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By Jeff • Nov 12th, 2010

Daryl Bem, one of the most influential and important social psychologists of our time, recently had a paper accepted at the Journal of Personality and Social Psychology, the premier social psych journal.  This, in and of itself, would not be noteworthy since Dr. Bem has published numerous papers in JPSP. What is noteworthy, however, is that in this paper he conducted 9 experiments that demonstrate the existence of precognition. Yup, that’s right, ESP (or Psi as he calls it). All of the studies are incredibly well run and I have no methodological qualms with them. However, given the nature of the claim, that ESP exists, I felt that it was my duty as a scientist to attempt to replicate his findings. I teamed up with Leif Nelson and we recreated Study 8 (retroactive facilitation of memory). The gist of the study is that studying after an exam helps you on the exam itself. In this case, the exam was a memory task involving 48 common nouns.

In any case, we ran this study online and wrote up the results (tl;dr: we did not replicate his results) in a short paper which can be downloaded on SSRN.

I also put together a public version of the experiment that anyone can try out (and even get their Psi score). You can try out the experiment here.

We’ve also started to get a bit of press for our failed replication at New Scientist. And now at Cosmic Log at MSNBC.


One Response »

  1. I am glad to see you and Leif investigating the astounding effect presented by Bem and Honorton.

    From a Bayesian perspective, I wonder how high the bar should be to come to a reasonable scientific conclusion that ESP (i.e., Psi) exists. Nonetheless, the ESP debate raises important methodological questions:

    1) what is the “best” procedure to test ESP?
    2) is null hypothesis testing the right framework to evaluate any one study?
    3) how big should the file drawer of failed studies be?
    4) what is the difference between practical significance and statistical significance?

    I could go on and on (but you probably knew that – get the joke??)

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