closeup photo of cutout decors




For years, I—and most other designers I know—have believed, and written, and taught that if you want whatever you’re designing to be easy to understand and use, then you have to make it easy to read. You have to use a font size that’s large enough, a font type that’s plain and not too decorative, and a background/foreground combination that makes it legible.

So imagine my surprise at discovering research—not just one study, but several—that shows that if text is harder to read, it’s easier to learn and remember. Apparently being easy to read isn’t the same thing as being easy to learn.

The underlying assumption that’s been leading us astray is that reducing the cognitive load (the amount of thinking and mental processing) that people have to do is always a good thing. It is often a good thing, but instructional design theory has claimed for a long time that increasing the amount of work that people do to learn information often leads to deeper processing and better learning. Is it possible that hard-to-read fonts stimulate deeper processing?

The Interesting Twist Of Disfluency

A term that learning psychologists use is “disfluency.” Connor Diemand-Yauman (2010) defines this as:

The subjective, metacognitive experience of difficulty associated with cognitive tasks

Disfluency is a feeling that something is difficult to learn. Fluency is a feeling that something is easy to learn.

Diemand-Yauman notes that when people feel that something is hard to learn, they process the information more deeply, more abstractly, and more carefully. The disfluency is a cue that they haven’t mastered the material, and so they’d better pay more attention. The result is that they learn it better and remember it longer. Fluency, on the other hand, can make people overconfident, so they don’t pay attention as well and they don’t learn the material as deeply.

The chapter on How People Think and Remember talks about Daniel Kahneman’s book Thinking, Fast and Slow, and about System 1 and System 2 thinking. When information is disfluent, people switch from automatic, intuitive easy thinking (System 1) into effortful and careful thinking (System 2). And this System 2 thinking helps them learn and remember.

Diemand-Yauman researched the idea that a hard-to-read font would lead to better learning and remembering. He gave participants information on three made-up species of space aliens. The participants had to read the material and learn about each species. Each alien species had seven features. (He was attempting to mimic what it’s like to learn categories of animals in biology class, but trying to control for previous knowledge.)

Some of the participants were in the “disfluent condition.” They read information about the alien species in 12-point, gray text. Some participants’ text was in Comic Sans MS, and some was in Bodoni MT:

The examples above use the same fonts as the experiment, but the information itself is not exactly the same as the information used in the experiment.

Diemand-Yauman comments that although the font differences are obvious when the text is presented together in this way, since participants saw only one font, the effect was more subtle.

Participants had 90 seconds to memorize the seven pieces of information of all three alien types. Then they were asked to do other, non-related tasks as a distraction. And after that, they had a memory test for the alien information. For example, they were asked, “What does a temaphut eat?”

He found that people in the disfluent condition remembered significantly more information (14 percent more) than the people in the fluent condition. There was no difference between the two disfluent groups (Comic Sans and Bodoni).

Next Diemand-Yauman wanted to see if the same effect would be true in a more realistic setting. He took the study to a high school (in Ohio in the United States) and tested 220 students. He screened the classes for those where the same teacher had been teaching at least two classes of the same subject and difficulty level and with the same learning material. The experimenters took all the worksheets and PowerPoint slides and changed the font. (The experimenters did not meet the teachers or the students or visit the class.)

Classes were randomly assigned to either a disfluent or a control category. The disfluent classes used material that was switched to one of these fonts:

In the control classes, no changes were made to the fonts. Teachers and students didn’t know the hypothesis that was being studied. They didn’t know whether they were in a fluent or disfluent group. The material was taught the same way it normally was taught. No other changes were made in the classrooms or the instruction.

Students in the disfluent condition scored significantly higher on their regular classroom tests. On a survey asking if they liked their course or course material, there were no differences in these preference ratings. There was no difference among the different disfluent fonts.

So, What’s a Designer To Do About Fonts?

If you design textbooks or e-learning modules, then this research has direct relevance to you. But what about people who design other things, like websites, instructions, or product packaging? What if you’re putting out a series of marketing emails? What should you do about fonts?

You might be tempted to make a distinction between what people are reading for information and what they’re reading in order to learn and remember. But that may not be as simple a distinction as it sounds. If people are reading a blog post about current events, are they “just reading”? Don’t they want to understand, learn, and remember the information?

I can’t make myself recommend that you use a font that’s slightly harder to read than you’re used to if you want people to learn and remember your content. However, that’s what I should say.

Learn better or believe more?

The research on disfluency has to be applied carefully. So far this chapter has talked about learning information and remembering it. If you’re trying to convince people that something is true, then you’re better off making it easy to read. In the chapter on How People Decide and Feel, you learned about “truthiness”—the idea that some things feel more true.

Back in 1999, Rolf Reber and Norbert Schwarz showed that text written in different colors on different backgrounds influenced whether people believed the information. Participants found information in hard-to-read background/foreground colors, like this,

to be less believable than information in easier-to-read colors.


  • When the most important goal is for people to believe that what they’re reading is true, make the text as legible as possible, using a simple font and plenty of contrast between the text and the background.
  • When people already believe the information and the most important goal is for them to learn and remember it, consider using a font that’s slightly harder to read. If the font is slightly harder to read, then people will learn and remember the information better.


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