Cracking the code of art's allure - eight laws of artistic experience

A bold new theory to identify the common denominator of all visual art

'If a Martian ethologist were to land on earth and watch us humans, he would be puzzled by many aspects of human nature, but surely art - our propensity to create and enjoy paintings and sculpture - would be among the most puzzling. What biological function could this mysterious behaviour possibly serve?

"Cultural factors undoubtedly influence what kind of art a person enjoys. But, even if beauty is largely in the eye of the beholder, might there be some sort of universal rule or 'deep structure', underlying all artistic experience?"

Vilayanur S. Ramachandran, Director of the Center for Brain and Cognition at the University of California at San Diego, has made a bold and controversial attempt to answer these intriguing questions by proposing a new scientific theory of art. The theory explains many familiar experiences, such as why a cartoon squiggle can evoke a well-known face more quickly than a full colour photograph, and why many men find the hour-glass figure of Marilyn Monroe sexy.

Professor Ramachandran's theory addresses three questions: (a)What are the "rules of art" that make something pretty? (b) Why did these rules evolve and have the form that they do? (c) What is the brain circuitry involved? Previous theories of art have looked at one or two of these questions, but this is the first time all three have been tackled together.

With his colleague William Hirstein, Ramachandran proposes a list of "Eight laws of artistic experience . . . that artists either consciously or unconsciously deploy to optimally titillate the visual areas of the brain," in particular that part of the brain known as the limbic system. Of the eight (see box page 42), three seem to be especially significant: a psychological phenomenon called the "peak shift effect"; the principle of"grouping"; and the benefit of focusing on a single visual cue.(1)

The 'peak shift effect'

The "peak shift effect" is a well-known principle in animal discrimination learning. For example, if a rat is taught to discriminate a square from a rectangle and rewarded for the rectangle, it will soon learn to respond more frequently to the rectangle. Moreover, if the rat is trained with a prototype rectangle of, say, aspect ratio 3:2, it will respond even more positively to a longer and skinnier figure - say, of aspect ratio 4:1. This curious result implies that what the rat is learning to value is not a particular rectangle but a rule: rectangles are better than squares. So the greater the ratio between the long and the short sides, i.e. the less square-like it is, the "better" the rectangle is in the rat's eyes. This is the "peak shift effect". Ramachandran argues that this principle holds the key for understanding the evocativeness of much of visual art.

How does the peak shift effect relate to human pattern recognition and aesthetic preference? Consider the way in which a skilled cartoonist produces a caricature of a famous face, say the late U.S. President Richard Nixon's. What a cartoonist does (unconsciously) is to take the average of all faces, subtract it from Nixon's face (to get the difference between Nixon's face and all others) and then amplify the differences to produce a caricature. The final result, of course, is a drawing that is even more Nixon-like than the original. The artist has amplified the differences that characterize Nixon's face in the same way that an even skinnier rectangle is an amplified version of the original prototype that the rat is exposed to. Hence Ramachandran's aphorism that "All art is caricature". (This is not literally true, as he admits, but it applies surprisingly often.) In other words, what the artist tries to do is not only capture the essence of something but amplify it in order to activate neural mechanisms more powerfully than the original object.

Look at the Chola bronze - the accentuated hips and bust of the Goddess Parvati [ILLUSTRATION FOR FIGURE 1 OMITTED] and you will see at once that this is essentially a caricature of the female form. Here the artist has chosen to amplify the "very essence" (called the rasa by Hindu artists) of being feminine, by moving the image abnormally far toward the feminine end of the female/male spectrum. The artistic amplification produces a "super stimulus" to which, Ramachandran conjectures, certain brain circuits respond. Artists may also try to evoke a strong direct emotional response by exploiting the peak shift effect along dimensions other than form. For instance, a Boucher, a Van Gogh, or a Monet may be thought of as a caricature in "colour space".

Perceptual grouping and binding

A second basic principle suggested by Ramachandran is "grouping" (or binding). The way this works can be illustrated by the Dalmatian dog picture shown in Fig. 2.This is seen initially as a random jumble of splotches. The number of potential groupings of these splotches is infinite, but once the dog is seen, your visual system links only a subset of these splotches together and it is impossible not to "hold on" to this group of linked splotches. Indeed, the discovery of the dog and the linking of the dog-relevant splotches generates a pleasant "aha" sensation. In "colour space" the equivalent of this would be wearing a blue scarf with red flowers if you are wearing a red skirt; the perceptual grouping of the red flowers and your red skirt is aesthetically pleasing. Artists understand the pleasure given by such effects.

The evolutionary value of such grouping of stimuli to pick out objects is obvious: it makes the detection of both prey and predators much easier. But how is such grouping achieved?The key idea is as follows. Given the brain's limited attentional resources and shortage of neural space for competing representations, every stage in the processing of visual information offers an opportunity to generate a signal that says, "Look, here is a clue to something potentially object-like!" Partial solutions or conjectures to perceptual problems are fed back from every level in the hierarchy to every earlier module to impose a small bias in processing, allowing the final percept to emerge from such progressive "bootstrapping".

