Extraordinary Claims Require Extraordinary Evidence: The Case of Non-Local Perception, a Classical and Bayesian Review of Evidences

📌 Appears in:

⚡ Ganzfeld Telepathy ⚡ Presentiment ⚡ Meta Debate

Plain English Summary

This companion review tackles the same question — real evidence for perception beyond physical senses? — laying out raw numbers impressively. Across 200-plus studies and 6,000-plus participants, Tressoldi examined six experimental setups using traditional statistics and Bayesian analysis (which measures how much data shifts odds toward one explanation). Every protocol beat chance statistically. But the Bayesian results get wild: ganzfeld experiments (relaxed participants identifying hidden images) hit a Bayes factor of nearly 19 million. Remote viewing reached 25 billion. Presentiment — your body seemingly reacting before something happens — scored an astronomical 2.89 trillion. Normal-consciousness protocols actually favored the skeptical explanation. Quality-versus-effect-size correlations ran modestly positive, meaning better-designed studies didn't produce weaker results — directly challenging the "it's all bad methodology" critique.

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

Companion paper to tressoldi_2011_extraordinary (same DOI, different folder for remote viewing content). Directly addresses 'extraordinary claims require extraordinary evidence' challenge. Provides both frequentist and Bayesian quantitative frameworks. Important for controversies #1 (ganzfeld), #2 (precognition), #5 (remote viewing), #10 (meta-debate). Bayesian analysis shows strong evidence for ganzfeld, RV, presentiment but not normal-consciousness protocols. Published in Frontiers in Psychology 2011;2:117.

This mini-review presents quantitative evidence from 7 databases covering 6 non-local perception (NLP) protocols, analyzed using both frequentist and Bayesian meta-analysis. Protocols include: ganzfeld free-response (108 studies, 3,650 participants), anticipatory psycho-physiological responses (37 studies, 1,064 participants), forced-choice ESP without ASC (72 studies, 69,726 participants), free-response with ASC (16 studies, 427 participants), free-response normal consciousness (14 studies, 1,026 participants), and remote viewing (Milton 1997: 78 studies, 1,158 participants; Dunne & Jahn 2003 PEAR: 366 participants). Frequentist analysis rejected null for all protocols (effect sizes d=0.007-0.28). Bayesian analysis showed strong evidence for H1 in 3 protocols: ganzfeld (BF=18,861,051), remote viewing (BF=25,424,503,838), anticipatory responses (BF=2.89×10^13). Normal consciousness protocols favored null (BF=0.003-0.029). Quality-effect size correlations were modestly positive (r=0.05-0.36). Total: 200+ studies, 6,000+ participants.