Art and the Conscious Brain

A Review of Robert L. Solso’s The Psychology of Art and the Evolution of the Conscious Brain
7 x 9, 294 pp., 138 illus., 24 color
MIT Press
ISBN 0-262-69332-1

Neuroaesthetics is the name of a new research field that uses methods and results from the neurosciences to investigate problems in aesthetics. It may be viewed as the logical extension of the long tradition, going back to Gustav Fechner, for psychological studies of art production and consumption, attempting to get at the neurobiological mechanisms instantiating the various functions unveiled by this research. As with other forms of cognitive neuroscience, the possibility of forming such a bond between neuronal mechanisms and psychological function rests on the actual availability of relevant results and methods. It is therefore not surprising that the first papers and book chapters to take a swing at providing neuroaesthetic answers to aesthetic problems first appeared in the 1970’s, in the wake of the preceding decade’s revolutionary research into the visual system’s physiology and anatomy. It should also not be a surprise that the invention of non-invasive neuroimaging techniques in recent years has energized the field enormously.

Critics sometimes ask if the illumination of neurobiological mechanisms adds anything important to old-fashioned – i.e., philosophical – aesthetic inquiry. I think that already Plato and Aristotle said that works of art are created with the express purpose of provoking a mental representation in the brains that experience themPlato and Aristotle effectively answered this question (even though they, of course, knew nothing of modern neuroscience!). As they pointed out, works of art are created with the express purpose of provoking a mental representation in the brains that experience them. Thus, to understand the nature of art you also have to understand the cognitive processes responsible for turning the perceptual properties of any art object into a mental representation. How colour, lines, etc. are magically transformed into Mona Lisa’s enigmatic smile is very much a question of how the brain works. So, aesthetics has really always, since the time of Plato and Aristotle, been a neuro-aesthetics by heart. It is only just now we have the means to add neurobiology to the equation.

A pioneer in bridging aesthetics with neuroscience is the American psychologist Robert Solso. In 1994 he published the first monograph to root the experience of visual art in the workings of the brain, Cognition and the Visual Arts. (Solso’s book has later been followed by other monographs, including books by renowned neuroscientists Margaret Livingstone [1] and Semir Zeki [2].) This book offered several examples of how artists may fool the brain into experience visual phenomena by activating neuronal mechanisms, even though the physical forms of a painting bear scant resemblance to the “real” objects vision evolved to detect. For instance, by varying the size of the elements in a painting, the artist can evoke the illusion of a 3-dimensional perspective, although the 2-dimensional canvas in reality has no depth. The reason for this is that the visual system has evolved a neuronal rule that the size of the retinal image varies in inverse proportion to the distance of an object. In a similar vein, other representational tricks can be explained by recourse to other perceptual “rules”. Indeed, it could be said that the range of possible aesthetic forms is delimited by the set of rules the brain happens to be equipped with. (This is the logic behind Zeki’s great bon mot: “The artist is a neuroscientist!” The artist’s job is to select a composition of forms and see how they affect the brain.)

Solso’s career was cut short by cancer in 2005. Just before his untimely death, though, he managed to finish a follow-up to Cognition and the Visual Arts. Entitled The Psychology of Art Indeed, the connection between cognition and emotion should be regarded as a big enigma and the Evolution of the Conscious Brain, this new book is very much a restatement of the first, at some places even using the same examples and illustrations as the previous book. Solso’s focus is still on visual art, and he is almost exclusively interested in the question of how representations are forged. (It is unclear to me if Solso in fact equates art with visual art, or is just pragmatically disregarding other art forms. In one passage (p. 73) he informs us that “of the five senses with which we behold the physical world – vision, audition, taste, touch, smell – vision is the faculty that is most directly related to the perception of art.” What about music, dance, spoken poetry, then?) Visual representation is naturally also a very important topic, but is should be noted that representation is only one of the two major components of the experience of art, the other being our emotional response to the work of art. Naturally, Solso realizes that art’s ability to affect us emotionally is an important part of its attraction, but he has nothing to say about what function this type of affect may play in the experience of art, nor about the putative neuronal mechanisms underlying it. This is a great pity, since one of the most exiting aspects of the recent advance of neuroaesthetics is exactly the, hitherto unattainable, possibility of using PET and fMRI to investigate why we attribute phenomenal values such as beauty or ugly to works of art, and why these values differ from person to person.

The neglect of the affective component of the experience of art in reality also impairs our understanding of the representational component. It is almost certainly the case that the emotional response instilled by a work of art modulates the perceptual and cognitive processing of it. Although this hasn’t been demonstrated experimentally yet, it is well known from studies of the perception of (non-artistic) affective pictures that afferents from structures such as the amygdala may influence processing in even early visual cortex. Just as a dangerous percept – think the proverbial bear! – warrants extraordinary attention, it seems probable that “strange” properties in a work of art will provoke closer perceptual scrutiny (is Mona Lisa in fact smiling, or is that really a sneer?), and that emotion play an important role in directing our attention to such “problems”. Indeed, the connection between cognition and emotion should be regarded as a big enigma, as its breakdown in various clinical cases testifies. (Recall the colour-blind painter in Oliver Sack’s An Anthropologist on Mars who, following a loss of his ability to see colours, at first experienced the visual world as highly unpleasant, since it now appeared “wrong” to him, but later regained a sort of aesthetic pleasure from the black and white objects he was now forced to encounter.)

