Each man in the group took the test twice, once after drinking 100 milligrams of caffeine dissolved in water, the same amount found in about two cups of coffee, and once after drinking plain water. Both times, the men had fasted for 12 hours before the test to prevent other substances from affecting their memory.
When taking the test with the caffeine advantage, the men were not only able to remember the sequence better, they also answered the questions significantly faster.
Reviewing brain scan images, the researchers found that the regions of the brain that control working memory and attention were significantly more active when the participants drank the caffeine.
While these results are promising, you may not want to rush over to the percolator every time you forget an item on your shopping list. Dr. Kopplestatter warns that less is known about how caffeine affects long-term memory and suspects that there may be differences in how frequent coffee or soda drinkers respond to caffeine.