The tongue map you learned in school isn’t actually true

Cast your minds back to high school. You're sitting in biology with your mates, and your teacher rolls out that picture of the human tongue.

Okay, that's quite a specific memory, but many people will remember being taught about the different sections of the tongue and its taste receptors.

The front of the tongue tastes sweet things, bitter things at the back of the tongue and salty and sour on the sides - or so they led us to believe.

Science History Images / Alamy Stock Photo

In actual fact, this theory on our taste receptors is wrong, and it turns out it was debunked a long time ago.

The truth is, as CBS reports, we can actually taste all of these things all over the tongue, so why on Earth would schools be teaching their kids any different?

However, it's not completely made up. In fact, there's still *some* truth in it, mainly that the edges of the tongue are significantly more sensitive to tastes than the rest.

The tongue map theory goes all the way back to a paper written by German scientist David P Hänig in 1901, after he began an investigation into the taste belt and how it reacted to salty, sweet, sour and bitter flavour profiles.

Pixabay

Hänig began by dripping stimuli corresponding to the four flavours onto the edge of the tongue, testing to see how much it stimulus it would take to register the taste.

Through his studies, the scientist found there was some variation in how long the different parts of the tongue took to register the flavours, but this difference was minuscule - but that's not the issue.

The problem lies in how Hänig chose to present his findings. The data showed the difference in sensitivity from one part of the tongue to the next, not how the different flavours affected this - which is how he made it appear.

It wasn't until the 1940s that this theory became visual, in the form of the tongue map. And for that, we have Edwin G Boring to thank.

Yep, that's his real name.

Harvard psychology professor Boring presented the artful interpretation in his book Sensation and Perception in the History of Experimental Psychology - which has also been refuted by many researchers in the years that have passed.

We now know there are two cranial nerves which are responsible for how we perceive taste in different areas of the human tongue.

Pixabay

At the front of the tongue, we have the chorda tympani branch of the facial nerve and in the back, we have the glossopharyngeal nerve.

So, any damage to areas of the tongue would result in loss of that taste, if that map was correct.

Still following? Okay, this is where it gets even more complex.

In the 1960s, a surgeon known as TR Bull discovered that patients who'd had their chorda tympani cut somehow didn't lose their sense of taste.

Not only that, almost 30 years later, Linda Bartoshuk from the University of Florida also learned that anesthetising nerve caused patients to taste sweet flavours even more intensely.

Since then, many scientists and researchers have wagged their tongues on the matter, proving that taste receptors can be found all over the tongue.

Anyway, I'm off to grab some chocolate and put that to the test.

Topics: Science

Emma Rosemurgey