|Image by Mayr from Wikipedia|
They found that people who chewed scored better on long- and short-term memory tests (measured by word recall).
The authors speculated on three possible explanations: brain activity in the hippocampus increases while people chew, so this might help with memory; gum chewing promotes the release of insulin, which might indirectly affect memory; and the most straightforward—chewing can increase heart rate slightly, and this increased blood flow could deliver more oxygen to the brain.
Follow-up studies in 2004 supported these initial findings.
A more recent study in 2009 using 101 student volunteers found that it wasn’t the gum per se but any candy (cinnamon candy in the study) or oral stimulus can help a person remember information. Based on this study, it was felt that the oral action as well as the scent of the candy/gum served as a memory cue for information.
Maybe those gum-smacking kids in class did know something the rest of us did not.
Fortunately, fear not teachers... There are other studies that have been done that have not replicated these results at all and even contradicts them.
Chewing gum can also exacerbate/cause TMJ problems.
Image taken from Wikipedia.