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Interpersonal psi: exploring the role of the sender in ganzfeld GESP tasks.

According to Morris, Dalton, Delanoy, and Watt (1995, p. 246), "one of the most important theoretical issues in parapsychology concerns the role of the sender in GESP procedures." Indeed, many of the most impressive spontaneous cases do seem to involve an active "agent" (cf. Beloff, 1993), whereas in the laboratory Palmer (1978, p. 97) noted that "whatever the status of 'pure telepathy,' the widespread use of GESP procedures in psi experiments is ample evidence that many experimenters believe the presence of an agent may improve the chances of a successful outcome." One means of assessing this possibility is to compare participants' performance under GESP conditions (where there is a sender) with that under clairvoyance conditions (where there is not). Unfortunately, the interpretation of the outcomes of some of these studies is confounded by the fact that participants were aware that there would be no sender for some trials and this may clearly affect their expectancy or motivation--or even the perceived credibility of the phenomenon under investigation--in ways that could lead to what we term a psychological sender effect (cf. Irwin, 1999). Palmer (1978) has similarly noted that "the percipient might be more relaxed, more confident, or more highly motivated if he thinks someone is sending to him, even if no agent actually exists" (p. 97). Among the interpretations of the putative sender/no sender difference offered by Morris et al. (1995) is one that argues that to many participants, it seems somehow more plausible that someone must first observe the target and send them a signal before they can gain any information about the target, and that having a sender may simply increase the feeling of teamwork or diffuse responsibility for failures (or perhaps more tellingly, for successes, reminiscent of the work of Batcheldor, 1966). This is perhaps illustrated in extremis by Langdon-Davies (1956), who described a basic clairvoyance study in which he was scoring at chance until he set up an imaginary agent (in fact, it was the well-known medium Eileen Garrett, whom he had never actually met) so that he had someone to share success or failure with. His next series of 200 runs exhibited significant hitting.

A number of forced-choice experiments have kept the participants blind to the fact that some trials were clairvoyant and others permitted GESP, and these constitute a better test of the influence of the sender. Palmer (1978) reviewed much of the early work of this type and reported that researchers who tested gifted individuals did tend to find the predicted difference in favour of telepathy (e.g., Birge & Rhine, 1942), whereas those engaged in group testing did not (e.g., Beloff, 1969, West, 1950). The former finding has been replicated more recently; for example, the gifted participant Lalsingh Harribance was misinformed that all trials were GESP when in fact alternate trials were clairvoyant. He scored significantly above chance on the former task but close to chance on the latter (Klein, 1972). (It should be noted, however, that Harribance was able to score above chance on clairvoyance tasks at other times when accurately briefed.) Bender (1970) similarly reported an abrupt drop in performance following an unannounced switch from GESP to clairvoyance. Schmeidler (1961) found suggestive support for better performance on GESP trials compared with clairvoyance trials, and Kreitler and Kreitler (1972) found that percipients who had to identify letters that were projected subliminally tended to perform better on trials for which an agent was attempting to transmit the correct letter. However, Lantz, Luke, and May (1994) described a nonganzfeld free-response ESP experiment with five "experienced receivers" (who had all produced significant effects in previous research) in which performance was better in the no-sender condition than with an agent, although the difference was not significant.

Senders and the Ganzfeld

In terms of sender effects within the ganzfeld paradigm, it is worth noting Honorton's (1995) meta-analysis of differences in sender and no-sender conditions. This database consisted of 73 studies, of which 61 used a sender, giving a mean effect size [ES] of 0.17 (the probability of the deviation of the combined outcome of the studies from MCE was 6x[10.sup.-9]) and 12 studies that did not (mean ES = 0.10, p = .095). The difference between the two conditions was not significant (ES = .023, p =. 137), but when the comparison was restricted to a subset of five investigators who contributed to both the sender and no-sender conditions to allow a more direct comparison, Honorton found that sender studies were significantly superior to no-sender studies (ES = .083, p = .0007).

To our knowledge, seven Ganzfeld studies have directly compared sender and no-sender conditions within the same study. In the first of these, Raburn and Manning (1977) manipulated both the actual presence of an agent and also the participant's information about the same, adopting a 2x2 design. Performance on trials when there was a sender was significantly superior to those trials when there was no sender, but also trials when participants believed there was a sender (whether or not a sender was in fact present) gave better scoring than when they believed the session to be a test of clairvoyance. This suggests that there may be evidence for an actual sender effect and also for a psychological sender effect. We are not aware of any attempts to exactly replicate this interesting finding, which we feel merits further, more detailed investigation.

