A Rainbow Is A Song: The Wild, Curious & Wonderful World of Synesthesia

What’s the Big Idea?

On a late winter day in 1922, the sound of a gun shot resounded with a loud boom in the hills surrounding the house of three-year-old Edgar Curtis. The sound itself wasn’t out of the ordinary, since the Curtises lived near a firing range. What was extraordinary was the question the boy turned to ask his mother: “What is that big, black noise?” 

A few days later, when his mother was putting him to bed, Edgar heard the chirping of a shrill cricket and demanded, “What is that little white noise?” For Edgar, low, rhythmic notes were dark in color. High-pitched sounds were pale, and, researchers later discovered, tones in between were variously red, blue, and purple. A rainbow was “a song.” 

Edgar Curtis’ story is an early example in the scientific literature of synesthesia, a neurological phenomenon in which one or more sensory modalities are linked. “There are many different forms,”  says David Eagleman, a neuroscientist known for his ability to garner important insights into the nature of perception and consciousness through idiosyncratic methods. “Essentially, any cross-blending of the senses that you can think of, my colleagues and I have found a case somewhere.”  

Watch our interview on synesthesia with neuroscientist David Eagleman: