The tongue paper, written by German Scientist D.P. Hanig, outlined Hanig’s research on the four known basic tastes (5 known today). He got together a group of subjects and tested the main tastes on each of them on various parts of their tongues until he figured he had a good map put together on where they tasted various tastes the most.
In reality, any undamaged taste buds can taste any of the five main flavors through many mechanisms, so any actual "taste map" really just depends mostly on density and location of the taste buds on a particular person tongue, which varies according to a persons age.
This myth endured, even among scientists, until the 1970′s and still endures today thanks to certain third grade teachers the world over. In the 1970′s, scientists decided they might actually want to think about testing the commonly held notion of “tongue maps” that go against the personal experience of pretty much everyone who has ever tasted anything… ever.
Source1, Source2, Source3, Source4
