Does Highlighting Help You Study? What the Research Says

Highlighting, as most people do it, does very little to help you learn. The 2013 review by Dunlosky and colleagues — published in the journal Psychological Science in the Public Interest — found that highlighting and underlining have generally failed to help students across a wide range of groups, from schoolchildren to undergraduates to Air Force trainees.

The catch is that highlighting feels effective, and that feeling is the trap. Recognizing a highlighted sentence when you reread it isn't the same as being able to recall or use that information later. Highlighting builds familiarity, and familiarity is easy to mistake for knowledge.

Dunlosky's team ranked ten study techniques by how well the evidence supported them. Only two earned a high utility rating: practice testing (quizzing yourself) and distributed practice (spreading study across time rather than cramming). The researchers singled these out because they help learners of all ages and abilities across many kinds of material.

Highlighting landed in the low utility group, alongside summarization, rereading, the keyword mnemonic, and using mental imagery for text. That's worth sitting with: the four habits most students lean on hardest — highlighting, rereading, summarizing, and re-copying notes — are clustered at the bottom, while the two that actually work are the ones people tend to avoid because they feel harder.

The core problem is that highlighting is passive. You can mark a page while barely processing it — the hand moves, the eyes skim, and almost no thinking happens. Learning comes from effortful processing: retrieving, connecting, explaining. A highlighter asks none of that.

There's a more specific cost too. Dunlosky's review notes that one study found students who highlighted while reading actually performed worse on later comprehension questions that required making inferences across the text. The explanation is telling: by zeroing in on isolated sentences to highlight, students spent less time thinking about how ideas connect. Highlighting can fragment your attention into a series of marked facts when understanding lives in the relationships between them.

And because highlighting is fast and feels productive, it crowds out the harder work that would actually help. The time goes to coloring the page instead of testing whether you can reproduce what's on it.

It would be unfair to call highlighting worthless. The same researchers are careful to say it can be a reasonable first step — a way to flag what matters on a first read — as long as it's the beginning of studying, not the whole of it. The failure mode is treating a highlighted chapter as 'studied.'

There's also evidence that how you highlight matters. Marking sparingly — a single key idea per section rather than drowning the page — forces you to make decisions about what's actually important, which is itself a mild form of processing. The student who highlights everything has highlighted nothing; the one who highlights one sentence per paragraph has at least had to judge what the paragraph was about.

The fix isn't to read more carefully — it's to make your studying active. Three evidence-backed moves do most of the work:

The hard part of switching from highlighting to active recall is making the questions — turning a chapter you've read into something you can quiz yourself on takes time most students don't spend. PocketNote closes that gap: it generates flashcards and quizzes directly from your own notes, PDFs, and slides, so the self-testing materials come from the exact pages you'd otherwise just be coloring in.

Its source-grounded chat also lets you ask questions about your material and see where each answer comes from — a fast way to check whether you actually understood a section or only recognized it. The point isn't to stop reading; it's to make sure reading is followed by retrieval, which is where the learning actually happens.