Having trouble remember where you left your keys? A double shot of espresso could help. A new study suggests that the same amount of caffeine you would find in a grande latte can enhance long-term memory in humans. “We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours,” Michael Yassa, a professor of brain science, said in a statement. For this study, 60 people were recruited who have a relatively low daily caffeine intake. The participants were asked to look at 200 pictures of everyday objects such as a chair, or a coffee mug on a screen and to tell the researchers whether the object was an indoor item or outdoor item. “It didn’t matter what they said, we just wanted them to pay attention to the pictures,” said Yassa. Five minutes after the task was completed, half of the participants were given 200 milligrams of caffeine in the form of two small pills and the other half were given two placebo pills that looked exactly the same. Neither the researchers nor the subjects knew who got which pills.
The following day, the subjects were asked to look at another set of images and identify which pictures they had seen the day before, which pictures were new, and which ones were similar, but a little different to the ones they had already seen. The researchers saw that while both groups had the same success rate when it came to identifying pictures that were the same and pictures that were different, the participants who received the caffeine pills were better at remembering that a picture was similar, but a little different to one they had seen before. “It is a much more detailed memory,” said Yassa. “If all they remembered was ‘coffee mug,’ they would say the picture was the same. But they were remembering the exact coffee mug they saw.” Scientists call this type of memory—where we can determine that something is similar but not exactly the same as something we have seen or done before—pattern separation memory.
Yassa explained that there is no magic in taking caffeine five minutes after something occurs that you need to remember. “Before or between or after or during, it would all work,” he said. “The only thing I would say is don’t drink caffeine to pull an all-nighter. Sleep is really good for memory, but if you are going to drink coffee to stay up you won’t get the boost from either one.” The next step for the research team is to figure out why caffeine helps with pattern separation memory.