Laplace’s Demon

if there could be any mortal who could observe with his mind the interconnection of all causes, nothing indeed would escape him. For he who knows the causes of things that are to be necessarily knows all the things that are going to be. (…) For the things which are going to be do not come into existence suddenly, but…

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Limitations of Bayesian Leave-One-Out Cross-Validation for Model Selection

This post is an extended synopsis of a preprint that is available on PsyArXiv. “[…] if you can’t do simple problems, how can you do complicated ones?” — Dennis Lindley (1985, p. 65) Cross-validation (CV) is increasingly popular as a generic method to adjudicate between mathematical models of cognition and behavior. In order to measure model generalizability, CV quantifies out-of-sample…

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On the Importance of Avoiding Shortcuts in Applying Cognitive Models to Hierarchical Data

This post summarizes the content of an article that is in press for Behavior Research Methods. The preprint is available on PsyArXiv. Psychological experiments often yield data that are hierarchically structured. A number of popular shortcut strategies in cognitive modeling do not properly accommodate this structure and can result in biased conclusions. First, we considered a modeling strategy that ignores…

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Musings on Preregistration: The Case of the Facial Feedback Effect

tl;dr. In 2016, the results of a multi-lab preregistered replication effort cast doubt on the idea, motivated by the “facial feedback hypothesis”, that holding a pen with one’s teeth (instead of with one’s lips) makes cartoons appear more amusing. The effect’s progenitor, Dr. Strack, critiqued the replication effort and suggested that the presence of a camera (put in place to…

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Karl Pearson’s Worst Quotation?

The famous statistician Karl Pearson was also a eugenicist, so there are a great many hair-raising quotations to choose from. I nominate the following two for being particularly shocking (for more information see Wikipedia and the Guardian). Brace yourself, here is quotation number one:                       “History shows me one way,…

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Karl Pearson’s Best Quotation?

NB. The next post will discuss two of Karl Pearson’s worst quotations.                 “The field of science is unlimited; its material is endless, every group of natural phenomena, every phase of social life, every stage of past or present development is material for science. The unity of all science consists alone in its…

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Quantifying Support for the Null Hypothesis in Psychology: An Empirical Investigation

This post summarizes the content of an article that is in press for Advances in Methods and Practices in Psychological Science.1 The preprint is available on PsyArXiv. In the traditional statistical framework, nonsignificant results leave researchers in a state of suspended disbelief. This study examines, empirically, the treatment and evidential impact of nonsignificant results. Our specific goals were twofold: to…

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