Mistaken concepts: the taste buds

OK, kids, we need to talk. No, you’re not in trouble. The people in trouble are health, anatomy, and psychology teachers who try to teach a specific concept that is WRONG.

Any guesses about what connects those teachers? No? Well, here’s the offending diagram.

Don’t believe images like this. EVER.

That, my lovelies, is a picture of a tongue. But see those cool segments that tell you what flavor is tasted by each segment of the tongue? They’re completely and totally unnecessary. Your tongue doesn’t work that way, despite what so many teachers and even college professors would have you believe.

No, don’t try to look all cute and happy, Mr. Boring. You’re on scientific trial here.

Let’s go back a bit to Harvard University circa 1901. A psychologist, Edwin G. Boring (more like Edwin G. Mistaken-Fact-Check) misinterprets data in a German paper, leading to the belief that each region of the tongue is specialized to taste exactly one of four basic flavors.

“OH! Cool!” he says, thinking this break-through will change the way we interact with food (or something).

Trust me, it didn’t.

Let’s fast forward to 1974, when Virginia Collins discovered that all tastes are distributed equally across the tongue. Case closed, right?

NOPE! People are STILL using the tongue map to explain taste buds in 2012!

Let’s expand your knowledge a bit, though. Why is this tongue map concept so incredibly insulting to the science of taste? Here’s three big reasons why!

Well, first off,  it is incorrect in the count of basic flavors. The map shows the four flavors (bitter, sour, salty, and sweet) that were known in 1901, but there are at least five that we know of now. The four that are on the map DO exist; the fifth wheel of taste we use at a wine and cheese party is actually one of the most important – umami. That’s the taste of savory things like meat and cheese, and was described as early as 1908, a mere seven years after Boring made his translational mistake.

Secondly, the map claims the receptors for each flavor only exist on the edges of the tongue, the very back, and the very tip. That leaves a HUGE bit of space that doesn’t really do much, right smack in the center… where most food hits the tongue.

Um. Science says, “Whoops?”

It’s an impractical model from the start, is what I’m trying to say.

Thirdly, our sense of taste is much more important in basic development and exploration than the map allows for. From the time we are born, we explore the world through all of our senses. Senses like sight don’t fully develop until we are between 6 and 18 months of age, but we make up for what we lack by using other senses, taste, in the case of infants.

Well, why is that particularly important, you ask? Because of chemistry. The basic correlation between chemistry and taste is that acids taste sour and bases taste bitter. The safest way of testing this is to taste a lemon, which is full of citric acid. It’s sour, right? Right.

Since things that are bitter are not necessarily desirable as food products, it’s very difficult to find them on market shelves. Egg whites and some crackers are the closest edible things you’ll find to basic foods.

Now, think back to childhood…. Do you think a baby would like something that tastes bitter? NO! That’s a natural response. It’s a safety precaution, too; bitter foods tend to contain deadly chemicals, like ammonia. According to the tongue map, those substances would have to hit the back of the tongue to be tasted, which probably means someone is going to have to call poison control because little Johnny has swallowed ammonia instead of spitting it back out because he tasted that bitterness immediately.

So, lesson of the day? Don’t think of the tongue as some city planner’s way of keeping the taste bud gangs from having turf wars. It’s much more accurate to think of it as a metro area, where everybody mixes and coexists while doing their jobs.

 

O’Connor, Anahad (November 10, 2008). “The Claim: The tongue is mapped into four areas of taste”The New York Times.

Hänig, David (1901). “Zur Psychophysik des Geschmackssinnes”Philosophische Studien 17: 576–623.

Wanjek, Christopher (August 29, 2006). “The Tongue Map: Tasteless Myth Debunked”Livescience.com.

 

Image sources:

www.leavingbio.net

www.igs.net/~pballan