Dunne, Warnock, and Bisaha (1977) described a single-participant study in which the ganzfeld stimulation period was divided into 10 min during which the sender remained blind to the target and a further 5 min when they became aware of it. Mentations for the two periods were independently judged. Only six trials were completed, but they gave rise to significant above-chance scoring for both periods. Performance improved nonsignificantly for the second period when the sender was aware of the target, but this may have been a function of greater absorption into the ganzfeld state.

Milton (1988-9) briefly described an unpublished ganzfeld study by Sargent, Milton, Payne, and Bennet (1982) that found scoring without an agent to be close to chance and significantly less than scoring in a GESP condition. No further details were given and may be difficult to retrieve (Milton, personal communication, 2003). In Milton's (1988-89) own study, scoring was higher with an agent than without, but the difference was not significant. The study was nonstandard in that although two of the three conditions involved a sender, on no trials did they actually see the target, which was kept sealed in an envelope. Broughton, Kanthamani, and Khilji (1989) briefly describe a ganzfeld study conducted by Kanthamani and Khilji that contrasted two clairvoyance conditions with two GESP conditions. We were unable to find a published report of this study, although Kanthamani and Palmer (1993) describe it in some detail. Kanthamani and Khilji tested 40 participants who were randomly assigned to one of four conditions; in the first of two GESP conditions, the agent concentrated on the target for only a brief time at the beginning of the sending period before becoming absorbed in other activities, so that any ESP transmission might take place at an unconscious level; the second GESP condition was more like a typical ganzfeld session, as the sender attempted to send actively throughout the 30-min sending period. In the two clairvoyance conditions the sealed target was either kept in the sender's room or was left untouched in a filing cabinet that held the target sets. Overall scoring was above mean chance expectation (30%) and was highest for the "unconscious sending" condition, although none of the condition comparisons achieved significance.

Williams, Roe, Upchurch, and Lawrence (1994) compared three conditions in which there was alternatively no sender, one sender, or two senders. Rather than manipulate expectancy by misinforming participants on some trials, Williams et al. attempted to separate out the psychological effects of knowing that there was a sender by keeping the receiver and experimenter blind to the condition, which was randomly determined by a computer during each trial. Unfortunately, the study resulted in overall psi missing, so no firm conclusions could be drawn about differences between conditions. It should perhaps be noted, however, that no hits at all were registered in the 12 no-sender trials, and a post hoc contrast analysis of the degree of superiority of the sender conditions over the no-sender condition gave rise to a suggestive z score of 1.51 (p = .065). Morris et al. (1995) also considered three conditions, but here they consisted of a no-sender condition with the receiver and experimenter blind, a sender condition with the receiver and experimenter blind, and a sender condition in which the receiver and experimenter were not blind. They achieved an overall hit rate of 33%, giving rise to an effect size (Cohen's h) of 0.18. Morris et al. reported no significant differences between conditions, although it is interesting to note that an analysis of sums of ranks (Table 4, p. 252) would yield z scores of 1.028, 0.712 and 0.237 for the informed sender condition, uninformed sender condition, and uninformed no sender conditions, respectively, which is in the direction suggested by Raburn and Manning (1977). They also found post hoc evidence for an experimenter effect, with one researcher responsible for the overall above-chance scoring. Given that participants were allocated at random to conditions it is possible that this particularly conducive experimenter may have run more sessions in some conditions than others, which could serve to obscure any actual condition differences. In summary, all seven ganzfeld studies that directly compared sender and no-sender conditions within the same study have reported better performance when there was a sender compared with when there was not, significantly so for two studies.

Sender Variables as Covariates of Psi Performance

The importance or otherwise of the sender could be further clarified if variables associated with them could be seen to covary with ESP success at a particular task. To date, research has concentrated on the level of acquaintance between agent and percipient (see Carpenter, 1977, for a review). Schmeidler (1961) reported some success in attempting to predict the performance of agent-percipient pairs on a GESP trial according to "compatibility" estimates based on Rorschach responses, and Honorton et al. (1990) noted an improvement in the hit rate of participants who brought in their own senders as opposed to those who had lab personnel assigned to be their sender, suggesting that the nature of the relationship may be an important factor. However, this was not replicated in later work (Bern & Honorton, 1994). Although these suggest that the agent-percipient relationship can act as a moderator variable for the generation of above-chance results, this again may simply be a psychological factor because the participant knew who would be acting as sender. Few studies have considered the personality of the sender, which may offer a more direct measure of any true sender effect (cf. Roe, Ali, & McKenzie, 2001).

