ASC 2012 (#3, also available by mind-reading)

This final morning at the ASC 2012 conference in Adelaide, I attended a keynote lecture by Sophia Rabe-Hesketh on GLMs that I particularly appreciated, as I am quite fond of those polymorphous and highly adaptable models (witness the rich variety of applications at the INLA conference in Trondheim last month). I then gave my talk on ABC model choice, trying to cover the three episodes in the series within the allocated 40 minutes (and got from Terry Speed the trivia information that Renfrey Potts, father to the Potts model, spent most of his life in Adelaide, where he died in 2005! Terry added that he used to run along the Torrens river, being a dedicated marathon runner. This makes Adelaide the death place of both R.A. Fisher and R. Potts.)

Later in the morning, Christl Donnelly  gave a fascinating talk on her experiences with government bodies during the BSE and foot-and-mouth epidemics in Britain in the past decades. It was followed by  a frankly puzzling [keynote Ozcots] talk delivered by Jessica Utts on the issue of parapsychology tests, i.e. the analysis of experiments testing for “psychic powers”. Nothing less. Actually, I first thought this was a pedagogical trick to capture the attention of students and debunk, however Utts’ focus on exhibiting such “powers” was definitely dead serious and she concluded that “psychic functioning appears to be a real effect”. So it came as a shock that she was truly believing in psychic paranormal abilities! I had been under the wrong impression that the 2005 Statistical Science paper of hers was demonstrating the opposite but it clearly belongs to the tradition of controversial Statistical Science that started with the Bible code paper… I also found it flabbergasting to learn that the U.S. Army is/was funding research in this area and is/was actually employing “psychics”, as well that the University of Edinburgh has a parapsychology unit within the department of psychology. (But, after all, UK universities also have long had schools of Divinity, so let the irrational in a while ago!)

Now I have neither intention nor time [given the poor connection!] of looking at the papers (or at the experiments) mentioned in the talk, but I did not find the presentation fair and balanced, in that the psychological experiments were only briefly mentioned and the whole  discussion was on the statistical analysis of observing a binomial outcome with frequency f=.33 and testing for p=.25, leading to a fairly obvious answer… What I would like to understand is why the simple binomial model made sense in those cumulated experiments (like, why should they share the same p? The slides 40 to 45 of an earlier presentation cover this generalisation with a noninformative prior leading to no rejection of the null.) and why the rejection of the null (not even that the answers were given at random, but that p=.25) led to an evidence of psi (sic). The Bayesian aspect mentioned in the title (“Bayes, bias and belief: how I became a temporary (?) Bayesian“) was also rather misleading in that the talk used power arguments and focussed on recent criticisms raised against some experiments (whose connection with psychic powers I could not fathom), criticisms that used Bayes factors constructed from very informative priors. And [see slide 29] that skeptics could only remain skeptics because their prior probability on the existence of psychic powers was unreasonably low… (Mine is reasonably and rationally equal to zero.) I found the conclusion most perturbing, in that, and I hope I misunderstood her!, the speaker seemed to attribute the lack of reproducibility in experiments run by sceptics to their own psychic powers that made the experiments fail! Which is a good if non-Popperian way to eliminate criticisms. Overall, I see not point in engaging into such catering to irrational beliefs, such as parapsychology and intelligent design. And certainly no pedagogical value in using such experiments when teaching Bayesian decision theory or frequentist testing (Ozcots is a conference on teaching statistics). Anyway, I noticed I was not the only one to react negatively to the talk and we sceptics had a nice dinner discussing this issue in Adelaide Chinatown…