Should Ganzfeld Research Continue To Be Crucial In The Search For A Replicable Psi Effect? Part I. Discussion Paper And Introductionto An Electronic-Mail Discussion

It is also possible that any number of additional, unidentified variables might have contributed to the success of the PRL studies; and so it is not possible to know whether the recent studies' failure to replicate the PRL work was due to their failure to exploit these variables to the same extent. There were a number of procedures used on all or almost all trials at PRL--the use of a sender, continuous auditory monitoring of the receiver's mentation by the sender, correspondence judging by the receiver rather than by an independent judge, (double-blind) prompting by the experimenter during the judging to correspondences that the receiver overlooked, a 14-minute pretrial relaxation procedure for both sender and receiver, and so on. The importance of these procedures has not been empirically determined. Any one or more of these procedures might be important for replication; however, without any evidence for their effects, it is not clear that the failure of the recent studies to replicate the findings of the PRL studies was due to the use of different procedures. It is not evident, at this point, what a replication of the PRL work in its essentials would have to consist of.

Since the convention presentation of our meta-analysis (Milton & Wiseman, 1997a), a number of colleagues have informally suggested that if we had restricted our database to "standard" ganzfeld studies (i.e., studies without unusual features) across-experimenter replication of the PRL effect size might have been evident. However, among the researchers who have discussed the issue with me there appears to be little agreement about the features of a standard ganzfeld study. Devising a rule to define such a study at this point could easily appear as a post hoc attempt to explain away a disappointing result, given that the previous ganzfeld meta-analyses included almost all studies and trials no matter how unusual their procedures (Bem & Honorton, 1994; Honorton, 1985; Hyman, 1985) and regardless of whether those procedures would be expected to result in success or failure. [2] Neither Hyman and Honorton (1986) nor Bern and Honorton (1994) specified that studies would have to have certain features to be considere d part of the replicability test that they proposed. It does not appear possible to selectively meta-analyze the recent studies and make a strong case that the ganzfeld effect is replicable; however, a selective meta-analysis with exclusion criteria stated in advance of studies being conducted would be a credible demonstration of replicability if it obtained positive results. In practice, it is unlikely that criteria could be set up that would anticipate all of the novel features that experimenters might introduce in their studies that would lead most researchers to expect them to be unsuccessful. In addition to having to conform to a basic set of criteria, the procedures planned for each study would therefore also have to be examined on a case-by-case basis to determine whether or not the study ought to be included in the replication test. The existence of such a project would neither affect the usual conduct of process-oriented research nor force experimenters to use certain procedures in their studies. It would simply be the case that studies eligible to be included in the meta-analysis would be included and others would not. Similarly, the project would not affect anyone's usual freedom to conduct a meta-analysis of their own. In particular, there is no reason anyone should not conduct a process-oriented meta-analysis involving all studies.