All those sticky bits of gum stuck under school tables might actually have helped those rebellious students concentrate, according to a new study.
Japanese research shows that our brains' reaction times are up to 10 percent faster when we're chewing gum.
"Our results suggest that chewing induced an increase in the arousal level and alertness in addition to an effect on motor control and, as a consequence, these effects could lead to improvements in cognitive performance," said the researchers from the National Institute of Radiological Sciences in Japan.
In the study they gave 17 volunteers two 30-minute tests –– in one test they chewed flavourless gum (to avoid distraction from the flavour) and in the other they didn't.
They had to watch a screen with arrows and press with their right or left thumb, depending on which direction the arrow was headed.
The researchers measured their alertness and reaction times, and also took brain scans to see which parts of the brain were activated.
When the volunteers were chewing, they took 493 milliseconds to react, while those not chewing took 545 milliseconds to react.
The scans showed that the areas of the brain responsible for attention and movement were most active when chewing.
The researchers suggested that chewing gum could have relaxed the participants, which could have improved their reaction time.
One past study showed chewing gum for 20 minutes increased people's heart rates, which then sent more oxygen to the brain. Another theory is that chewing increases insulin production, which can also help alertness and memory.
The study was published in the journal Brain and Cognition.