Is rereading and highlighting the best way to study?

Where the idea came from

Rereading and highlighting are the study habits students pick up on their own, and many adults remember using them. They're easy, they feel like work, and they produce a sense that the material is familiar.

John Dunlosky and colleagues chose to review highlighting and rereading among ten techniques precisely because students report relying heavily on them, so it matters how well they work.

What the research says

The comparison that matters is with practice testing: closing the notes and trying to recall the material. Henry Roediger and Jeffrey Karpicke's 2006 experiment is the classic demonstration. Students who reread a passage did better on a test five minutes later, but students who had instead taken recall tests remembered substantially more two days and a week later. The rereaders were also more confident they'd remember, which is the trap.

Two meta-analyses generalize the finding. Olusola Adesope and colleagues found practice tests helped learning more than restudying and more than every other comparison condition, with the size depending on the kind of test, the learners and the outcome. Christopher Rowland's meta-analysis of testing versus restudy found testing produced better retention, and that recall tests (write the answer) helped more than recognition tests (pick the answer).

Dunlosky and colleagues' review of ten study techniques rated practice testing and spreading study over time high utility, and rereading and highlighting low utility: they don't consistently boost performance, so students should use other techniques in their place, such as practice testing instead of rereading.

Why it hangs on

Familiarity feels like learning. Reading something a second time is easier than the first, and that ease feels like mastery. Roediger and Karpicke's rereaders were more confident, and remembered less.

Testing feels worse. Trying to recall and failing is uncomfortable, so students avoid it, even though that effort is part of what helps.

Nobody teaches studying. Students are told to study, but rarely shown how. They default to what feels natural.

Highlighting looks like work. A page full of color is visible proof of effort, to the student and to adults. Recall practice leaves little to show except a slightly better memory, which nobody sees until the test.

What to do instead

Teach students to study the way the research supports:

1. Close the book and recall. Write everything you remember about the topic, then check your notes and fill the gaps in a different color.
2. Quiz yourself. Turn headings into questions, or use flashcards, and answer before you look.
3. Space it out. Twenty minutes on each of four days generally beats eighty minutes the night before; see spaced practice.
4. Use rereading only to check. Reread to find what you got wrong, not as the main way to study.

In class, model it: run a short retrieval practice warm-up, then show students their own results as evidence that recall works better than reading again.

A one-lesson demonstration

Give the class two short lists of ten unfamiliar facts. For the first list, students read it three times. For the second, they read it once and then cover it and write down as many facts as they can, twice. Two days later, without warning, test both lists. Many classes see the pattern for themselves, and students remember the lesson better than any poster about study skills. It also gives you a way to talk about why rereading feels better in the moment: the facts look familiar, so it seems they're learned.

Questions teachers ask

Is rereading useless?

Not useless, but weak compared with testing yourself. It can help you find what you missed after a self-test. As the main way to study, it gives a feeling of familiarity that the research shows is misleading.

Is highlighting bad?

Dunlosky and colleagues rated it low utility: it doesn't consistently improve performance. Marking a few key terms to turn into questions later is fine; coloring the page isn't studying.

How do I get students to self-test?

Make it part of class first, with short low-stakes quizzes and brain dumps, and show students their own results. Give them a simple study plan before tests that builds in self-testing over several days.