You May Be Synaesthetic And Not Know It

We post often about synaesthesia, a strange neurological condition characterized by a link between two or more senses. (A particular musical note "sounds" red, etc.) New research suggests that many more people may have synaesthesia than realize it. In one experiment at McMaster University in Canada, self-described non-synaesthetes associated the smell of certain foods with certain colors and textures. From New Scientist:
When the researchers analysed the results, along with some obvious associations – lemon with yellow and peppermint with smooth, hard and sticky – they found some odd ones.

Significantly more people than chance, for instance, associated the smell of mushrooms with the colours blue or yellow. Lavender elicited the colour green and the texture of sticky liquid, while ginger was perceived as black and sharp.

"The influence of learning is there," (researcher Ferrinne) Spector told a meeting of the American Synesthesia Association in Hamilton on 27 September, "but it cannot explain all associations."
Do we all have some synaesthetic ability?

Previously on BB:
Many more synaesthesia posts


  1. Sometimes when I’m dketching I’ll try to press command-z to take back a stroke only to realize I’m using a pencil and paper.

  2. Interesting, however I thought that it was already established by the Kiki/Bouba effect that most people make synaesthesia-like connections. I guess it varies between individual manifestations, but probably most people have some form (or degree) of synaesthesia.

    Funny enough, I was having a conversation with a self proclaimed non-synaesthete friend, and he proclaimed that the number 3 would not be a trustworthy character. My jaw dropped because I have always associated personalities to numbers and 3 was indeed a sly, conniving bastard. He couldn’t explain why he also came to that conclusion, but he still claimed having no synaesthesia. Weird coincidence.

  3. I’m must be one of them : I always associated sound frequencies with colors. High ranges are yellow, mid-ranges are brown, low ranges are dark…
    And so are you ;-)

  4. @ #6
    “I have always associated personalities to numbers and 3 was indeed a sly, conniving bastard”

    That’s more like slight schizophrenia, not the latent connection between otherwise distinct sensory perception.

  5. There are differences between:
    1) having consistent associations between sensations, e.g. associating the sound of a trumpet with red, such that when I hear a trumpet I usually then think of redness;
    2) consistently personalising things which aren’t normally thought to have personalities, e.g. thinking of the number 3 as a sly bastard; and
    3) experiencing things in one sensory modality as also in another, e.g. experiencing a trumpet note as red.

    I’d have said that only (3) is synaesthesia. (1) and (2) are just the normal human habit of connecting stuff up in our minds (see the works of David Hume, passim). It isn’t particularly surprising that we’re predisposed to make some associations and personalisations rather than others (trumpet is red rather than green, for instance), given that we’re all working with the same east-African plains ape brains.

  6. So, is “synaesthesia” a neurological condition having to do with (for lack of a better term) crossed paths in perception, or is it defined more as cross-sense associations? For example, I have a number of cross-sense associations, but they’re all, well, associative; I couldn’t claim to perceive the smell of pie as orange, but I do have that association.

    The reason that I ask is that these seem like pretty different conditions, and would be treated differently. I can see how the former would be a very interesting physiological condition, while the latter seems much more psychological (and, unless I’m misreading it pretty severely, the linked experiments seem to focus on the latter).

  7. @ 8 & 9

    Personalisation of numbers is categorized as a form of synaesthesia called ‘ordinal linguistic personification’.

  8. @sam c,

    Much more eloquently said than my ramblings, thanks.

    Also, it should be noted that the experimenters themselves forced the associations. From the article:

    “They asked 78 people who considered themselves non-synaesthetes to smell 22 separate odours in glass jars and assign each a colour and a texture.”

    So, yeah.

  9. Synaesthesia seems to be making a run at Asperger Syndrome for the most self-diagnosed condition among internet users, with Trypophobia coming in at a close third.

  10. When I taste carrots, I think of the color orange and I think of the sensation of crunchiness. Does that make me synaesthetic?

  11. I’ve always thought of numbers as shapes and spaces. E.g., 3 and 8 ‘fit’ well with 7.

    The weirder part is that I’m not terribly good with math, unless the end result is a multiple of 5.

