Bryan Caplan  

Highlighting a Waste of Time

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Garett Jones' top catchphrase is, "If only there were a vast empirical literature on X."  When you're well-aware of the vast empirical literature to which he's alluding, it's funny.  Whenever you discover a new-to-you vast empirical literature, though, it's humbling.  The world's packed with vast empirical literatures.  Anytime you open your mouth in earnest, you're probably running afoul of one of them. 

Dunlosky et al.'s "Improving Students' Learning With Effective Learning Techniques" (Psychological Science, 2013) is an outstanding example.  I've been in school for almost four decades, teaching for almost two.  But I never investigated the effectiveness of any of the pedagogical methods this paper explores.  The results are shocking.  Some ubiquitous study techniques are crummy - and some rare study techniques rock.

Let's start with a prime example of a crummy yet popular approach: highlighting. 
As an introduction to the relevant issues, we begin with a description of a prototypical experiment. Fowler and Barker (1974, Exp. 1) had undergraduates read articles (totaling about 8,000 words) about boredom and city life from Scientific American and Science. Students were assigned to one of three groups: a control group, in which they only read the articles; an active-highlighting group, in which they were free to highlight as much of the texts as they wanted; or a passive-highlighting group, in which they read marked texts that had been highlighted by yoked participants in the active-highlighting group. Everyone received 1 hour to study the texts (time on task was equated across groups); students in the active-highlighting condition were told to mark particularly important material. All subjects returned to the lab 1 week later and were allowed to review their original materials
for 10 minutes before taking a 54-item multiple-choice test. Overall, the highlighting groups did not outperform the control group on the final test, a result that has unfortunately been echoed in much of the literature (e.g., Hoon, 1974; Idstein & Jenkins, 1972; Stordahl & Christensen, 1956).

However, results from more detailed analyses of performance in the two highlighting groups are informative about what effects highlighting might have on cognitive processing. First, within the active-highlighting group, performance was better on test items for which the relevant text had been highlighted (see Blanchard & Mikkelson, 1987; L. L. Johnson, 1988 for similar results). Second, this benefit to highlighted information was greater for the active highlighters (who selected what to highlight) than for passive highlighters (who saw the same information highlighted, but did not select it). Third, this benefit to highlighted information was accompanied by a small cost on test questions probing information that had not been highlighted.
Overall:
On the basis of the available evidence, we rate highlighting and underlining as having low utility. In most situations that have been examined and with most participants, highlighting does little to boost performance. It may help when students have the knowledge needed to highlight more effectively, or when texts are difficult, but it may actually hurt performance on higher-level tasks that require inference making. Future research should be aimed at teaching students how to highlight effectively, given that students are likely to continue to use this popular technique despite its relative ineffectiveness.
In light of this evidence, Caplan Family School has abandoned highlighting.

Coming soon: Two underused pedagogical methods that work.

HT: Nathaniel Bechhofer




COMMENTS (20 to date)
Colombo writes:

The Highlighting push in education was a neat plot created by the highltigher industry, but now we know better and we won't get fooled again. Maybe.

___

"Future research should be aimed at teaching students how to highlight effectively, given that students are likely to continue to use this popular technique despite its relative ineffectiveness."

That sounds like telling psycopath to use two condoms when he goes out to rape a prostitute. Sorry for being crude.

I have a better idea. Tell students to "put one cent in this piggy-bank every time you use the highlighter". That way research should pay itself.

Yaakov writes:

On my job I constantly need to read texts and I use highlighting. The circumstances, however, are very different from those met by most students.

The texts I read include large sections which are totally useless, including ballpark paragraphs. These I cross out so that I will not read them in a second review. Also, the text includes small gems I may need, hidden in large sections of low utility words. I highlight the gems.

I assume that if the texts you read are of uniform importance sections (you may be tested on any statement in the text) then highlighting is of low or no value. But for texts which include sections of vastly different importance, highlighting could be very effective.

I therefore believe highlighting should not be discarded. Instead, students should be taught when to use it.

