It makes sense that the word feeling can refer to an emotion and a sense of touch. Like smells and songs, certain textures can call up specific emotional states — the sense of calm coziness, for example, that comes from stroking the fur of a cat, or wrapping yourself up in a fleecy blanket.
Most of the time, these connections follow pretty predictable patterns. Studies on touch preference over the years have generally yielded the same results: We like things that are soft or smooth; we dislike things that are jagged or sharp; depending on what we’re feeling, we experience a mild sense of pleasure or displeasure. Research has shown that these preferences can have measurable effects, influencing our moods and how we relate to others. We’ve made room for these patterns in our metaphors, too: A particularly harrowing experience is “rough.” A sweet moment makes you feel “warm and fuzzy.”
In some rare cases, though, the link between touch and emotion can take some strange and extreme turns. Imagine being so disgusted by denim, for example, that running a hand over jeans makes you want to puke. Or feeling the urge to laugh whenever you touch silk. Or getting the creeps whenever you put on a fabric glove. That’s life for people with tactile-emotional synesthesia, a mysterious condition in which seemingly arbitrary textures can be enough to make someone laugh or cry.
Broadly speaking, synesthesia is when senses or information-processing pathways bleed over into one another. Synesthetes can hear colors, or see numbers as faces, or feel that they’re touching something if they see another person touching it. There are no hard numbers on synesthesia’s prevalence, but researchers have estimated that anywhere from 0.02 percent to 4 percent of people have some form of it. One of the most common types is grapheme-color synesthesia, in which letters or numbers are consistently perceived as certain colors (the numeral “4” is always orange, for example).
Tactile-emotional synesthesia is among the rarest forms, or at least one of the most sparely studied. It was first identified in 2008 by V.S. Ramachandran, a neuroscientist at the University of California, San Diego, and his former graduate student David Brang, now a postdoctoral research fellow at Northwestern University. In the journal Neurocase, the researchers described the unusual experiences of two women in their 20s, AW and HS: Both were mentally and neurologically normal, except for the fact that, both women, since early childhood, had experienced strong emotions brought on by certain textures. “Certain types of textures evoke raw or primal emotions such as joy or disgust,” the authors wrote, “whereas others generate subtle nuances of emotion such as jealousy or guilt”:
In the case of subject AW, the most extreme sensations arise from the texture of denim, causing feelings of depression and disgust, and silk, generating the experience of perfect happiness and contentment. With subject HS, the most acute sensation is gained from soft leather, which she personally describes as “making my spine crawl.” The intensity and quality of each emotion experienced is consistent over time for any given texture (e.g., denim always causes extreme disgust). In both subjects there are textures that elicit no sensation (human skin or paper).
For AW in particular, the researchers noted, the emotions differed depending where on her body the tactile sensations were happening. Emotions were strongest from her pinky and index fingers, but could come from anywhere on her hands and feet (though often with different results — when she felt ceramic tile with her hands, for example, it brought a sense of calmness, but feeling the same material with her feet triggered a sense of power). If she felt a texture someplace other than her hands or feet, she’d experience a weaker sense of the same emotion — denim on her face, for example, made her vaguely uncomfortable, but didn’t trigger the same feelings of disgust.
So what separates regular feelings brought on by touch from tactile-emotional synesthesia? After all, past studies have shown links in non-synesthetes between what we touch and how we think and feel: Holding a warm beverage, for example, can as a buffer against negative emotions. Handling rough objects can make us harsher in our judgments of social interactions, while softer surroundings can make us more generous.
In part, it’s a matter of degree: “It’s an exaggeration of something that’s present in all of us in a limited extent,” Ramachandran says. He lists two main criteria for this particular form of synesthesia: The tactile-emotional connection has to be strong, and it has to be idiosyncratic. That vague sense of stroking-the-cat coziness doesn’t count; AW’s account of becoming confused and disoriented when she felt corduroy, on the other hand, meets both qualifications.
Researchers still don’t know precisely what causes tactile-emotional synesthesia, but Ramachandran believes it has to do with excess connections between different areas of the brain: “In the brain of the fetus, everything is connected to everything. And there are genes which then prune these connections, sculpt the modular organization of the adult brain, so they remove the excessive connections,” he explains. But in some cases, these genes express themselves abnormally, leaving stronger-than-normal links.
Ramachandran and Brang have also studied grapheme-color synesthesia; in those cases, Ramachandran says, the part of the brain that processes shapes is hyperconnected to the part in charge of color. The same thing, he believes, may be happening in people with tactile-emotional synesthesia: It’s possible that the insular cortex, which regulates emotion, may never have been fully pruned from the somatosensory cortex, which processes touch (Ramachandran describes it as “a map of the entire body surface,” with different areas processing tactile sensations for different body parts).
Another piece of the puzzle, though, is how each connection forms in the first place — why denim in particular is disgusting, or why silk is joyful. On the one hand, Ramachandran says, it’s possible that some of these responses are born out of memory, a particularly traumatic or positive experience with a certain texture creating a lasting unconscious reaction.“They’re not born with a response to denim,” he says, “so they must have had exposure of some kind.” But, on the other hand, certain quirks seem to suggest that these links truly are as arbitrary as they seem: If AW’s synesthesia was connected to a memory of ceramic tile, for instance, the emotions should have been the same regardless of whether she felt it on her hands or feet.
If these associations are learned, it may be possible for synesthetes to unlearn them, if they want to. The original case study suggests they might, at least in certain cases: “Switching rapidly across different textures from an array is reported to be ‘emotionally draining,’” the researchers noted, and both women in the original case study had developed tricks to help themselves navigate a texture-rich, emotional roller coaster of a world. HS, for example, relied on size and temperature to guide her — the same object could inspire very different feelings depending on whether it was cold or hot, large or small. AW, meanwhile, would sing or hold a calming piece of silver in one hand whenever she had to touch something unpleasant.
At the same time, though, their synesthesia often came in handy, giving them a consistent, immediate way to regulate their mood: If they were stressed or upset, all it took was a touch of the right texture to pick them back up. It’s like having the control panel to your emotions at your fingertips, with the power to press any button at will. Except, of course, you don’t always know what each button will do. And inevitably, you have to spend some time pressing the bad ones. When seemingly any touch can send you up or down, the world becomes more thrilling and more frightening — and more emotionally evocative, a phrase we sometimes use interchangeably with the word “touching.”