This article is an excerpt from the Shortform book guide to "Learning How to Learn" by Barbara Oakley and Terrence Sejnowski. Shortform has the world's best summaries and analyses of books you should be reading.
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What are some practical ways to study more efficiently? What study habits can help your brain perform better?
Authors Barbara Oakley and Terrence Sejnowski explain how neurons work in your brain and how stronger synapses make it easier to recall information. Then they discuss four study habits you can use to promote neuron growth: exercising between study sessions, testing yourself with active recall, practicing spaced repetition, and getting enough sleep.
Keep reading for details on how to study efficiently.
Stimulating Neuron Growth
Oakley and Sejnowski discuss how to study more efficiently by strengthening synapse chains in your brain. You can do this by stimulating growth in parts of your neurons.
To understand how these techniques improve your learning, you have to understand the anatomy of a neuron. The authors explain that every neuron has one arm called an “axon” and multiple arms called “dendrites.” The dendrites are covered with tiny dendritic spines. The axon of one neuron will transmit electrical signals to be picked up by the dendritic spines of other nearby neurons. The gap between the axon (sender) and the dendritic spines (receivers) that the signal jumps across is the synapse. The more spines there are on a dendrite of a receiving neuron and the closer they are to an axon sending a signal, the stronger the synapse. And, as we’ve said, stronger synapses make it easier to recall the information that they contain.
| Myelin Also Helps Synapse Strength In Make it Stick, Henry Roediger and Mark McDaniel note that synapse strength is enhanced by myelin, a substance that sometimes coats axons. Myelin acts like insulation on a wire, preventing signals from dissipating into their surroundings. This keeps the signal strong and ensures that it’s transmitted to the right dendritic receptors. So if you have more myelin on your neurons, your synapses will be stronger. Roediger and McDaniel also report that the more you practice a skill, the thicker a myelin coating becomes, furthering Oakey and Sejnowski’s claims that you can take purposeful actions to strengthen your synapse connections. |
Tip #1: Exercise Between Study Sessions
The authors’ first tip for promoting neuron growth is to exercise between study sessions. They assert that interspersing exercise with your studies can make your studying more effective because physical fitness promotes neural health. Specifically, exercise causes your body to produce a hormone called BDNF, which stimulates the growth of dendritic spines on neurons, strengthening your synapses.
(Shortform note: Kelly McGonigal elaborates on this concept in The Joy of Movement. She explains that BDNF is part of a class of chemicals called myokines that your muscles produce during physical exercise. These myokines circulate through your bloodstream and stimulate various parts of your body, including your brain. She asserts that myokines not only increase your cognitive performance, but also alleviate both physical pain and emotional depression. As such, she shows how exercise can help you improve many areas of your life, not just your test scores.)
Tip #2: Test Yourself With Active Recall
Oakley and Sejnowski’s next tip is that the most effective form of studying is active recall. Active recall consists of deliberately reproducing or rephrasing ideas from memory, rather than passively rereading them from your notes or other sources. Active recall can take a variety of forms, depending on what you’re studying: If you’re memorizing facts, try to recite them or write them down from memory—don’t just reread them in your textbook or from your notes. If you’re learning a problem-solving technique, work through a problem with it—don’t just read an example solution. If you’re learning a hands-on skill, practice doing the work—don’t just watch someone else do it.
As Oakley and Sejnowski explain, the common theme here is that you’ll always learn more by actively practicing than by passively studying because active recall initiates the growth of dendritic spines, which strengthens synaptic connections in ways that passive learning doesn’t.
| The Testing Effect In psychology, the principle that active recall is more effective than passive studying is known as the “testing effect” because it was initially studied using tests: The researcher would present the same material to two groups of students. One group would then take a test on the material, while the other group would not. Later, both groups would be tested on the material, and the group that took the first test would do better. Recent studies have shown that the same holds true for other methods of active recall. For example, one study demonstrated the effectiveness of having students write down whatever they could remember after reading an assignment. |
Tip #3: Practice Spaced Repetition
Another tip from Oakley and Sejnowski is to study a little every day, rather than cramming before a test or trying to do all your studying in one big session. They call this “spaced repetition,” and assert that spreading out your studies like this gives the synapse chains that represent what you’re learning time to grow and solidify in your mind.
