Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Monday, January 21, 2019

Contention in the ganzfeld

I just ran into an article over at Psychology Today that I thought deserved a close examination.

It's by Steve Taylor, senior lecturer in psychology at Leeds Beckett University, and is called "Open-Minded Science."  A one-line summary of the article is that science has an inherent bias against considering parapsychological phenomenon, and that there is compelling evidence of telepathy (known as "psi" by aficionados) from what is known as the ganzfeld experiment.

So, a little background.  Ganzfeld is a German word meaning "entire field," and purports to set test subjects up to maximize their ability to collect data from another mind telepathically.  First proposed by German psychology researcher Wolfgang Metzger, what the procedure entails is placing the subject in complete (or as complete as can be managed) sensory deprivation.  A series of patterns or letters, either on cards or on a computer screen, is observed by the researcher, and the subject attempts to identify what the researcher is seeing.  The removal of other sensory inputs, supporters claim, makes subjects better able to sense telepathic signals, and results in a far higher than chance ability to select the correct target patterns.

The gist of Taylor's article is that these positive results -- well beyond what would be considered statistically significant support for psi -- are being ignored by the scientific establishment because of an entrenched bias against anything that's "paranormal."  Taylor writes:
In recent years, a series of studies showing significant results from psi phenomena have been published in a whole range of major psychology journals.  A number of comprehensive overviews of the evidence have also been published.  Most notably, last year American Psychologist carried an article by Professor Etzel Cardeña entitled “The experimental evidence for parapsychological phenomena: A Review.”  Cardeña showed clearly that the evidence for phenomena like telepathy, precognition and clairvoyance has proven so significant and consistent over a massive range of difference experiments that it cannot simply be explained away in terms of fraud, the “file drawer” effect (when researchers don’t bother to publish negative results) or poor methodology.  Cardeña also showed that there is no reason at all to take the view that these phenomena break the laws of science, science they are compatible with many of the theories and findings of quantum physics (which is why many quantum physicists have been open to their existence.)
As I mentioned in a previous post, it drives me nuts when people start attributing psychic phenomena to quantum physics, because those associations are usually based upon scant knowledge of what quantum physics actually says.  But let's look past that for now.  Taylor goes on to say that the evidence has been mounting for years:
A meta-analysis of more than three thousand Ganzfeld trials that took place from 1974 to 2004 had a combined ‘hit rate’ of 32 per cent.  A seven percent higher than chance rate may not seem so impressive, but over such a large number of experiments, this equates to odds of thousands of trillions to one—and a figure far too significant to explained in terms of the file drawer effect.  In addition, in Ganzfeld experiments that have been undertaken with creative people, there has been a significantly higher than normal rate of success.  In 128 Ganzfeld sessions with artistically gifted students at the University of Edinburgh, a 47% success rate was obtained, with odds of 140 million to one.  Similarly, in a session with undergraduates from the Juilliard school of performing arts, the students achieved a hit rate of 50%.
If these figures are correct, then Taylor's right; this is evidence that demands an honest analysis.  As skeptics, we can't just pay attention to the evidence that lines up with the way we already decided the world works, and ignore everything else.  So let's take a look at his claim.

In 1999, Richard Wiseman and Julie Milton, of the University of Hertfordshire and the University of Edinburgh respectively, published a meta-analysis of ganzfeld results in the Psychological Bulletin.  Wiseman and Milton were unequivocal:
The new ganzfeld studies show a near-zero effect size and a statistically nonsignificant overall cumulation.  Out of three autoganzfeld internal effects that the new database examined, only one effect was replicated, and it turns out to have been mistakenly reported by Bern and Honorton (1994) as having been statistically significant in the autoganzfeld studies...  Whatever the reason, the autoganzfeld results have not been replicated by a "broader range of researchers."  The ganzfeld paradigm cannot at present be seen as constituting strong evidence for psychic functioning.
The pro-psi researchers then launched their own rebuttal.  A paper by Daryl Bem, John Palmer, and Richard S. Broughton in the Journal of Parapsychology, published in September of 2001, didn't argue with Wiseman and Milton's analysis, but said that there were ten new studies, and when those are added to the ones analyzed by Wiseman and Milton, "the overall ganzfeld effect again becomes significant."  Thus they stood firm on claims Daryl Bem and Chuck Honorton had made seven years earlier, when they had published their own meta-analysis in Psychological Bulletin in which they stated outright that "the psi ganzfeld effect is large enough to be of both theoretical interest and potential practical importance."

