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How neuroimaging is transforming our understanding of aesthetic taste

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How neuroimaging is transforming our understanding of aesthetic taste

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This is a preprint of a chapter that will appear in A. Chatterjee & E. Cardillo (eds.), Brain Beauty, and Art: Essays Bringing Neuroaesthetics into Focus. Oxford University Press. Please do not cite this version.
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This is a preprint of a chapter that will appear in A. Chatterjee & E. Cardillo (eds.),
Brain Beauty, and Art: Essays Bringing Neuroaesthetics into Focus. Oxford University
Press. Please do not cite this version.
How neuroimaging is transforming our understanding of
aesthetic taste
Martin Skov
Comment on: Skov, M. (2019), Aesthetic appreciation: The view from neuroimaging.
Empirical Studies of the Arts, 37, 220-248.
Neuroaesthetics studies several different problems (Nadal & Skov, in press), but
probably none as vigorously as the question of why we like some sensory experiences
and dislike others. Neuroaesthetics contributes to the investigation of this problem by
using different neuroscientific methods to characterize the neurobiological processes
employed by the brain in producing liking and disliking. Its aim is an eventual
understanding of the computational principles regulating these processes.
Inherent to this approach is the assumption that liking and disliking originate in
the human brain. This idea – that we come to like and dislike the sensory objects we
encounter as a result of the way our mind responds to sensory information – was first
introduced by the British philosopher Francis Hutcheson in 1725 (see Kivy, 2003).
Hutcheson proposed that the human mind is equipped with a “faculty of taste,” a
dedicated psychological system that responds to perceived sensory stimuli by eliciting
either pleasure or pain. These sensations are the basis of judgments of beauty or the
sublime. This idea generated most of the key questions that have subsequently
preoccupied scientists interested in the question of taste: What is the identity of this
putative faculty of taste? Hutcheson conceived of taste as a kind of sense, operating
according to specific rules, but many later researchers have suggested other systems
as the possible seat of taste. If liking and disliking emerge as a result of subjective
responses to sensory objects (courtesy of the faculty of taste), does this mean that
taste is in the eye of the beholder, or are some stimuli universally liked? If not, what
accounts for the variance in individual taste responses?
The most prevalent method neuroaesthetics has used to pursue these questions is
non-invasive neuroimaging, including specific techniques such as MEG, fMRI, or
PET. Neuroimaging allows neuroscientists to map neural processes in the human
brain that are associated with experiences of liking and disliking. Many
neuroaesthetics studies have employed neuroimaging to help establish the location of
such processes. This method can also characterize the way these processes work,
giving us an idea of the computational principles that determine if a stimulus becomes
liked or disliked. By comparing individuals who vary in how they respond to a given
object or experience, it is also possible to use neuroimaging measurements to gain an
understanding of why processes causing liking or disliking operate differently in
different brains.
Though neuroaesthetics can be thought of as a continuation of previous aesthetic
thinking with novel neuroscientific means, the answers it provides very much break
with earlier ideas. This break should not surprise us. Making sense of human
neurobiology was a slow and arduous process. Even as late as the 1960s and 1970s,
both philosophers and psychologist were forced to treat the brain more or less as a
black box. This long period of ignorance could hardly fail to produce speculative
hypotheses about the putative faculty of taste that would turn out to not conform well
to empirical facts about how the human brain actually produces liking and disliking
for sensory objects.
In “Aesthetic appreciation: The view from neuroimaging” (Skov, 2019), I tried to
summarize how neuroimaging research conducted over the last 20 years has
challenged and transformed a series of psychological assumptions that guided much
thinking about aesthetic taste before neuroaesthetics. My most important point is that
previous conceptions of aesthetic taste are not consistent with current neuroscientific
evidence. The philosophical-psychological tradition before neuroaesthetics conceived
of the faculty of taste as a unique mental system, specific to humans, to appreciate the
aesthetic qualities of the sensory world. While unknown in its details, the faculty of
taste was believed to produce taste responses that are distinct from other adaptive
responses we employ when, say, deciding what to eat or with whom to mate. It was
widely believed that aesthetic taste responses are disinterested or non-utilitarian
taste responses are generated without serving a functional purpose. Many scholars
also believed that aesthetic taste responses are characterized by distinct affective
states, including intense feelings of pleasure. While “ordinary” taste was thought to be
elicited by biologically relevant objects, aesthetic taste was thought to be triggered
only by “aesthetic” objects, especially art.
None of these assumptions have turned out to be supported by the empirical
findings produced by neuroasthetics experiments. Rather, most neuroimaging studies
have found that neural activity involved in generating sensory liking and disliking is
common to all forms of taste appraisals. Regardless of the kind of sensory object
researchers have asked people to evaluate – food, faces, money, visual art, music, etc.
– their subjective liking correlates with enhanced activity in the same functional
network: the mesocorticolimbic reward circuitry. This finding strongly suggests that
humans are not endowed with a specialized neural system for “aesthetic” taste
responses.
