Most spices are probably mostly olfactory, but the hot ones such as chili
peppers (capsaicin), pepper (piperine), and ginger (zingerone) stimulate pain
fibers. Although chili peppers do have a flavor, which is about the same as
sweet peppers, the hotness comes from pain alone. One can demonstrate this by
putting hot sauce on the lips and other skin areas that have no taste buds.
More than one researcher of capsaicin has learned to his discomfort to wash the
hands before going to the bathroom.
Concerning the distribution of taste buds, I enclose something I wrote for a
different audience (How to think like a Psychologist, Prentice Hall, 1996). By
the way, my friend and colleague Linda Bartoshuk was reporting the work of my
student Virginia Collings, not her own work in the reference cited by a previous
poster to TIPS.
" Many introductory psychology books have a figure in the chapter on the senses
that shows how sensitivity to salty, sour, sweet and bitter vary over the
surface of the tongue. They show an area at the tip that is sensitive to sweet,
two areas a little to either side that are sensitive to salty, two farther back
along either side that are sensitive to sour, and a single area in the back of
the tongue that is sensitive to bitter.
Only one problem: It isn't so. It is true that sensitivity to the different
taste qualities varies somewhat over the tongue, and the areas listed are for
the most part the ones most sensitive to the various tastes. But, with the
exception of the middle of the tongue, which is totally insensitive to any
taste, all areas of the tongue are sensitive to all taste qualities.
Why should you believe me instead of your textbook? I could say that I am an
expert in taste and so I know about these things. But, better, you can easily
demonstrate this for yourself. Lick your finger and dip it in the sugar bowl.
Then touch your finger to various parts of your tongue. You will easily taste
the sugar on all parts of the tongue except the middle, where you can't taste
anything. (You won't be able to touch your finger to the back of the tongue
without gagging. You could try reaching that area with a long handled Q-tip.)
Then why does your book have this wrong information? Well, back in 1901 a man
named Hanig found that there were differences in taste sensitivity across the
tongue and published his results in the form of a map of the tongue. This map
found its way into textbooks and has been copied from one book to another ever
since. Now, two things are interesting about Hanig's results. First, he did
not say that only certain areas were sensitive to the four taste qualities. He
said that certain areas were more sensitive than others. The textbooks that
copied each other dropped this subtlety, something like what happens in the
party game "rumor."
The second interesting thing about Hanig's data are that no one ever replicated
his results for seventy three years, until Virginia Collings did so in my
laboratory. As did Hanig, she also found that the differences between areas
were small, on the order of two or three to one. This difference is quite
trivial when one considers that the tongue must respond over a range of at least
tens of thousands to one.
So, a result that was found only once was parroted for decades by books, and
not even correctly, because they copied from one another instead of going back
to look at the original source.
Do you suppose that Collings's experiment corrected the situation? It has
been twenty years since she published her data, and various review articles have
pointed out the actual situation, but the wrong maps keep showing up in
textbooks. I expect to see these wrong maps for a long time to come. "
don
Donald McBurney
University of Pittsburgh
Patrick Mattimore wrote:
> According to the work of Linda Bartoshuk (1993), the taste buds are not
> really divided. The "tongue map" showing areas supposedly most sensitive to
> taste was based on a misleading graph published in 1942 and it is simply,
> wrong. The four basic tastes can be perceived at any spot on the tongue that
> has receptors, and differences among the areas are small. (see Wade and
> Tavris, Psychology, 5th ed. p. 231)
> Patrick Mattimore. South San Francisco High School
> -----Original Message-----
> From: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Date: Tuesday, September 07, 1999 7:07 PM
> Subject: Exotic Spices
>
> >Listfriends,
> >
> >No I haven't deteriorated to posting soft core porn to the list. This is
> re:
> > Sense and Perception unit. In discussing the division of the taste buds -
> >sweet, sour, salty, and bitter, a student asked what areas of the tongue
> >registered the really exotic and strong spices. I told her that I
> suspected
> >that these spices would register combinations of the basic four, but also
> >told her (because that was just a good guess) that I would confirm with the
> >more knowledgable folks in the field.
> >
> >So, was my guess good, or is there more/more accurate information I can
> give
> >to this student?
> >
> >Thanks so much.
> >
> >Nancy J. Melucci
> >Utility Infielder/B&SS
> >El Camino College
> >Torrance, CA