Here's where we get into murky water.  Psychological researcher Susan Blackmore, who has a well-deserved reputation for being one of the clearest, most open-minded thinkers on the subject -- and who herself is not willing to dismiss psi out of hand -- clobbered Bem and Honorton in a 2017 article in Skeptical Inquirer, stating that they had included in their analysis a series of studies by Carl Sargent that had been widely criticized for methodological flaws, and in which "the better the quality of the study, the smaller the apparent psi effect."  More troubling still is that Bem and Honorton, apparently deliberately, never mentioned Sargent's name as the source of some of their data, knowing that -- quite rightly -- this would cast doubt over their whole analysis.  Blackmore writes:
They also admitted that “One laboratory contributed 9 of the studies.  Honorton’s own laboratory contributed 5…  Thus, half of the studies were conducted by only 2 laboratories.” (Bem & Honorton, 1994, p 6).  But they did not say which laboratory contributed those nine studies.  Even worse they did not mention Sargent, giving no references to his papers and none to mine.  No one reading their review would have a clue that serious doubt had been cast on more than a quarter of the studies involved. 
I have since met Bem more than once, most recently at one of the Tucson consciousness conferences where we were able to have a leisurely breakfast together and discuss the evidence for the paranormal.  I told Bem how shocked I was that he had included the Sargent data without saying where it came from and without referencing either Sargent’s own papers or the debate that followed my discoveries.  He simply said it did not matter.
But one study -- and one researcher's apparent shoulder-shrug at including debunked studies in his analysis -- doesn't mean much.  There was an in-depth analysis done in 2013 by Jeffrey Rouder, Richard Morey, and Jordan Province, published in Psychological Bulletin, that had the following to say:
Psi phenomena, such as mental telepathy, precognition, and clairvoyance, have garnered much recent attention.  We reassess the evidence for psi effects from Storm, Tressoldi, and Di Risio's (2010) meta-analysis...  We find that the evidence from Storm et al.'s presented data set favors the existence of psi by a factor of about 6 billion to 1, which is noteworthy even for a skeptical reader.  Much of this effect, however, may reflect difficulties in randomization: Studies with computerized randomization have smaller psi effects than those with manual randomization.  When the manually randomized studies are excluded and omitted studies included, the Bayes factor evidence is at most 330 to 1, a greatly attenuated value.  We argue that this value is unpersuasive in the context of psi because there is no plausible mechanism and because there are almost certainly omitted replication failures.
And because there can never be enough meta-analyses, researcher and skeptic Andrew Endersby did his own in 2005, and had the following to say:
At the end of my research I find a hit rate of between 28.6% and 28.9% depending on certain choices concerning which scoring methods to use on particular experiments.  This doesn't have quite the headline grabbing appeal of 1 in 3 instead of 1 in 4 but the hit rate is still highly significant for 6,700 sessions.  However, this contains all experiments.  Flawed or not, standard or not.  There's no doubt that this figure can be tweaked up or down according to ruling in or out certain experiments.
Not exactly a ringing proclamation of support.