Importantly, neuroscience has not merely produced correlational data in favor of
this “common currency” hypothesis. The existence of a common taste system is also
supported by different types of intervention studies. For example, studies that have
manipulated the distribution of opioid neurotransmitters in the nucleus accumbens and
the orbitofrontal cortex have found that if opioid-related activity is inhibited, people
report diminished liking for art as well as for ingested food and drink. Together with
other studies manipulating the activity of processes in the reward circuit, such
findings indicate that humans have come to enjoy (or dislike) art and other cultural
artifacts by engaging molecular processes that first evolved to facilitate the appraisal
of natural resources important to survival.
That “aesthetic” appreciation involves neurobiological mechanisms whose
function is to regulate adaptive behavior suggests that evaluating art and other objects
for their aesthetic qualities also produces neural activity that influences behavioral
urges and decisions. Evidence that aesthetic evaluation is embedded in a larger
network for behavioral control comes from many lines of research, including studies
demonstrating that appraising a sensory object changes how it is represented and how
it prompts behavioral expectations (Skov & Nadal, 2019). Experiments also find that
the aesthetic value attributed to a sensory object modulates the way we interact with it,
including our willingness to expend resources on it and engage with it, or how we
treat fellow humans and animals we encounter in our daily life.
In sum, many of our intuitions before neuroaesthetics about aesthetic taste, and
the psychological components we would expect an aesthetic taste system to exhibit,
have been refuted by empirical evidence. As I argue in Skov (2019), this discovery
warrants a re-thinking of many of the core concepts used in aesthetics scholarship.
The more consequential effect of neuroimaging and other neuroscientific methods
being applied to the phenomenon of aesthetic taste is that the questions science seeks
to answer is undergoing a revolution as well.
Neuroscientific research has made it clear that the human brain is not equipped
with a distinctive faculty that generates ”aesthetic” liking when certain stimuli are
encountered. It has also revealed that liking and disliking – regardless of the type of
object being perceived – is the result of dynamic and interacting neural processes,
involving many different neural systems. Sensory liking occurs because nuclei in the
reward circuitry respond to perceptual information. How these sensory and reward
processes unfold is affected by signals from other parts of the brain, especially
information that reflects the internal homeostatic state of the body, and the organism’s
behavioral goals (Figure 1). How we like the things we experience is determined not
only by the constitution of the thing itself, but also our current needs, expectations,
and the tasks we happen to be engaged in (Skov & Nadal, 2019).
Figure 1. Model depicting core functional systems known to be involved in the computation
of aesthetic evaluation of sensory stimuli. Pleasure and displeasure are computed by nuclei
located in the reward circuit. Activation of these nuclei rely not only on information relayed
from perceptual-cognitive system representing sensory inputs, but also from interoceptive and
executive systems reflecting homeostatic states and control of behavioral action. Figure
reprinted with permission from Skov (2019).
This computational complexity raises several novel problems for neuroaesthetics
(Skov & Nadal, 2020). How is information transferred from perceptual systems to the
reward system? Which reward signals do specific inputs from perceptual and
cognitive systems engage? What happens when a sensory object is being evaluated
under different circumstances? These and other questions about the fine-grained
computational machinery of aesthetic evaluation pose the great challenge for
neuroaesthetics research in the coming years.
References
Kivy, P. (2003): The Seventh Sense (2. Ed). Oxford: Clarendon Press.
Nadal, M., & Skov, M. (Eds.). The Routledge International Handbook of
Neuroaesthetics. London: Routledge. In press.
Skov, M. (2019). Aesthetic appreciation: The view from neuroimaging. Empirical
Studies of the Arts, 37, 220-248.
Skov, M., & Nadal, M. (2019). The nature of perception and emotion in aesthetic
appreciation: A response to Makin’s challenge to Empirical Aesthetics. Psychology of
Aesthetics, Creativity and the Arts. Advance first publication.
DOI:10.1037/aca0000278
Skov, M., & Nadal, M. (2020): A farewell to art. Perspectives on Psychological
Science, 15, 630-642.
ResearchGate has not been able to resolve any citations for this publication.
Article
Alexis Makin argued in a recent paper that Empirical Aesthetics is unable to properly advance our understanding of the mechanisms involved in aesthetic experience. The reason for this predicament, he claims, is an inability of current research methods to capture the psychological properties that truly characterize aesthetic experience, especially the unique perceptual and emotional processes involved in the aesthetic experience. We show that Makin's argument rests on assumptions that are at odds with scientific knowledge of the neurobiological mechanisms involved in the appreciation of sensory objects. We thereafter show that such mechanisms are rooted in shared neurobiological systems and operate according to computational principles that are common to many domains of experience. This casts doubt on the notion that aesthetic experiences constitute a distinct kind of experiences that can be defined according to a set of special and unique qualities. Finally, we discuss how attributing this specialness to "aesthetic" experiences leads Empirical Aesthetics astray from mainstream psychology and neuroscience.
Article
Our understanding of aesthetic appreciation has undergone a profound change during the past 20 years, as a result of the ability to study the human brain through neuroimaging. A number of findings cast into doubt important tenets of previous theories and models. Specifically, neuroscientific evidence suggests that aesthetic appreciation is not a distinct neurobiological process assessing certain objects, but a general system, centered on the mesolimbic reward circuit, for assessing the hedonic value of any sensory object. Furthermore, neuroscientific research also makes it clear that hedonic values are not determined solely by object properties, but subject to a range of object-extrinsic modulatory factors. This article reviews these findings and discusses how they demand a new experimental approach to aesthetic appreciation.