PDF Summary:Learning How to Learn, by Barbara Oakley and Terrence Sejnowski

According to Barbara Oakley, anyone can master any subject by applying good study techniques. You don’t have to be gifted or have natural abilities in a particular subject to excel at it. And Oakley should know: She failed math in high school, but later overcame her fear of numbers and eventually earned a doctorate degree in engineering.

In this book, Oakley and co-author Terrence Sejnowski explain study tactics that you can use to excel in whatever you’re learning. To make them immediately applicable, we’ve organized this guide as a list of actionable study tips, and we’ve cross-referenced the authors’ advice with other sources, such as Why We Sleep, which discusses the importance of sleep to learning, and the work of psychologist Edward de Bono, who advises on how to alternate between modes of thinking to get the most out of your learning.

(continued)...

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.

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.)

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.

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.)

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.)

Manipulate Your Modes of Thinking to Maximize Your Learning

Oakley and Sejnowski also offer a number of tips for enhancing your learning that are based on your brain’s ability to alternate between different modes of thinking. They assert that your brain operates in two separate modes, each of which contributes to learning and problem solving in different ways. They call these two modes “focused thinking” and “diffuse thinking.”

The authors explain that focused thinking happens when you focus on something, such as a specific problem you’re trying to solve. In this mode, your brain activity gets concentrated in a particular network of neurons (which network depends on what you’re focusing on). Focused thinking can process information in detail, but it limits the scope of your thoughts to ideas that are already connected to that particular network.

They then explain that diffuse thinking happens when you let your mind wander, not focusing on anything in particular. In this mode, your brain activity is delocalized—it’s not concentrated in any particular network of neurons. Diffuse thinking doesn’t process information in detail, but it can link ideas from diverse parts of your brain to generate creative solutions or help you see the big picture.

Additional Modes of Thinking

Oakley and Sejnowski’s descriptions of diffuse and focused thinking correspond to what psychologist Edward de Bono calls “lateral” and “vertical” thinking, respectively (as Oakley herself notes in A Mind for Numbers). However, there is a subtle difference in how de Bono distinguishes between the two modes: He identifies lateral (diffuse) thinking as a mechanism for generating new possibilities, while vertical (focused) thinking is a mechanism for analyzing possibilities and selecting between them.

Thus, Oakley and Sejnowski’s emphasis on using diffuse mode to generate creative solutions is consistent with de Bono’s presentation. But to Oakley and Sejnowski, the difference is between focusing on something and letting your mind wander, while to de Bono, it’s the difference between creatively generating new possibilities and analytically eliminating possibilities.

Nevertheless, the authors all agree that you must use both modes to solve any difficult problem. De Bono arguably makes an even stronger case for this than Oakley and Sejnowski, because you have to use vertical (focused) thinking to select or implement a solution, and you have to use lateral (diffuse) thinking to generate the solution or list of possible solutions before you select one to implement.

Oakley and Sejnowski present focused and diffuse thinking as the only modes of thinking: If you’re not focused on something, then you’re thinking in diffuse mode. But de Bono later goes on to define six modes of thinking, or “thinking hats,” as he calls them:

• “Blue hat” thinking: You’re thinking about the big picture, your overall objectives, or how something fits into achieving them.

• “White hat” thinking: You’re taking in objective information.

• “Red hat” thinking: You’re considering how you feel about something, emotionally.

• “Black hat” thinking: You’re looking for problems and risks, or voicing criticism.

• “Yellow hat” thinking: You’re looking for benefits or voicing positive feedback.

• “Green hat” thinking: You’re thinking outside the box, looking for original, creative ideas.

Alternate Between Focus and Rest

The authors’ first tip related to modes of thought is that you should alternate between periods of intense mental focus and mental rest breaks. This improves your ability to solve problems because it leverages the handoff between your two modes of thinking.

Here’s how this looks in practice. First, focus on your studies until you get stuck or stop making progress. This focused thinking enables you to understand the problem (which requires processing detailed information). Then, take a break and let your mind wander. This allows your diffuse mode to find the solution when focused thinking no longer makes progress because the solution lies outside the active network. Finally, use focused thinking again to implement the solution, since that also requires more detailed processing.

Additional Diffuse Thinking Tactics

Other authors agree that your brain can only focus for a certain amount of time before you’ll get stuck, and they discuss additional diffuse thinking tactics to help your brain rest so that you can start making progress again after you get stuck. Two specific tactics they recommend are positive constructive daydreaming (PCD) and psychological halloweenism:

• To practice PCD, first shift your attention to something that takes very little focus, such as walking or folding laundry. Then, deliberately imagine a scene that evokes positive, playful feelings, such as a fond childhood memory, or an imaginary vacation. From this starting point, let your thoughts turn inward and just follow your mind wherever it wanders. Studies show that this type of daydreaming is more likely to generate creative solutions, possibly because it makes you less prone to slip into unproductive worry when you let your mind wander.

• To practice psychological halloweenism, imagine that you are someone else trying to solve the same problem. By putting yourself in someone else’s shoes, you may be able to see the problem from a different angle and come up with a creative solution.

