The Limits of “Desirable Difficulties”: Catching Up with Sans Forgetica

We have lots of research suggesting that “desirable difficulties” enhance learning.

That is: we want our students to think just a little bit harder as they practice concepts they’re learning.

Why is retrieval practice so effective ? Because it requires students to think harder than mere review.

Why do students learn more when they space practice out over time? Because they have to think back over a longer stretch — and that’s more difficult.

We’ve even had some evidence for a very strange idea: maybe the font matters. If students have to read material in a hard-to-read font, perhaps their additional effort/concentration involved will boost their learning.

As I wrote last year, a research team has developed a font designed for exactly that reason: Sans Forgetica. (Clever name, no?) According to their claims, this font creates the optimal level of reading difficulty and thereby could enhance learning.

However — as noted back then — their results weren’t published in a peer-reviewed journal. (All efforts to communicate with them go to their university’s publicity team. That’s REALLY unusual.)

So: what happens when another group of researchers tests Sans Forgetica?

Testing Sans Forgetica

Testing this question is unusually straightforward.

Researchers first asked participants to read passages in Sans Forgetica and similar passages in Arial. Sure enough, they rated Sans Forgetica harder to read.

They then ran three more studies.

First, they tested participants’ memory of word pairs.

Second, they tested memory of factual information.

Third, they tested understanding of conceptual understanding.

In other words, they were SUPER thorough. This research team didn’t just measure one thing and claim they knew the answer. To ensure they had good support behind their claims, they tested the potential benefits of Sans Forgetica in many ways.

So, after all this thorough testing, what effect did Sans Forgetica have?

Nada. Bupkis. Nuthin.

For example: when they tested recall of factual information, participants remembered 74.73% of the facts they read in Sans Forgetica. They remembered 73.24% of the facts they read in Arial.

When they tested word pairs, Sans Forgetica resulted in lower results. Participants remembered 40.26% of the Sans Forgetica word pairs, and 50.51% of the Arial word pairs.

In brief, this hard-to-read font certainly doesn’t help, and it might hurt.

Practical Implications

First, don’t use Sans Forgetica. As the study’s authors write:

If students put their study materials into Sans Forgetica in the mistaken belief that the feeling of difficulty created is benefiting them, they might forgo other, effective study techniques.

Instead, we should encourage learners to rely on the robust, theoretically-grounded techniques […] that really do enhance learning.

Second, to repeat that final sentence: we have LOTS of study techniques that do work. Students should use retrieval practice. They should space practice out over time. They should manage working memory load. Obviously, they should minimize distractions — put the cell phone down!

We have good evidence that those techniques work.

Third, don’t change teaching practices based on unpublished research. Sans Forgetica has a great publicity arm — they were trumpeted on NPR! But publicity isn’t evidence.

Now more than ever, teachers should keep this rule in mind.

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