Highlighting a Waste of Time
By Bryan Caplan
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.
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.