and aesthetic judgment are
involved simultaneously in the overall perception of aesthetics.
Location of the orbito-frontal cortex shown through MRI
Prefrontal cortex
The prefrontal cortex
is previously known for its roles in the perception of colored objects,
decision making, and memory. Recent studies have also linked it to the
conscious aesthetic experience because it is activated during aesthetic
tasks such as determining the appeal of a visual stimuli. This may be
because a judgment is needed, requiring visiospatial memory. In a study
performed by Zeki and Kawabata, it was found that the orbito-frontal cortex (OFC) is involved in the judgment of whether a painting is beautiful or not.
There is high activation in this region when a person views paintings
which they consider beautiful. Surprisingly, when a person views a
painting which they consider ugly, no separate structures are activated.
Therefore, it is proposed that changes in the intensity of activation
in the orbito-frontal cortex correlate with the determination of beauty
(higher activation) or ugliness (lower activation). Additionally, the
medial OFC has been found to respond aesthetics in terms of the context
of which it is presented, such as text or other descriptions about the
artwork. The current evidence linking the OFC to attributed hedonistic
values across gustatory, olfactory, and visual modalities, suggests that
the OFC is a common center for the assessment of a stimulus's value.
The perception of aesthetics for these areas must be due to the
activation of the brain's reward system with a certain intensity.
Prefrontal cortex is highlighted in orange. Location of Brodmann's areas indicated by numerical tabs.
Additionally, the prefrontal dorsalateral cortex
(PDC) is selectively activated only by stimuli considered beautiful
whereas prefrontal activity as a whole is activated during the judgment
of both pleasing and unpleasing stimuli.
The prefrontal cortex may be generally activated for directing the
attention of the cognitive and perceptual mechanisms towards aesthetic
perception in viewers untrained in visual arts.
In other words, related directly to a person viewing art from an
aesthetic perception due to the top-down control of their cognition. The
lateral prefrontal cortex is shown to be linked to higher order
self-referential procession and the evaluation of internally generated
information. The left lateral PFC, Brodmann area 10,
may be involved in maintaining attention on the execution of internally
generated goals associated with approaching art from an aesthetic
orientation. As previously mentioned, directing of attention towards aesthetics may have evolutionary significance.
Additional areas
Emotions
play a large role in aesthetic processing. Experiments designed
specifically to force the subjects to view the artwork subjectively (by
inquiring of its aesthetic appeal) rather than simply with the visual
systems, revealed a higher activation in the brain's emotional
circuitry. Results from these experiments revealed high activation in
the bilateral insula which can be attributed to the emotional experience of viewing art.
This correlates with other known emotional roles of the insula.
However, the correlation between the insula's varying states of
activation and positive or negative emotions in this context is unknown.
The emotional view of art can be contrasted with perception related to
object recognition when pragmatically viewing art. The right fusiform gyrus has been revealed to show activation to visual stimuli such as faces and representational art.
This holds importance in the field because as Ramachandran also
speculated, object recognition and the search for meaning can evoke a
pleasant emotional response. The motor cortex was also shown to be involved in aesthetic perception. However, it displayed opposite trends of activation from the OFC.
It may be a common correlate for the perception of emotionally charged
stimuli despite its previously known roles. Several other areas of the
brain were shown to be slightly activated during certain studies such as
the anterior cingulate cortex, previously known for its involvement in the feeling of romance, and the left parietal cortex, whose purpose may be to direct spatial attention.
Different artistic styles may also be processed differently by the brain. In a study between filtered forms of abstract and representation art, the bilateral occipital gyri, left cingulate sulcus, and bilateral fusiform gyrus showed increased activation with increased preference when viewing art.
However, activation in the bilateral occipital gyri may be caused by
the large processing requirements placed on the visual system when
viewing high levels of visual detail in artwork such as representational
paintings.
Several areas of the brain have been shown to respond particularly to
forms representational art perhaps due to the brain's ability to make
object associations and other functions relating to attention and
memory. This form of stimuli leads to increased activation in the left frontal lobe and bilaterally in the parietal and limbic lobes. Also, the left superior parietal lobule, Brodmann's area 7,
has been shown to play a role in active image construction during the
viewing of art specifically containing indeterminate forms such as soft
edge paintings.
Bottom up processes such as edge detection and the exploration of
visual stimuli are engaged during this type of aesthetic perception.
These roles are consistent with previously known parietal lobe
responsibilities in spatial cognition and visual imagery.
Criticism
There are several objections to researchers' attempts to reduce aesthetic experience to a set of physical or neurological laws. It is questionable whether the theories can capture the evocativeness or originality of individual works of art.
Experiments performed may not account for these theories directly.
Also, current experimentation measures a person's verbal response to how
they feel about art which is often selectively filtered. Ramachandran
suggests the use of galvanic skin response
to quantify the judgment associated viewing aesthetics. Overall, it can
be argued that there is lack of proportion between the narrow approach
to art taken by researchers versus the grand claims they make for their
theories.
Since
2005 the notion of bridging brain science and the visual arts has
blossomed into a field of increasing international interest. In his 2008
book, Neuroarthistory: from Aristotle and Pliny to Baxandall and Zeki, Professor John Onians of the University of East Anglia
considers himself to be at the forefront of the field of neural
scientific biased art historical research, although such a 'history' is
much shorter than Onians would have us believe. Many historical figures
he deals with as precursors for neuroarthistory (Karl Marx, for example)
have very little to do with modern neuroscience as it is understood
today. Contemporary artists like Mark Stephen Smith
(William Campbell Gallery, USA) and others have developed extensive
bodies of work mapping the convergence of brain science and painting.
Smith's work explores fundamental visual analogies between neural
function and self-expression in abstract art. The past decade has also
seen a corresponding growth in the aesthetics of music studied from
neuroscientific approaches. Psychological and social approaches to art
help provide other theories of experience.
