New research in Frontiers in Psychology suggests that caffeine benefits cognition, but only during certain times of the day.

The study on “evening-type” college students found that caffeine improved memory recall performance in the early morning, but not in the late afternoon.

PsyPost interviewed the study’s corresponding author, Lee Ryan of the University of Arizona. Read her responses below:

PsyPost: Why were you interested in this topic?

Ryan: I’m very interested in ways to overcome memory problems, and caffeine is something that we’ve shown benefits memory under specific circumstances – when people are tired and not at their optimal functioning. We’ve shown that it benefits young adults early in the morning, and also older adults in the late afternoon, when both groups are at the low point of their circadian rhythm.

What should the average person take away from your study?

I think the biggest take-away message is for educators. The majority of young people are at a disadvantage in the early morning in terms of learning new information and taking tests. This isn’t because they’re just “lazy”, it’s driven to a large extent by the natural cycling of their physiology. They are just not optimally “awake” in the early morning.

The second important take-away is that the effect was due to caffeinated coffee. It wasn’t just a general effect of physiological arousal, because vigorous exercise that made people feel more awake didn’t have the same effect. So there’s something special about the effects of caffeine on memory function.

Are there any major caveats? What questions still need to be addressed?

Although caffeinated coffee can help overcome the morning disadvantage on a memory test that young people experience, we don’t know whether caffeine taken on a regular basis would have any impact on memory in a way that would have real-world impact. For example, if a student drinks caffeinated coffee prior to taking a big test at 8am, does it really make a difference in their grades? Or do they learn more over the course of an entire semester by using caffeine?

Is there anything else you would like to add?

Remember that caffeine is a drug. You don’t need much of it to make a difference in physical arousal and memory. Too much of it, and it will do the opposite by making you jittery and unable to focus, just the opposite of what you want. More isn’t always better, and in fact sometimes it can be dangerous if taken in too large quantities, especially in conjunction with other stimulants.

The study, “Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day“, was also co-authored by Stephanie M. Sherman, Timothy P. Buckley, and Elsa Baena.