Why Summarizing Is Better Than Highlighting (But Still Not Great)
# Why Summarizing Is Better Than Highlighting (But Still Not Great)
Highlighting is one of the most popular study methods in the world. Walk into any college library and you will see textbooks glowing in shades of yellow, pink, and green. Students highlight because it feels active - you are doing something to the text, engaging with it, marking what matters.
But the research is clear: highlighting is one of the least effective study strategies ever tested. And while summarizing is meaningfully better, it still falls short of the methods that actually produce durable learning.
The Problem With Highlighting
A comprehensive review by Dunlosky, Rawson, Marsh, Nathan, and Willingham, published in *Psychological Science in the Public Interest* in 2013, evaluated ten common study strategies and rated highlighting as having "low utility." The researchers concluded that highlighting does little to boost performance beyond simply reading the material.
Why does highlighting fail? Several reasons:
It requires no processing. Highlighting is a mechanical action. You drag a marker across text. Your brain does not have to transform the information, connect it to other knowledge, or generate meaning from it. You can highlight an entire paragraph without understanding a word of it.
It creates an illusion of engagement. The act of highlighting feels like studying. You are physically interacting with the material, which creates a sense of accomplishment. But feeling productive and being productive are different things. The highlighted text sits on the page looking important, but no additional learning has occurred.
It encourages passive re-reading. When students return to highlighted material, they typically re-read the highlighted passages. This is still passive review - the same low-yield activity, just applied to a subset of the text.
It does not require discrimination. Many students highlight too much. When 80% of a page is highlighted, nothing is emphasized. The inability to distinguish critical information from supporting detail is itself a sign that the material has not been deeply processed.
Why Summarizing Is Better
Summarizing - the act of reading a passage and then writing a condensed version in your own words - outperforms highlighting because it requires deeper cognitive processing.
When you summarize, you must:
- Identify the main ideas and distinguish them from supporting details.
- Translate the author's language into your own words.
- Organize information into a coherent, condensed form.
- Make decisions about what to include and what to leave out.
These are all active processes that require engagement with the meaning of the material, not just its surface features. The Dunlosky review rated summarization as having "low to moderate utility" - better than highlighting, but not in the top tier.
Research by Leopold and Leutner (2012) found that students who generated summaries while reading showed better comprehension and transfer than students who simply read or highlighted. The act of generating - producing output rather than passively consuming input - is what drives the learning benefit.
Why Summarizing Still Falls Short
If summarizing is better than highlighting, why is it not a top-tier strategy? Three reasons:
It can become mechanical. Students often fall into a pattern of summarizing by extracting key sentences and lightly paraphrasing them. This "copy-delete-paraphrase" approach requires less processing than genuine summarization and produces weaker learning benefits. Effective summarization requires real cognitive effort, and many students shortcut that effort.
It does not involve retrieval. Summarizing is typically done while looking at the source material. You read a section, then write your summary with the text still open. This means you are reorganizing information you can see, not retrieving it from memory. The testing effect - the learning boost from retrieval practice - is absent.
It can miss the forest for the trees. Students sometimes produce accurate summaries of individual sections without understanding how those sections connect. Summarization focuses on comprehension of what is on the page, but exam success often requires applying that knowledge to new situations - a deeper level of understanding that summarization alone does not reliably build.
What the Research Actually Recommends
The Dunlosky review identified two strategies with "high utility" ratings: practice testing (retrieval practice) and distributed practice (spacing). These are the methods with the strongest evidence for producing durable, transferable learning.
Practice testing means quizzing yourself on the material - answering questions, completing problems, or trying to recall information without looking at your notes. It works because the act of retrieval strengthens memory traces in a way that re-reading, highlighting, and even summarizing do not.
Distributed practice means spreading your study over time rather than concentrating it in a single session. It works because the partial forgetting and re-learning that occurs between spaced sessions builds more durable memories.
Neither of these strategies feels as comfortable as highlighting or summarizing. Retrieval practice is effortful and sometimes frustrating - you are confronting what you do not know. Spaced practice means returning to material when it is not fresh, which feels harder than immediate review. But that difficulty is precisely what makes them effective.
A Better Workflow
Instead of abandoning highlighting and summarizing entirely, consider integrating them into a workflow that culminates in retrieval practice:
- First pass - Read and annotate lightly. As you read new material, use minimal highlighting or marginal notes to mark key concepts. The goal is orientation, not learning. You are identifying what matters so you can study it effectively later.
- Second pass - Summarize from memory. Close the book. Write a summary of what you just read without looking at it. Then open the book and compare your summary to the original. The gaps between your summary and the source material are your knowledge gaps.
- Third pass - Test yourself. Use practice questions, flashcards, or the blank page technique to test your ability to recall and apply the material. This is where the real learning happens.
- Subsequent passes - Spaced retrieval. Return to the material days later and test yourself again. Each successful retrieval at a longer interval strengthens the memory.
In this workflow, highlighting and summarizing serve as preliminary steps - ways to engage with and organize new material. But they are not the main event. Retrieval practice is.
The Comfort Trap
The popularity of highlighting and summarizing is partly explained by what researchers call desirable difficulty. Effective learning strategies feel harder than ineffective ones. Highlighting is easy and feels productive. Retrieval practice is hard and feels frustrating. Students naturally gravitate toward what feels good rather than what works.
This is worth stating plainly: if your study method feels easy and comfortable, it is probably not working as well as you think. The methods that produce the strongest learning are the ones that make you confront your own knowledge gaps, struggle to recall information, and experience the discomfort of not knowing.
That discomfort is not a sign that something is wrong. It is a sign that learning is happening.
The Bottom Line
Highlighting is study theater - it looks like studying but produces minimal learning. Summarizing is a genuine step up because it requires active processing, but it still misses the critical ingredient of retrieval. The methods that actually work - practice testing and distributed practice - are less comfortable and less intuitive, which is exactly why most students do not use them.
If you currently rely on highlighting, switch to summarizing. If you currently summarize, add retrieval practice. And if you want to study in the most effective way the research supports, make self-testing the core of your study routine.
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