Why do people chew gum? If an anthropologist from Mars ever visited a typical supermarket, they’d be confounded by those shelves near the checkout aisle that display dozens of flavored gum options. Chewing without eating seems like such a ridiculous habit, the oral equivalent of running on a treadmill. And yet, people have been chewing gum for thousands of years, ever since the ancient Greeks began popping wads of mastic tree resin in their mouth to sweeten the breath. Socrates probably chewed gum.

It turns out there’s an excellent rationale for this long-standing cultural habit: Gum is an effective booster of mental performance, conferring all sorts of benefits without any side effects. The latest investigation of gum chewing comes from a team of psychologists at St. Lawrence University. The experiment went like this: 159 students were given a battery of demanding cognitive tasks, such as repeating random numbers backward and solving difficult logic puzzles. Half of the subjects chewed gum (sugar-free and sugar-added) while the other half were given nothing. Here’s where things get peculiar: Those randomly assigned to the gum-chewing condition significantly outperformed those in the control condition on five out of six tests. (The one exception was verbal fluency, in which subjects were asked to name as many words as possible from a given category, such as “animals.”) The sugar content of the gum had no effect on test performance.