Remember those studies about how chewing gum might improve your brain power? The idea was that, somehow, chomping and cogitating at the same time helped your short-term memory so that you could be better at remembering the name of someone you just met, remembering the knitting instructions you just read, remembering what you were supposed to pick up at the grocery store and the like.
Researchers from Cardiff University in the United Kingdom were never quite convinced by those studies. They wondered why chewing gum while trying to think would be such a good idea when many other studies have shown that multitasking is a bad idea—it makes us more distracted and less efficient.
So they performed their own study to try and settle the matter.
Should we stock up on Wrigley’s or Trident before tackling a task that involves our short-term memory?
This new study proposes an interesting answer…
Michail Kozlov, the lead researcher and a PhD candidate at the university, told me about experiments that he and his colleagues conducted.
In one experiment, subjects were shown a sequence of seven letters in a random order—each letter flashed briefly on a computer screen, one at a time. Afterward, all seven letters appeared on the screen together, and students were asked to place them in the order that they’d been shown. (That’s called testing for “order.”) In another experiment, students were shown eight different single-digit numbers that each flashed briefly on a computer screen in random order. Then they were shown seven of the eight single-digit numbers and were asked to name which number was missing. (That’s called testing for “identity.”)
When students performed the tasks while chewing gum, their recall was, overall, 5% worse on both “order” and “identity” tasks, compared with when they performed the tasks without chewing gum.
For good measure, the researchers tested both “natural” and “vigorous” gum chewing—with the same result for both.
“The findings clearly warrant a reevaluation of the assertion that chewing gum benefits short-term memory,” Kozlov said. “Instead, we found that chewing has the opposite effect—a negative impact on short-term memory.”
Now, you may be wondering, how can similar studies lead to such dissimilar findings? And how can we be sure that these new findings trump others from the past?
When I asked Kozlov about the contradiction, he said that the experiments that were done in prior studies tested only “identity,” not “order”—and that “order” is important because it’s what’s really needed in everyday life tasks, such as sequencing numbers on a spreadsheet or even just remembering things you read, for example.
Plus, he said, short-term memory tasks should be done quickly, within seconds. The longer information is stored, he said, the more likely that long-term memory is involved. In previous research on gum, the tasks tended to last minutes rather than seconds (which is how long Kozlov’s experiments took).
He told me that there’s no storage device in our brains for short-term information. Instead, we use other skills to keep that kind of information active—like repeating an unfamiliar phone number over and over to ourselves as we go to dial it. This kind of activity engages the brain, but if you’re simultaneously doing something else, such as tapping your finger, twirling your hair or, it seems, chewing gum, then you don’t have as much brain power to devote to remembering the phone number.
So if you find yourself in a situation where you need to process information immediately, then you’re better off with nothing in your mouth. Save the gum-chewing for when you’re not intensely focused on a task!
