Are a person’s eyes the only way to see color? That’s one of many sensory related questions assistant professor of philosophy Brian Glenney has been exploring for the past several years in his scholarship and research, using color sonification sensory substitution devices (SSD) to test his theories. Next month at a conference in Scotland on sensory worlds, Dr. Glenney will present some of his findings. His abstract below describes the highlights of  his talk:

Hearing Real Colors with Adaptive Technologies

By Brian Glenney

“African Grey Parrots (Psittacus erithacus) have a tetrachromat visual system with a fourth pigment sensitive to ultraviolet wavelengths (Bennett and Cuthill 1994). So, trichromat humans cannot be expected to share the same color categories as their feathered friends. For one, parrots perceive more colors.  Two, this fourth band of wavelengths influences how all colors are perceived by parrots (Shepard 1997). For instance, it influences their categorization of colors at the opposite end of the spectrum, of red and orange colors, like the color of a ripe grapefruit (Pepperberg 1999). So, physiological differences suggest that color perception is better for parrots than humans and if not better, at least different. It is therefore prima facie unreasonable to think that the parrot and the human both see “real” colors, or colors that represent real color properties of objects.

The physiological details need not derail color realism across species as it may be argued that ecological differences—differences in how species respond to their environment with respect to different action potentials evolved out of their distinctive ecological niche—primarily influence a species’ color categories (Matthen 2005). For instance, the color of a ripe grapefruit for a parrot might be the color of an unripe grapefruit for a human. So, the real color of a ripe grapefruit might be a point of irresolvable contention in a debate with parrot, for both physiological and ecological reasons. That is, unless real color is just a label for what’s ecologically relevant to a species, a view advocated by Mohan Matthen’s (2005) called “Pluralistic Realism.”

The central question I would like to raise in this paper is whether the perception of real color might include stimuli from any sensory system whose input was within the visible and near-visible spectrum.  For instance, might color content be processed by an auditory system with color receptors? For instance, might subjects wearing a color sonification sensory substitution device (SSD) that processes color content using the auditory system hear real color much like a parrot or a human sees real color? To argue “yes” is to advocate “Radical Pluralistic Realism.”  What makes it radical is that, unlike Matthen’s view, color content can be processed by a visual system that did not evolve out of processes relevant to an ecological niche.”