Caffeine is a beloved stimulant, which people enjoy consuming in coffee, tea, soda, or other forms. It helps wake us up, making us feel mentally alert. But while we feel mentally active when we use caffeine, studies have not shown conclusive links between consuming caffeine and memory… until very recently, that is. Earlier this week, researchers published findings showing that caffeine does, in fact, help with memory, but not in ways previously suspected.
Previously, it’s been explored whether taking caffeine affects a person’s memory by giving participants caffeine before a memory exercise. Those studies saw no clear improvements in memory. However, the new study found that if caffeine is taken right after a memory exercise, this improved the memory of participants for at least the following 24 hours.
Specifically, participants studied a series of images, and then were given a 200 milligram (mg) caffeine tablet five minutes later. 24 hours later, they were shown the same images as well as some new, similar ones mixed in. Participants who’d taken the caffeine tablet more accurately identified the new images as “similar” instead of incorrectly calling them “the same” as the original images (when compared to participants who’d only had a placebo tablet). Mentally differentiating between two similar things – such as images or experiences – requires a type of discrimination called pattern separation. If the researchers had only looked at memory recall of the same images, they most likely would have missed this key finding.
The amount of caffeine administered in the study – 200 mg to each participant – is about the same as a strong cup of coffee, or a few cups of caffeinated tea. Although dried tea has more caffeine than the same amount of dried coffee, because much less tea is used when making a drink, a cup of coffee actually has a lot more caffeine than a cup of tea. While a five ounce cup of drip coffee has 60 to 180 mg of caffeine, a same-size cup of black tea only has 25 to 110 mg caffeine, and green tea has even less, at 8 to 36 mg. That said, the exact amount of caffeine in any given cup of tea is very variable, and can be affected by a number of factors, such as the specific environment the plant was grown in, which leaves were used from the plant, and how hot and long the leaves are steeped for.
As an interesting side note, the participants in the study did not regularly consume caffeine. I wonder whether the same effects would be seen on people who regularly do drink coffee, tea, caffeinated sodas, or energy drinks, or if regular consumption would interrupt the memory-enhancing process somehow. This is a very relevant question since 80% of adults in the U.S. consume caffeine on a daily basis.
So while you’re groggily reaching for the coffee pot in the morning, there could now be one more reason to be grateful for this multi-purpose stimulant – but you may want to drink it after studying for that midterm to get the best benefits!
For further reading:
- Daniel Borota et al.’s article “Post-study caffeine administration enhances memory consolidation in humans” in Nature Neuroscience
- ScienceDaily’s article “It’s All Coming Back to Me Now: Researchers Find Caffeine Enhances Memory”
- Latarsha Gatlin’s article “Caffeine has positive effect on memory, Johns Hopkins researchers say”
- Teisha J. Rowland’s book Biology Bytes: Digestible Essays on Stem Cells and Modern Medicine