Back in 2002, New Scientist reported on a study undertaken at the University of Northumbria (UK) (http://bit.ly/1kBgMEt). The authors of the 75-person study suggested that the act of gum-chewing might improve short and long-term memory. Rather than the chewing gum itself having an effect, three explanations were proposed, with the most likely being that the gentle exercise of chewing could “raise a person’s heartbeat and increase the flow of oxygen to the brain”. In addition, the authors proposed that the act of chewing might trigger the release of insulin in the body, “which could increase the uptake of blood sugar by the brain”. They also made reference to an earlier Japanese study that made a link between chewing and brain activity in the hippocampus, a region of the brain important for memory.
Fast-forward to 2011 and another study at St. Lawrence University (NY, USA), published in the journal Appetite (http://1.usa.gov/1lCuiXw) and reported by LiveScience (http://bit.ly/1KEoy6s), added weight to the earlier claims, but with a caveat. This larger, 224-person study found that a “burst of gum-chewing” before testing improved a student’s initial test performance, but only for a short period: “The effect was strongest right after gum-chewing, and dropped to normal levels within 20 minutes. The gum-chewing helped during recall and memory tasks especially.”
Importantly, this study indicated that those students who continued to chew gum during the test showed no improvement. The authors of the study surmised that the extra brainpower it takes to actually chew the gum might take away from the brain's ability to take the tests, however, they also added that “because the participants were specifically asked to chew the gum, it's possible they were thinking about it a little more than they would be normally” and, "In real-world situations the chewing might be more unconscious, automated, in which case it would take up very little cognitive resources and probably not affect performance much.”
More recently in 2013, a further study carried out at the National Institute of Radiological Sciences (NIRS) and other academic research centres in Japan, published in the journal Brain & Cognition (http://bit.ly/1m4Hl02) and reported on by the UK’s NHS (http://bit.ly/1SIFRbF) sought to find out whether chewing has an effect on attention and cognitive processing speed. This smaller, 17-person study, showed mixed results in fMRI analysis, “with some areas of the brain thought to be involved in alertness and movement becoming more active, while others did not.”
The researchers also found that “chewing did cause some areas of the brain, such as the anterior cingulate cortex, to become more active, but the overall results were inconclusive. Some areas of the brain also associated with alertness actually became less active during chewing.”
So where does this leave us? The science would seem to be somewhat inconclusive as to whether gum-chewing could actually improve your test/exam scores. Yes, the study by St. Lawrence University does seem to hold some weight, especially as to the potential benefits of gum-chewing prior to a test, but the so-called “window of effect” is only 15-20 minutes after chewing. Therefore, unless we’re talking about a basic Spanish vocabulary test or similar, it would seem that you probably can’t expect gum-chewing to improve your memory recall for the entirety of a three hour paper. In fact, I would strongly bet against it.
There are also other reasons why I would advise against gum-chewing during tests/exams. Instead of relying 100% on the science, I put this to the test myself during my first year legal exams. I noticed that the only benefit to me of gum-chewing could have been that it relaxed me a little, but this may have been merely a psychosomatic effect. On the other hand, I found that as the taste of the gum wore off, it actually began to distract me more and more from my work. What’s more, most common brands of sugar free gum contain aspartame, a synthetic sweetener that nearly all health experts now agree is a substance best avoided and, if gum is chewed in large quantities (say, over the course of a three hour paper), it can even result in a laxative effect.
In conclusion, while there does seem to be some speculative evidence as to the benefits of gum-chewing before a test/exam (which you could try), gum-chewing during a test/exam wouldn’t seem the best idea for a number of reasons as outlined above. And, if you do intend to chew gum before a test/exam, try a xylitol-based gum.
NB. I hope it goes without saying that if you’ve read and followed what I have to say in The Holy Grail of Exam Success, you shouldn’t be thinking about whether gum-chewing could give you an edge. Sleep, nutrition, exercise and good study technique will always be preferable where tests/exams are concerned.