John Thacker writes:

So if you highlight, then you tend to remember what was highlighted better, but don't learn the non highlighted things as well. It doesn't raise net learning of the passage but redistributes it.

MG writes:

Highlighting also has costs -- the depreciation of the book in question (and the cost of stocking highliters). This ought to raise the bar for adoption.

Thomas B writes:

The technique I used to survive an engineering degree was not to highlight each piece of key text, but rather to rewrite and paraphrase it in a notebook. My goal was to boil the point down into a very short statement in my own words.

This had three benefits. First, like highlighting, it forced me to identify the key points. Second, unlike highlighting, it forced me to understand them, in order to paraphrase them. Third, sort-of like highlighting (but better) it left me with notes, all in one place, summarizing the whole course in my own words, for review before exams.

Even the most complex engineering courses could usually be boiled down to bullet points on four - usually two - standard sheets of paper, in my own words.

I have never owned a highlighter.

Thomas B writes:

The technique I used to survive an engineering degree was not to highlight each piece of key text, but rather to rewrite and paraphrase it in a notebook. My goal was to boil the point down into a very short statement in my own words.

This had three benefits. First, like highlighting, it forced me to identify the key points. Second, unlike highlighting, it forced me to understand them, in order to paraphrase them. Third, sort-of like highlighting (but better) it left me with notes, all in one place, summarizing the whole course in my own words, for review before exams.

Even the most complex engineering courses could usually be boiled down to bullet points on four - usually two - standard sheets of paper, in my own words.

I have never owned a highlighter.

Thomas B writes:

Sorry for the double post - human error, but also bad software!

I see from the paper that summarization is rated as having "low utility", i.e., it's a waste of time. Interesting!

We also made extensive use of practice tests ("high utility") and distributed practice ("high utility").

As I think about it, the summarization served two purposes: it ensured that we understood the material to begin with; and it provided an easy-to-use reference, or "cheat sheet", to go along with the practice tests, since during practice tests it would take too long to find the right content in the right textbook. The paper makes the point that summarization is a skill, and a large part of the "low utility" evaluation has to do with students who summarize inappropriately: I can't think of a way, offhand, to address that.

Bryan S writes:

When I require students to highlight or annotate, it is always with a purpose. For example, highlight arguments that support the main idea; arguments in one color and counter arguments in another color; compare and contrast; etc. Occasionally, we use it for key vocabulary, but, mostly, we use highlighting to analyze and organize ideas. And, by the way, always with a writing assignment to assess students' understanding.

Jon F. writes:

Highlighting may not be valuable for active learning, but it is a lifesaver for writing and research. If you don't highlight a key text, then you may end up spending hours scrawling through less important text to find the quote or data that you want later.

Paul writes:

What?! I found myself highlighting Bryan's post on the ineffectiveness of highlighting.

Well, I have a bit of ADD, so I will continue to highlight despite the post.

PD writes:

What?! I found myself highlighting Bryan's post on the ineffectiveness of highlighting.

Well, I have a bit of ADD, so I will continue to highlight despite the post.

Josiah writes:

The proper response to this research is not to abandon highlighting, but to highlight the entire reading.

Swami writes:

I am skeptical.

I think the study throws two groups together. People who aren't good at highlighting and are asked to do it, and people who are good at it and would have done so without being asked. The latter group is familiar with their personal learning style, is experienced at highlighting critical passages and knows that highlighting requires a subsequent act of rereading and consolidating the highlighted text.

The benefit of highlighting is in the long run. Nobody can remember everything they read. But if one is an experienced highlighter, you can develop the skill to reread the highlighted sections to get the key points relevant to you the reader.

My assumption is still that highlighting is extremely beneficial to those who are good at it, experienced at it, dedicated to reread the highlights, and interested in absorbing knowledge into their own pursuits. I suggest it be a suggested option for those who can thrive with it, which admittedly isn't everyone,

Kenny writes:

How could you not cite Tyler's second law?