To Solso the brain forms a hierarchy of computational modules. He identifies three major processing stages in this hierarchy: first the transduction of photons into neural impulses in the eye; second, the extraction of primitive features in the visual cortex, and the assembly of these features into categorized objects; and, thirdly, the association between categorized objects and the person’s personal knowledge and “worldview” (see Figure 1). Most of the neural mechanisms Solso discusses relate to stage 1 and 2. As regards the third stage he contends that “the neurological trail grows cold after leaving the primary visual cortex and the various ‘streams’ that ensue” (p. 254). Instead he subsumes what ever processes that take place at stage 3 under the shorthand “schema”. A schema is a pair of conceptual glasses that filters the perceptual signals through a point of view, or a hypothesis about the world. It is the stage 3 schema that makes you “see” the glass as either half-full or half-empty. Thus, although clouded in mystery, stage 3 actually plays the most significant role in the brain’s construction of an aesthetic representation. It is through the imposition of a schema on the perceptual object that a work of art attains its “meaning” or “interpretation”.

Figure 1

Now, clearly something is right about Solso’s account. But is also strikes me as much too simplistic. First of all, I think we actually have some idea as to what constitutes top-down modulation, and from what (admittedly little) we already know it seems clear that many different functions underlie Solso’s “schemata”, including memory, attention, error-detection, and selection mechanisms. There exists, today, other models that attempt to incorporate some of these processes in a more sophisticated manner (see, for instance, Figure 2, based on a model proposed by Helmut Leder and colleagues). I also think the notion of “stages” is potentially misleading. Although Solso acknowledges top-down modulation in his theory, he still maintains the idea of a signal passing through stage 1, 2, and 3, as in the good-old AI flow charts. However, results from many experiments suggest that a much more complicated back and forth goes on. For example, language research have showed that selection mechanisms located in the inferior frontal gyrus help select between competing conceptual choices generated by structures in the temporal lobe. Or, consider style. The computation of style rests on both the processing of perceptual features early in the visual system and on later classification processes, including memory (do I know this style?). And we know that feedback-loops connect these processes in the brain.

Figure 2

Solso’s “schema” sometimes reads like a homunculus that receives the result of perceptual processing and imbues it with meaning. Says Solso: “Convincing evidence has been collected indicating that schemata influence perception and recall of visual events, even if the schemata are artificially induced. We see the world through a veil that presents it to us, not as it is, but as we expect it to be.” Such statements smack too much of social constructivism for my taste. The “seen-through-a-veil” notion also disregard a very important aspect of art: works of art are intentionally constructed to induce mental representations. This means, that the perceptual forms have been chosen by the artist so as to be engaged by the viewer. Hence, to my mind at least, it is much more satisfactory to see our experience of art as an “interactive” process where we try to make sense of the perceptual features presented by the particular work of art. You can’t possibly experience the Guernica as a painting of animals grassing in a Belgian forest; but, within the representational frame set by the perceptual features, you can interpret it in a number of different ways. (For instance, your interpretation may rely on the scene depicted by the painting: this is a painting on the folly of war; or you may take your departure from its style: this is Picasso’s finest attempt to leave cubism).

Compared to his first book Solso does introduce two new topics, both reflected in the title. First he situates his discussion of representation’s putative neurocognitve mechanisms in an Something clearly happened during the Upper Palaeolithic. The big question is what? evolutionary context. This is a very important addendum to the proximate mechanisms that usually preoccupy neuroaesthetics. The manufacturing of art objects is a historic thing: the earliest artefacts that can be claimed to resemble a work of art, engravings on pieces of ochre found in the Blombos cave, date to around 77.000 years ago. Following that, cave art and figures exploded onto the scene some 30.000-40.000 years ago. Barring the fact that some types of art, such as music, dance, and story-telling, doesn’t leave any archaeological evidence behind, and thus may have originated earlier, something clearly happened during the Upper Palaeolithic. The big question, of course, is what? Solso mentions a number of factors that may have impacted on the development of the homo sapiens brain, including a change in diet, climatic changes, and changes in social structure. He refrains, very prudently, from singling out just one adaptive function as responsible for the emergence of art, although he appears to favour a story somewhat along the lines of Steven Mithen’s The Prehistory of the Mind. “These profound changes,” he writes, “could only have been brought about by changes in the organization of brain structures and processing networks. Mere size and number of neurons were not sufficient to bring about the changes in human culture, language, and technology.” (p. 61.) Given his overall idea of a processing hierarchy, going from local perceptual features to schemata, he seems guided by a Mithenean idea of the latter stage somehow integrating the information available from the former modules.

Secondly, Solso speculates that the change in brain architecture could be coupled to a change in consciousness. He proposes that homo erectus didn’t posses the same type of consciousness later to develop in homo sapiens. Unfortunately, he doesn’t really discuss how consciousness relates to hominid brain development – exactly what form of consciousness is unique to us modern humans (access, phenomenal, less unconscious processing, or what)? It would have been exiting to see him attempt to pair up the idea of early modules being more strongly connected to frontal integration mechanisms with a theory of consciousness such as Baars and Dehaene’s workspace theory. At least Solso is absolutely right to insist on seeing consciousness as a crucial part of the experience of art, and as far as I know he is the first to do so within the budding field of neuroaesthetics.

The Psychology of Art and the Evolution of the Conscious Brain will succeed in convincing the reader, I believe, that neuroscience must play an integrated part in our quest to understand the phenomenon of art. It contains several great examples of how neuronal mechanisms form the basis of mental representations. It also convincingly suggests that to such proximate causes we must add ultimate causes. At the same time it leaves much to be explained, most importantly how early perceptual processes interface with later “steering” mechanisms, and how representation interacts with the brain’s emotion system. Regrettably, we will not get a third book by Solso targeting these issues.

© 2006 Martin Skov

Author Information

Martin Skov
Danish Research Centre for Magnetic Resonance
Copenhagen University Hospital, Hvidovre

See his blog Brainethics.

References

1. Margaret Linvingstone (2002): Vision and Art. Harry N Abrams.
2. Semir Zeki (1999): Inner Vision. Oxford University Press.