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.
Michael Erard, Babel No More: The Search for the World's Most Extraordinary Language Learners
gum, language-learning, memory