Researchers at the Johns Hopkins University have found that caffeine enhances memory. The results of the experiment are published in the journal Nature Neuroscience. 

Michael Yassa, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins, and his fellow researchers found that caffeine has a positive effect on long-term memory in humans. Their research shows that caffeine enhances memories at least up to 24 hours after it is consumed.

“We’ve always known that caffeine has cognitive-enhancing effects, but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans,” remarked senior author Yassa in a Johns Hopkins news release. “We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours.”

Participants who did not typically consume and drink caffeinated products were given either a placebo or a 200-milligram caffeine tablet five minutes after studying a number of photos. Salivary samples were taken from the participants before they took the tablets to measure their caffeine levels. Samples were taken again one, three and 24 hours after consuming the tablets.

The next day, both groups of participants were asked to identify images from the previous day’s experiment. Some of the photos were the same as from the day before, some were new images and some were similar but the same as the images previously studied. The researchers documented that more participants in the caffeine groups were able to successfully identify the new images as “similar” to previously studied photos versus incorrectly identifying them as the same.

The brain’s ability to identify the difference between two similar but not identical items, an ability called pattern separation, demonstrates a deeper level of memory retention.

“If we used a standard recognition memory task without these tricky similar items, we would have found no effect of caffeine,” Yassa said. “However, using these items requires the brain to make a more difficult discrimination — what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case.”

Prior to this study, caffeine’s effects on long-term memory had not been examined in detail. The general consensus was that caffeine had little or no affect on long-term memory retention.

The next challenge is to identify and understand the brain mechanisms behind this enhancement.