Does Chewing Gum Make You Smarter? What the Studies Show

Chewing gum does not make you smarter. The best evidence shows that chewing for a few minutes can briefly raise alertness and speed up simple reactions (by about a third of a standard deviation in a small pooled analysis), but the effect fades within 15 to 20 minutes, the famous memory boost has not held up, and no study shows any change in intelligence.

This article covers the 2002 study that started the idea, the failed replications that followed, what the evidence on attention and alertness shows, why timing matters if you chew before a test, and why studies linking chewing to brain health in older adults say little about gum itself.

The modern interest in gum and thinking began with a short report in the journal Appetite by Lucy Wilkinson, Andrew Scholey and Keith Wesnes in 2002. Volunteers were assigned to chew sugar-free gum, to mimic chewing without gum, or to do neither while they completed a computerised test battery. The gum group scored better on immediate and delayed word recall and on working memory tasks, with a raised heart rate and no difference in attention. Press coverage ran with headlines such as "Chew your way to intelligence."

The follow-up studies were far less kind:

• Tucha and colleagues (2004): in a randomised comparison of no chewing, mimed chewing, tasteless gum and spearmint gum, chewing did not improve memory at all. It improved sustained attention but made alertness and mental flexibility worse. The authors concluded that claims of better cognition from gum "should be viewed with caution."

• Johnson and Miles (2007): chewing gum while learning a word list made later recall worse, suggesting that chewing interferes with encoding new information.

• Kozlov, Hughes and Jones (2012): across three experiments, chewing gum reduced short-term recall of letter lists. Manual tapping produced a similar impairment, which points to chewing as a competing movement task that takes up some of the mind's capacity.

Short-term recall of lists draws on working memory, the mental workspace that holds information while you use it. If chewing helped working memory reliably, these experiments should have shown it. Instead the results range from a benefit to a cost, which is what you would expect from a small effect, or no effect, studied in small samples.

The evidence is more favourable for alertness and attention than for memory. Yoshiyuki Hirano and Minoru Onozuka reviewed 22 studies of chewing and attention in healthy children and adults. They classified 14 (64%) as showing a positive effect, 5 (23%) as mixed, 2 (9%) as showing no significant effect and 1 (5%) as negative. That is a count of studies, not a measure of how large the effects were, and it was compiled by a research group whose own experiments had reported benefits from chewing.

A 2023 systematic review by Ma. Therese Sta. Maria and colleagues gives a rough size. Pooling three small crossover studies in young adults, they found that reaction times were faster while chewing, with a "standardised mean difference" (an effect size in standard deviation units) of -0.35. If an effect of that size applied to an IQ score, it would be about 5 points, but reaction time on a simple task is a long way from a full IQ test, and no one has shown that the benefit carries over.

Andrew Smith's 2009 study is the closest the literature comes to an IQ test. Volunteers who chewed gum were more accurate on the Alice Heim test, a standard group intelligence test, and felt about 10% more alert at the end of the session. The same study found no effect of gum on recall of a story or on short memory tasks.

The benefits are not universal. Lara Tucha and colleagues found that chewing gum made vigilance worse in children with ADHD and in typically developing children. Some of the positive work has also had industry support: a 2015 paper by Andrew Allen and Andrew Smith reports that the first author's PhD studies were supported by the Wrigley Science Institute. That does not make the findings wrong, but it is one reason to weigh independent replications more heavily.

The most useful practical finding comes from Serge Onyper and colleagues. Across several experiments, people who chewed gum for five minutes before testing did better on several cognitive measures than people who did not chew. People who chewed throughout the testing session did no better than controls. The advantage lasted only for the first 15 to 20 minutes and did not extend to every type of task.

The authors proposed two processes. Chewing raises arousal, which helps for a short while. Chewing during a task also competes for mental resources, which cancels the benefit. That account fits the memory failures above, where people chewed while learning or recalling.

For anyone sitting an exam or an IQ test, the honest summary is that a few minutes of chewing beforehand may make you slightly more alert at the start, and chewing during the test is more likely to distract you than help. Caffeinated gum adds a separate drug effect, which is covered on our page about IQ and caffeine. Neither is a substitute for a good night's sleep. Hirano and Onozuka also note that early reports of lower stress while chewing were not consistently replicated.

A separate line of research looks at chewing in older adults. The same 2023 review found that older adults with poor chewing ability had lower scores on the Mini-Mental State Examination, a brief screening test for dementia (a standardised mean difference of -0.59 across five case-control studies), and that people with fewer teeth were more likely to be cognitively impaired.

