If you want big improvements, she said, chew gum. Gum? Sure enough, chewing gum has been shown to improve a person's immediate recall of learned words by some 24 percent. Long-term recall improves by a larger 36 percent. To get the benefit, you actually have to chew gum as you are studying; for some reason you can't merely move your jaw up and down. I also discovered that drinking sage tea increases one's recall of words modestly, as does the odor of rosemary. Something as mundane as coffee provides a benefit, too. Drinking two cups of coffee increases neuronal activity in the frontal lobe, where working memory is controlled, and in the anterior cingulum, where attention is controlled.

Babel No More: The Search for the World's Most Extraordinary Language Learners