Mark V Anderson writes:

I think Yaakov made a good point. It all depends on how the study was done. If the students indeed highlighted the most important points, then I would think studying the text later would be more efficient if it was highlighted. But perhaps in the study they purposefully wrote the exam about all areas equally. In that case, highlighting is probably a waste of time. So how the study was conducted is a key component.

Also, in my opinion social science studies should NEVER be taken seriously as single studies. There are too many things that can mess up the results, so one generally needs at least a dozen studies pointing to the same result before using the findings in real life.

JK Brown writes:

A few years ago, I came across
How to Study and Teaching How to Study (1909) by F. M. McMurry, Professor of Elementary Education, Teachers College, Columbia University.

An interesting book targeted at teachers explaining that kids can learn to study and how to teach them. The author speculated kids as young as 3rd grade could learn to study. The 1st and 2nd grades being more "vocational" training, i.e., reading, writing, numbers, etc.

I pulled the 8 factors from the book:

The factors of studying:
1. Provision for Specific Purposes
2. The Supplementing of Thought
3. The Organization of Ideas
4. Judging the Soundness and General Worth of Statements
5. Memorizing
6. The Using of Ideas
7. Provision for a Tentative rather than a Fixed Attitude toward Knowledge
8. Provision for Individuality

You may see as I did that the factors essentially require thinking about the material. It is this organized consideration that brings success and often little required effort for rote memorization. It fits how kids and adults learn subjects for which they have an personal interest. The techniques are good for those things you just aren't that interested in, like many school subjects.

The first 5 factors are better explained in this excerpt:

The student has accomplished much when he has discovered some of the closer relations that a topic bears to life; when he has supplemented the thought of the author; when he has determined the relative importance of different parts and given them a corresponding organization; when he has passed judgement on their soundness and general worth; and when, finally, he has gone through whatever drill is necessary to fix the ideas firmly in his memory. Is he then through with a topic, or is more work to be done?

Another book, Freshman Rhetoric, John Rothwell Slater, Ph.D. Professor of Rhetoric and English Literature in the University of Rochester, (1913), had an excellent chapter on note taking. And good note taking essentially requires doing the first 4 factors of studying. There is also, the post class organizing, etc. that require though on the material as well. Sadly, the later edition of this book available from Amazon dropped the note taking chapter. But the earlier edition is available online in pdf.

I see Yaakov's description of his practice to require the thinking of good study as opposed to passing thought highlighting. Similarly, with Thomas B's paraphrasing.

I will be interested in seeing if the techniques that work have an underlying requirement to think about, organize and pass judgement on the material.

Nathan W writes:

Having identified material that I thought could be asked on an exam, I always reformulated the factoids into question form.

Then, for studying, I would work through all these questions until I could answer them all.

Great for factoid-filled science classes, a little more cumbersome for social sciences stuff where the argumentation can get more complex.

Mike Rulle writes:

Like Thomas B, I was a note taker. The objective was to be able to remember more than I wrote. I always found highlighting to be extremely restrictive for this purpose.

Hazel Meade writes:

Based on only my own personal experiences, I agree. What I've found to be far more effective is actually copying down information in one's own notes either from the text or from lecture.
It takes longer, but I think it works better because it forces more of your brain to process the information. With just reading and highlighting it's easy to let your eyes glaze over and think about something else. But if you have to actually write something down then you have to think about it, and probably process it into a simpler and more condensed form, which requires one to try to grasp the core concept.

Now the funny part is, I would almost never actually read my notes again afterwards. Just writing stuff down fixed it in my brain well enough that I would remember it without having to check my notes.

Radford Neal writes:

Well, I think I've never highlighted a single word in a book. I'd feel that doing so was a bit of a desecration, actually. If a word or phrase actually needs more emphasis, wouldn't the author have put it in italics?

I've never felt any regret from not highlighting.

As a teacher, I've come across students who highlight and underline incessantly, with underlines, double underlines, yellow marker, etc. until sometimes the entire text is highlighted in one way or another. I think that's pathological, and even the less extreme cases are simply the result of insecurities. At best, highlighting is a crutch, which prevents students from learning more effective reading strategies, which don't involve deciding one second after reading a sentence whether it is important or not.

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