New scientific research has provided additional evidence that caffeine can boost your memory. After ingesting caffeine pills, human subjects were found to be more successful at image-based memory tests than their caffeine abstaining counterparts, suggesting that the stimulant drug can strengthen our memories and make them more permanent. However, the specific timing and amount taken can make a big difference.
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To find out if caffeine has an enhancing effect on long-term memory, US researchers from the Johns Hopkins University in Maryland analysed the effects of caffeine on forgetfulness using a behavioral discrimination task. During the experiment, 150 people were divided into two groups with one given caffeine pills and the other a placebo.
Before ingesting the pills, the subjects were shown pictures of everyday objects. They were then shown a second batch of near-identical images 24 hours after taking the pills. The people who had ingested caffeine were significantly more successful at noticing the differences between the old and new images.
Caffeine enhanced performance 24 h after administration according to an inverted U-shaped dose-response curve; this effect was specific to consolidation and not retrieval. We conclude that caffeine enhanced consolidation of long-term memories in humans.
While both the placebo and caffeine pill groups were able to correctly identify pictures as 'new' or 'old', those who had taken caffeine were more accurate at distinguishing 'similar' pictures from the original ones. The placebo group, meanwhile, incorrectly identified similar pictures as the old originals.
For best results, the study suggests an optimal dose of 200 milligrams which translates roughly to a single cup of strong coffee. Anything more can result in debilitating side-effects such as headaches and agitated composure. Timing was also found to be an important factor: there was no significant improvements in memory performance when caffeine was given one hour before the picture identification test.
In other words, if you're keen to give your memory a boost for a specific date such as a university test, your best bet is to drink a single cup of coffee 24 hours beforehand.
Post-study caffeine administration enhances memory consolidation in humans [Nature Neuroscience]