In young adults, afternoon naps benefit episodic memory retention, but such benefits decrease with advancing age, a recent study found. In a sleep laboratory, 50 healthy young adults (aged 18-29) and 45 community-dwelling older adults (aged 58-83) were randomly assigned to a 90-minute nap opportunity or an equal interval of quiet wakefulness. Participants also studied words that were individually followed by the instruction to “remember” or “forget.” Following a 90-minute retention interval filled with quiet wakefulness or a nap opportunity, they were asked to free recall and recognize those words. Researchers found:

• Young adults retained significantly more words following a nap interval than a quiet wakefulness interval on both free recall and recognition tests.
• There was modest evidence for greater nap-related retention of “remember” items relative to “forget” items for free recall but not recognition.