Their experiment — which focuses on visual learning — suggests that rather than one stage being more important than the other for learning new skills, both play essential and complementary neurochemical processing roles.They found that while non-REM sleep enhances our performance of newly acquired skills by restoring flexibility, REM sleep stabilizes those improvements, and prevents them from being overwritten by subsequent learning.“I hope this helps people realize that both non-REM sleep and REM sleep are important for learning,” says corresponding author Yuka Sasaki, a professor of Cognitive, Linguistic, and Psychological Sciences at Brown.