Synesthesia is the source of near-endless fascination for neuroscientists. It’s “probably the sexiest neurological phenomenon around,” Michael Mays observed on Studio 360 last February. Synesthetic people tend to reflexively blend their senses together, seeing colors in response to music, for example, or link shapes with specific tastes.
A new study, highlighted by the New Scientist, documents the first known cases of an unusual form of synesthesia where textures blend with emotions. For these synesthetes, corduroy may produce confusion, while dry leaves might trigger disgust.
For the study, neuroscientists V.S. Ramachandran and David Brang tested their subjects twice over the span of eight months to confirm that they felt textures in emotionally specific ways. Their associations stayed the same throughout the tests: One woman described the sensation of sandpaper as “telling a white lie” in the first round of tests, and said she felt “guilty” after touching it the second time, “but not a bad guilt.”
The study follows only two subjects, so this particular form of synesthesia is likely rare, but it’s more than a curiosity. Neurologist Richard Cytowic estimates that 1 in 23 people experience some kind of synesthesia.
Ramachandran theorizes that synesthesia may be an evolutionary adaptation that helps people think creatively and metaphorically. He describes synesthetic experience as a spectrum, where nearly everyone has the ability to make some form of synesthetic connections. For example, he sees traces of tactile-emotional synesthetic thought in the widespread use of phrases like “sharp criticism” or a “rough night.” In fact, Ramachandran thinks that studying synesthesia could help explain some key milestones in human evolution, like the development of language.