Sleep, learning, and memory are complex phenomena that are not entirely understood.
Although current research suggests that sleep is essential for proper memory function, there are unanswered questions, as in any area of active scientific inquiry.
The second approach examines how sleep deprivation affects learning.
Sleep deprivation can be total (no sleep allowed), partial (either early or late sleep is deprived), or selective (specific stages of sleep are deprived).
Sleep researchers study the role of sleep in learning and memory formation in two ways.
The first approach looks at the different stages of sleep (and changes in their duration) in response to learning a variety of new tasks.