Given that the role of the sender in ganzfeld trials is thus far from clear, it would seem to be worthwhile to consider whether certain personality dimensions associated with the sender have any impact upon success. In this study we also had an opportunity to attempt to replicate the most promising correlates of ganzfeld ESP performance, which according to Bem and Honorton (1994) include prior belief and, for novice (first-time) participants, reported personal psi experiences, involvement with meditation or other mental disciplines, and extraversion. It will be interesting to see if any of these putative relationships also hold for senders in ganzfeld ESP studies. Bern and Honorton (1994) did report that high scorers on the Feeling and Perception dimensions of the Myers-Briggs Type Indicator (MBTI) may also perform better, but this claim has been queried (Milton & Wiseman, 1999), and we do not regard the MBTI as a reliable personality measure (see Roe, Davey, & Stevens, 2003), and so did not include it here. Thus our planned predictions were:

1. Irrespective of condition, participants will award a similarity rating to the target that is higher than the average rating for the three dummy clips, expressed as a deviation of the z score from 0.

2. Z scores for target ratings will be higher for actual sender trials than for actual no sender trials.

3. Z scores for target ratings will be higher for trials in which a sender is expected than for trials in which a sender is not expected.

4. There will be an interaction between sender status (present/ absent) and receiver expectancy (that a sender would be present or absent) upon z scores for target ratings.

We also planned to conduct exploratory analyses to consider relationships between z scores for target ratings and measures of prior belief, reported personal psi experiences, involvement with meditation or other mental disciplines, extraversion, and creativity.



This study adopted a 2x2 factorial experimental design in which the variables of sender status (sender present, sender absent) and receiver's knowledge of the sender status (given true information, given false information) were manipulated. The dependent variable was prespecified as the z score of the target clip's similarity rating. A series of four pilot sessions and 40 trials was planned. (1) Because the experimenter for any particular trial had to remain blind to the experimental condition, the condition was randomly determined by the computer program so that it was not possible to ensure exactly equal numbers of trials in each of the four conditions.

Apparatus and Materials

This study used an automated ganzfeld computer system developed by Paul Stevens and written in Microsoft Visual Basic v5 that presented video material via the API for Media Player v7. Video clips are stored digitally as MPEG files, labelled la, 1b, 1c, and so on. Three separate monitors for the experimenter, sender, and receiver are controlled by the experimenter PC via separate video cards, which prevents video leakage. Security measures within the program lock the experimenter out of the system completely during a session so that it is not possible to switch to another application or access the computer except by aborting the session. Audio signals are split into left and right channels for sender and experimenter/receiver, respectively, so that it should not be possible for audio leakage to occur.

The target set consisted of 116 one-min-long digital video clips arranged in 29 sets of 4. These had mainly been produced at University College Northampton (UCN), drawn from popular television programmes and commercial films, although some had been taken from the pool previously used at Edinburgh. Copies of the target pool are available on CD from the first author on request. Randomisation was achieved using the Visual Basic pseudorandom algorithm (rnd), having been seeded using the timer at the start of the program ("Randomize Timer"). Once the "Start" button was pressed, the computer first selected a target set, then selected 1 of the 4 clips within that set. The order of presentation of the 4 clips at judging was similarly randomised.

All trials were completed using specialist facilities in the Psychology Building at UCN. The receiver room is sound attenuated and is separated from a public corridor by two lockable doors. The sender's and receiver's rooms are separated by approximately 38 m. The room layout is depicted in Figure 1. A security camera is located outside the sender's room so that any activity there can be monitored by the experimenter and automatically video recorded.

The Participant Information Form (PIF) is a 55-item measure that was constructed for general use with parapsychological research at UCN and includes questions concerning biographical and contact details (11 items); religious and parapsychological background (5 items); computer experience (2 items) ; practice of mental/physical disciplines (2 items); belief in luck (2 items); clumsiness and punctuality (2 items); competitiveness (1 item); absorption (2 items); sleep and dreams (4 items); imagination and fantasy-proneness (3 items); creativity (2 items); and physical and mental health (1 item). The remaining items relate specifically to knowledge, belief and experience of anomalous phenomena, including telepathy, clairvoyance, precognition, psychokinesis, "communication with the dead," and out of body experiences (18 items); and hypnagogic/hypnopompic experience in a range of modalities (10 items). The form concludes with an open question inviting descriptions of personal anomalous sleep-related experiences. Copies of all in-house measures are available from the first author on request.

