Science to Live By: Our Senses (Part One): Synesthesia


© J. Dirk Nies, Ph.D.

“Papa, would you please transpose this song into the key of E?” Ryan frequently asked this of me when I was playing the piano. My son had perfect pitch, so he discerned with ease the key of a musical composition. But I suspected something more was at play in his recurrent requests. Ryan’s answers to my inquiries led me to discover the fascinating field of synesthesia, a way of perceiving the world experienced by perhaps as many as one in every 2,000 people who are as diverse as the late Nobel Prize winning physicist Richard Feynman, jazz pianist and radio personality Marian McPartland, and the cartoonist Michel Gagné, creator of the synesthetic taste sequences in Disney/Pixar’s animated movie “Ratatouille.”

Our senses provide us avenues of awareness to our surroundings. They send inklings of reality to our sentient (from Latin sentire, “to feel”) minds. Our minds, in turn, are conscious of, interpret and respond to these received sense impressions. For most of us, our nervous system and our brain keep our senses separated. For those with synesthesia, direct linkages exist between them.

Synesthesia is a perceptual condition that augments and expands a given sensation into multiple sensations. Stimulation of one sense (e.g., hearing) elicits a sensation/experience in one or more of the others (e.g. vision, taste, touch). Solomon Shereshevsky, the late Russian mnemonist with the ability to remember and recall unusually long lists of data or entire speeches word for word after one hearing, experienced synesthesia linking all five of his senses. When asked to memorize a new word, he would not only hear it, he would see its color, taste its flavor in his mouth, and feel it on his skin.

Sound γ color synesthesia (chromesthesia) occurs when voice, music or other sounds prompt color or colored shapes to appear and then fade in the mind when the sound ends. When Ryan heard an E major chord or melody in the key of E, he simultaneously “saw” blue (his favorite color) in his mind’s eye. But not only this, he “tasted” the sweetness of sugar in his mouth and “felt” the mood of happiness. No wonder his repeated appeals to transpose music into the key of E! The benefit is especially pronounced when transposing from the key of D, which evoked in Ryan the color red and is the saddest of the keys.

In addition to one sense evoking other senses, some synesthetes perceive distinct colors when they look at letters, numbers and geometric shapes (which collectively are called graphemes). For them, the alphabet from a to z and the digits from 0 to 9 create a kaleidoscope of color.

Ryan had grapheme γ color synesthesia. The letter A and the number 2 always take on the color red, while the letter R and the number 1 always appear blue. The other letters and numbers are tinted brown, orange, yellow, yellow-green, green, cerulean, blue or purple. Some such as 7 or T remain black. For Ryan, these elicited colors appeared even when the letters or numbers were shaded with a color that differed from his synesthetic palette.

Here is a little ditty of a poem I wrote to convey a sense of what the world was like for Ryan, and for all synesthetes.

Violets are like 1 and R, roses like A2;

E major is a cheerful sweet, and also a deep blue.

E minor shifts to sour sad, orange now its hue,

Perceptions as a synesthete, prism the view.

nies-diagramContext can make a difference in grapheme γ color perception. Notice that the middle circle took on a different color for Ryan depending upon whether he perceived the grapheme pictured as a number, letter or geometric figure.

Our senses are a vital feature of what it means to be alive. When one or more of our senses are impaired or lost, often another becomes heighted to compensate. By placing her exquisitely sensitive and highly trained fingers on a speaker’s mouth, Helen Keller, who was both deaf and blind, could “hear” words by “reading” lips.

Our use of sensory metaphors reflects the foundational importance of our senses. A get-rich-quick scheme can “smell” like trouble or “sound” too good to be true. When we make poor or irrational choices (which can leave a bitter “taste” in our mouth), we often are told we’ve lost “touch” with reality, or we were “blinded” by love.

Providing links not only to the present, our senses afford bridges to the past. The aroma of fresh baked pie hot from the oven, the squawk of sea gulls and the smell of a freshening sea breeze, or the pungent odor of a gym locker can transport us to another place and time, summoning memories long idle or forgotten.

In future articles, I will highlight our scientific understanding of the processes empowering our sense of smell, taste, touch, hearing and sight; and our sense of time. While we share these senses in common, we each perceive in our own way. Our lives are broadened and enriched when are senses are attentive and attuned to the natural and cultural worlds in which we live, all the more so when we celebrate the distinctive perspectives others bring to the familiar.


  1. Dirk,
    You descirbe the extraordinary way in which Ryan experienced the world. It was a gift as well as a burden I am sure.
    We all need to undersatnd this more.
    Keep writing!

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