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

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This morning, I was about to tweet the super insightful quote:

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

and 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 further. Where did this idea come from, why has it taken hold in a lot of the social sciences, and has it benefited anyone’s thinking about 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 reached out to 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 then reached out to Kenneth Koedinger, who said, “But I first heard it as ‘Theories are like toothbrushes… ‘” and then goes on to cite one of the blogs below.

Following up on that search trend takes us all the way 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 that 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 retired in 2007, and there the trail goes cold. I can’t find any records or obituaries. I guess I could push harder in this research, but I’m not the girl with the dragon tattoo.

By 2008, the phrase starts 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

Late 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 in order 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, so to speak.

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

The very first Twitter mention in is 2009, which doesn’t provide a lot of context.

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

Starting in 2014, it 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 really gets legs in at the 2019 D&I conference, where there is at least attribution.

Google trends isn’t helpful in seeing whether there is any other contextual information; there just isn’t enough information to plot searches over time. It doesn’t really show up in PubTrawlr either, since it’s hard to detangle it from research into toothbrushes proper.


So, where does this leave us? An interesting catchphrase that has it 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 own frameworks and heuristics as others with my own work in Readiness and R=MC2. I’ve been asked more than once how this relates to CFIR, or 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 in terms of intellectual property and marketing, the constant reinvention of toothbrushes does seem kind of pointless.

And yes, the stock photo header is ridiculous.

last updated 2.18.21

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