| Reference code: | PT/FB/BL-2010-141.04 |
| Location: | Arquivo PCA - Pasta 15/2010
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Title:
| How to handle expectation bias in presentiment experiments: A recommendation
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| Publication year: | 2013
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URL:
| http://www.parapsych.org/uploaded_files/pdfs/00/00/00/00/39/2013_pa_convention_abstracts_of_presented_papers.pdf
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| Abstract/Results: | ABSTRACT:
Here we reconsider expectation bias, with focus on how to handle it in experiments attempting to demonstrate presentiment. Presentiment is usually demonstrated by showing that significant physiological differences precede stimuli of different arousal levels, with all stimuli being presented in a randomized order with replacement. Often the direction of these differences suggests that physiological arousal is more likely to precede arousing rather than neutral stimuli. The possibility exists that such reactions can be explained as resulting from expectation bias. Expectation bias is based on the (false) notion that the likelihood of an arousing stimulus being presented grows as the number of consecutive calm stimuli increases (the gambler´s fallacy). Different ways of minimizing or avoiding the bias are discussed.
On the basis of this discussion, our recommendation is to use analysis of variance (ANOVA) to separate the effect of the bias from the hypothetical presentiment effect, preferably at the trial-bytrial level. We also recommend ANOVA to be applied to each participant separately to avoid mixing within- and between- participant pre-stimulus effects, and to use a “counting” method to test for possible presentiment effects at the group level. The favored method is illustrated using both a simulated one-participant example and real, multi-participant data. Finally, we anticipate that ANOVA can be performed to handle not only the expectation bias, but also other similar biases, like the so-called “hot hand” bias, in presentiment experiments as well as in conscious precognition experiments involving feed-back.
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| Accessibility: | Document exists in file (full paper)
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Copyright/Reproduction:
| By permission
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Language:
| eng
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Author:
| Dalkvist, J.
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Secondary author(s):
| Mossbridge, J., Westerlund, J.
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Document type:
| Abstract book
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Number of reproductions:
| 3
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Reference:
| Dalkvist, J., Mossbridge, J., & Westerlund, J. (2013). How to handle expectation bias in presentiment experiments: A recommendation. In M. Biondi & P. Tressoldi (Eds.), Abstracts of Presented Papers of the 56th Annual Convention of the Parapsychological Association (p. 19). Viterbo, Italy: Parapsychological Association.
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| Indexed document: | No
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| Keywords: | Presentiment / Expectation bias / ANOVA / Analysis of variance / The gambler's fallacy / Precognition
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How to handle expectation bias in presentiment experiments: A recommendation |