Academic journal article The Journal of Parapsychology

A Further Consideration of the Sender as a PK Agent in Ganzfeld ESP Studies

Academic journal article The Journal of Parapsychology

A Further Consideration of the Sender as a PK Agent in Ganzfeld ESP Studies

Article excerpt

Despite the relative success of clairvoyance designs in eliciting evidence for ESP when used with other protocols (see, e.g., reviews by Rhine, Pratt, Stuart, Smith, & Greenwood, 1940/1966, and Utts, 1996), it has been commonly assumed that a sender can make some positive contribution to the outcome of ganzfeld studies. Relatively few ganzfeld experiments have adopted a clairvoyance design except when the objective of the study was to compare sender and no-sender conditions. Honorton (1995) found that of 73 ganzfeld studies only 12 did not employ senders. His meta-analysis comparing sender and no-sender experiments showed that those including senders generated better performance than those that did not, although the effect seemed to be confined to those experimenters who had used both conditions at some time. If it could be shown that the sender were unnecessary, this would have practical advantages in that sessions would be easier to co-ordinate for only one participant at a time and security would be more straightforward since no person need know the identity of the target until after the participant's judgments had been recorded.

Eight previous ganzfeld studies have directly compared sender and no-sender conditions within the same study (see Roe, Sherwood, & Holt, 2003, for a more detailed review), which together give a reasonably consistent picture. Two studies have reported scoring when a sender is aware of the target to be significantly better than when a sender is absent (Raburn & Manning, 1977; Sargent, Milton, Payne, & Bennet, unpublished, cited in Milton, 1988-1989), and four have described a nonsignificant advantage for telepathy conditions compared with clairvoyance conditions (Dunne, Warnock, & Bisaha, 1977; Kanthamani & Khilji, n.d., described in Kanthamani & Palmer, 1993; Milton, 1988-1989; and Williams, Roe, Upchurch, & Lawrence, 1994). Although Morris, Dalton, Delanoy, and Watt (1995) concluded that there were no significant differences overall, the reported target ranks give rise to z scores of 1.028 and .237 for their informed sender and uninformed no-sender conditions, respectively. Roe, Sherwood, and Holt (2003) reported a slightly improved performance for sender trials compared with no-sender trials in terms of direct hits but the reverse pattern when considering sums of ranks and z scores of similarity ratings.

Taken together, these findings may offer some encouragement for the suggestion that the sender serves some active role in a typical ganzfeld ESP session, particularly given that the experimental manipulations of the independent variable here are rather gross; for example, it does not systematically take into account the possible moderating effect of variables such as the sender-receiver relationship (see Honorton, 1985, but also Bem & Honorton, 1994). The designs also tend to assume that any sender effect will be readily apparent in the receiver's overall performance, despite this relationship's dependence upon the receiver's not only being able to detect any sender-mediated impressions but also to accurately interpret them and to be able to discriminate them from internally generated "noise" during judging. Recently we reported on an alternative method for gauging any potential sender effect that promised to circumvent such complications by replacing the receiver with a random number generator (RNG) "virtual receiver" that would generate a virtual mentation by randomly selecting statements from among an array of descriptors. Although this is a somewhat unusual procedure, a variant of this approach had previously met with some success (Roe, 1996).

Roe, Holt, and Simmonds (2003) conducted an initial test of this method within a ganzfeld setting: 40 pairs of participants experienced a "standard" autoganzfeld, but during the sending period a "virtual" receiver in the form of an RNG located in the receiver's room operated to generate random numbers corresponding to items in a pool of 768 statements. …

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