Researched by Erin GeorgenPublished - January 12, 2016 Last Updated - February 8, 2019
Does Sleeping on a Problem Work?
Sleeping on a problem works. Studies show a positive correlation between sleep and cognitive function. Contemplating a problem and then “sleeping on it” can result in better problem solving due to the way our brain organizes long-term memories using REM sleep.[1][7][8][9]
Even Naps Help Improve Problem Solving
Even a nap will significantly improve problem-solving skills, but only if an entire sleep cycle is achieved. Short NREM naps slightly boost performance, but a 90-minute nap including a REM cycle boosts problem-solving power 40% more than a short NREM nap.[9]
This video discusses dreams as being the source for problem-solving. This is likely due to a common misunderstanding about the association of dreams and REM sleep. Research indicates that achieving REM sleep, and not dreaming, is what improves problem-solving. The “replaying” of memories that happens in REM sleep, whether it comes with a dream or not, helps to strengthen links made during the day in long-term memory. Aside from the disassociation, the video does a good job explaining the process.
Do REM Sleep or NREM Sleep Help Cognitive Function?
There is strong evidence that both non-rapid eye movement (NREM) and rapid eye movement sleep (REM) are beneficial for cognitive performance. NREM sleep improves alertness and ability to focus attention while REM sleep improves problem-solving, memory, and abstract thinking.[2]
REM helps to stabilize, consolidate, and enhance connections between memories. Information that was stored in long-term memory during the day is activated (also called rehearsed) and turned into useful connections while we experience REM sleep.
FACT: Our brains rewire somewhat while we are awake, but the bulk of the reconnecting happens during sleep. The process of our brains rewiring is called synaptic plasticity.
People experience several cycles through NREM and REM sleep during a normal nights sleep.
How Does REM Sleep Affect Problem Solving?
Scientists have not yet fully defined the biological function of REM Sleep, but we do know that it plays important roles in a variety of cognitive functions:
Forming Long-term Memory Associations – The brain receives a lot of random sensory input during a given day, we process some of this in short term / working memory and some are stored in long-term memory. During sleep, and specifically, REM sleep cycles, the brain replays information stored in long term memory during the day, these neural connections are strengthened, new associations are made, and the non-essential information is discarded. The connections and associations the brain makes during REM can help us to solve the problem we couldn’t “figure out” during our waking hours.[6]
Focused Attention – During REM Sleep, the body is in a sense disconnected from the random neural firing happening in the brain. This not only to prevent physical movement of the body, but it also allows the brain to focus attention on REM tasks by limiting sensory input.[1] This may be part of the boost in problem-solving skills during REM.
Emotional Association/Consolidation – Studies have correlated REM sleep in creating emotional connections, but this is only apparent when researching dreams. Dreams are difficult to study objectively. Not everyone has dreams or remembers them, and dreams are inherently subjective. Still there is a significant correlation between a person’s emotions and their dreams during REM sleep.[3][10]
NOTE: Our memories are sensory memories. We store blips of information in specific neurons that handle specific sensory memories. These blips are connected to form a memory and then connected again to other neural memories and sensory blips to form a useful understanding of the world. What we feel, hear, smell, taste, and understand spatially is all connected and our brains make sense of it using all the sensory information they already have.
What Does it Mean to “Sleep” on a Problem?
In the most basic sense, the term describes thinking about a problem just before bed or falling asleep while thinking about it. In practice, spend 5-15 minutes thinking about a specific problem within 30 minutes of bedtime. What’s important is that you are waiting to try to solve the problem until morning; instead, you are spending 10 stress-free minutes contemplating, familiarizing, and reviewing. Think of it as giving your REM cycle fresh information to file and indicating the information’s significance by spending time focusing attention on it.
If you have a big test that you are preparing for, reviewing your notes just before falling asleep the night before will give you an advantage. Doing it every night for a week before the test will give you an even bigger advantage.
If your homework is to read and answer questions, try doing the reading and read the questions just before bed, but wait until morning to actually answer the questions.
For personal and more complex problems, write about the issue in a journal for 5-15 minutes, but again, try to focus on gaining a thorough understanding of the problem. When you wake up, immediately journal your thoughts and insights. Complex issues are usually multi-faceted; solutions will take time and patience. The first part of solving the problem might be to understand Why is this a problem? or Is this a problem that I can fix/change?
Does it Matter When We Learn / Sleep?
Different parts of our brain store different types of memories. There are two main types of long-term memory: explicit (or declarative) memory and implicit (or procedural) memory. One study found declarative memory was better recalled if learned in the afternoon while procedural memories were better recalled if learned just before bed.
Is it Ever Better Not to Sleep?
It is usually a good idea to “sleep on it”, but not always. For example, immediately following a traumatic experience it is better to avoid sleep to reduce the risk of developing Post Traumatic Stress Disorder (PTSD).[4][5]
It indicates that PTSD may in part be caused by memories and emotional associations forming strong long-term connections too soon after the experience. This process is normally beneficial to emotional and cognitive function. Immediately following a traumatic experience, unfortunately, a person is in a heightened “fight or flight” state with intense fear and anxiety. For people who suffer from PTSD, this experience is on repeat and often includes invasive memories of the event.
It is also not clear how long someone should avoid sleep after trauma, but probably it depends on the person’s emotional state and other circumstances of the experience. Sleep is essential for health and healing, in cases involving injuries it may be risky or impossible to avoid REM. Assuming a person can avoid safely sleep following a traumatic experience, the goal should probably be to avoid sleep until well after the state of “fight or flight” has ended and/or the person has been able to work through the negative experience enough to find some amount of closure.
Notes
Author’s Thoughts
Interestingly, people suffering from PTSD usually struggle with difficulty falling asleep and/or staying asleep. Sleep is disrupted with invasive unpleasant memories of the event or imagery that evokes the same stress and anxiety. For example, a person with PTSD after barely escaping a fire might have nightmares about being trapped in a fire or they might have nightmares about being swept out to sea by a tidal wave. Both nightmares evoke the same emotional stress. Others might become anxious every time they even try to fall asleep. Perhaps this is actually the brains attempt to disrupt the connections/associations process until after the trauma has been consciously worked through and no longer elicits the same intense emotional response. It will be interesting to see how the research investigating this link between REM sleep and PTSD progresses and how it will shape future treatments of PTSD.
Conclusion
“Sleeping on it” increases your problem solving skills. Even taking a nap can give you an advantage, but only if you achieve REM sleep.
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