Participants also completed the short extraversion and neuroticism subscales of the EPQ-R (Eysenck, Eysenck, & Barrett, 1985). Each subscale has 24 items with a dichotomous yes/no response format. Although Palmer (1977) has noted that Eysenck's measure did not predict forced-choice performance so reliably as other extraversion measures that he reviewed, it was preferred here because, as Palmer noted, it shows a clearer differentiation from the personality dimension Neuroticism, and because of its general psychometric properties (Kline, 1993, pp. 452-3, describes it as having highly satisfactory reliability and factor analytic validity that is "impeccable"). Honorton, Ferrari, and Bern (1998) noted a significant relationship between extraversion and free-response ESP performance and that the effect was sufficiently robust to be evident across a range of different measures of extraversion.

The 18-item Australian Sheep-Goat Scale (ASGS, Thalbourne & Delin, 1993), with a 5-point Likert scale ranging from "strongly agree" to "strongly disagree," was also completed.

Post-ganzfeld measures included a Sender Strategy Questionnaire that asked about the type of sending strategies used; whether this was active or passive, holistic or atomistic, focused on target clip or on the receiver, realistic or associative, and continuous or episodic. A Receiver Questionnaire asked about the receivers' experiences, instructing them to reflect on their state of consciousness and to identify particularly meaningful or unexpected elements among their impressions.


An opportunity sampling method was used to draw 40 pairs of participants (mean age of senders = 29.7 [range = 18 - 60], 14 males and 26 females; mean age of receivers = 28.0 [range = 18 - 60], 15 males and 25 females). These mainly consisted of friends and acquaintances of the experimenters, and staff and students at UCN, although attempts were made to recruit participants from the wider community using posters and media appeals. Participants were not selected on the basis of prior belief or experiences, nor personality and attitudinal dimensions that might predict psi performance (although such variables were measured). Each participant provided his or her own sender. Lab personnel did not serve as participants. The mean ASGS belief score for receivers in this sample was 44.5 (SD = 10.4) and for senders it was 46.6 (11.27). These figures are somewhat below the theoretical mean for the scale (M = 54), suggesting that the members of the sample were moderately skeptical. Among this sample, five senders and five receivers had previously participated in formal parapsychological studies, but all were ganzfeld novices; 17 senders and 12 receivers had previously participated in casual testing; 17 senders and 19 receivers had practised a mental discipline such as meditation; and 12 senders and 15 receivers had practised a physical or spiritual regimen such as yoga or tai chi. All three authors acted as experimenters in the running of trials, with NH conducting 17 trials, CR 13 trials, and SS 10 trials. Trials were allocated to researchers on the basis of their availability at times agreed upon with participants as being most convenient for them.


Potential participants were sent an information sheet illustrated with photographs that described the nature of the study. This provided a rationale for the ganzfeld paradigm and outlined the stages of the experimental procedure, focusing on the roles of the experimenter, sender, and receiver. Thus participants were made fully aware of all aspects of the experiment, including that the sender may not be required for the trial and in that event would be asked to complete an alternate task--but not about the minor deception that may have been involved--so that those who were not comfortable with the procedure had the opportunity to withdraw from the study. Prior to the trial both senders and receivers completed a battery of measures. A video player was set to record the input from the security video camera as the experimenter prepared for the session and continued recording until after the session was over. Participants were greeted on arrival and escorted to a reception room that had been specially prepared with comfortable chairs, a coffee table, rugs, and curtains to make participants feel as comfortable and relaxed as possible prior to the trial. Experimenters encouraged an informal and positive atmosphere, discussing the procedure and answering any questions arising while sharing refreshments. Briefing included a description of the sender and no-sender conditions so that participants were reminded that there might not be a sender on their particular trial, in which case the nominal sender would complete an alternative task. (2) Participants were free to decide among themselves who would be sender and who receiver. (3) Participants were then given a guided tour of the facility as the roles of sender and receiver were again explained.

With the assistance of the sender, the experimenter prepared the receiver for the ganzfeld and wished him/her success. Receivers were seated in a reclining chair and encouraged to relax. They were invited to remove their shoes and cover themselves with a blanket if desired. Receivers wore headphones with a microphone attached through which they could communicate with the experimenter and be heard by the sender. Halved ping-pong balls were placed over their eyes and held secure with micropore tape. A red light was shone on the receiver's face, positioned immediately in front of him/her at a comfortable distance (typically 1 m). Receivers were then locked in the room (unless they were uncomfortable with this) and senders were guided back to their room. At this point senders were informed of the possibility that the experimenter and receiver may be misinformed as to the true nature of the trial (e.g., be told that it was a no-sender trial when in fact there would be a sender) to enable us to look at the effects of expectancy.

