Assessing the noise reduction model in parapsychology

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Posted on Dr Matthew Smith's Face book.

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 were significantly higher than the mean effect size of the nonganzfeld noise reduction and the standard free-response databases. 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.

http://www.ncbi.nlm.nih.gov/pubmed/20565164

[Admin]

I wonder whether someone else doing the meta-analysis in the same area would get the same results?

Meta-analyses can be good if done rigorously but they are very prone to selection and scoring biases of the researchers.

[Harryprice]

Surely Ganzfeld is a noise INCREASING method! By stopping normal sensory input you encourage your brain to increase the amount of stuff it makes up ie. upping the sensory noise levels! It's like putting a microphone in a very quiet room. When you play back your recording, you have to increase the volume to hear anything and all you get is a lot of background noise that normally you would never notice.