In a 1997 study entitled “Effects of Mastication on Regional Cerebral Blood Flow in Humans Examined by Positron-Emission Tomography with 15o-labelled Water and Magnetic Resonance Imaging,” I. Mamose, et al., observed that chewing gum had the effect of increasing the recall of words.
Referring to the above study, Helen Abadzi wrote:
Insulin mops up glucose in the bloodstream, and chewing causes the release of insulin, because the body is expecting food. Insulin receptors in the happocampus may be involved in memory. Therefore, it has been hypothesized that chewing might improve long-term memory. In an experiment, one-third of 75 adults tested chewed gum during a 20-minute battery of memory and attention tests. One-third mimicked chewing movements, and the rest did not chew. Gum-chewers’ scores were 24 percent higher than the controls’ on tests of immediate word recall, and 36 percent higher on tests of delayed word recall. They were also more accurate on tests of spatial working memory. Chewing gum elevated heart rate significantly above that in the sham chewing and control conditions. This response may improve cognitive function due to increased delivery of blood to the brain. But attentional tasks, which might be described as assessing purer aspects of “concentration,” were unaffected by chewing gum. Thus, chewing gum may improve performance in certain memory tasks. Nevertheless, teachers typically ask students to stop chewing gum when they enter the class.