Updating the Ganzfeld Database: A Victim of Its Own Success?
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Plain English Summary
Here's a detective story about telepathy research. The ganzfeld procedure (where a 'receiver' relaxes in sensory isolation while a 'sender' transmits mental images) had shown promising results, but a 1999 meta-analysis declared the effect had vanished. Bem, Palmer, and Broughton fired back, arguing the disappearance was an illusion from lumping good and sloppy studies together. They found 10 overlooked studies that alone hit 36.7% success (chance is 25%). The key move: independent raters scored how closely each study followed the standard recipe. Studies sticking to protocol succeeded at about 31%. Studies that deviated? A flat 24% -- basically chance. The practical takeaway: when a promising experiment stops 'working,' maybe the question isn't whether the effect is real, but whether people are running it correctly.
Abstract
The existence of psi—anomalous processes of information transfer such as telepathy or clairvoyance—continues to be controversial. Earlier meta-analyses of studies using the ganzfeld procedure appeared to provide replicable evidence for psi (D. J. Bem & C. Honorton, 1994), but a follow-up meta-analysis of 30 more recent ganzfeld studies did not (J. Milton & R. Wiseman, 1999). When 10 new studies published after the Milton-Wiseman cutoff date are added to their database, the overall ganzfeld effect again becomes significant, but the mean effect size is still smaller than those from the original studies. Ratings of all 40 studies by 3 independent raters reveal that the effect size achieved by a replication is significantly correlated with the degree to which it adhered to the standard ganzfeld protocol. Standard replications yield significant effect sizes comparable with those obtained in the past.
Related Papers
Cites
- Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer — Bem, Daryl J (1994)
- Does Psi Exist? Lack of Replication of an Anomalous Process of Information Transfer — Milton, Julie (1999)
- "Future Telling": A Meta-Analysis of Forced-Choice Precognition Experiments, 1935-1987 — Honorton, Charles (1989)
- Does Psi Exist? Comments on Milton and Wiseman's (1999) Meta-Analysis of Ganzfeld Research — Storm, Lance (2001)
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📋 Cite this paper
Bem, Daryl J, Palmer, John, Broughton, Richard S (2001). Updating the Ganzfeld Database: A Victim of Its Own Success?. Journal of Parapsychology.
@article{bem_palmer_broughton_2001_updating_ganzfeld,
title = {Updating the Ganzfeld Database: A Victim of Its Own Success?},
author = {Bem, Daryl J and Palmer, John and Broughton, Richard S},
year = {2001},
journal = {Journal of Parapsychology},
}