Synesthesia: When Senses Intertwine
“In the beginning, [the speech therapist’s] presence was just the sound of her voice, which tasted like tamarind pickle. As days passed, her presence became a peacock blue, dipped in the taste of tamarind pickle…” (Mukhopadhyay 2008).
Mukhopadhyay has synesthesia, also spelled “synaesthesia,” which is “a perceptual anomaly in which a sensory stimulus…automatically triggers” an unrelated sensory experience, called a “photism.” In the example of Mukhopadhyay, the sound of the therapist’s voice evoked a taste while her presence evoked a color. For other synesthetes, “musical tones elicit the visual experience of colors.” These photisms are different for each person.
Most sources say that roughly 4% of people experience some kind of synesthesia.
Synesthesia is Real
Many people do not consider synesthesia to be a real psychological phenomenon “despite a century of research.”
One study used a diagram with “an array of 2’s in the form of a triangle…hidden within a field of distracter graphemes such as 5’s.” For many synesthetes, the 2’s appeared in a different color than the 5’s, so they could easily find the hidden triangle of 2’s.
History of Synesthesia
Synesthesia is not a new anomaly. In 1812, Georg Sachs published a dissertation where he discusses not only his albinism but his synesthesia. In the dissertation, which is the earliest valid record of synesthesia, he describes the colors he associates with “numbers, the days of the week, the time periods of history and of human life, the letters of the alphabet, and other similar things.”
What he experienced is grapheme-color synesthesia, in which the synesthete “[perceives] letters or numbers printed in black ink” as a different color. For letters, Sachs saw “D [as] yellow; F [as] dark gray; [and] H…[as] bluish ash-colored,” to name a few. For numbers, he saw “8…[as] brown…[and] 9…[as] nearly dark-green,” to give some examples.
Sachs’s photisms were not only triggered by linguistic sequences but also by music. The colors of musical tones coordinated with the associations Sachs had for letters; therefore, he saw the tone “D” as yellow and the tone “F” as dark gray.
Characteristics of Synesthesia
- Synesthesia is specific.
The photisms in a synesthete’s head are so specific that it can be hard for them to describe what they see or feel. For example, Sachs described the letter E as “more inclined to rose,” perhaps because he could not describe the vivid detail he saw.
- Synesthesia is consistent.
Unlike learned associations, a synesthete’s photisms do not change. In one study, nonsynesthetes were conditioned to associate a color with a letter of the alphabet. Then, synesthetes and nonsynesthetes were asked what color they associated with each letter. A week later, during a retest, “nonsynesthetes had less than a 38 percent consistency” to their original answers, “even though they had been told to expect a retest.” Synesthetes, however, were 93 percent consistent to their original responses when they were tested a year later.
Sachs noted this consistency in his dissertation when he said that his photisms were “intimate and recurring.”
Types of Synesthesia
Some synesthetes experience photisms only from a specific stimulus, called lower synesthesia. Others experience photisms based on the abstract concept of a stimulus, called higher synesthesia.
For example, for grapheme-color synesthesia, lower synesthetes may see the color green associated with the Arabic numeral “7,” but the Roman numeral “VII” would not evoke the color in the synesthete’s brain. Instead, the synesthete would see Roman numerals in the colors that align with their alphabet photisms. My friend, who is a lower synesthete, sees the letter “I” as red and “v” as dark lavender, so to her, “IV” appears in the colors of red and dark lavender respectively.
Higher synesthetes, however, would be triggered by both Arabic and Roman numeral 7, as well as an array of seven dots, because their synesthesia is based off the abstract concept of the number 7. In the case of “IV,” the higher synesthete would see “IV” in the same color as he or she sees the Arabic numeral “4.”
Another distinction for this perceptual anomaly is between bimodal and multimodal synesthesia. Bimodal synesthesia involves only two different areas of perception (sensory modalities), such as when a “sound triggers the perception of a color.” Grapheme-color synesthesia is considered to be bimodal.
Multimodal synesthesia, on the other hand, is “when stimulation of one sensory modality triggers simultaneous sensations in several other senses.” For example, a person could “experience the taste of the sound while simultaneously seeing the [color] and experiencing tickling sensation on the skin.” The multimodal type is usually more unpleasant than the bimodal type because it is overwhelming; the synesthete “can experience stress, dizziness and information overload.”
Each variety of synesthesia adds to the synesthete’s experience of the world.
Most synesthetes could not imagine living without their abilities; it is a part of who they are. Synesthesia, the beautiful anomaly, brings unique sensations to what would be considered ordinary.