Time to ditch the highlighter pens?

Thursday, April 17, 2025

The Truth About Highlighters: Helpful or Harmful for Revision?

Highlighter pens are a favourite among students. Bright, colourful, and satisfying to use, they feel like an easy win during revision. But how effective are they really?

Research by Professor John Dunlosky, published in Psychological Science in the Public Interest, suggests that highlighting may not be as useful as students think. His studies found that students often focus too narrowly on individual points when highlighting, failing to see how ideas connect — ultimately damaging their overall understanding.

While highlighters may not be inherently bad, Dunlosky and others warn against using them as the only study strategy. Here's what students need to keep in mind:

• Highlighting alone doesn’t equal learning. Just because notes are marked in fluorescent pink and green doesn’t mean the information has been understood or memorised. Highlighting can give a false sense of achievement — a phenomenon known as the “illusion of knowing.”

• Most students struggle to highlight effectively. Without clear guidance, everything ends up highlighted, defeating the purpose. When “everything is important,” nothing stands out. Most good revision guides these days are so concise, it is hard to know what shouldn't be highlighted.

• Better strategies exist. Dunlosky ranks highlighting as a low-utility technique. In contrast, retrieval practice (actively recalling information) and spaced practice (spreading study over time) are far more effective ways to boost memory and long-term learning.

So go ahead and highlight, but don’t stop there. Highlighting alone may feel like and look like revision, but the real learning begins when students do something with the information they’ve marked—revisit it, recall it, and space it out. That’s where the magic happens.