Extraordinary Claims Require Extraordinary Evidence: The Case of Non-Local Perception, A Classical and Bayesian Review of Evidences
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Plain English Summary
Can psychic phenomena survive the toughest statistical scrutiny? Tressoldi tackles the famous challenge that "extraordinary claims require extraordinary evidence" using two heavyweight methods: traditional meta-analysis and Bayesian analysis (a technique calculating how strongly data supports one theory over another). He examined seven databases spanning six protocols testing perception beyond normal sensory reach. Three produced jaw-dropping numbers. Ganzfeld experiments (where sensory-reduced participants identify hidden targets) scored a Bayes factor of nearly 19 million favoring the effect being real. Remote viewing hit 25 billion. Presentiment — the body reacting to future events before they happen — reached 28 trillion. Experiments under normal waking consciousness flopped, favoring the null. The kicker for skeptics: study quality didn't predict weaker results, undermining claims that sloppy methods explain everything.
Actual Paper Abstract
Starting from the famous phrase "extraordinary claims require extraordinary evidence," we will present the evidence supporting the concept that human visual perception may have non-local properties, in other words, that it may operate beyond the space and time constraints of sensory organs, in order to discuss which criteria can be used to define evidence as extraordinary. This evidence has been obtained from seven databases which are related to six different protocols used to test the reality and the functioning of non-local perception, analyzed using both a frequentist and a new Bayesian meta-analysis statistical procedure. According to a frequentist meta-analysis, the null hypothesis can be rejected for all six protocols even if the effect sizes range from 0.007 to 0.28. According to Bayesian meta-analysis, the Bayes factors provides strong evidence to support the alternative hypothesis (H1) over the null hypothesis (H0), but only for three out of the six protocols. We will discuss whether quantitative psychology can contribute to defining the criteria for the acceptance of new scientific ideas in order to avoid the inconclusive controversies between supporters and opponents.
Research Notes
Important methodological paper directly addressing the 'extraordinary claims' challenge central to psi research. Combines frequentist and Bayesian approaches across multiple paradigms. Shows strong Bayesian evidence for ganzfeld, RV, and presentiment but not for normal-consciousness protocols. Essential for controversy #10 (meta-debate about psi research) and controversies #1-3 (specific paradigms). Cites Storm 2010, Mossbridge presentiment meta-analysis, Milton 1997 RV, Dunne & Jahn 2003 PEAR.
This mini-review presents quantitative evidence supporting non-local perception (NLP) — the hypothesis that human perceptual abilities may extend beyond space-time constraints of sensory organs. Tressoldi analyzes seven databases covering six experimental protocols: ganzfeld free-response, remote viewing, dream-ESP, presentiment/anticipatory responses, implicit precognition, and forced-choice ESP. Using both frequentist meta-analysis (weighted effect sizes) and Bayesian meta-analysis (Bayes factors), the paper evaluates whether cumulative evidence meets 'extraordinary evidence' standards. Frequentist analysis rejects the null for all protocols (effect sizes d=0.007-0.28). Bayesian analysis shows strong evidence for H1 in three protocols: ganzfeld (BF=18.8 million), remote viewing (BF=25.4 billion), and anticipatory responses (BF=2.89×10^13). Normal consciousness protocols favored the null. Quality-effect size correlations were modestly positive (r=0.05-0.36), contradicting methodological artifact claims.
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Cites
Cited By
- On the Correspondence Between Dream Content and Target Material Under Laboratory Conditions: A Meta-Analysis of Dream-ESP Studies, 1966-2016 — Storm, Lance (2017)
- Parapsychological Phenomena as Examples of Generalized Nonlocal Correlations—A Theoretical Framework — Walach, Harald (2014)
- A Call for an Open, Informed Study of All Aspects of Consciousness — Cardeña, Etzel (2014)
Extended By
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📋 Cite this paper
Tressoldi, Patrizio E (2011). Extraordinary Claims Require Extraordinary Evidence: The Case of Non-Local Perception, A Classical and Bayesian Review of Evidences. Frontiers in Psychology. https://doi.org/10.3389/fpsyg.2011.00117
@article{tressoldi_2011_extraordinary,
title = {Extraordinary Claims Require Extraordinary Evidence: The Case of Non-Local Perception, A Classical and Bayesian Review of Evidences},
author = {Tressoldi, Patrizio E},
year = {2011},
journal = {Frontiers in Psychology},
doi = {10.3389/fpsyg.2011.00117},
}