Nerenberg Lecturer Glimpses into Aesthetics

After announcing that the seventh Nerenberg Lecture, given on March 9, was entitled “Chaotic music and fractal art: a glimpse into the neurophysiology of aesthetics,” Professor Leon Glass said that he was “not a philosopher of aesthetics.” However, Glass is the holder of the Isadore Rosenfeld Chair in Cardiology and professor of Physiology at McGill University. It is from this physiological perspective that Glass explored how audio or visual patterns generated through chaotic equations or random dot patterns can affect human perception.

By way of example, Glass showed how chaotic equations work, these equations are described as non-linear and possess irregular dynamics. That is, for certain initial values the equation will yield new values, when those new values are entered into the equation they yield more values that are either positive or negative, large or small, there is no telling beforehand how the equation will behave. Through this iterative process, even tiny differences made to the initial values placed into the equation, will result in an entirely different pattern. Yet, the unpredictable behaviour does follow the rules and a pattern does eventually emerge. Glass then played recordings of the late Jeff Pressings audio demonstration of chaos equations after which Glass commented that “most people hate this.” Glass concluded that chaotic music is alien to our ears, “it does not use familiar devices of rhythm, harmony, nuance, orchestration or even a familiar set of tones.”

The situation is different when chaos is represented as fractal art. Glass showed different aspects of the Mandelbrot Set and pondered why this representation of chaos should be so aesthetically pleasing to so many people. He suggests that the visual complexity of the natural world is captured by fractal patterns. Glass cited examples of riverbeds and the branching patterns of trees and plants.

The last section of the talk focused on the random dot patterns that Glass generated in the early seventies. In those days the imperfections in photocopiers tended to produce random black dots and, if those images were recopied, the black dots would become more pronounced and the copies would be stretched slightly in one direction. When Glass tried to superimpose these images over each other, he noticed that circular patterns would just pop out. He soon learned that by manipulating these random dots in certain configurations he could generate ellipses, spirals and hyperbolas. Throughout all of these images, the underlying patterns were still random. Glass soon realized that these patterns could be used to probe how the brain processes images and how the visual system works. To this day, these Glass patterns are used to identify areas that process global forms in the macaque visual cortex through functional magnetic resonance imaging.

Glass concluded the Nerenberg lecture by saying that by probing the physiological basis of perception, the quest for understanding what is beautiful must ultimately be addressed by neurophysiologists as well as philosophers.

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