Consistency between partial high-level "hypotheses" and earlier low-level ensembles generates a pleasant sensation - .g. the Dalmatian dog "hypothesis" encourages the binding of corresponding splotches which, in turn, further consolidate the "dog-like" nature of the final percept and we feel good when it all finally clicks in place. And what the artist tries to do is to tease the system with as many of these "potential object" clues as possible - an idea that would help explain why grouping and "perceptual problem-solving" are both frequently exploited by artists and fashion designers.

Isolating a visual signal

The third principle (in addition to peak shift and binding) emphasized by Ramachandran is the need to isolate a single visual modality before you amplify the signal in that modality. The brain's ability to do this explains why an outline drawing or sketch is more effective as "art" than a full colour photograph. Consider a full-colour illustration of Nixon, with depth, shading, skin tones and blemishes, etc. What is unique about Nixon is the form of his face (as amplified by the caricature), but the skin tone - even though it makes the picture more human-like - doesn't contribute to making him "Nixon-like" and therefore actually detracts from the efficacy of the form cues. This explains why one not only "gets away" with just using outlines - they are actually more effective than a full-colour half-tone photo, despite its having more information. Hence the aphorism "more is less" in Art.

Additional evidence for this view comes from the "savant syndrome" - autistic children who are "retarded" and yet produce beautiful drawings. The animal drawings of the eight-year-old artist Nadia, for instance, are almost as aesthetically pleasing as those of Leonardo da Vinci (Fig. 4). Ramachandran argues that this is because the fundamental disorder in autism is a distortion of the "salience landscape"; savants shut out many important sensory channels, thereby allowing them to deploy all their attentional resources on a single channel.

'Lie detector' testing

Ramachandran believes that the "peak shift principle" can be tested directly. The method would employ skin conductance response (SCR), the technology used in "lie detectors". The size of the SCR is a direct measure of the amount of limbic (emotional) activation produced by an image. It is a better measure, as it turns out, than simply asking someone how much emotion they feel about what they are looking at, because the verbal response is filtered, edited, and sometimes censored by the conscious mind. Measuring SCR allows direct access to "unconscious" mental processes.

The experiment would compare a subject's SCR to a caricature of, say, Einstein or Nixon, to his SCR to a photo of the same individuals. Intuitively, one would expect the photo to produce a large SCR because it is rich in cues and therefore excites more modules. If one found, paradoxically, that the caricature actually elicited a larger SCR, this would provide evidence for the operation of the peak shift effect - the artist would have unconsciously produced a super stimulus.

Critical responses

Ramachandran says that one could also compare the magnitude of an SCR to caricatures of women (or indeed, to a Chola bronze nude or a Picasso nude) with the SCR to a photo of a nude woman. It is conceivable that the subject might claim to find the photo more attractive at a conscious level, while registering a large "unconscious aesthetic response" - in the form of a larger SCR - to the artistic representation. That art taps into the "subconscious" is not a new idea, but our SCR measurements may be the first attempt to test such a notion experimentally.

Not surprisingly, Ramachandran's attempt to reduce aesthetic experience to a set of physical or neurobiological laws has already met with stout criticism. A symptom of trouble to come has been seen in his use of the term "pretty". If used at all by serious art critics, the word damns with faint praise. Prettiness is not seen as a synonym for beauty, but as a shallow impostor. Yet Ramachandran uses it without irony as a positive attribute. This one piece of unfortunate terminology might be forgiven, but other elements in his work are all of a piece with it.

First, there is the heavy reliance on the female form and upon the erotic in his examples. Then he seems to equate "arousal" (as measured by SCR) with a positive aesthetic response - an assumption felt by critics to presuppose the reductionist case he is trying to prove. Taken together, these points seem to some critics to confuse pornography with high art.

The "science of art" has also been attacked from the scientific side, on the grounds that its proponents have not yet conducted any serious empirical tests of their ideas. At best they have offered a manifesto for a research programme and made some suggestions for possible lines of investigation. Even then, it has been pointed out that the narrow range of examples used hardly justifies the lofty claims to be dealing with the whole of art, let alone to have uncovered the "laws of aesthetic experience". Nor has hitching his bandwagon to the Buddhist train, by associating his "eightfold laws" with the Buddha's eightfold noble path won Ramachandran any friends, though to be fair, he admits himself that this is a slightly whimsical association.

Criticism has centred on the lack of proportion between the narrow approach to art taken by Ramachandran and the grandiloquent claims he makes for his theory - although, as he admits, he initially proposed it "in a playful spirit". But the very audacity with which its author propounds it guarantees that we shall be hearing a lot more of it in the coming months.

The eight laws of artistic experience

1 The 'peak shift principle' makes exaggerated elements attractive

2 Isolating a single cue helps to focus attention

3 Perceptual grouping makes objects stand out from background

4 Contrast is reinforcing

5 Perceptual 'problem solving' is also reinforcing

6 Unique vantage points are suspect

7 Visual 'puns' or metaphors enhance art

8 Symmetry is attractive

1. V.S. Ramachandran and William Hirstein are publishing a fuller exposition of this subject later this year in the Journal of Consciousness Studies under the title "The Science of Art, A Neurological Theory of Aesthetic Experience".

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