How to remember what you read
Most of what we read fades within days. What memory research says about forgetting, and six simple habits that help the best passages stay with you.
· 4 min read
In short
- Forgetting is normal and fast: without another look, most details of what we read fade within days.
- Coming back to a passage after a pause, and trying to recall it before you reread it, does more for memory than reading it again right away.
- Highlighting marks what matters, but on its own it does little. It pays off when you return to your highlights.
- A note in your own words and a regular look back are habits most readers can keep.
On this page (8)
You finish a book you loved. A month later someone asks what it was about, and all you can offer is a feeling and one half-remembered idea. If that sounds familiar, you are in good company. It isn't a sign of a bad memory or careless reading. It is how memory works, and the same research that describes the forgetting also shows what helps against it.
Why we forget most of what we read
In the 1880s the German psychologist Hermann Ebbinghaus spent months memorising lists of nonsense syllables and testing himself on how much remained after an hour, a day, a week. The result, now known as the forgetting curve, has held up remarkably well since: we forget most quickly right after learning something, and then more and more slowly.
Meaningful material, like a good book, is forgotten more slowly than nonsense, but the shape of the curve stays the same. By the time you reach the last chapter, much of the first has already faded. That isn't a flaw. A memory that kept everything would be useless; it keeps what comes up again and lets the rest go.
Which points to the remedy: let the passages you care about come up again.
Highlighting alone doesn't do much
In 2013 a group of psychologists led by John Dunlosky reviewed the research on ten popular study techniques. Highlighting and rereading, the two most common, came out among the least effective. Two others came out on top: practice testing, which means trying to recall what you learned, and distributed practice, which means spreading your reviews out over time.
That doesn't make highlighting useless. A highlight is a decision: this sentence matters to me. But the decision is only the start. A highlight you never see again is a bookmark in a book you never reopen.
1. Come back after a pause
Reviewing something once right after reading it helps a little. Reviewing it again after a few days, and again after a few weeks, helps a lot more. This is the spacing effect, one of the most reliable findings in memory research, and the idea behind spaced repetition apps.
The pause is the point. When a memory has started to fade, bringing it back takes a little effort, and that effort is what makes it last. Rereading a passage you remember perfectly feels productive but adds little. We go deeper into this in spaced repetition for readers.
2. Try to recall before you reread
In a well-known study from 2006, Henry Roediger and Jeffrey Karpicke had students read short texts. Some then read them again; others wrote down what they could remember. A week later, the students who had practised recalling remembered more, even though those who had reread expected to do better.
For a reader, this takes ten seconds. When you come back to a book or a highlight, first ask yourself what you remember about it: the argument, the scene, why you marked it. Then read it. The small strain of trying is the useful part.
3. Write one line in your own words
A highlight holds the author's words. A note holds yours: why the passage struck you, what it reminds you of, where you disagree. Putting an idea into your own words forces you to understand it and connects it to what you already know, and connected memories are easier to find again.
It doesn't need to be long. “This is why I left my old job” or “compare with chapter 3” is enough. On a Kindle you can add a note to any highlight, and it travels with it; here is how to take notes on a Kindle.
4. Highlight less, but on purpose
When half a page is yellow, nothing stands out, including on the day you come back to it. Try to mark the sentence that carries the idea rather than the paragraph around it. Fewer, sharper highlights are easier to review and more likely to mean something later.
5. Tell someone about it
Explaining an idea to a friend is recall and rephrasing at once. You notice what you actually understood, and the conversation gives the idea a place in your life beyond the page. If there is nobody to tell, a short message to yourself works too.
6. Make returning a routine
The hard part isn't knowing any of this, it is doing it. A routine that asks little works best:
- While reading, highlight sparingly and add a short note where something strikes you.
- When you finish, pick the five or ten passages that matter most.
- Come back to them after a week, after a month, and again months later. Recall first, then reread.
And if you want to go a step further, keep the passages that survive a second reading somewhere of your own, the way readers have for centuries in a commonplace book.
