Ambiguity in Art and in the Brain (review)

Commercial Ambiguity

“Use Dr. _____ Sachets de Toilette, and mothers and daughters will look like sisters.”

    — Gentlewoman

(cited in Punch, October 1907)

With new art historical work being published on ambiguous “potential images” [1], and the hybrid discipline of neuroaesthetics becoming more widely recognized as a specific strand in the larger debates about art and consciousness [2], I was intrigued to learn what one of the leading proponents of neuroaesthetics, Semir Zeki, had to say about the neurological basis of ambiguity. The exploitation of ambiguity has been a deliberate artistic strategy not only amongst modern and contemporary practitioners but throughout the pre-modern world and across many different cultures. Ambiguities have been presented sometimes as a kind of amusement or curiosity (as in certain optical devices, or the quote above) and sometimes as a way of profoundly affecting the viewer, resisting stasis and multiplying perceptual and conceptual possibilities (as in analytic cubist paintings or Vermeer's enigmatic domestic interiors).

Zeki's contribution is to attempt an account of artistic ambiguity from a neurological standpoint, drawing on his own extensive research into color constancy and the nature of visual perception. He is keen from the outset to situate his analysis within the context of consciousness studies, and in particular to stress his theory of “microconsciousness.” In contrast to those who regard conscious experience as singular and unified, Zeki proposes a model in which the various functionally specialized areas of the brain (such as those responsible for color perception or motion perception) in themselves constitute regions of conscious activity needing no higher interpretation. The impression we have of an immediate holistic conscious experience is in fact illusory, given that, as Zeki has shown experimentally, we see color a fraction of a second before we see motion, even though a moving red bus seems to form a perceptual unity. Over longer time frames (greater than one millisecond), such temporally distributed events form a “macroconscious” state, which might further be modulated by those higher conscious states conditioned by culture and language, ultimately generating the kind of conscious awareness we associate with our everyday general activity. Even though these higher conscious processes are prone to error, by misconstruing the reality of what is present in the world, the functionally specialized areas cannot in themselves be fooled into seeing what is not there. The perception of color, for example, can never be ambiguous because color is nothing but a product of functionally specialized brain regions. As Newton had already pointed out, there is no color “out there” in the world for us to see, only variations in the frequency of electromagnetic radiation, which we experience in a chromatic register.

Although many perceptual processes result in visual experiences that we cannot consciously influence (such as color), there are other kinds of visual phenomena that are subject to cognitive contingencies—ambiguous images being prime examples. In the familiar Necker cube or Schroeder staircase (examples from Zeki's lecture can be found at <http://turner.stanford.edu/art/zeki_images/>), we are able to some extent to determine the apparent orientation of the object, which lies in one of two directions. (I would also suggest it is possible to see other kinds of orientations, but for the purposes of this review I will accept the convention that there are two.) In such cases, Zeki argues, the functionally specialized visual areas (those responsible for recognizing lines and angles) draw upon other brain processes, notably those concerned with memory and experience, to produce a cognitive interpretation containing spatial information that is actually absent in the image. This cognitive interpretation is prone to vacillate between the ambiguous readings, but is also subject to some degree of conscious control, insofar as we can force ourselves to see one orientation or the other.

For Zeki, this way of understanding ambiguity differs markedly from its dictionary definition as “doubtful” or “uncertain.” On the contrary, each of the possible interpretations is, for the viewer, an utter certainty...