A recent study in Science suggests that at least some of our primate cousins can. Researchers showed that brief naps (without rapid eye movement, or REM, sleep) improved macaques’ performance on a visual-perception task. The scientists then reproduced this boost by electrically stimulating the brains of awake monkeys in a way that mimicked sleeping brain activity—inducing a kind of “artificial nap.” The process, if effective in humans, might one day help boost cognition and treat sleep disorders.