Do the math: 930,000 U.S. kids with synesthesia, out of 60 million students. (Okay, “synaesthesia” for the British search programs.)
You might have one. A pyschologist in Britain did the research.
For the first time, psychologists have documented the prevalence of a form of synaesthesia – the condition that leads to a mixing of the senses – in a large sample of children. Over a twelve month period, Julia Simner and colleagues tested 615 children aged six to seven years at 21 UK schools and conservatively estimated that 1.3 per cent of them had grapheme-colour synaesthesia, in which letters and numbers involuntarily trigger the sensation of different colours.
“[This] implicates over 170,000 children age 0–17 in the UK alone, and over 930,000 in the USA,” the researchers said, “and suggests that the average primary school in England and Scotland (n = 168 pupils) contains 2.2 grapheme-colour synaesthetes at any time, while the average-sized US primary school (n = 396 pupils) contains 5.1.” Inevitably, the prevalence for synaesthesia as a whole, considering all the sub-types, would be even higher.
A hall-mark of grapheme-colour synaesthesia is that the colour triggered by a given letter or number is always the same – a fact the researchers exploited to identify the condition in school children.
Indeed, when asked to associate letters with colours, the children identified as synaesthetes showed more consistency over a 12-month-period than the other children did over a ten second period!
Researchers calculated about 5 such students in the average U.S. school, assuming a student population of about 400.
400! In Texas that’s a tiny high school that may have difficulty fielding a football team.
In Brain, a journal of neurology (abstract available, full text with subscription).
J. Simner, J. Harrold, H. Creed, L. Monro, L. Foulkes (2008). Early detection of markers for synaesthesia in childhood populations. Brain, 132 (1), 57-64 DOI: 10.1093/brain/awn292
Tip of the old scrub brush to Research Digest Blog.
Resources:
- More synesthesia research noted at Research Digest Blog
- Simner’s site at the University of Edinburgh (with links to news stories)
- BBC 2005, “Why some see colours in numbers”
- BBC’s Horizon, program on synesthesia
- New York Times, “When people see a sound and hear a color,” 1999
- New York Times, “Synesthesia: A strange gift,” letter to the editor, July 2, 2006
- New York Times, “A reason we call our cheddar ‘sharp’ and shirts ‘loud,'” Sandra Blakeslee, April 10, 2001
- The Man Who Tasted Shapes, Richard Cytowic (MIT Press 2003) (a reissue of the 1993 book?)
- Cytowic’s website, entry on The Man Who Tasted Shapes
- [Michael S. Gazzaniga reviewed Richard Cytowic’s The Man Who Tasted Shapes in the October 24, 1993 edition of the New York Times; I can’t find the review, but there are letters in response]; “All mixed up,” letter to the editor, November 21, 1993; second letter, same date
- Invitation to join the Synesthesia List, at the bottom of this page
Posted by Ed Darrell 
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