Meta-analysis of free-response studies, 1992-2008: assessing the noise reduction model in parapsychology
Language: 
English
Short Title: 
Meta-analysis of free-response studies, 1992-2008
Abstract: 

We report the results of meta-analyses on 3 types of free-response study: (a) ganzfeld (a technique that enhances a communication anomaly referred to as "psi"); (b) nonganzfeld noise reduction using alleged psi-enhancing techniques such as dream psi, meditation, relaxation, or hypnosis; and (c) standard free response (nonganzfeld, no noise reduction). For the period 1997-2008, a homogeneous data set of 29 ganzfeld studies yielded a mean effect size of 0.142 (Stouffer Z = 5.48, p = 2.13 x 10(-8)). A homogeneous nonganzfeld noise reduction data set of 16 studies yielded a mean effect size of 0.110 (Stouffer Z = 3.35, p = 2.08 x 10(-4)), and a homogeneous data set of 14 standard free-response studies produced a weak negative mean effect size of -0.029 (Stouffer Z = -2.29, p = .989). The mean effect size value of the ganzfeld database was significantly higher than the mean effect size of the standard free-response database but was not higher than the effect size of the nonganzfeld noise reduction database [corrected].We also found that selected participants (believers in the paranormal, meditators, etc.) had a performance advantage over unselected participants, but only if they were in the ganzfeld condition.

Author(s): 
Storm, Lance
Tressoldi, Patrizio E.
Di Risio, Lorenzo
Item Type: 
Journal Article
Publication Title: 
Psychological Bulletin
Journal Abbreviation: 
Psychol Bull
Publication Date: 
2010-07
Publication Year: 
2010
Pages: 
471-485
Volume: 
136
Issue: 
4
ISSN: 
1939-1455
DOI: 
10.1037/a0019457
Library Catalog: 
PubMed
Extra: 
PMID: 20565164

Turabian/Chicago Citation

Lance Storm, Patrizio E. Tressoldi and Lorenzo Di Risio. 2010-07. "Meta-analysis of free-response studies, 1992-2008: assessing the noise reduction model in parapsychology." Psychological Bulletin 136: 4: 471-485. 10.1037/a0019457.

Wikipedia Citation

<ref> {{Cite journal | doi = 10.1037/a0019457 | issn = 1939-1455 | volume = 136 | pages = 471-485 | last = Storm | first = Lance | coauthors = Tressoldi, Patrizio E., Di Risio, Lorenzo | title = Meta-analysis of free-response studies, 1992-2008: assessing the noise reduction model in parapsychology | journal = Psychological Bulletin | date = 2010-07 | pmid = | pmc = }} </ref>