Student Report: All I Want for Christmas is Synaesthesia

Today I’m looking at synaesthesia, but more specifically lexical-gustatory synaesthesia in which certain phonemes (smallest unit of speech such as the /l/ sound in jelly) trigger specific tastes. For example, in Jamie Ward and Julia Simner’s (2003) report, Lexical-gustatory synaesthesia: linguistic and conceptual factors, a case study was done on a forty year old business man who reported tasting specific tastes in response to certain phonemes. In this case the man reported tasting cake when the phoneme /k/ was used in a word. Synaesthesia is thought to occur due to the crossing over or connection of neurons in certain areas of the brain that regulate and process senses. However, there are differing theories as to how this arises.

One idea is that certain neural connections linking sensory areas are not destroyed in infant stages of development as done in normal development. Synesthetes therefore link one sensation with another because connections are not destroyed. The second theory is that, rather than sensory areas in the brain being directly connected, they are connected through neural pathways in higher processing areas. For instance, instead of just hearing a phoneme and having just any taste sensation, it is the processing of the sequences of phoneme in the word used that links to specific learned schemas connected to the phonemes leading then toward a specific taste. Ward and Simner examined this in their case study.

Through documentation of tastes stimulated by specific words and phoneme triggers, Ward and Simner found that their data supported the latter of the two theories. The largest support comes from the idea that the subject’s tastes are specific for certain learned phoneme association rather than just random association of tastes to arbitrary phonemes. For example, as stated earlier, certain phonemes consistently trigger specific tastes such as the phoneme /k/ and the taste of cake. Also, the use of semantics in the sensory process is a strong argument for higher processing connections as food names exhibit their tastes (cabbage triggers the taste of cabbage). Much of this may be because certain patterns of phonemes can trigger specific tastes that have the same sequence of phonemes. So college, having the phoneme sequence /edg/ triggers the taste of sausage which also contains the phoneme sequence /edg/. These associations are done through higher processing which is learned throughout life, supporting a connection through higher processing areas of the brain rather than direct connection between sensory areas.

Although the idea of a direct connection between sensory areas from birth is not disproved by the study, it has supported that there is higher processing connections involved that have developed through learning. There is still much work in the field of synaesthesia, and with any luck, it will lead us to a better understanding of how our brains develop and process information. But despite all this, the best thing to do right now if you are not a lexical-gustatory synesthete is eat leftover turkey, potatoes (cheesy or mashed), and some pumpkin pie. Happy holidays.
~Bright Lights


  1. says

    Very neat.

    I have some familiarity with linguistics, so the first question that came to mind as you were describing the higher processing hypothesis was whether or not the relationship between the triggering phoneme(s) and the tastes experienced is always linguistically sensible.

    The two examples you’ve given, /k/-‘cake’ and /ij/-‘sausage/college’ are, but are there cases in which, for instance, a person might experience the taste of sour milk whenever they hear the phoneme /v/?

  2. CG in Tucson says

    Yes, fascinating stuff!!

    I wonder if there are intances of synaesthesia in deaf sign-language users, and if so, what characteristics of a given sign might attach to a particular taste (or other sensation).

    Do you suppose a synesthete would find it easier or harder than the rest of us to diet?

  3. Ktesibios says

    College tastes like sausage? Cool, but would that be a nice hot Italian sausage or something awful like liverwurst?

  4. Encolpius says

    You better not come up with a mistaken hypothesis — you might be forced to eat your words.

  5. TomK says

    Whatever you think about synesthesia, it needs to be compatible with the fact that otherwise normal people can experience it on hallucinogens. That theory about birth connections doesn’t seem easily compatible with normal people eating a mushroom, experiencing synesthesia, and then being normal 6 hours later. The other theory seems compatible with hallucinogens causing synesthesia as hallucinogens scramble higher order processing.

  6. doug l says

    Very interesting. Recently watched a lecture from the TED conference in which Vilayanur Ramachandran present an intrigueing (and entertaining) look at the current state of our understanding of the brain. If this subject,synesthesia, interests the readers they’d find this worthwhile.

  7. Dahan says

    I’m an artist/designer and so am aware of synaesthetes. What I’ve always wondered is how it may be affected by someone who is color-deficient (commonly confused with the much less common disorder of color-blindness) like myself. Would the synaesthesia be different than in someone who saw colors “properly”? Have there been any studies on people who are both synaesthetes and color-deficient? Seems like this would be an interesting variable to toss into a study.

  8. Mooser says

    One word, people: suggestability. Always watch for it when people tell you about themselves.

    How many times a week do you go to church?

  9. says

    BTW, synaesthesia comes up quite a lot during the course of Peter Watts’ novel, Blindsight. He has some scientist characters who uses synaesthasia as extra tools during analyses. (Watts is also a fellow squid lover.)