Sharing your toothbrush with strangers

The “toothbrush problem” refers to the challenge of making cumulative progress in behavioral science. I will argue that this is difficult in part because behavioral theorizing often extends what is currently already believed -- a form of exploitation that is made easy by verbal hypothesizing and by weak links between theoretical premises and concrete predictions, as the vagueness inherent in verbally specified theories allows them to be tailored to any currently favored theoretical framework or to incidentally available data. To address this vagueness, I propose the use of minimodels: a structured quantitative framework that transforms low-resolution theoretical predictions into explicit, testable components, implemented as multivariate Bayesian tests. Minimodels clarify theoretical implications, facilitate consistent evidence assessment, and provide a standardized format for theory communication. By integrating findings across multiple studies and enabling direct comparison between competing ideas, such models can serve as a common language for theorists to communicate ideas more effectively, encouraging collaboration, critical evaluation, and cumulative science in a field sometimes hindered by weak bonds between verbal theory and quantitative observation. This approach allows not only accumulation of evidence over studies, but also allows current beliefs to be challenged, and may lead to new theory and advance behavioral science.