Most people will be familiar with the classic ‘tongue map’, where sections of the tongue responsible for detecting sweet, sour, bitter, and salty tastes are clearly demarked. This theory is taught widely at schools and is considered to be a fact by most people. However, in reality, we taste different flavors using taste buds spread across all parts of the tongue.
So where did the tongue map come from? It was actually a mistranslation of a German thesis, written by Edwin Boring in 1901, that was disproven in 1974. But, for some reason, the map has persisted.
It is true that certain areas of the tongue are more sensitive to certain flavors - for instance, sweet or sour - but the differences are small, they vary between individuals, and are not as neat as the famous tongue map.
Also, many of us were taught that there are just four primary tastes: bitter, sour, salty, and sweet. In fact, there is a fifth - umami - a savory, meaty taste associated with monosodium glutamate (MSG).