This article reveals what modern neuroscience has learned about sleep as it applies to learning and memory. I believe this information can be of great benefit not only to students looking to improve their study skills, but to anyone interested in improving their memory and learning potential.

Most of us think of sleep as a time of rest … a time when the brain
settles down, relaxes, and becomes quiet. After a busy day of attending classes, talking with friends, studying, and stressing out, the brain finally gets to shut down and take a break from it all. Sounds logical, right? Well, that’s not quite what happens. Actually, when you’re asleep, your brain is continuing to learn the material you’ve been exposed to during the day.

You Sleep, But Your Brain Works

Dozens of intriguing studies over the past several years show clearly
that your brain is active—very active—during sleep. (Reference 1-7) It’s busy doing something miraculous, something that we can’t even come close to explaining.

Basically, your brain goes on automatic pilot. Without your being aware of it, something inside your head comes alive and starts mulling over all the things you learned that day. It sorts through them, organizes them, considers them, calculates them, decides what’s important and what’s not.

From all the information that your brain soaked up during the day, it derives meaning. It works through unsolved problems and somehow comes up with answers. Its powers, however, extend even farther than that. A spooky awareness speeds through neural circuits. As it does so, it changes the physical structure of brain cells so that specific pieces of knowledge are etched more permanently in memory. In the neurologic literature, these miraculous processes are referred to as consolidation.

What your brain is doing, without any conscious effort on your part, includes:

• reviewing,
• sorting,
• organizing,
• prioritizing,
• problem solving, and
• memorizing.

All this is happening while you sleep! As you can see, effortless sleep-learning is not only possible, it is a reality.

The amazing truth is that learning continues after the actual studying is done. In fact, research indicates the maximum benefit of all your hard hours of studying comes about only after a good night’s sleep.

Furthermore, even though you may have stopped studying, knowledge and skills continue to improve over several nights of sleep. Although sleep on the first night following training offers the most dramatic benefit, subsequent nights of sleep continue to provide smaller, less pronounced gains.(Reference 2)

Consolidation and Physical Skills

Athletes, pianists, surgeons, and video game addicts take note: This process applies to learning not just information but motor skills as well. One recent study showed that sleep after practice enhanced the speed of skilled motor performance by 33.5 percent on average and reduced the error rate by 30 percent, as compared with corresponding intervals of wakefulness.(Reference 7)

To extend this concept just a little bit further: Amazingly, learning does not stop when practicing and studying end. It turns out that performance and learning improvement occur not only during sleep but also during periods of wakefulness. (Reference 2,7) After you finish reading a chapter, your brain goes to work on that information over the next few hours, slowly learning and consolidating it. This subconscious processing of learning information is above and beyond what you did consciously during your actual study session.

An everyday example of this subconscious processing is the tip-of-the-tongue phenomenon. Try as you might, when asked, to remember the name of a movie, store, or restaurant, you may find that you can’t. But several minutes or even hours later, it may come to you like a flash of lighting out of the blue. Why? Without your conscious knowledge, that spooky awareness we talked about earlier spreads through your neural networks, searching for the answer. When your brain finally finds the item you were seeking, it tosses it back up for your conscious mind to grasp. Imagine what happens when you throw a stone into a pond: The effect of the stone upon the water does not cease at impact. Long after the rock hits the water, waveforms slowly ripple out toward the periphery. So it is with the mind. When you ask something of it, the neural reverberations of the question (the “rock”) persist long after the question is asked.

Key Findings of Consolidation Research

So what, in brief, do we know about how the brain consolidates information?

• Development of procedural/motor skills does not stop when practice ends but continues over hours.
• Development of memory does not stop when studying ends but continues over hours.
• Neural activities during sleep contribute significantly to the formation of different types of memories and skills.
• For a given period of sleep vs. one of wakefulness, consolidation will be greater with sleep.
• The first nightly sleep period after practicing or studying is extremely important for starting consolidation of the skill or memory. Going without this initial first night of sleep will have a very negative effect on the consolidation of that particular skill or memory.

Making the Most of Sleep Learning (consolidation)

You can use what you now know about sleep-learning to substantially improve your performance in school and in other activities. Here are some techniques to try out.

The Secrets of A+ Students

One common trait of top students is that they always seem to be several chapters ahead of the rest of the class. Given how the brain works, there’s a huge advantage to following this technique. If the professor gives the first exam four weeks into the course, and the A+ students are already two weeks ahead from the get-go, their subconscious minds have been consolidating, churning, working, and memorizing the material effortlessly for a total of six weeks, while the brain of the typical student has had just four weeks of study. This means that their brains have been learning and consolidating the material for 50 percent longer than most students’ brains have. No wonder they’re getting the A+!

Here’s a simple plan to try: Treat the first two weeks of the semester like the last two weeks before finals. By the second week of the course, you’ll be several chapters ahead of the rest of the class. Then slow down the pace and study the rest of the semester at the same rate as the class (notice that you’ll always be ahead by several chapters).

