Neurological Agreement in Color Perception

Article: Do you see red like I see red?
Source: The Conversation, via Knowable Magazine
Published: February 5, 2021

This article from general science news is extra special in that the authors of the news article are also the authors of the research. The research was aimed at answering the question of color perception, both the purpose of color perception and the physiological agreement of color perception, from a neuroscience perspective. Two studies were discussed. In one study, by a different research team, participants were shown real-world stimuli illuminated by low-pressure-sodium lights (similar to the kind found in parking garages). The yellow light (perhaps any colored light) prevents the retina from properly encoding color. The participants could still recognize objects, such as fruits, but those fruits appeared unappetizing. The participants could still recognized faces, though those faces looked green and sick. The researchers think that when normal color perception expectations are violated, this sends an error signal to the brain to interpret the situation as amiss, that there is something wrong. In other words, such studies confirm that color perception encodes meaning.

But what about individual variations in perception of color? There is of course the physical basis of color in the wavelengths of visible light. But is one person's perception of red the same as another person's? In the second study, conducted by the authors, magnetoencephalography  (MEG) was used to measure participants' brain wave activity in response to different color relationships. Note that the study design does not answer the much tougher question of whether responses to specific colors are similar across people. Rather, it is a measure of responses to color relationships, such as a person's perception of the relationship between red and orange. The MEG results showed that a person's neurological response to more closely similar colors, such as light green and dark green, is more similar than the response to less closely similar colors, such as yellow and brown. Furthermore, these relationships are preserved across people. As the authors conclude, “Physiological measurements are unlikely to ever resolve metaphysical questions such as 'what is redness?' But the MEG results nonetheless provide some reassurance that color is a fact we can agree on.”

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