An ESP experiment with the sequential card search task.
The first SCS study was conducted by Copenhagen in 2000 with 26 participants recruited from 2 subpopulations: (a) clairvoyants, participants practising ESP in their community sessions (Group C, n = 11), and (b) controls, participants not claiming any ESP abilities (Group N, n = 15). A software implementation of the SCS task (program jcards) on a portable computer was used to run the experiments at participants' homes. Five classic Zener symbols were used. Each participant completed 1 run consisting of 100 complete trials.
The ASRL statistics showed no significant departure from the mean chance expectation (MCE) in either Group C or N; the difference between the groups was also not significant. Hit rates were analyzed separately by successive subtrials, as the hit probability due to chance varies with the number of alternatives from which to choose, and numbers of subtrials naturally decrease with decreasing number of alternatives. The deviations of hit rates from hit probabilities by chance show similar profiles between Groups C and N, but the deviations, taken as a whole, are not significant.
The most remarkable feature of the data structure is an asymmetry observed at extreme ends of ASRL distributions in both Groups C and N: extremely low values (i.e., in the expected direction) deviated farther from MCE than the extreme values on the opposite wing of the distributions. Although this observation has to be taken with extreme care, the joint probability of these departures, given the null hypothesis, is rather low (p [approximately] .012). This observation is strongly suggestive of an inhomogeneity in the source population; one might hypothesize that the experimental samples were statistical mixtures of a major portion scoring on the chance level and a minor fraction using an unknown, extra-chance cognitive process.
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|Title Annotation:||extrasensory perception|
|Author:||Wackermann, Jiri; Benthin, Rebecca; Putz, Peter|
|Publication:||The Journal of Parapsychology|
|Article Type:||Brief Article|
|Date:||Dec 1, 2001|
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