Joop M. Houtkooper
Center for Psychobiology and Behavioral Medicine
Justus Liebig University of Giessen
Otto-Behaghel-Strasse 10, 35394 Giessen, Germany
email: joophoutkooper at gmail.com
Volitional strategies in PK experiments have been reported by early experimenters acting as their own subjects. A study by Gissurarson, in which he obtained volitional strategies from the participants after the PK task, put this on a broader basis. In the present experiment, part of the Mind Machine Interaction (MMI) replication study, 74 subjects participated, contributing a total of 271 sessions. In the PK task, volitional strategies have been freely chosen by the participants before starting each run. The preliminary findings of this study confirmed Gissurarson's finding, that the "resonance" strategy was associated with the best PK performance. This strategy is also linked to subjective reports of "effortless effort" as a psi-conducive state of mind. In the present paper, the differences between the experimenters in the same study are analyzed. Apart from the interest in experimenter effects per se, this is relevant for the expected reproducibility of the findings. The finding of the resonance strategy turns out to be less robust, than the earier report suggested. However, major differences, specific to individual experimenters have been found. These differences are particularly striking for the "confidence" volitional strategy, where one experimenter obtained highly significant psi-hitting (p-2t<.002), whereas the other two experimenters both obtained significant psi-missing (p-2t<.02 and <.003). The interaction effect between experimenters and volitional strategies on PK-scoring is highly significant (p=.000024). Comparison of analyses by run and by session provides evidence that PK performance varies on a time-scale of minutes, dependent on the consciously chosen volitional strategy, but also dependent on the person of the experimenter.