Re: Psi and Science Fiction

Damien Broderick (
Fri, 06 Aug 1999 12:42:34 +0000

At 04:28 PM 5/08/99 -0700, Hal wrote:

>The latest meta-analysis (where
>multiple studies are combined to get more data) was not able to show
>a statistically significant effect, unlike an earlier meta-analysis.
>The controversy is now over which studies to include, which should not
>be included, why some studies show much higher results than others, etc.
>It is quite a mess.
>Online at:

A mess, yes, but an interesting one. Consider this cite from the brief report above:

The metanalysis has generated heated discussion among psychologists. Some argue that Milton and Wiseman were unjustified in lumping all 30 studies together because their results were so disparate. Milton contends that a standard statistical test of variation among the results showed that they could treat the studies as a uniform set.

Bem says, however, "The reason the effect isn't significant is that there are three studies that are pulling down the average, and those studies are very nonstandard." Further, 6 of the 30 studies showed significant psi effects—more than would be expected by chance, he adds.

Since the metanalysis was completed, nine more ganzfeld studies have been published. Milton acknowledges that the psi effect would be statistically significant if the analysis were updated to include these studies. However, she observes, a single study had an especially strong result, but no clear-cut effect spans the broad range of investigations. "That will be a crucial thing to demonstrate in order to make a strong claim that the studies show a genuine anomaly," she says.

This will strike obdurate skeptics as just so much waffling by the anomalists - `very nonstandard' indeed, harrumph - but, hey... the bottom line is, as admitted by the *skeptical* meta-analyst, that including *all* the extant evidence gives a *positive*, pro-psi result.

This is not the sort of self-evidently bogus, jeez-I-can-see-through-this-bullshit result that skeptics might expect if psi were no better than iridology.

Damien Broderick