I visited a neuropsychologist recently who told me I have Synesthesia. I never really knew what it was, but it's fascinating and I can't believe it isn't the norm among people. For me, certain numbers just have had personalities.

For some reason, the more difficulty I had with the number, the more complex personality it had. For instance, I had a lot of trouble with odd numbers, and larger numbers. Therefore, 1 and 2 do not have personalities. On the contrary, 7 and 9 are the most developed personalities.

How rare is this condition?

  • $\begingroup$ Mia, I took out the part asking for personal stories, as that makes the question "not constructive" by Stack Exchange standards. However, feel free to fill that in with more scientifically-based questions about the topic. $\endgroup$ – Chuck Sherrington Dec 30 '12 at 5:37
  • $\begingroup$ I feel like more initial research could be done on this question. Start by googling synesthesia demographics. I think there's more than one kind of synesthete too (upper vs lower) $\endgroup$ – Keegan Keplinger Dec 31 '12 at 18:27
  • $\begingroup$ Thanks, I have researched it but the results have been varied. I get different answers for each site I get. $\endgroup$ – Mia Dec 31 '12 at 19:13
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    $\begingroup$ V.S. Ramachandran has studied this syndrome intensively edge.org/3rd_culture/ramachandran07/ramachandran07_index.html scholarpedia.org/article/Synesthesia#Genetics_of_synesthesia $\endgroup$ – Hauser Jan 5 '13 at 19:35
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    $\begingroup$ It's not really clear how rare it is, because so many people probably have it without knowing that it's a condition. So the population may vary from 1 in 200 to 1 in 200000. Nobody knows how many exactly. $\endgroup$ – Elso05 Jul 5 '17 at 8:23

From Hubbard & Ramachandran (2005):

[...] the estimated prevalence of synesthesia has varied dramatically, between as many as 1 in 20 (Galton, 1883) and as few as 1 in 25,000 (Cytowic, 1989). The most widely cited study to date suggests that synesthesia occurs in at least 1 in 2000 people (Baron-Cohen et al., 1996), although this is now generally regarded as an underestimate. Our own informal samples have suggested that the prevalence of grapheme-color synesthesia might be between 1 in 200 (Ramachandran and Hubbard, 2001b) and 1 in 100 (Mulvenna et al., 2004). Subsequent large-scale studies have suggested that the prevalence of synesthesia might be as high as 1 in 20 across all forms and 1 in 100 for grapheme-color synesthesia (J. Simner, personal communication). This high prevalence argues against the notion that synesthesia is merely a “benign cognitive variant” (see Ward and Mattingley, 2005) and instead suggests that it is a widespread phenomenon that may provide novel insights into the neural basis of the mind (Ramachandran and Hubbard, 2001b).


Hubbard, E. M., & Ramachandran, V. S. (2005). Neurocognitive mechanisms of synesthesia. Neuron, 48(3), 509.


The wikipedia Article on Synesthesia cites some prevalence studies

Random population studies ... determined that 1 in 23 individuals have some kind of synesthesia, while 1 in 90 have colored graphemes (Simmer et al 2006). Colored days of the week and colored graphemes are the most common types(Simmer et al 2006; Campen, 1999).


  • Simner J, Mulvenna C, Sagiv N, et al. (2006). "Synaesthesia: the prevalence of atypical cross-modal experiences". Perception 35 (8): 1024–33. doi:10.1068/p5469. PMID 17076063.
  • Campen C (1999). "Artistic and psychological experiments with synesthesia". Leonardo 32 (1): 9–14. doi:10.1162/002409499552948.

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