One of the best things about science is how it corrects mistakes. And one of the worst things about popular culture is how it perpetuates them. Today, Daniel, Peter, and Mary discover the truth behind a popular science myth when they get tongue tied!
It was a bright, sunny Saturday afternoon and life was just about perfect. Daniel had come to visit Mary and Peter that morning and they’d spent several hours experimenting with kites, trying to discover what sort of tail made a kite fly best. What they had discovered was that the person flying the kite was even more important than the tail. Peter’s kites always flew into trees or crashed into the ground. Mary could keep her kites flying but had a very hard time launching them. But Daniel was a natural kite-flyer and could make even the most unlikely of kites soar high above.
To make the day even better, when they’d gotten back to Mary’s back yard, they found that her father had set up a picnic for them, complete with hot dogs, potato salad, three kinds of pickles, and fresh watermelon. The three friends enthusiastically munched through the piles of food, only slowing down once they reached the slices of watermelon.
“Pass the salt, please,” Mary asked.
“I still don’t get it,” Daniel said as he salted his slice of watermelon and then passed her the condiment. “How can adding salt to watermelon make it taste so good?”
“Dunno,” Peter said. “It just does.”
“Is that any kind of attitude for a scientist to display?” Mary’s father chided gently. “A real scientist would try to figure it out.”
“OK, how do we do that?” Peter replied.
“In science, you always start with what you know. What do we know about taste?”
“Well, last year Mrs. Krabapple had us map our tongues with four tastes,” Mary said. “So we know that there are four different tastes and that they are in different parts of the tongue.”
“As a wise man once said, it isn’t what we know that causes us problem; it is what we think we know that really ain’t so,” her father sighed. “Your teacher was wrong on two counts. First, a taste isn’t found in just one part of your tongue. And second, there are more than four tastes.”
“Huh?” the three young scientists chorused.
“This is sort of like the myth that we only use 10% of our brains when we actually use the whole thing. What happened is that a reporter misheard something and told everyone about it. The tongue story got started when a psychologist by the name of Boring had translated a German paper that showed different parts of the tongue were more sensitive to different tastes. For some reason, this got reported by the popular press as though those tastes could only be sensed in those parts of the tongue. But you can easily prove that this isn’t true,” Mary’s father said.
“How?” Daniel asked.
“Spoken like a true scientist!” Mary’s father beamed. “First, stick out your tongue and dry it off with a napkin. That will make it certain that the taste doesn’t get spread by the saliva in your mouth. Now take a piece of water melon and touch it to the different parts of your tongue – on the front, on each side, in the middle, and in the back. See how you can taste it all over your tongue?”
The three experimenters followed his directions and quickly discovered that he was right. As they finished their experiment, he continued.
“Now watermelon has a lot of sugar in it, so you were mainly tasting ‘sweet’. We can repeat the experiment with the other tastes if you like, but what it will prove is that you have taste buds for every taste on every part of your tongue. There are actually taste buds on your cheeks and in your throat as well.”
“Wow!” Peter said. “Mrs. Krabapple never said anything about that!”
“She may not have known,” Mary’s father replied. “Sadly, many teachers don’t get the support they need in order to teach science properly.”
“But what about the number of tastes?” Mary demanded. “You said that there aren’t four tastes.”
“That’s right,” her father replied. “Depending on how you want to count them, there may be as few as five or as many as thirteen different distinct tastes. The five tastes that just about everyone agrees on are sweet, sour, bitter, salty, and umami.”
“Ohh-what-si?” Daniel asked.
“‘Ooh-mommy’,” Mary’s father repeated. “It is sometimes called ‘savoriness’ or ‘meatiness’ because it is sort of like the taste of a good steak. Those hot dogs you three scarfed down had a lot of umami.”
“That’s pretty neat, but what do the different tastes have to do with why we like watermelon better with salt on it?” Peter asked.
“Ah, I think I’ll let you figure that out for yourselves. Stay here for a second!”
With that, Mary’s father went back into their kitchen. Mystified, the three young scientists looked at each other. From the kitchen, they heard a variety of cabinets being opened and closed and the clink of plates. After a few minutes, Mary’s father came back out carrying five different plates. As he put the plates on the table in front of them, he explained what the experiment would be.
“In each plate, we’ve got an example of a different taste. The first one has salt for saltiness. The second plate has baking cocoa for bitterness. The third plate has vinegar for sourness. the fourth plate has low-sodium soy sauce for meatiness. And the last plate has sugar for sweetness. And here are a bunch of water crackers; they don’t really have much in the way of flavor,” he paused as Peter grabbed a cracker and tasted it.
“Ugh!” Peter exclaimed. “It tastes like cardboard.”
“Right!” Mary’s father said. “Now here’s the experiment. First, you’ll dip a cracker into each of the different tastes and eat it. That will help you get familiar with the tastes. Then you’ll try dipping the cracker into two different tastes and then eat it. What do you think will happen?”
“Well, the two different tastes will just be two different tastes in our mouths,” Peter said. “Nothing will change.”
“I don’t know,” Daniel said. “Remember what happened when we added salt to the watermelon?”
“That’s right!” Mary exclaimed. “I’ll bet that the tastes change each other somehow.”
“Well, there’s only one way to be sure,” Mary’s father said. “Start tasting!”
What do you think will happen? Try the experiment yourself!
The three young scientists quickly grabbed crackers and dipped them into each of the plates. From their grimaces, it was clear that they didn’t much care for the tastes by themselves. But something changed when they started dipping the crackers into to tastes before eating them.
“Hey!” Peter excitedly said. “Did you guys try this? Sweet plus bitter – it tastes almost like a candy bar!”
“Cool!” Daniel replied. “I like sour and salty – it tastes like a pickle!”
“And salty plus umami is wonderful!” Mary added. “This is so delicious!”
“Can you figure out why it is so good,” Mary’s father asked. “You’ve definitely got enough information to form a hypothesis now.”
“Well, one taste by itself isn’t very good,” Peter said. “And it only hits one set of taste buds.”
“But two different tastes together are good, ” Mary said.
“And they hit two different sets of taste buds,” Daniel added. “So maybe the more different taste buds that get excited, the better the food tastes?”
“That’s right!” Mary’s father said. “That’s why the best recipes always have several different tastes in them. Cookies always have sweet and salty. Soda usually has sweet and sour. Soup has umami and salty. And so forth. Companies spend billions of dollars trying to find the perfect combination of different flavors. For example, what do you think would happen if you used umami with your watermelon instead of salty? Or if you used bitter?”
“I don’t know,” Peter started.
“But we sure want to find out!” Daniel and Mary chorused together. Smiling, the three scientists grabbed watermelon slices and began their most edible experiment of the day.