What do you think of this fact?
Plenty of people saw it in their biology textbook: a tongue split into colored zones. Sweet at the tip, salty and sour on the sides, bitter way at the back. Try it yourself and you’ll quickly notice it doesn’t hold up.
A German study from 1901
It all starts with the German researcher David P. Hänig. In 1901, he had volunteers test the four basic tastes known at the time on different parts of the tongue and asked how strongly they sensed them. His finding: some areas are a tiny bit more sensitive to certain tastes.
A tiny bit. Not exclusively.
The map from 1942
In 1942, Harvard psychologist Edwin Boring picked up Hänig’s data. He converted it into numbers and plotted it so that areas with slightly lower sensitivity looked like they couldn’t taste anything at all. “Somewhat less” turned into “not at all”, and the tongue map that generations of schoolkids memorized was born.
In 1974, researcher Virginia Collings checked it all again. The differences between the zones were small and basically didn’t matter.
Today it’s clear: the whole tongue can sense every basic taste more or less equally. There are taste receptors even on the soft palate and the epiglottis.
Bonus fact: One taste is missing from the old map entirely. Umami, the savory taste you know from broth, was tested by neither Hänig nor Boring.
One taste per zone would be pretty impractical anyway. According to Live Science, each taste bud holds 50 to 100 receptors for each taste.
So the tongue map was a chart that claimed more than its data could back up. Happens in the best textbooks.