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A useless history of the “Frameworks are Like Toothbrushes” quote

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This morning, I was about to tweet (or is it “X?”) the super insightful quote:

Frameworks are like toothbrushes. Everyone has one, but nobody wants to use someone else’s.

I got to thinking about the attribution. I first heard this quote from the great Soma Saha from WE in the World, but the roots had to go back. Where did this idea come from, why has it taken hold in many of the social sciences, and has it benefited anyone’s thinking apart from a nice little chuckle? Even XKCD gets in on the action.

To start at the beginning, the first formal articulation of this quote comes in 2001 by Chris Schunn, a cognitive and learning professor. Notably, the phrase doesn’t come from his work directly; rather, people are just quoting back that he said it, as cited in this paper. I contacted Chris directly, who replied, “I think I got it from David Klahr, but I also suspect he got it from someone else.”

In this blog on a Carnegie Data Science tutoring, we find this quote, “Klahr (quoting a favorite Koedinger analogy) says it’s a classic “toothbrush problem”–researchers treat other peoples’ theories like toothbrushes, and they don’t want to use someone else’s.”

I reached out to Kenneth Koedinger, who said, “But I first heard it as ‘Theories are like toothbrushes… ‘” and then cited one of the blogs below.

Following up on that search trend takes us back to 1984, in a commentary by Michael Watkins on a memory paradigm. He says (with emphasis mine):

To be sure, the Maltese cross does in principle provide a framework within which more specific theories could be explored. But it is doubtful whether it will be used much. Not many investigators will accept the distortion or shift in emphasis necessary to fit their own theory into the framework, for it is well understood that theoretical frameworks are potentially as variable as the more specific theories. The Maltese cross is a bit like someone else’s toothbrush – it is fine for that individuals use, but for the rest of us . . . well, we would just rather not, thank you. I fear that bringing the information processing approach to memory into some kind of order will require even more ingenuity than was required to launch it.

After reading it, Ken later said, “…[Watkins] uses the idea differently than later users — in defense of not adopting others theories/models/frameworks rather than against the practice of reinventing the wheel and calling it a “roundy.” Michael Watkins retired in 2007, and the trail goes cold. I can’t find any records or obituaries.

By 2008, the phrase started filtering into the psychological sciences with a formal title: The Toothbrush Problem. As described by Walter Mischel, he notes:

Years ago, a wit (I have forgotten his name) called it the toothbrush problem: Psychologists treat other peoples’ theories like toothbrushes — no self-respecting person wants to use anyone else’s. It’s amusing, but it also points to a conflict that we may be nurturing within our profession to the detriment of our science.

Mischel, the Toothbrush Problem

Later in this piece, he talks about how this reluctance to use other frameworks creates a problem for cumulative science because academics on the tenure track seek innovation and novelty to seek tenure rather than adapting other methods and paradigms. This sounds somewhat related to the well-known Replication Crisis, and the drawbacks of working in someone’s else sandbox.

At the same time, we see a similar source attributed to Connie Morella at a leadership dinner talking more about standards than frameworks.

The very first X mention is in 2009, which doesn’t provide much context.

It then shows up in 2010 as attributed to Carnegie Mellon Professor Jodi Forlizzi, at a Design and Emotion conference in Chicago.

Starting in 2014, this quote seems to have jumped from the tech world into the improvement and implementation sciences. It’s floating around in a few sources, though this knowledge translation post seems to mangle the metaphor?

Trish Greenhalgh then had a slide with this quote at the 4th International Health Care Reform Conference in 2018, and it was off to the races. It gets legs in at the 2019 D&I conference, where there is at least attribution.

Google Trends doesn’t help see whether there is any other contextual information; there isn’t enough information to plot searches over time. It doesn’t show up in PubTrawlr either, since it’s hard to detangle it from research into actual toothbrushes.


So, where does this leave us? It is an interesting catchphrase that has its roots in the psychological sciences. And, as a field, we sure love our frameworks.

I’ve seen the Lewin quote, “Nothing is as practical as a good theory,” given Talmudic-like reverence. Certainly, I’m as guilty of developing my frameworks and heuristics as others with my work in Readiness and R=MC2. I’ve been asked more than once how this relates to CFIR, Weiner’s model, or others. And while I can give you long and short answers about the added benefits and practicality, the general principle remains the same. And since academics don’t often think about intellectual property and marketing, the constant reinvention of toothbrushes seems kind of pointless.

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An earlier version of this post first appeared over at The Dawn Chorus Group

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