Sleep is a powerful restoration process vital for all human beings and will take up to one-third of every person's life. According to the National Institute of Neurological Disorders and Stroke, "without sleep, you cannot form or maintain the pathways in your brain that let you learn and create new memories, and it's harder to concentrate and respond quickly." A person's body will rest during sleep, but the brain remains busy processing information from that day and creating memories. Most students have experienced staying up into the wee hours of the morning, cramming for an exam, whether it was in high school or college. Did it work for you? Most of the time, it does not work, and the student fails to retain any of the information they studied because they are sleep deprived. It would be more useful to sleep and play audio of whatever you are trying to learn than to stay up and study. New studies have emerged that suggest that it is possible to learn further information while sleeping. To fully grasp the concept of learning while sleeping, it is essential to understand how the process of sleep impacts memory and learning.
What is Memory? How Does Sleep Play A Role?
According to Web MD, there are different types of memories, which falls into one of three categories, such as fact-based, episodic, or instructional. Fact-based memory centers on remembering things like vocabulary or state capitals, while episodic memories are based on events like a first date. Instructional memories are procedural such as learning to play the guitar or bake a cake. Memory encompasses three functions:
- Acquisition – learning something new
- Consolidation – the memory becomes fixed in the brain
- Recall – being able to pull the memory up in the future
Acquisition and recall occur when a person is awake, but consolidation of memory happens during sleep. Dr. Robert S. Rosenberg, a board-certified sleep medicine specialist, stated, "during sleep, recent memories, such as those of that day, are transferred to the higher cortical centers where they are consolidated into long term memories."
Is Learning Possible While Sleeping?
Virtually everyone has heard that listening to a foreign language while asleep will assist in learning the language. Is it true? Experts found learning new fact-based concepts, like learning a foreign language or learning to play a musical instrument while asleep is possible. One Dutch study analyzed a group of 41 German-speakers and found that they could incept participants' brains with vocabulary from a non-existent language and link those words to German meanings while the participants slept. "What we found in our study is that the sleeping brain can encode new information and store it for the long term. Even more, the sleeping brain can make new associations," said study author Dr. Marc Züst at the University of Bern.
The Process of Sleep and Learning
It is essential to fully understand what occurs in various sleep stages to understand the above study results. The main two phases are rapid-eye-movement (REM) and non–rapid-eye-movement (NREM). Sleep starts with the NREM state, and that state goes through four stages: onset (Stage 1), light sleep (Stage 2), and deep sleep (Stages 3 and 4). After an hour to an hour and a half, there is a transition into REM sleep, which lasts around 30 minutes, and then NREM sleep returns to start a new sleep cycle. During one night, a healthy person should experience four to six consecutive sleep cycles.
The Difference Between NREM and REM
NREM and REM sleep occurs back-to-back, and both are important for health, but both phases are starkly different. During NREM sleep, the body moves, but the eyes do not move like when REM sleep happens. However, a person's breathing and heart rate slow down. Brain activity and blood flow to the brain slow down.
REM sleep is the opposite of NREM sleep in many ways. For example, the body does not move, and the eyes dart rapidly in all directions. The blood pressure, heart rate, and respiratory rate swing up and down during this phase. Dreaming is most common during REM sleep, but it may also occur during the early stages of NREM sleep.
Empirical Data Proves That Learning Can Happen While Sleeping
A 2010 Harvard study found that dreaming helps reorganize newly learned material, which inadvertently improves memory. This study included 99 college students who agreed not to consume alcohol, caffeine, and drugs before the experiment. All students showed standard sleep patterns before enrolling in the study. For the experiment, each student was asked to spend one-hour learning how to navigate a three-dimensional maze-like puzzle. After training, half of the students were allowed to take a 90-minute nap, while the other half relaxed. All students were given lunch, but the only students whose performance improved were the few who dreamed about the maze during their naps. Interestingly, the dreams did not depict solutions to the puzzle, but experts concluded that the dreams showed that dreaming consolidates memories. The researchers also found that the dreams happened early in NREM sleep.
Sleep, learning, and memory are complicated and not entirely understood. However, studies suggest that adequate sleep broadly impacts learning and memory. Empirical data supports the idea that quality sleep positively impacts learning and memory in two significant ways. Firstly, if one is sleep-deprived, one cannot focus and will not learn efficiently. Secondly, sleep is vital for the consolidation of memory, which is crucial for understanding new information. Acquisition and recall only happen during wakefulness, but several studies found that memory consolidation occurs during sleep by strengthening neural connections that help form memories. There is no consensus about how rest makes this process possible. Still, many researchers think that brainwaves' specific characteristics during different phases of sleep are interconnected with the formation of particular memories. Therefore, it is better to get adequate sleep instead of cramming for exams or listen to an audio of the information that one needs to learn while sleeping.