Hard-To-Understand Items and Problems

Some school courses require rote memorization and are not mentally challenging. Some, however, present concepts that are quite difficult to understand. You might at times find yourself spending 30–45 minutes fixated on one difficult problem or concept, struggling and becoming frustrated but not really making any progress.

Try this instead: Work on the difficult concept for a short while, then move on, and then go back to the issue several hours later. If you still haven’t overcome the roadblock, return to problem the next day.

Walking away from something incomprehensible (or difficult to solve) allows your spooky awareness to hammer away at the challenge. It will try to understand the concept or come up with an answer without any conscious effort on your part—sort of the way the tip-of-the-tongue phenomenon happens. Chances are good that when you come back to the problem, your subconscious will have solved it or have at least come closer than where you were before. Spending 45 minutes struggling consciously with something is a huge waste of time and mental resources.

Cramming

Let’s take two college students—Steven and John—as examples. It’s the end of the semester, two weeks before the economics final exam. Steven studies faithfully and regularly the whole semester. The last two weeks, he puts in an average of one hour a night for review.

John, on the other hand, has not been so faithful and regular. He has done almost no studying the whole semester. The last two weeks, he spends five hours a night cramming for the exam. He goes to bed around 3–4 A.M.

In the past two weeks, John has studied 70 hours. Over the semester he has managed to put in 20 hours. In total, he has put in 90 hours studying for the economics course. Steve has also put in 90 hours, but his studying time has been distributed over the entire semester.

Observations: Steve has 90+ sessions of effortless sleep-learning and processing on his side. John, who has done the vast majority of his studying the last two weeks, has only about 24. Given what we’ve learned above—namely, that neural activity during sleep contributes significantly to memory and skill formation—can you see whose studying will be markedly more effective?

Without doubt, cramming is counterproductive in that it does not take advantage of automatic, effortless, and vitally important sleep-learning. Experience shows that people who cram never come away from a class with as deep and permanent an understanding of the material as those who study regularly throughout the entire semester. If the same students were to be retested a half-year later (as happens on national, standardized tests) or were required for some reason to reproduce the knowledge at a later time (many courses build on prior course knowledge), there is no question that the crammer would come up short.

Before Sitting Down to Study

As mentioned above, every bit of information that enters your mind sets off reverberations that last long after the initial encounter. Your brain processes these echoes without your conscious awareness. Therefore, before sitting down to read a chapter,

• skim through it, and
• take note of the introduction, headings, subheadings, tables, charts, diagrams, key words, and conclusions

Once your mind has been loaded with the basic scaffolding of the information you’re about to acquire, it will automatically go to work trying to connect the pieces. Your reading will therefore be more meaningful and go faster.

Give this a try: Do your chapter skimming 2–4 hours or even one day before actually sitting down to read the chapter text word for word.

Test Taking

Recommendation: When you reach a difficult test question and can’t think of the answer, come back to it later. Sometimes, when you return to the question, you’ll find the answer has indeed come to you. You can even keep coming back to the item several times (as time permits) if you don’t get the answer the first time you return to the problem.

Why does this recommendation work? As you move on to other test questions, reverberations are set up in your brain, and that spooky awareness travels far and wide looking for the answer—all on its own, without conscious awareness, even while you are answering other test questions. Therefore, it’s not productive to spend very long fretting and puzzling over a specific question. Move on, but be sure to come back to the item later. You may need to give your brain several prods before it comes up with the answer. Additionally, struggling too long on a difficult test question will destroy your confidence and ruin your mindset for the rest of the examination.

Take-Home Message

Those who fully understand the brain processes of sleep-learning and consolidation are in a solid position to substantially improve performance in school as well as other activities.

References:

1. Kali S, Dayan P. Off-line replay maintains declarative memories in a model of hippocampal-neocortical interactions. Nat Neurosci. Mar 2004;7(3):286-294.

2. Walker MP, Brakefield T, Hobson JA, et al. Dissociable stages of human memory consolidation and reconsolidation. Nature. Oct 9 2003;425(6958):616-620.

3. Maquet P, Schwartz S, Passingham R, et al. Sleep-related consolidation of a visuomotor skill: brain mechanisms as assessed by functional magnetic resonance imaging. J Neurosci. Feb 15 2003;23(4):1432-1440.

4. Pennartz CM, Uylings HB, Barnes CA, et al. Memory reactivation and consolidation during sleep: from cellular mechanisms to human performance. Prog Brain Res. 2002;138:143-166.

5. Hoffman KL, McNaughton BL. Sleep on it: cortical reorganization after-the-fact. Trends Neurosci. Jan 2002;25(1):1-2.

6. Peigneux P, Laureys S, Delbeuck X, et al. Sleeping brain, learning brain. The role of sleep for memory systems. Neuroreport. Dec 21 2001;12(18):A111-124.

7. Fischer S, Hallschmid M, Elsner AL, et al. Sleep forms memory for finger skills. Proc Natl Acad Sci U S A. Sep 3 2002;99(18):11987-11991.

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