When I was a kid in the 90s we were taught that the tongue had specific zones that tasted specific tastes. There was a diagram and everything. I think it was long debunked even then.
It's a good case study in society's ability to believe things despite the fact that every single individual in the society has direct personal experience falsifying the belief. If you've ever eaten candy, you've experienced the taste of sugar all across your tongue.
It takes only a couple of seconds to run an experiment that conclusively disproves the tongue map. But there it is in the reference books.
> all taste sensations come from all regions of the tongue, although different parts are more sensitive to certain tastes