Taste has historically been one of the least understood sensory mechanisms. Misinterpretations of research conducted in the late 1800's, led to "tongue maps" that suggested that the basic tastes are sensed primarily by specific areas, such as the tip or center. Subsequent investigation proved that taste buds on the entire surface of the tongue can sense all of the various tastes.
(there are about 9,000 nerve receptors called buds on the average tongue)
Sensitivity to specific tastes varies considerably with individuals. It is possible in fact to be taste-blind. The test uses a chemical called phenylthiocarbamide, which tastes extremely bitter to some persons and quite bland to others. Some research has suggested that there is higher alcoholism incidence among the genetically taste-blind.
