There are countless tips for memorizing things, but few of them have actually been tested for effectiveness. In 2013, a research team led by Dunlosky evaluated 10 common study techniques across hundreds of studies and rated each one as having "high," "moderate," or "low" utility.
Drawing on that evaluation and later research, this article sorts out the methods known to work and the popular methods that work less well.
High utility: the two you should not skip
In Dunlosky's evaluation, only 2 of the 10 techniques received the top rating of "high utility."
- Practice recalling (retrieval practice). Trying to recall what the material said without looking at it. Solving problems, writing out what you know on a blank sheet, and covering a word's meaning and answering all count
- Spaced reviews (spaced practice). Repeating study over time instead of doing it all at once
Both have been replicated extensively, with effects confirmed across types of material and age groups. Just as important, they can be combined. "Review at spaced intervals, in a form that makes you recall": this is the core that current learning science can recommend with confidence. The spaced repetition article explains how it works in detail.
Effective under the right conditions: choose where to use them
From the middle "moderate" rating and from later research, here are a few methods that work under certain conditions.
- Explaining to yourself (elaborative interrogation and self-explanation). Try to explain "why is this so?" in your own words. Suited to content with cause-and-effect relationships (science, the purpose behind a law, the course of history). Not suited to simple paired memorization (a word and its translation)
- Interleaved practice (interleaving). Instead of working through problems of the same type in a block, mix the types together. It tends to be most effective in subjects where you can practice the decision of "which method to use," such as choosing a solution method in math
- Mnemonics and memory devices. Effective for material with no meaningful connections (the digits of pi, lists with no inherent order). But they take time to create, so using them for things you could learn through understanding is inefficient
Popular but less effective: don't let them eat your time
On the other hand, these three are widely used but were rated "low utility."
- Rereading. Reading the material again gives you a sense of "I know this," but that is an illusion of fluency and is not the same as being able to recall it. Spending the same time practicing recall leads to better retention
- Highlighting and underlining. The act of marking itself has almost no effect. It only helps if you later use those marks as cues for recall
- Summarizing (without training). Good summarizing is effective, but the skill of summarizing itself needs to be trained, which makes it poor value for the effort
"Feeling like you studied" and "remembering" are two different things.
These methods are not "bad." The problem is that they feel productive but do not stick, so all that builds up is the feeling of having studied. If most of your study time goes to rereading and highlighting, simply replacing part of it with "close the material and recall" will make a visible difference in how much the same amount of time leaves you with.
Putting it into practice
Translated into daily study, all of this comes down to the following.
- Right after learning something, close the material and recall it once (your first retrieval practice)
- From the next day on, keep repeating recall-based reviews at gradually widening intervals
- Go back to the material only for what you could not recall, and if possible, try saying "why is this so?" in your own words
- Do not count rereading and highlighting as "reviewing"
It is simple, but whether you have a system that keeps these four steps going is what makes the difference a few months from now.
Summary
- In a cross-study evaluation of hundreds of studies, only two techniques were rated "high utility": practicing recall and spaced reviews
- Self-explanation, interleaving, and mnemonics are effective when they fit the content
- Rereading and highlighting feel productive but do not stick. It is safest not to count them as "reviewing"
- The two effective methods can be combined: review at spaced intervals, in a form that makes you recall