Researchers found that caffeine enhances memory.From Science Daily:
It's All Coming Back to Me Now: Researchers Find Caffeine Enhances Memory
Michael Yassa, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins, and his team of scientists found that caffeine has a positive effect on long-term memory in humans. Their research, published by the journal Nature Neuroscience, shows that caffeine enhances certain memories at least up to 24 hours after it is consumed.
According to the U.S. Food and Drug Administration, 90 percent of people worldwide consume caffeine in one form or another. In the United States, 80 percent of adults consume caffeine every day. The average adult has an intake of about 200 milligrams -- the same amount used in the Yassa study -- or roughly one strong cup of coffee or two small cups of coffee per day.