So where are we now?  Same place, pretty  much.  You've got your true believers, your fervent disbelievers, and people in the middle like myself who would very much like to know if there's actually something there to study.  Because if the ganzfeld effect actually works, it would be kind of earthshattering, you know?  It would mean that there actually was a mechanism for information transfer between minds, and would overturn the basic assumption we have about neuroscience -- that what occurs in your mind is solely the result of electrical and chemical signaling within your own skull.  Even The Skeptic's Dictionary -- usually squarely on the side of the scoffers -- is unwilling to discount it out of hand.  Here's how the entry for the ganzfeld effect ends:
Actually, what we know is that the jury is still out and it probably will never come in if the best that parapsychologists can come up with is a statistic in a meta-analysis that is unlikely due to chance.  Even if we take the data at face value, we know that no matter how statistically significant the results are, the actual size of this psi effect is so small that we can’t detect it in a single person in any obvious way.  We have to deduce it from guessing experiments.  What hope do we have of isolating, harnessing, or expanding this power if a person who has it can’t even directly recognize its presence?
I'll end with another quote from Susan Blackmore, which I think is spot-on.  If anyone has replicable, well-controlled experiments showing the existence of psi, I'm more than willing to consider them.  But until then:
Perhaps errors from the past do not matter if there really is a repeatable experiment.  The problem is that my personal experience conflicts with the successes I read about in the literature and I cannot ignore either side.  I cannot ignore other people's work because science is a collective enterprise and publication is the main way of sharing our findings.  On the other hand I cannot ignore my own findings—there would be no point in doing science, or investigating other people's work, if I did.  The only honest reaction to the claims of psi in the ganzfeld is for me to say "I don't know but I doubt it. "

This week's Skeptophilia book recommendation is a brilliant look at two opposing worldviews; Charles Mann's The Wizard and the Prophet.  Mann sees today's ecologists, environmental scientists, and even your average concerned citizens as falling into two broad classes -- wizards (who think that whatever ecological problems we face, human ingenuity will prevail over them) and prophets (who think that our present course is unsustainable, and if we don't change our ways we're doomed).

Mann looks at a representative member from each of the camps.  He selected Norman Borlaug, Nobel laureate and driving force behind the Green Revolution, to be the front man for the Wizards, and William Vogt, who was a strong voice for population control and conversation, as his prototypical Prophet.  He takes a close and personal look at each of their lives, and along the way outlines the thorny problems that gave rise to this disagreement -- problems we're going to have to solve regardless which worldview is correct.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]


  1. I think that's a fair piece on the whole, but unfortunately Susan Blackmore's statements - and particularly her personal attack on Daryl Bem - need to be treated with caution.

    Her recent article gives the impression that in 1987 she had publicly accused Carl Sargent of "almost certainly" cheating. In fact she wrote then that what she had seen eight years earlier might have been the result of cheating or it might have been the result of carelessness, but that the evidence wasn't conclusive. Sargent and his coworkers responded with strongly worded rebuttals. That's the background to the paper by Bem and Honorton, published in 1994, that she is criticising:

    Blackmore also seems to have misunderstood that paper. She says that "Bem included these [Sargent's] data in his meta-analysis without referencing the doubt cast on them". In fact it was two earlier meta-analyses, by Hyman and Honorton, which had included Sargent's data. These had appeared in 1985, before her criticisms of Sargent's work had been published. Bem and Honorton simply discussed these earlier meta-analyses in the literature review that formed the first part of their 1994 paper.

    Nor is it strange that Bem and Honorton failed to cite Sargent's papers. No doubt they had been cited in the original meta-analyses, but as far as I can see Bem and Honorton didn't cite any of the constituent studies of those meta-analyses. Nor did they refer to any of the labs involved, except Honorton's own.

    Perhaps Blackmore's paper should still have been mentioned, even though Sargent's data had only formed part of the older meta-analyses. Judging from her article, 24 years later she was still very unhappy that it hadn't been. But I don't think it was right for her to attack Daryl Bem's integrity on that basis.

  2. Hello, Andrew Endersby here. Interesting article and thanks for the namecheck, although I feel I should point out I'm not a psychologist.

    1. Glad to do it. I'd like to correct my error -- how would you like to be identified?

    2. Golly, that's a good question. Researcher, I suppose.