Why the Map of the Tongue is Wrong
And How It Got That Way
O nly the four basic tastes — sweet, sour, bitter, and salty — are perceived in the mouth, though some would argue for the addition of other tastes, such as metallic or the meaty taste that the Japanese call umami, represented by MSG. The rest of flavor is aroma, perceived by smelling before tasting or through vapors rising from the back of the mouth into the nose. The complex interaction between the two senses is little understood, but certainly the mind creates the impression of an array of flavors in the mouth.By Edward Behr
It is no coincidence that a number of the scientists who study flavor are psychologists. Linda Bartoshuk is a psychologist at Yale who studies the perception of sweetness. The first thing I learned when I spoke to her is that the well-known map of the tongue, showing exactly where we are supposed to be sensitive to sweet, sour, bitter, and salty, is plain wrong — however often it has appeared in print. She traces the map to an old error. In 1901 a German named Hänig, student of Wilhelm Wundt, father of experimental psychology, wrote a thesis for which he measured sensitivity to the four tastes by dabbing samples of them in spots around the tongue. Hänig drew a graph revealing that the differences among the various locations were actually slight. But a Harvard scientist misunderstood the graph and reported the differences as large, and the mistaken data were seen by someone else to suggest a map of the tongue. The map was made and the mistake perpetuated because for years no one repeated the experiment. The truth is that all our taste buds respond well to all tastes.
The taste buds are arranged in an oval around the tongue, Linda Bartoshuk explains, leaving the center bare. The bumps covering the tongue are called papillae, and the taste buds are buried within certain of them. Three kinds of papillae make up the oval: parallel lines along the sides, large bumps at the back of the tongue, and quite small ones in front. (The papillae in the center without taste buds are a fourth kind.)
Linda Bartoshuk calls the gourmet’s taste for particular foods “eccentric” in that it has nothing to do with physiological needs. The gourmet’s preferences are strongly influenced by other epicurean opinion, but, she says, these acquired sensitivities, the skills used in making distinctions, are real, along with the pleasure taken. She makes the comparison to an appreciation for music: “subtlety for its own sake.” ●
