Meta-Analysis of Free-Response Studies 2009-2018: Assessing the Noise-Reduction Model Ten Years On

Abstract

We report the results of an update to the meta-analysis by Storm, Tressoldi, and Di Risio (2010). Three types of free-response design were assessed: (i) ganzfeld (a technique that enhances a communication anomaly referred to as ‘psi’); (ii) nonganzfeld noise reduction using alleged psi-enhancing techniques (e.g., dreaming, hypnosis, relaxation, and meditation); and (iii) standard free-response (nonganzfeld; no noise reduction). These experimental (laboratory-based) designs allegedly elicit a communications anomaly known as extrasensory perception (ESP; a.k.a. psi). For the period 2009 to 2018, a dataset of nine new ganzfeld studies (Category 1) yielded a mean ES = 0.119; 19 new nonganzfeld noise-reduction studies (Category 2) yielded mean ES = 0.045; and 15 new free-response studies (Category 3) yielded mean ES = 0.050. Stouffer Z scores for all three databases were significant, but each new database was not significantly different from its respective database in Storm et al. (2010). The increased ganzfeld database (N = 38) yielded a mean ES = 0.133; the nonganzfeld noise-reduction dataset (N = 37) yielded mean ES = 0.072; and the standard free-response studies (N = 33) yielded mean ES = 0.027. Again, Stouffer Z scores were significant. We did find category differences, and participants (selected vs. unselected) performed differently, but there were no differences between modality (i.e., type of psi), types of target (e.g., film clips, photographs), or experimenter/laboratory. There was also no evidence of a decline effect across the 44-year period. Finally, we conducted a Bayesian analysis and found that the case for a communications anomaly using free-response designs was upheld.

Mediumship accuracy: A quantitative and qualitative study with a triple-blind protocol

“…All studies on telepathic abilities have shown that it is possible only to send and receive images, short video clips or other types of visual or auditory information using this method, but always via mental interaction with a specific individual partner (e.g. Storm and Tressoldi, 2020).…”

Is Mind Quantum?

“…Of those, studies using targets sets with 4 possible targets included 3,885 test sessions, resulting in 1,188 hits, corresponding to a 30.6% hit rate. [46,47] With chance at 25%, this excess hit rate is 8.1 sigma above chance expectation (p = 5.6 × 10 -16 ). Analysis of these studies showed that similar effect sizes were reported by independent labs, that the results were not affected by variations in experimental quality, and that selective reporting biases could not explain away the results.…”

Anomalous Perception: An Umbrella Review of the Meta-Analytic Evidence

“…There are thirteen meta-analyses, for a total of 628 studies. The oldest of which is that by Honorton and Ferrari (1989) related to forced-choice precognition experiments carried out from 1935 to 1987, whereas the more recent one, is that by Tressoldi and Storm (2020) related to free-response experiments, with particular focus on nonlocal perception studies in a ganzfeld environment carried out from 1974 to 2020.…”