Is it true that chewing gum impairs the perception of information?

Since school, many of us have been told that if you chew gum during class, you will learn the material worse. We decided to check whether there is scientific evidence for this belief.

Information that chewing gum impairs the perception of information can be found on websites dental clinics, V blogs And Media. Explain This relationship is due to the fact that “chewing movements affect the process that is usually used to memorize some information by ear,” and Also the fact that “blood rushes from the brain to the masticatory muscles and other organs of the maxillofacial region.” Reported also about the long-term negative consequences of such a habit: “Regular chewing of gum leads to deterioration of short-term memory.” Some resources even include The use of chewing gum is listed among the things that make us stupid, on the same list as iodine deficiency in utero, corporal punishment in childhood and second-hand smoke.

The first chewing gum was patented in 1869 by American dentist William Finley Semple. It consisted of rubber with the addition of chalk, charcoal and flavorings. However, humanity has previously used various viscous substances for chewing. The oldest chewing gum is a piece of resin with teeth imprints, dating back to the 3rd millennium BC. e., was discovered in Finland, in the town of Kirikkikangas. In addition to resin, ancient people used beeswax, rubber, and a mixture of plant leaves and seeds with slaked lime. 

Scientists are still studying how chewing gum affects a person's teeth, digestive system, facial and jaw muscles, and mental health. Exists a lot research, demonstratingthat chewing gum reduces level of the stress hormone cortisol. The influence of the chewing process on the perception of information and mental activity has been no less studied.

In 2012, scientists from Cardiff University led by Mikhail Kozlov held a series of experiments in which they came to the conclusion that chewing gum impairs short-term memory. First, volunteers were asked to vigorously chew unflavored chewing gum developed for the experiment and at the same time remember a sequence of seven random letters. Then they chewed gum in their usual rhythm and memorized the same set of letters, and at the end they completed the same task without chewing gum. Then, in the same order, they completed an attentiveness test - finding the missing element in the sequence. Finally, in the final, they worked on both types of tasks without chewing gum, but by tapping a rhythm with their fingers. The researchers noted that chewing, whether vigorous or natural, as well as finger tapping, led to poorer test scores. Based on this, they concluded that both processes distracted participants from test tasks and worsened the result.

However, in later experiments their data did not receive scientific confirmation. At the same Cardiff University, another group of scientists led by Kate Morgan and Andrew Johnson came to opposite conclusions. They published their results in the British Journal of Psychology in 2014. 38 student volunteers took part in the study. The experimenters divided them into two groups: the first chewed gum, the second did not. Both groups listened to the same sequence of numbers for half an hour, in which they had to note all the cases in which even and odd numbers alternated (for example, 7 - 4 - 3). Those who chewed gum performed better overall on the task, showing a particular advantage at the end of the experiment. Those who didn't chew gum started out slightly ahead, but soon began to fall behind. The scientists concluded that chewing gum promoted concentration on tasks requiring constant control over a relatively long period of time. 

The advantage of chewing volunteers over non-chewing volunteers was also demonstrated in experiment with visual stimuli, conducted by scientists from the Netherlands University of Groningen in 2011. As in the auditory perception experiment, the chewing-gum group was slightly inferior to the non-chewing group at first, but then caught up and even outperformed the control group. 

In 2015, Japanese scientists published results of a systematic review of accumulated evidence. Using international scientific knowledge bases, they selected 22 relevant studies and analyzed their results. Chewing gum improved alertness and cognitive function in 14 studies; five studies showed both the positive and negative aspects of chewing; in two studies, researchers found no benefit for either the chewers or the non-chewers; and in only one study, chewers performed worse on a given task. Considering that in more than half of the studies, the chewing group showed better results, the scientists concluded that chewing does improve alertness and cognitive function.

At the same time, the tests that the participants performed in the experiments bear little resemblance to the tasks that schoolchildren and students face every day. The gap was filled by Turkish and Australian scientists.

First held randomized controlled trial on a group of 100 university students. Those who chewed gum performed better on the exam than those who did not chew. Moreover, the chewing group experienced less stress and anxiety. Scientists in the conclusions to their work recommended that students chew gum before exams to overcome anxiety and increase job success.

Australian scientists concentrated on recreating the atmosphere of a lecture, not an exam. 40 volunteers, divided into two groups, listened to a lecture on physiology for 20 minutes. Chewing participants showed better mastery of terminology and general understanding of the subject. Another 39 volunteers, also divided into two groups, took a nine-minute course on mental math strategies (doing math calculations in the head). The chewing group also performed better than the non-chewing group in a subsequent practical test on applying the acquired knowledge.

Experiments have shown that chewing has a positive effect not only on studies, but also on professional activities. Scientists from Ireland and Great Britain dialed a group of 126 people, including 36 secretaries, 36 university teachers and researchers, 12 managers, ten technical workers, four psychologists, four marketing specialists, four customer service workers, two dentists, two teachers and another 16 people from other professions. First, all the volunteers underwent a series of mental health tests after a normal day at work, and then half of them were offered a ten-pack of chewing gum the next day so that they could chew it at any time of the day they wanted. The second half of the participants went to their workplace without chewing gum. At the end of the day, the chewing group showed lower levels of stress and inattention, and also subjectively rated themselves as less tired than the previous day. Anxiety and depression in both groups remained at approximately the same level. Scientists have concluded that chewing helps to concentrate on work tasks and is associated with a greater degree of relaxation, regardless of a person’s profession.

Scientists cannot unequivocally answer the question of why chewing improves cognitive functions. Perhaps this is how the substances contained in chewing gum act on the brain. Research team from Northumbria University dialed 75 volunteers, during the tests, a third of them chewed gum, a third did not chew, and a third made movements with their jaws and tongue while chewing imaginary gum. The group who chewed real gum performed better, but the group with imaginary gum did not differ in any way from the group who did not chew. The researchers noted that the heart rate in the group chewing real gum was higher, which in turn helped oxygenate the brain. In explaining the advantage of the chewing group, scientists also assumedthat the issue may be insulin, which is released during chewing in response to substances contained in chewing gum and activates the hippocampus, the area of ​​the brain responsible for storing information. This aspect may explain the worse performance of the chewing group in the first experiment described, because there, unlike other experiments, participants were asked to chew not the usual chewing gum, but a tasteless analogue specially designed for the experiment. 

Thus, the vast majority of experiments demonstrate an advantage for those who chew gum. They show better results in tests of attention, in mastering new theoretical material, and in the practical application of acquired knowledge. Experiments with students and workers in various professions have shown that chewing helps to concentrate and achieve better results, and also reduces stress and anxiety. 

Cover image: Photo by Andra C Taylor Jr on Unsplash

Not true

What do our verdicts mean?

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