ABSTRACT
A group of recent, well-controlled ganzfeld studies failed to replicate the positive findings of earlier work (Milton & Wiseman, 1999a). This presents a challenge to claims that a ganzfeld psi effect can be replicated across experimenters under methodologically stringent conditions. Because of the ganzfeld’s history as a focus for proof-oriented questions, this situation has implications for parapsychology as a whole. In this paper, it is shown that replication of effect size in the recent ganzfeld studies is not demonstrated across experimenters, regardless of whether the database is updated to include recent studies or whether outcome and cumulation statistics different from those preplanned are applied. Problems with interpreting as strong evidence for psi other parapsychological meta-analyses of less clearly well-conducted studies and apparently consistent process-oriented findings are discussed. The case is made for continuing with ganzfeld research as an important focus of parapsychology’s claims for replicability. It is argued that if there is a replicable ganzfeld psi effect, however, the procedures necessary to produce it have not yet been identified. It is proposed that process-oriented work be directed to the goal of identifying which studies should be able to replicate an above-chance effect, and that these studies, identified by their planned procedures before they have been conducted, should provide the basis for future tests of replication.
The organization of an international, electronic-mail discussion of these issues among 41 researchers with a special interest in ganzfeld research is described. The edited transcript of the discussion is presented in Part II.
