Repeatedly revising information to learn it makes sense. “Any kind of reactivation of a memory trace will lead to it being strengthened and reconsolidated,” says James Cousins at the Duke-NUS Medical School in Singapore. “With any memory, the more you recall it, the stronger the memory trace.”

However, sleep is also thought to be vital for memory. A good night’s sleep seems to help our brains consolidate what we’ve learned in the day, and learning anything when you’re not well rested is tricky. Many people swear by a quick afternoon kip.

So if you’ve got an hour free, is it better to nap or revise? Cousins, along with Michael Chee and their colleagues, also at Duke-NUS Medical School, set out to compare the two options. The team mocked-up a real student experience, and had 72 volunteers sit through presentations of about 12 different species of ants and crabs. The participants were asked to learn all about these animals, including their diets and habitats, for example.

After 80 minutes of this, the students were given an hour to either watch a film, have a nap, or revise what they had just learned. After this hour, they had another 80 minutes of learning. Then they had to sit an exam in which they were asked 360 questions about the ants and the crabs.

Long-term benefits

“The napping group got the best scores,” says Cousins, whose work was presented at the Society for Neuroscience annual meeting in San Diego, California on Tuesday.

Cousins and his colleagues called the volunteers back for another test a week later. The nappers scored the highest in this test, too. And while the crammers significantly outperformed the movie-viewers on the first test, they lost their edge in the second test – there was no significant difference in the two groups’ scores a week later.

“It could indicate that cramming information might be good in the short term, but in the long run, the benefits might not be that great,” says Cousins.

However, Cousins is holding back on drawing definitive conclusions from his work – while the nappers were significantly better than film watchers, and crammers and film-watchers were statistically as bad as each other, the difference between the nappers and crammers did not come out as statistically significant. So until the team has conducted bigger studies, the evidence suggests napping is at least as effective as cramming, and might be better.

Napping in the lab

Cousins’s team isn’t sure why napping might be so beneficial. It’s possible that some memories are laid down in the brain during a short sleep, or more likely, a refreshing rest can leave you better able to learn. “It could be that what the nap is doing is making them more alert,” says Gareth Gaskell at the University of York in the UK. “It’s an interesting question, but we need more research,” he says.

Either way, the team are embracing afternoon napping. “There’s a natural dip in alertness at around 3 pm,” says Cousins. “I would say take a nap then. We do it in our lab.” Some members have futons in their offices, he says, while others nod off at their desks. “Napping is encouraged.”

And Cousins has some advice for students: “Don’t stress yourself out just cramming some information into your head,” he says. “Taking a nap is just as good.”