If students want to retain information better, hitting the pillow may be better than hitting the books, a new study suggests.

Scientists at the University of Chicago have recently discovered sleep improves memory.

Test subjects were given specific tasks to learn. One task included training subjects to hear murky words spoken by a voice synthesizer and then having the subject type their English equivalent into a computer. No words were repeated. The subjects were then tested either the next morning after a night’s sleep, or several hours later with no sleep.

Groups tested got 30 to 40 percent correct at the end of the day, but the groups tested right away in the morning got 30 to 50 percent correct, said Howard Nusbaum, associate professor of psychology at the University of Chicago and co-author of the study.

The groups tested the next day improved from their pre-training test by about 20 percentage points, whereas the group tested several hours later only improved by 10 percentage points.

“Something happened during the day so they lost some of their learning, but if they [slept] they [got] it back,” Nusbaum said. “Sleep restores some of what is lost during the course of the day.”

There were about 12 people in each group and 60 or 70 total groups consisting of college-aged people, he said.

Kenneth Malmberg, assistant professor of psychology, said he found the results of the study interesting.

“Usually what we find is that the ability to remember something decreases as the retention interval increases,” Malmberg said. “They found the opposite pattern.”

Malmberg said at the core of the study is the idea of consolidation, which is the way in which some scientists believe memory is only temporary until sleep causes it to be permanent.

“A cognitive system is assumed to have a limited capacity,” Malmberg said. “When you’re asleep, the resources devoted to paying attention and remembering aren’t being used, so now those resources are available for storing things in a long term manner.”

Malmberg said an example of this is when a person experiences head trauma in a motorcycle accident.

Injured people are sometimes able to remember events that happened to them years ago, but lose memories from a few hours before the accident. This is because those memories have not yet had a chance to become consolidated.

This study may also help to explain memory loss in older people, Malmberg said.

In the United States, the ability to remember decreases as a person gets older, which could be linked to the difficulty older people have in falling asleep. Older people might not be as good at consolidating their memories, Malmberg said.

The study may have important practical applications by helping to explain the processes used in learning a second language, and in understanding the recovery of aphasia, a brain impairment caused by strokes in which the ability to use and understand speech is damaged, Nusbaum said. New therapies could be crafted for aphasia.

Malmberg said sleep is a popular topic of different studies.

“It’s an important issue in society,” Malmberg said. “People are working harder and harder, and sleeping less and less. People might be busier in order to make ends meet, but that might be harming their ability to perform effectively at work.”

Students should never pull all-nighters, since the ability to consolidate the information will be lost, Malmberg said.

Jinny Krogman, senior in apparel merchandising, design and production, said she has never pulled an all-nighter.

“I would make time during the day to study,” Krogman said. “It would have to be an important test. I would take off work before I’d pull an all-nighter.”

Kalli Polemikos, senior in early childhood education, said when she was a student in architecture she was forced to pull an all-nighter once.

“[The next day] I was pretty sleepy,” Polemikos said. “I wasn’t making much sense when I was talking.”

She said her project turned out OK, but it could have been a lot better. She doesn’t recommend all-nighters to others.

“In the end, you could probably do a better job if you just pace yourself out and manage your time better,” Polemikos said.