Remember the map of the tongue that showed how different regions of the tongue perceive specific tastes? The one with sour in the back and on the sides and sweet on the tip? Well, it is wrong, and it always has been wrong. Not only is the mapping of tastes wrong, but it never even included all the tastes our tongues can perceive!
The story begins in 1901 when the German scientist D.P. Hänig published a paper on the sensitivity of parts of the tongue to the four basic tastes (sweet, sour, bitter, and salt).
He demonstrated that the tastes were perceived everywhere but that their intensities varied by region. In 1942, a famous psychologist, Edwin Boring, translated that paper, did some calculations, made a graph, and published it in his classic psychology text. Unfortunately, he didn’t label his graph well, so readers, quite understandably, misinterpreted what he was saying and they proceeded to make the false tongue map that we all know and no longer love.
In 1974, Virginia Collings tried to replicate Hänig’s work. While some of her data disagreed with his, she was able to support his original thesis—that the tongue’s sensitivity to different tastes varied across regions. I suspect she then realized the tongue map was wrong and traced it back to Boring. Unfortunately, I cannot begin to surmise how the simplistic tongue map has managed to survive all the years since then!
It is now well established, even at the cellular level, that not only are the tastes perceived all around the tongue, but that some types of taste buds will respond to more than one taste. What we also know is that, conclusively, there is a fifth taste, umami.
Umami is not a well-recognized flavor in Western food culture but it is very familiar in Asia, where it was discovered.
Umami was discovered in 1909 by a Japanese researcher, K. Ikeda. He worked with a traditional soup base, called dashi, which is made from kelp (seaweed). The taste is usually described as meaty, brothy, or savory and is evinced by the amino acid glutamic acid or its dissociated versions, glutamates. Ikeda discovered the technique to produce a salt for commercial purposes. We know it as monosodium glutamate. Between the lack of experience with this taste and the fact that the original research paper was written in Japanese, it took a long time before Western sensory scientists accepted umami as a taste.
Researchers are currently debating the existence of a sixth taste, fatty. So, we may need to revisit the topic of the tongue’s tasting abilities. Of course, most of what we think of as flavor is actually derived from smell, which explains the diversity of flavors we perceive.
But, that’s a topic for another book.