(Shortform note: While other authors corroborate Oakley and Sejnowski’s point, some studies also show that you can take it too far. Studies show that there’s an optimal point for how much you split up your studying: You’ll learn better by studying in multiple sessions spread out over a period of time than in one big cram session, but if you split up your studying into too many short sessions, this can also make your studying less effective.)
Tip #4: Get Enough Sleep
The authors’ final tip on how to encourage neuron growth is to get enough sleep. They say sleep is the key to making your studies effective because sleep plays several important roles in learning and brain function:
As we’ve discussed, active recall initiates growth of new dendritic spines, which strengthen synaptic connections, solidifying ideas in your brain. However, Oakley and Sejnowski note that while active recall initiates this growth, dendritic spines only grow when you sleep. Additionally, while you sleep, unused dendritic spines get cleared away, allowing your brain to divert energy to strengthening the connections you use most. Thus, without adequate sleep, you won’t be able to advance in your learning, because you won’t be able to strengthen your synaptic connections.
| Sleep Can Repair Information In Why We Sleep, Matthew Walker provides additional insight on the importance of sleep for learning. He notes that sleep improves your brain’s long-term retention of important facts and allows it to eliminate trivial facts, as we’d expect from Oakley and Sejnowski’s description of sleep’s effect on dendritic spines. Walker goes on to emphasize that your brain has a remarkable capability to distinguish between relevant and irrelevant information while you’re asleep. This allows your brain to distill information down to its essence and to repair damaged information. So if you sleep after studying, you’ll wake up with a better understanding of the concepts, and you’ll be able to fill in gaps that you couldn’t remember before. |
Sleep Reorganizes Information to Help You Remember
According to Oakley and Sejnowski, sleep is also essential for organizing information in your memory. They explain that as you learn new things, new synapse chains initially form in the hippocampus, a part of your brain near the center of your head where new neuron growth is particularly active. Thus, your hippocampus acts as an initial staging area for information that you store in long-term memory. When you sleep, your brain copies the new synapse patterns from your hippocampus to your cerebral cortex, where they are consolidated and preserved for the long term. This makes room for more new patterns to be formed in the hippocampus.
(Shortform note: In Moonwalking with Einstein, Joshua Foer cites studies that observed this process in rats, and adds a nuance to the principle. Specifically, the studies showed that the rats’ synapses fired in identical patterns while running a maze exercise and while sleeping after the maze exercise. We can infer that this activity represents the copying process that Oakley and Sejnowski describe. Foer asserts that this process consolidates the information, rather than just moves it around. Therefore, not only does the information get preserved in long-term memory, but it also gets stored in a more compact, well-organized way.)
Sleep Cleanses Your Brain
Another reason sleep is crucial for learning, according to the authors, is that it helps manage toxins that your neurons generate as a byproduct of normal thought processes. These toxins build up in your brain when you’re awake, but when you sleep, your brain flushes them out. Without adequate sleep, the toxins can build up to levels that inhibit certain brain functions, making it harder for you to learn.
Oakley and Sejnowski also caution that chronic sleep deprivation, and its resulting toxin buildup, can have additional negative effects on your body such as increased risk of cancer and mental illness.(Shortform note: In Why We Sleep, Matthew Walker identifies some additional problems that neurotoxins can cause when you don’t get enough sleep. He asserts that sleep deprivation inhibits your ability to focus, increases your reaction time, impairs your ability to control your emotions, increases your tendency to take risks, makes you more susceptible to addictions, and increases your likelihood of contemplating suicide. To highlight the significance of these problems, he cites statistics on traffic accidents and medical mistakes attributed to the driver or physician being sleep deprived.)
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- How anyone can learn to master any subject
- Study tactics that you can use to excel in whatever you’re learning
- A look at the neuroscience behind how you learn
