Spencer and others have studied sleep’s effect on memory, but her newest work illustrates that sleep also facilitates and enhances complex cognitive skills, such as decision making. “We have looked at healthy young adults and see that when you learn something about a choice set and then sleep,” says Spencer, “you make better decisions regarding that material than if you didn’t sleep.” This role of sleep in everyday life hasn’t been well characterized by science until now, Spencer adds.
She and post-doctoral fellow Ed Pace-Schott suggest that the benefit of sleep on decision making arises from enhancement of underlying emotions during sleep. ”Our gut instinct, that is often hard to tap, comes out. This may depend on rapid-eye-movement (REM) sleep, which is the creative period of our sleep cycle,” Spencer notes.
In the study, participants were briefly exposed to the Iowa Gambling Test, a widely accepted game of decision making, particularly noted for capturing financial SLEEP decision making. Participants select from four decks of cards, two of which yield overall financial gains and two yield losses. The decision being tested is an example of low-level emotional processing: which deck should I choose from? Just as in making a purchase, the goal is to make financially optimal decisions.
The 18- to 23-year-old participants introduced to the game in the evening and tested 12 hours later, after a normal night’s sleep, were able to more quickly develop a rewarding decision-making strategy than those who learned in the morning and were tested the same day, without sleep. “It is not because you are tired or sleepdeprived at the end of the day either,” says Pace-Schott. “Time-of-day effects on alertness don’t fully account for the better performance for the group who slept.”
“When you are sleeping, you are actually revisiting a lot of information in your brain,” Spencer adds. Dreams reflect heightened activation of the day’s memories, but ou also reactivate all the things you know about features in those memories. The findings have implications for learning as well. “This seems really useful for college students to know,” says Spencer. “Not only is your memory for the organic chemistry lecture reactivated during sleep, but you can integrate information across lectures and reading.” In theory, this should result in better decisions when answering exam questions.
The result of the most recent testing is just one piece of the puzzle that Spencer’s team is looking at. They are also asking what happens to this sleep processing in older adults. As a Family Research Scholar in the UMass Amherst Center for Research on Families, Spencer has sought to extend her research across the lifespan.
With funding from the National Institute on Aging, she has begun to develop a new understanding of inevitable sleep conditions, some of them undesirable, that await us as we age. For example, we sleep fewer hours and have more restless sleep. Spencer and her team have shown that sleep and cognitive decline in aging may go hand in hand. Could elderly individuals make better decisions, regarding their health and their finances, if their sleep were improved?
Farther out, Spencer will look at children and people with Parkinson’s disease and Attention Deficit Hyperactivity Disorder. Ultimately, her work should open up studies that can lead to new models of sleep behavior and different sleep drugs, impacting every home. Spencer reminds us that sleep is a family issue: for parents, for the elderly, for caregivers, for children.
David Bartone '12G
“When you are sleeping, you are actually revisiting a lot of information in your brain," says UMass Amherst psychologist Rebecca Spencer.