  12. I have synæsthesia.

    The human brain does not have dedicated portions for dedicated tasks – there is not a “visual cortex” per se – there is a region that is especially good at processing 3-dimensional spatial relations, and one good at discerning depth differences by comparing the view from each eye, and one good at inferring depth cues from shinyness versus haze.

    There is one good at determining 3-dimensional spatial relations by comparing phase shifts in sound wave interpretations from both ears.

    This does not mean that the signals from our senses do not make their way to those portions of our brains that we have determined to “normally” process signals from one particular sense; It is that the information produced by those processing centers happens in such instances to not be as strong as competing signals (from the “normal” sense), or do not register to our consciousness (the amount of sensory information our conscious mind discards or considers irrelevant is very large), or is not consistent with the way we have learned to view the world.

    People who consciously experience synæsthesia simply never learned to fully discard the cross-signal processing outcomes, or could not learn because they were biologically wired to have strong outcomes, or simply have learned to quiet their minds.

  13. Haven’t heard much about my kind. Bruises and other pains have specific musical notes attached to them. Like, right now, the bump I just gave my forehead at lunch is a D major, one octave below middle C. Anybody else have this?

  14. @sekino,

    Maybe I’ve missed it completely, but that wouldn’t seem like synaesthesia at all, unless the assigned personality traits were triggered by a secondary sense (for example, if I perceived the written numeral ‘3’ as a sarcastic whisper).

  15. So, is “synaesthesia” a neurological condition having to do with (for lack of a better term) crossed paths in perception, or is it defined more as cross-sense associations?

    According to the definition I know, synaesthesia occurs when the brain creates connections between adjacent (but not necessarily directly related) areas. For instance, regions that identify letters and numbers are next to the region involved in color processing, same as the area representing ordinal sequences is adjacent to regions involved with the identification of personality.

    I’m pretty sure they have to still find out for sure how it works exactly, but it sounds like a very plausible theory. I would be tempted to think synaesthesia isn’t really a ‘condition’ but instead a very common occurence in people’s brain.

  16. @bardfinn,

    Thanks for the info — cool to know.

    Is there a distinction in the field between a first-order sensory input and something associative (given that I’m not sure what the right terms are here). What I mean, for example, is the distinction between the mental rendering of a scene and an interpretation of something more abstract, like the distance a viewed object is from the viewer.

    Is the distinction meaningful?

  17. Maybe I’ve missed it completely, but that wouldn’t seem like synaesthesia at all, unless the assigned personality traits were triggered by a secondary sense (for example, if I perceived the written numeral ‘3’ as a sarcastic whisper).

    Well, again, I’m not making it up: look up ‘ordinal linguistic personification’ and it is classified as a form of synaesthesia (and it is very much what I was describing). Synaesthesia doesn’t only occur between sight/hearing/taste, although the most common ones are letters or sounds associated with colours.

    Perhaps they are all related, as it seems people often report many forms of synaesthesia. I also always saw numbers and letters as coloured: So 2 was always blue and a workaholic, J is always bright green…

    So, yeah, it probably means my brain is a big messy ball of badly wired neurons :P But it’s still called synaesthesia (from all the sources I can find).

    But I think what Glossolalia (#17) is experiencing is even wilder ;)

  18. @#13
    Maybe Synaesthesia and Aspergers are being frequently self-diagnosed because lots of people actually have some minor form of them, especially the kinds of geeks who read boing boing. Most of the programmers, record collectors and artists that I know fit the description of Aspergers and it wouldn’t surprise me if they experience minor synaesthesia (like me).

  19. @ Glossolalia black, the bruise is a D major chord? Or a scale? Or is it in some indefinable way in the of D major?

    I’m just being curious/pedantic, because “D major” is not a single musical tone. It can be a chord, a scale, or a pitch centre.

    This is interesting to me, because my experiences in music school have made me roll my eyes reflexively whenever I hear the word “synaesthesia”. Largely because every music school has its irritating wankers who sit around instead of practicing, arguing about whether the key of D flat is more purple or more cobalty and try to drag every conversation they have into bragging about their unique experience. Add them to the people with perfect pitch who claim to experience physical pain when they heard something that’s out of tune, and you get four years of dodging annoying losers.

