How to learn efficiently

I am frustrated by the difficulty of creating new memories and retaining them. People say that you lose recall for 90% of what you learned in a lecture in a matter of days. Even after I review/study for a test and pass comfortably, I find that I lose the majority of that knowledge after a month or so. Med school is about a ton of memorization. When our future as medical students and doctors depends so heavily on amassing a large amount of knowledge to form a foundation for clinical reasoning, finding efficient ways to learn is a priority for success.

This break I read the popular (read: dumbed down and interesting) non-fiction book Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School by John Medina, a developmental neurobiologist at University of Washington School of Medicine. My research mentor recommended it when I asked him for suggested winter break reading. Here are the main lessons I gleaned.

First, Brain Rules offers a number of general life tips that have been shown to improve learning and memory. These seem obvious but to take them to heart and motivate action, you really have to be convinced of their truth and effect size. That’s why I’d recommend reading the book or articles on the topic. These tips will inform my New Year’s resolutions.

  1. Exercise. Regular aerobic exercise boosts brain power. Even in healthy, young adults, the evidence indicates that executive functions like working memory updating and task-switching improve with exercise. Anecdotally, I’ve found that exercise improves my attention for the rest of the day. When I find my mind wandering while studying, I will take a break to jog instead of clutter my mind with the latest Facebook updates. More regularly and specifically, I resolve to go to my gym to just jog 10 minutes and stretch every Tuesday and Thursday night. (Lift weights other times when I feel like it.)
  2. Don’t multitask. Multitasking harms efficiency. True multitasking does not exist: you have to switch your focus of attention rapidly between tasks. The time for each switch is a loss in efficiency. Remove temptations to multitask. I’ve installed  StayFocusd, a Chrome extension, to limit the amount of time per day I spend on Facebook to 10 minutes. As I find more ways to distract myself, I resolve to add other sites to the blocked list (e.g. Google News, Reddit, SDN, Google Reader).
  3. Sleep and nap. A full night of sleep is critical for attention, memory consolidation, executive function, mood, working memory. Don’t fool yourself into thinking you’re in the small percentage of people who can function well on less than 6 hours of sleep a night. In addition to sleeping until you’re rested, a short (20 minute) nap in the middle of the day (afternoonish) will boost performance for the rest of the day. One recent example relevant to medicine is that interns who napped just 8.4 minutes in the middle of the day (during a 20 minute protected session) improved cognitive performance and reported fewer attention failures. Thus, I resolve to get 8 hours of sleep per day, with a small portion of that derived from napping.
  4. Don’t stress. Stress impairs memory consolidation. At the extreme, people involved in traumatic events have psychogenic amnesia. When I can’t fall asleep for a midday nap, I’ll practice breathing meditation for 10-15 minutes instead. Plenty of evidence suggests that mindfulness meditation, even brief practice, reduces stress and anxiety. Sustained practice can also improve attention and other cognitive factors.

Now for the complicated part. 

The psychologist Hermann Ebbinghaus hypothesized more than a century ago that memories are lost exponentially with time, with a rate of decay that is inversely proportional to the strength of the memory trace. The strength of a memory depends on factors like its initial representation, its salience/meaning, among others (stress, sleep). Along this line, Ebbinghaus thought that techniques for better representation (encoding with mnemonics) and repetition could improve memory strength.

To address the former, I’ve made a habit of looking up mnemonics for most difficult facts I encounter. But not all mnemonics are created equal. Some of my classmates say it’s help to remember lists of stuff by just taking the first letters of each word and stringing them together into some weird sounding garble (e.g. OpSROLAuMJ  for foramina in the skull, anyone?) or other nonsensical association (e.g. LR6 SO4 for the innervation of extraocular muscles). I think this is the least effective kind of mnemonic device, one that is least vivid and decays most rapidly, but at least it is better than nothing. One step up is the common practice of stringing together the letters and reassociating those with another set of words that have some meaning (e.g. Oh oh oh to touch and feel a virgin’s girl’s vagina ah heaven, for the cranial nerves). These are commonplace in First Aid.

The best mnemonics, however, are visual. Brain Rules devotes an entire chapter to the superiority of visualization in memory encoding, dubbed the visual superiority effect, explained briefly in visual form here. The mnemonic systems that world-champion memorizers use are always based on some visualization system, e.g. the method of loci (a.k.a. memory palace, journey method) or peg system. These are also the hardest to use because they require significant creativity in creating and synthesizing visual narratives. Luckily, websites like Picmonic have made a business out of developing visual mnemonics for common medical facts. The visuals dramatically reduced the pain required to memorize strings of facts.

Now about repetition. In the graph below, each green line represents successive repetitions of a memory.

For maximal efficiency, repetitions have to be spaced to occur at just the right intervals. Too much time passes and you’ll have forgotten everything. Too soon and you’re needlessly reviewing material you remember well, wasting time. Further, you increase the frequency at which you may introduce errors into your memory because every instance of access of a memory causes that memory to be re-inscribed. But the point is, at each repetition, you strengthen that memory (the cellular mechanism is known as long term potentiation).

Therefore, a few friends and I are adopting the use of Anki for regular review in the new year.

The plan is to develop a deck of facts learned during medical school that is high-yield for Step 1 and future clinical practice, and to use these every single day. There are a bunch of Anki decks for Step 1 floating out there, used with great alleged success, but even these can be enhanced and customized according to Wozniak’s 20 rules. Looking forward to the challenge. This feels like a mind-hack.


6 thoughts on “How to learn efficiently

  1. great post. i’ve been using anki for a while to review for my exams but i stop after each system. probably should keep going back but i’m not sure how motivated i am. i do like its algorithm, though. i find i *really* end up remembering the things i flashcard on anki vs. the things i don’t.

  2. You might be interested in our product:

    We’re combining a modern online note-taking system with spaced repetition and online tools to ensure that you are learning in the most efficient way possible.

    We’d love to hear any suggestions you have too.

  3. “For maximal efficiency, repetitions have to be spaced to occur at just the right intervals.” Is that graph implying that we have to review that material every day?

    • Yes, you will review some selection of material every day. The material you review on a given day will differ and its scheduling depends on the algorithm. You won’t review the same fact for multiple consecutive days.

      On Wednesday, September 24, 2014, Anastomosed wrote:


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