In an experiment conducted by Michael Yassa, formerly an assistant professor of psychological and brain sciences at Johns Hopkins University, and his team, one cup of strong coffee, or 200 milligrams of caffeine, were found to enhance long-term memory.
"I have been a coffee drinker for quite some time," said Yassa in an informational video, above. "I'm one of those people who can't function without their coffee and I've always been curious about the kind of effect it can have on my memory and on my cognition."
Yassa, who has since moved his lab to UC Irvine, recruited 60 study participants who did not regularly eat or drink caffeinated products. They were all asked to study images of everyday objects. Five minutes later, some were given a placebo and others were given an identical-looking 200-milligram caffeine tablet. Samples of the participants' saliva were taken to study their caffeine levels before and after being given the placebo or tablet. Samples were then taken one hour, three hours and 24 hours after.
The following day, both the placebo and caffeine groups were shown images and asked to relate them to the images they were shown the day before. Some of the images were the same, some were slightly different and some were completely different.
Researchers found that more people from the caffeine test group showed an elevation in pattern separation, the ability to recognize the differences between two similar but not identical items. For example, a picture of a rubber duck with a lightning bolt on it shown the first day might be shown the following day with no lightning bolt. This, according to the scientists, shows a deep 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
Johns Hopkin's HUB." 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."
Yassa's study is one of the first to examine the effects of caffeine on long-term memory. Prior experiments gave subjects the caffeine or placebo tablets before being asked to study objects rather than after. This enabled Yassa to rule out effects other than the caffeine on the subject's attention to the images such as focus, vigilance and other factors.
The next step for Yassa is to study the brain mechanisms behind the memory enhancement.
"We can use brain-imaging techniques to address these questions," Yassa said. "We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer's disease."
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