    This may be a function of all of us being 20 years old and completely full of ourselves, though.

    Anyway, good to hear that the blathering idiots I’m talking about aren’t as special as they like to think.

  20. ‘synaesthesia’ seems to have adopted umbrella term status. my understanding always was that the condition had an involuntary cognitive dimension – ie, associations, however strong, were just that. a strong indicator of true synaesthesia is that it doesn’t change over time. synaesthetes will replicate complex and nuanced correlations after an interval of many months or even years, whereas associations tend to change.
    that said, its hard to see how ‘ordinal linguistic personification’ can have a concrete cognitive element.
    a friend who has studied this in depth told me that there is quite a famous synaesthete (among those who study it) who has an involuntary body posture for each letter of the alphabet, and who has agreed to undergo open-ended tests ‘in the field’. so occasionally someone with a clipboard will ambush him and say ‘do a ‘W”. poor chap.

  21. Kay:

    I don’t have perfect pitch, and I don’t experience pain when something is out of tune, but there are physically painful hearing experiences for me – both tonal and in the realm of rhythm. I have a very attuned sense of how long notes /ought/ to last, how their amplitude envelopes /ought/ to collapse, the most /appropriate/ tempo to play a reel, jig, or polka at when the quarter-notes last a certain length of time.

    You could play an off note for me and I wouldn’t know it from the ‘pure’ note, can’t tell one scale from another – but put two banjos with un-complementary natural note periods in the same sitting, and it is all I can focus on.

  22. @sekino (#22)

    Too true. It looks like the definition I’ve internalized is a bit too narrow (and I think your phrase, “big messy ball of badly wired neurons”, is about the best general description of the normal human brain that I’ve ever heard).

  23. isolatedgestalt:

    It is my understanding that most of what we are conscious of experiencing is a result of second- or third-order associations. I believe that i.e. determining distance is a second-order process, as it depends on some portion of the brain reconstructing some or all of an image and then comparing various cues.

    I’ve had experiences while not sleeping where various first- or second-order processes stepped up or cut out entirely, either by accident or by my own design to induce them. I understand that similar situations occur to people undergoing religious experiences or certain types of drug phenomena. It distorts the experience of the world or the psyche and was for me often an experience I could not have imagined nor prepared for.

  24. I didn’t realize that I had number->spatial synesthesia until I was 18. I’m still finding out little things that amount to a million “minor” synesthetic connections.

  25. @avraamov,

    Perhaps my sarcasm detector is broken, but that chart doesn’t seem very arbitrary, but rather fairly consistent — most of the selections simply map the visible spectrum to an octave, as coordinating increasing frequencies.

    It does raise a question, though, for those whose synaesthesia manifests itself as a color visual for particular tones. Is there a relationship between a particular scale element and the perceived colors, or is it more continuous? I.e. do you see, for example, purple for every C#, or would the C# and D immediately above middle C have similar color, while a C# an octave up differ?

  26. Anechdotic example:

    When I was a kid, sounds and bodily feelings had colour.

    If I kicked out or stretched and the movement had a pangy pain to it, the feeling was kind of yellow. Sharp sounds were yellow or light blue. Deeper, more substantial sounds were red or brown, I think.

    After puberty these things disappeared little by little, I think, but until then it was part of my daily experience.

  27. @24 It’s currently fading off into a higher tone (G Maj)… but you know the white keys on the piano? Like the D key there, but not a particular instrument, just a tone. Does that clarify?

    Different types of injury will also change the type of tone it is, whether it’s more “clangy” or “buzzy”, etc.

  28. 0 is white
    1 is black
    2 is red
    3 is blue
    4 is green
    5 is sortof a burnt orange
    6 is a blueish-green
    7 is yellow
    8 is dark green… almost black
    9 and above don’t have colors.

  29. @ 34, if it is a single pitch it is properly referred to simply as “D”. “D major” refers to, as I said above, a chord, scale, or tonal centre.

    Weird. I actually kind of get it – for me a headache has a vague pitch (very high and buzzing). If I had to pin it down I personally would say a bruise was a diminished 7th chord.

  30. @35, Jim, you seem to have my problem, except the colors are different.

