The Myth

Walk into any library during exam season and you’ll see it: students hunched over textbooks, highlighters moving in confident strokes across pages. Yellow, pink, green, blue—the rainbow of study habits on full display. These students believe they’re actively engaging with material, marking what matters, creating a roadmap for later review.

The highlighting myth runs deep. Students rate highlighting among their most-used study strategies. Teachers recommend it. Study guides endorse it. The implicit promise: mark the important parts now, and they’ll be easier to remember later.

But here’s the uncomfortable truth: highlighting doesn’t work the way people think it does. The science is clear, consistent, and largely ignored.

Why People Believe It

Highlighting survives because it exploits several psychological biases that make ineffective strategies feel effective.

Visible progress. Highlighting creates tangible evidence of effort. A page full of yellow marks looks like work accomplished. Compare this to active recall, which leaves no visible trace but produces dramatically better learning. Our brains confuse visible effort with effective effort.

The fluency illusion. When you review highlighted text, it looks familiar. That familiarity feels like knowledge. But recognition and recall are fundamentally different—you can recognize a highlighted passage as familiar without being able to reproduce or explain its contents. The ease of re-reading creates false confidence.

Minimal cognitive demand. Highlighting requires almost no mental effort. You read, you mark, you move on. This passive studying feels comfortable precisely because it doesn’t challenge your brain. Unfortunately, learning requires challenge. The strategies that feel easiest often produce the weakest retention.

What Research Actually Shows

The evidence against highlighting as a learning strategy is overwhelming and consistent across dozens of studies.

Dunlosky’s landmark review. In 2013, researchers analyzed ten popular study strategies across all available scientific evidence. Highlighting ranked among the least effective techniques. The conclusion was direct: highlighting “does little to boost performance” on tests of learning.

No better than simply reading. Controlled studies comparing highlighting to plain reading find minimal differences in later recall. Students who highlight remember roughly the same amount as students who just read—sometimes less, because highlighting creates false confidence that reduces additional study effort.

Selection difficulty. Effective highlighting would require knowing what’s important before you understand the material—a logical impossibility. Students often highlight too much (diminishing any benefit) or highlight the wrong content (missing key concepts while marking vivid but peripheral details).

Interference effects. Some studies find that highlighting can actually impair learning by discouraging deeper processing. When students mark “important” passages, they often stop thinking critically about the material. The highlighting becomes a substitute for understanding rather than a supplement to it.

The Truth

Understanding why highlighting doesn’t work reveals what actually does.

Learning requires retrieval, not re-exposure. Memory strengthens when you practice pulling information out of your brain, not when you see it again. Highlighting creates re-exposure; testing yourself creates retrieval. The mental effort of recall—even when difficult—builds the neural connections that support lasting memory.

Encoding requires elaboration. Information sticks when you connect it to existing knowledge, explain it in your own words, or apply it to new situations. Highlighting provides none of this elaboration. It’s a selection activity, not a learning activity.

Difficulty signals learning. Strategies that feel harder often work better. Active recall feels effortful because it forces your brain to reconstruct information from memory. That struggle is the learning happening. Highlighting feels easy because nothing is happening—no neural pathways are being strengthened.

What This Means for Your Reading

Recognizing the highlighting myth creates opportunity. Every minute you used to spend highlighting can now go toward strategies that actually work.

Replace marking with questioning. Instead of highlighting sentences, write questions in the margins. “What does this term mean?” “Why does this process work?” “How does this connect to the previous section?” Questions transform passive reading into active engagement and create built-in self-tests for later review.

Summarize, don’t select. After each section, close the text and write a brief summary in your own words. This forces retrieval and elaboration—both proven learning strategies. If you can’t summarize, you haven’t learned, and that’s valuable diagnostic information.

If you must highlight, use it strategically. Highlighting can serve as a selection tool if—and only if—you later do something active with the highlighted content. Mark passages you’ll return to for self-testing, not passages you want to remember by highlighting alone. The marker identifies what to study; it doesn’t do the studying.

Embrace productive difficulty. When a study strategy feels easy and comfortable, question whether it’s working. Real learning requires mental effort. The struggle of active recall, the challenge of explaining without notes, the work of connecting ideas—these difficulties are features, not bugs.

For comprehensive techniques that actually improve retention, explore the Strategies & Retention pillar or browse all 140 Reading Concepts.