Do the Hardest Problems First

Oakley and Sejnowski’s second tip for maximizing different modes of thinking is to tackle the most difficult problems or subjects first when you’re taking a test, doing homework, or studying. They give two reasons for this:

First, you’ve got a better chance of solving a problem when you’re fresh than after your brain starts to get tired.

Second, starting with the hardest problems gives you more time to solve them, which gives you more opportunities to alternate between focused and diffuse thinking. If you’re pressed for time, you can work on a hard problem until you get stuck, then solve an easier problem or two before you come back to the hard one. According to Oakley and Sejnowski, this isn’t quite as effective for diffuse thinking as taking an actual break, but it still stimulates some diffuse thinking that can help you find the solution.

(Shortform note: Some experts disagree with Oakley and Sejnowski on this. For example, authors Judi Kesselman-Turkel and Franklynn Peterson recommend solving the easy problems first. They argue that starting with the easy problems stimulates your brain, much like doing warm-up stretches before intensive exercise prepares your body for the exertion. Some standardized testing agencies also advise you to do the easy problems first because the test is timed, and you can get more points by answering all the easy questions than by spending all your time on a few hard ones.)

Make Efficient Use of Your Memory

Finally, let’s discuss some tips that are based on making the best use of your brain’s memory. Oakley and Sejnowski note that your brain has two different types of memory: working memory and long-term memory.

Your working memory resides in your prefrontal cortex (the part of your brain just behind your eyes). It holds whatever you’re actively thinking about at the moment, and tends to drop any neural connections that go unused for more than about ten seconds. On average, it can only hold about four ideas (or active chains of synapses) at once.

(Shortform note: Different studies have come up with different numbers for how many ideas your working memory can hold at once. In the 1950s, researchers thought working memory could hold about seven ideas, but by the early 2000s, studies indicated it could hold only about four. Today, there is still little agreement on a definite number—some studies indicate working memory can hold two or three ideas at the same time, while others suggest it might be as high as six.)

On the other hand, your long-term memory resides in your cerebral cortex (the outer part of your brain), although the synapse chains for long-term memories initially form in your hippocampus. It can hold an unlimited amount of information and ideas and store them indefinitely, but to think about any of them, you have to load them into working memory.

Types of Long-Term Memory

Oakley and Sejnowski’s description of long-term memory correlates with other authors’ descriptions of a specific type of long-term memory called “declarative memory.”

In Moonwalking with Einstein, Joshua Foer says your long-term memory is divided into “declarative” memory and “nondeclarative” memory. Declarative memories consist of facts and experiences that you can consciously recall. Foer says declarative memories are stored in synapse chains that form in your hippocampus. This matches Oakley and Sejnowski’s description.

Meanwhile, nondeclarative memory holds information that you access subconsciously. This includes motor skills (like riding a bike) and your basic sense of self. Foer says these memories are formed in other parts of the brain, such as the neocortex, cerebellum, and basal ganglia. This is something Oakley and Sejnowski don’t discuss.

Avoid Distractions

Oakley and Sejnowski’s first tip on how to efficiently use your brain’s two types of memory is to eliminate distractions while you’re studying. Distractions tie up some of the limited capacity of your working memory. Since you learn by connecting ideas in working memory, reducing the amount of working memory that you have available will slow down your learning.

Thus, the authors recommend that when studying, you might, for example, silence your cell phone, turn off the TV, find a quiet place to study, or set aside a certain time block so you can tell your friends not to disturb you during that time.

Types of Distractions and What to Do About Them

In his book Indistractable, Nir Eyal provides a systematic approach to eliminating distractions. First, he observes that distractions tend to come from either people or technology. Then, he identifies the four most common distractions of each type and offers advice on how to eliminate them.

Eyal says people-based distractions typically come in the form of in-person interruptions, email, chat/text, and meetings. He recommends managing them by reserving specific blocks of time in your day for dealing with these kinds of communications and keeping people informed of when you are and are not available.

Technology-based distractions typically come from your smartphone, desktop clutter, articles, and social media. Eyal recommends deleting apps that you don’t need, blocking or disabling most automatic notifications, and keeping anything that you don't need for what you’re currently working on out of sight instead of leaving it open on your desktop where it could distract you.

Avoid Multitasking

The other tip the authors provide based on types of memory is to avoid multitasking. When you work on multiple tasks in parallel, you are constantly shifting your focus from one to the other. Every time you switch from one task to the other, your brain has to clear your working memory and load different information into it. This takes mental energy, so the more you multitask, the more you wear yourself out mentally.

(Shortform note: Like Oakley and Sejnowski, Brian Tracy argues that multitasking reduces your productivity. Specifically, he claims that after being interrupted or shifting your focus, it takes about 17 minutes to fully refocus on the task at hand. Based on the neurological model that Oakey presents, we’d say this 17-minute period is the time it takes your working memory to reload all the synapse chains that you need. This also implies that if you’re shifting your focus every 17 minutes or less because you’re trying to multitask, you may not get any focused work or studying done.)