    0: white, 1: black, 2: sky blue, 3: yellow, 4: evergreen, 5: red, 6: white, 7: burnt orange, 8: dark blue, 9: brown

    Incidently, that means that when I picture ‘1941’, it comes out black-brown-green-black, and looks like military drab… The 194? makes that whole decade look like war colors. I tend to associate various centuries with the hundreds digit in the year (so 19th century is dark blue, 16th century is red, and the 10th century is brown).

    It also means the hardest thing for me in electronics is the resistor code. The color mapping is wrong, and I will never, ever memorize it.

  31. Glossolalia, I’m sorry – my last post was supposed to have humourous pedant, /pedant tags around the first paragraph…don’t know why they didn’t show up. Without them I look like a dick. Sorry. ;<

  32. @IsolatedGestalt

    actually i wasn’t being sarky – i just see more chaos than pattern in the chart as an overall image. but you are right – F has a consistently green correspondence for example. it would be interesting to see some pre-newton examples; i think newton’s optics was pretty influential, and it may have corralled things statistically. it’s interesting that helmholtz’s are markedly different from the rest.

  33. The cleanser commonly used in cleaning restaurant restrooms smells pink. I’m not sure why, since it isn’t sickly sweet, which is the smell I would intellectually associate with pink. I just can’t come up with any other description of it than pink.

    I don’t think I usually do this, so I’ve always found it a bit odd. I’m very conscious of it, though, because something in the cleanser also irritates my throat and sinuses.

  34. I don’t find this surprising. The brain isn’t divided into water-tight insulated compartments, and it’s an electrochemical system. It’s reasonable to expect some bleed-over from one subsystem to another, even if the trimming of direct neural connections that occurs during brain development goes smoothly.

  35. “Lavender elicited the colour green and the texture of sticky liquid.”

    Did it? And did it also elicit the squeak of clean dinner plates?

  36. i’ve noticed at night before i fall asleep i’ll see sharp sounds like a door slam or a car alarm as a flash of light in a certain direction.

  37. Isn’t there a well-established theory that babies have to learn to distinguish sensory input into their “correct” categories? Which suggests that synaesthesia might be more of a sensory response continuum than a specific condition.

    I recall using colours, shapes and personalities as a mnemonic to help me remember numbers when I was in grade school. I still sometimes remember the thin spinster when I see the right sort of numeral 5.

  38. Olivia associates passages of reading / information with smells. I think it’s more the style of writing than the actual content.

    I’m not a synaesthete. I’m highly symbolic, and I perceive everything as it is written- like speech, ideas, I process in language, whether English or pidgin German Spanish- to the point of being utterly unvisual. I don’t ‘see’ mental images really.

  39. Me on the phone to my boyfriend this morning: “There’s a weird smell coming from the fridge, but it’s not like rotten food. It’s…low-pitched.”

    I certainly don’t have any neurological form of synesthesia, but I do make some weird cross-sense associations sometimes. I find this especially helpful while writing; I’m a Creative Writing major, and some of my best lines (and some of the lines I most enjoy by actual authors) come from synesthetic descriptions.

  40. Call me crazy and insensitive, but I really wish I had synesthesia…I think trying to map the interplay between senses and exploring the connections would be fascinating.

    However, I’m not fascinated enough to try using hallucinogens to try to duplicate it. Maybe someday I can electrically stimulate my brain through the skull or something and see how purple tastes…

  41. I still experience music in visio-spatial terms. And by the way, all musical visualizers so far suck.

    I still remember what color the various numbers are. And it’s consistent, and always has been.

    Synaesthesia is probably deeply rooted in normal brains. Pattern recognition is a deeper capability than the sensory modality of the pattern.

  42. I have always associated concepts and sounds strongly with colors and shapes, and used to visualize them pretty clearly in my mind. I always assumed that it was just a way to make an intangible concept more easy to understand.

  43. I have always associated colours with musical notes as long as I can remember. Always the same colours my whole life, since I was 3 (42 years ago). E is deep forest green, A is bright red, C is blue, D is light green, G is orange, B is brown, Bb is silver/white, Eb is yellow, C# is black, F is purple, Ab is maroon. F# is a different green than D and E, it’s hard to explain but I can see it. Sort of bluish green.

