The mysterious cognitive effects of chewing gum
“I guess people chew harder when they are sad,” William Wrigley Jr. said during the Great Depression, as his gum empire kept making money while tens of thousands of businesses went bankrupt. A 1918 Wrigley ad promised gum “steadies nerves.” Now, with gum sales down by almost a third since the pandemic and classics like Fruit Stripe discontinued, companies are reviving that pitch — telling people to “chew through” their problems.
The strange thing is, it might actually work. According to National Geographic, studies consistently show that chewing gum increases alertness and sustained attention by around 10 percent and reduces stress in lab settings. People who chewed gum before giving a five-minute presentation and taking a math test had lower stress levels. Women who chewed before elective surgery had lower anxiety. But scientists still can’t explain the mechanism. “How do you go from muscle tension to nerve stimulation to the changes that occur in the brain?” asked one researcher. “That hasn’t been figured out.”
The theories are all over the place: maybe chewing increases blood flow to the brain, or facial muscle activation is involved, or chewing distracts from stressors. One evolutionary biomechanic suggested humans might just like repetitive motions — tapping toes, clicking pens, fidgeting. Chewing gum could be fidgeting confined to the mouth. The word “ruminate” means both to chew and to think something over.
Humans have chewed gum for at least 8,000 years. The oldest piece ever found, from Scandinavia, was birch bark pitch with tooth marks from children as young as five — probably chewing for fun, not to make tools. “From a purely physiological perspective, chewing something without swallowing is pointless,” wrote novelist Karl Ove Knausgaard. But then he admitted he can’t write without his Juicy Fruit.