Rainbows in the Brain

Studies show increasing arousal levels in humans responding to the perception of increasing wavelengths of light, from blue to green to red, in the same order that colors are arranged in a rainbow.

Thermoaesthetics

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The scarlet macaw (Ara macao). Photo by Pedro Rivera on Unsplash

“I procured me a Triangualar glass-Prisme, to try therewith the celebrated Phenomena of Colours. And in order thereto having darkened my chamber, and made a small hole in my window-shuts, to let in a convenient quantity of the Suns light, I placed my Prisme at his entrance, that it might be thereby refracted to the opposite wall. It was at first a very pleasing divertissement, to view the vivid and intense colours produced thereby; but after a while applying my self to consider them more circumspectly, I became surprised to see them in an oblong form; which, according the received laws of Refraction, I expected should have been circular.”

— Issac Newton, “New Theory About Light and Colours” (Egger et al. 2011)

Contents

Color and Arousal
Embodiment of Physical Realities
Animal Coloration Patterns
Emotional Arousal Versus Valence
Moderation and Mixtures of Color
Rainbows in Animals
Rainbow Bias
Works Cited

Color and Arousal

Wilms and Oberfeld (2018) measured skin conductance and heart rate as indicators of arousal in subjects observing red, green or blue light presented on a screen in an otherwise dark room. The results showed a significant effect of color on arousal, with red being most arousing, green being moderately arousing and blue the least. Different studies have had similar results, and others might fill in the remaining colors of the rainbow, putting orange and yellow between red and blue arousal-wise, for instance. Wilms and Oberfeld’s experiment was special in that it controlled for color brightness and saturation, which interact with hue in determining how colors are perceived. Arousal increased significantly with increases in both the saturation and brightness of a color.

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Thermoaesthetics

A concept of aesthetic complexity based on universal animal preferences for mixtures of simple, more and less exciting physical and psychological opposites.