Those are correlations, and they are open to confounding. Tooth loss can reflect poorer general health and dental care, and the review's authors noted that self-reported chewing ability may itself be shaped by education and cognitive ability. People who are already declining may also find it harder to look after their teeth. The review's authors described most of the included evidence as low level with a high risk of bias. None of it shows that chewing gum protects the brain, and it says nothing about intelligence in healthy younger adults. Anyone worried about memory changes in an older relative should talk to a family doctor rather than look to diet or habits for an answer.

The original 2002 study reported better word recall with gum, but later experiments found no benefit and several found that chewing while learning made recall worse. The evidence does not support gum as a memory aid.

Chewing for about five minutes before a test may give a brief lift in alertness that lasts around 15 to 20 minutes. Chewing during the test has not shown the same benefit and may be a distraction.

No study has shown a lasting change in IQ from chewing gum. One study found better accuracy on an intelligence test while chewing, a short-term performance effect rather than a change in ability.

Researchers think chewing raises arousal, heart rate and blood flow for a short time, which can sharpen alertness. Chewing is also a movement task, so doing it during mental work can compete with the task itself.

Caffeinated gum delivers caffeine, which has its own well-studied short-term effects on alertness. Those effects come from the caffeine, not from chewing.

Chewing gum can nudge alertness and reaction speed for a few minutes, especially if you chew just before a task. The early claim that gum boosts memory has not survived replication, and nothing suggests gum changes intelligence. The same caution applies to anything sold as a quick intelligence boost, from gum to nootropics. If you want an accurate measure of your reasoning ability, arrive rested, skip the props and take a full-length online IQ test.

1. Wilkinson, L., Scholey, A., & Wesnes, K. (2002). Chewing gum selectively improves aspects of memory in healthy volunteers. Appetite, 38(3), 235-236. [doi.org/10.1006/appe.2002.0473](. doi.org

2. Tucha, O., Mecklinger, L., Maier, K., Hammerl, M., & Lange, K. W. (2004). Chewing gum differentially affects aspects of attention in healthy subjects. Appetite, 42(3), 327-329. [doi.org/10.1016/j.appet.2004.01.003](. doi.org

3. Johnson, A. J., & Miles, C. (2007). Evidence against memorial facilitation and context-dependent memory effects through the chewing of gum. Appetite, 48(3), 394-396. [doi.org/10.1016/j.appet.2006.10.003](. doi.org

4. Kozlov, M. D., Hughes, R. W., & Jones, D. M. (2012). Gummed-up memory: Chewing gum impairs short-term recall. Quarterly Journal of Experimental Psychology, 65(3), 501-513. [doi.org/10.1080/17470218.2011.629054](. doi.org

5. Hirano, Y., & Onozuka, M. (2015). Chewing and attention: A positive effect on sustained attention. BioMed Research International, 2015, 367026. [doi.org/10.1155/2015/367026](. doi.org

6. Sta. Maria, M. T., Hasegawa, Y., Khaing, A. M. M., Salazar, S., & Ono, T. (2023). The relationships between mastication and cognitive function: A systematic review and meta-analysis. Japanese Dental Science Review, 59, 375-388. [doi.org/10.1016/j.jdsr.2023.10.001](. doi.org

7. Smith, A. (2009). Effects of chewing gum on mood, learning, memory and performance of an intelligence test. Nutritional Neuroscience, 12(2), 81-88. [doi.org/10.1179/147683009X423247](. doi.org

8. Tucha, L., Simpson, W., Evans, L., Birrel, L., Sontag, T. A., Lange, K. W., & Tucha, O. (2010). Detrimental effects of gum chewing on vigilance in children with attention deficit hyperactivity disorder. Appetite, 55(3), 679-684. [doi.org/10.1016/j.appet.2010.10.001](. doi.org

9. Allen, A. P., & Smith, A. P. (2015). Chewing gum: Cognitive performance, mood, well-being, and associated physiology. BioMed Research International, 2015, 654806. [doi.org/10.1155/2015/654806](. doi.org

10. Onyper, S. V., Carr, T. L., Farrar, J. S., & Floyd, B. R. (2011). Cognitive advantages of chewing gum. Now you see them, now you don't. Appetite, 57(2), 321-328. [doi.org/10.1016/j.appet.2011.05.313](. doi.org

11. FoodNavigator. (2002, March 21). Chew your way to intelligence. [foodnavigator.com](. foodnavigator.com

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