Anomaly or Artifact? Comments on Bem and Honorton
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Plain English Summary
When Bem and Honorton published results claiming telepathy worked in their ganzfeld experiments -- where a "receiver" in a relaxed, sensory-deprived state tries to pick up mental images from a "sender" -- skeptic Ray Hyman got an invitation to respond in the same prestigious journal. His reanalysis of their 330 sessions uncovered a striking pattern that became a big deal in later debates. He found that hit rates were strongly tied to how often a particular target image appeared in the pool (correlation of .83 -- remarkably high). Even more damning, when experimenters prompted participants and targets came up repeatedly, hit rates shot from a dismal 14% to an impressive 44.5%. That's a huge jump, and it points toward a mundane explanation: some targets were just easier to guess because they showed up more often, not because of psychic ability. Hyman also noted that the claimed effect was really a mash-up of very different results for video clips versus still images, undermining the idea of a consistent, replicable phenomenon. His bottom line: sloppy randomization and uneven target frequencies could account for what looked like evidence of psi. This critique became a cornerstone concern that ganzfeld researchers had to wrestle with for years afterward.
Research Notes
Published alongside Bem and Honorton (1994) in Psychological Bulletin as the invited skeptical commentary. Introduced the target-frequency x experimenter-prompting artifact that became a central methodological concern in subsequent ganzfeld research. Part of Hyman's sustained engagement with the ganzfeld paradigm spanning 1985-2010.
Reanalysis of 11 autoganzfeld experiments (N = 330 sessions) from Bem and Honorton (1994) reveals inconsistencies challenging the claim of a replicable psi effect. Hit rate correlates strongly with target occurrence frequency (Spearman r = .83, p = .013), and a significant interaction with experimenter prompting shows hit rates jumping from .140 (first occurrences) to .445 (later occurrences; chi-squared = 14.702, p = .0001). The overall effect is a composite of different rates for dynamic (.372) versus static (.271) targets, undermining claimed consistency with the original ganzfeld database. Hyman concludes that inadequate randomization testing and target-frequency patterns cast doubt on whether results reflect psi or artifact.
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π Cite this paper
Hyman, Ray (1994). Anomaly or Artifact? Comments on Bem and Honorton. Psychological Bulletin. https://doi.org/10.1037/0033-2909.115.1.19
@article{hyman_1994_anomaly,
title = {Anomaly or Artifact? Comments on Bem and Honorton},
author = {Hyman, Ray},
year = {1994},
journal = {Psychological Bulletin},
doi = {10.1037/0033-2909.115.1.19},
}