My day begins with four cups of black tea. A co-worker will stop for Starbucks. Another will down an energy drink. We’re all trying to wake up and get our bodies going for the workday, and caffeine is the easiest and quickest way to do that.
Caffeine consumption, though, may have another good benefit: enhancing memory. Researchers at Johns Hopkins University discovered that long-term memory is positively effected by caffeine, and that it can enhance certain memories for up to 24 hours after it’s ingested.
“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,” said Michael Yassa, an assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins University. “We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours.”
Participants, in a double-blind trial, who did not regularly eat or drink caffeinated products were given either a placebo or a 200-milligram of caffeine tablet after viewing a series of images. Saliva samples were taken before and one, three, and 24 hours afterwards to check for caffeine levels. Tests were conducted the next day on both groups to gauge their ability to recognize the images from the previous day. Participants in the caffeine group were more able to identify the images and similar images as compared to the placebo group. It is this ability to recognize the difference between two similar but not identical items, the researchers said, that shows 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.”
The study is different from previous experiments.
“Almost all prior studies administered caffeine before the study session, so if there is an enhancement, it’s not clear if it’s due to caffeine’s effects on attention, vigilance, focus or other factors,” Yassa said. “By administering caffeine after the experiment, we rule out all of these effects and make sure that if there is an enhancement, it’s due to memory and nothing else.
“The next step for us is to figure out the brain mechanisms underlying this enhancement,” Yassa continued. “We can use brain-imaging techniques to address these questions. We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer’s disease. These are certainly important questions for the future.”