What you learned in school
Biology textbooks taught that the human tongue could detect exactly four basic tastes: sweet, sour, salty, and bitter. Students memorized this as established scientific fact and learned to identify these taste regions on tongue diagrams. Science classes presented this four-taste system as complete and comprehensive.
What we know now
Biology textbooks consistently taught that humans could only detect four basic tastes: sweet, sour, salty, and bitter. Taste maps showed different areas of the tongue responsible for each taste. This was considered scientific fact and was taught alongside the anatomy of taste buds. In the 1980s, umami (savory/meaty) was recognized as the fifth basic taste, particularly through the work of Japanese scientist Kikunae Ikeda who identified glutamate receptors. The taste map of the tongue was also debunked - all tastes can be detected across the entire tongue.