    I have perfect pitch because of this. I didn’t know it was synesthetic.

  44. Reading about synaesthesia is fascinating but I never see anything about my particular variation. I associate visual cues as sounds. I may see a movement or action that is normally silent & unconsciously imagine or “hear” a sound, which can make the way someone walks particularly interesting or a blinking light somewhat annoying.

  45. Now I’m going to assume that this is at least tangentially related to this thread. Any insight (easy on the snark, please) would be appreciated:

    For almost as long as I can remember I have conceptualized the months of the year as following the path of the small intersection I grew up on for part of my childhood. And part of that depiction includes a street that doesn’t really exist but completes the circle of the 12 months.

    Now I wrote about this when my hs English teacher asked as to write something that could be described as “abstract.” And after he read it he acted as if I was from another dimension.

  46. I have consistently associated colors with taste. Skim milk is gray, cammomille teas are purple, fruits are both determinate and indertimate shade variants of white to yellow, everything my mother cooks tastes like brown (this became an ongoing family joke), and may more that I would need to directly experience again (for example not liking most mushrooms because they taste like my feet smell).
    for a more contemporary analysis on word/ object relation and meaning formation see works of Sellars and also Quine

  47. Fascinating subject. It doesn’t surprise me that a large percentage of people make some sort of sensory crossovers, given what we know about the way our brains and minds work. Like most mental conditions / phenomena / disorders, I’m happy with thinking of synaesthesia not as a black or white (zero or one?) distinction but the name for the region at one end of a sliding scale.

    What does surprise me is how much of the geek/tech set experience these phenomona to some extent. Not just from this BB post – in general for many years it seems that I’ve found this section of society in particular enjoys/suffers from sensory crossover.

  48. I’ve always attributed it to memory association rather than synaesthesia, especially regarding music. Certain songs always remind me of what I was doing when I heard it (eating, painting, etc). I imagine most self diagnosed synaesthetes are the same way, and are simply trying to ‘force the trip’.

    On the other hand, acoustic guitars always make my teeth feel fuzzy.

  49. @ Midnightbreakfast

    You can read up on the SNARC effect (spatial–numerical association of response codes). Apparently, it is a very common but not widely studied form of synaesthesia that causes people to see numbers, days or months in a spatial arrangement.

    Your representation of streets is pretty quaint ;) I, for one, would have loved to see your essay on that. I’m always surprised when I hear people having no clue about synaesthetic experiences (like your English teacher) because from what I see, they are very common. Maybe they just tune their own perceptions out or don’t notice them because they are so automatic and innate.

    I see months arranged in a large circle, as if I am ‘standing’ right over June/July so these are usually blurry (in my peripheral vision). August to December are very spacious and spread-out while January to May seem clumped together. I think a lot of people view months in a circle, though.

  50. I view months as a very strict linear sequence from January to December, with nothing after December at all. The concept of viewing the months as circular is entirely alien to me, despite this being, you know, how they actually occur. It’s quite a wrench when the year changes, I have to force myself to adopt a new mental depiction of the year.

    Funny, I never really thought about this before or that anyone else would think of time differently. I know we’ve got off synaesthesia here but it’s all interesting!

  51. Yay! I love me some BoingBoing synaesthesia posts!

    0= glass/see-through
    1= white
    2= light blue
    3= yellow
    4= green
    5= tomato red
    6= berry red
    7= lavender
    8= very dark navy
    9= strange color, maybe dark green or brown
    10= black

    From 11 up it’s the colors combined, just like the others said.

    Then the weekdays have colors, odors have colors (hello perfumes in wrong colored bottles!), people can have colors, but for that I need to know their personality. Oh, and feelings/moods have colors as well (like: “Tody I can only wear mint-green.”) and certain situation/emotion combinations can cause a taste in my mouth. THAT’S cool, but only occurs like 4 times a year and when I realize it it just vanishes, like dreams you wake up from when you realize you are dreaming.

    But I don’t have anything with sound or music as far as I know. Oh, and I hate numbers and math (still was class best in school though).

Comments are closed.