Once the experimenter had returned to the experimenter's room and established contact with the receiver, the trial commenced. Receivers began by listening to and following a series of progressive relaxation instructions. At the end of the relaxation period, the computer program determined whether the session would be a sender or no-sender trial and whether the experimenter and receiver would be accurately or falsely briefed. The receiver and experimenter heard a prerecorded message indicating whether or not the trial would involve a sender. At this stage receivers were not aware that the computer briefing might be false. For no-sender trials senders received an on-screen message asking them to remove their headphones and move over to the other computer in the sender's room to complete an alternative task. The monitor in the sender's room did not show the target clip during no-sender trials. For sender trials, senders watched a randomly selected video clip that was played 15 times with 1-min intervals between plays. Drawing materials were provided for them should they have wished to sketch elements of the target clip during these "quiet" periods. During this 30-min mentation period receivers listened to white noise being played through their headphones and reported on any impressions or sensations that they experienced. The experimenter listened to the receiver's mentation via headphones from the experimenter's room and took notes. In the sender condition, senders could also hear any comments made by the receiver during the mentation period.

Following the mentation period, the experimenter read the receiver's mentation back to him/her and asked if there was anything further that he/she would like to add or elaborate upon. Receivers were then asked a series of questions regarding their experiences in the ganzfeld. Simultaneously, senders completed a questionnaire concerning their interaction with the target and sending strategies employed. At the judging stage receivers were asked to remove their eye-shields but were encouraged to remain in a relaxed state as they watched four video clips, giving each one a percentage similarity rating. After viewing all four clips, they were able to view any or all of them as many times as they wished and to alter their ratings if necessary. Senders were able to listen to the clip soundtracks and the interaction between the receiver and experimenter during the judging stage, but did not view the dummy clips. (4) Once receivers were satisfied with their ratings, these were confirmed and saved as a permanent record. Only after the data were saved was the target clip revealed and replayed. The sender, experimenter, and receiver then convened for a discussion and debriefing session in the receiver's room. Receivers were only made aware of the possibility that they had been misinformed concerning the experimental condition during debrief, at which stage they were free to withdraw their data from the study. None chose to do so. A copy of the trial data record was printed and signed by all parties to confirm the details of the session.


Our primary psi measure was prespecified as the z score of the target clip's similarity rating. However, for completeness and to facilitate future meta-analyses, Table la gives the number of direct hits and sum-of-ranks data for sender and no-sender conditions. Note that sums of ranks for sender and no-sender trials cannot be directly compared because there were 23 sender trials and only 17 no-sender trials. Nevertheless, it can be seen that based upon sums of ranks, participants performed slightly worse than chance expectation in the sender condition and slightly better than chance in the no-sender condition. Overall performance is well within chance expectation.

Table 1b gives the number of direct hits and sum-of-ranks data for the receiver's expectancy that there would or would not be a sender for his/her session. Based upon ranks, participants did seem to perform slightly worse than chance expectation in both conditions, although the hit rate for sender expected is a little higher than MCE of 25%.

To assess our first prediction, that irrespective of condition participants would award a similarity rating to the target that was higher than the average rating for the three dummy clips, z scores were calculated. The distribution of z scores is given in Figure 2. We can see from this that the hypothesis is not supported. The overall mean z score was actually slightly negative (mean z = - .10, SD = .95) but did not differ significantly from 0, one-sample t(39) = -.66, p = .52, two-tailed, (5) ES(r) = -0.10.


Considering Covariation of Performance Across Conditions

To assess whether performance was affected by the presence or absence of a sender and by the receiver's expectancy of whether a sender was actually present, target rating z scores for each of the four conditions are summarised in Table 2. We can see from this that the only overall positive value (i.e., where the target is rated higher, on average, than the decoys) occurs where there was no sender but participants were misinformed that there was a sender, and worst performance was where participants believed there wasn't a sender when in fact there was. Taken together, these suggest that receiver expectancy is more important than whether or not a sender was actually present. However, the mean differences are relatively small in comparison to within-group variance, and there is no overall difference between sender and no-sender conditions, Mann-Whitney z (N = 40) = -0.479, p = .632 (two-tailed), or between receiver expectancy that a sender would be present or absent, Mann-Whitney z (N = 40) = -0.299, p = .765 (two-tailed). There is no evidence of an interaction between actual sender role and receiver expectancy. Given the small effect sizes and the relatively small sample size, statistical power is low.

Covariation of Performance With Personality and Attitude Measures

In this study we also planned to consider the most promising correlates of ganzfeld ESP performance as identified by Bem and Honorton (1994). Measures of prior belief, reported personal psi experiences, involvement with meditation or other mental disciplines, extraversion, and creativity, were correlated with success at the ganzfeld task. These analyses are given in Table 3. We can see that none of the correlations is significant, offering only weak support for these variables as predictors of performance. (6) We might note that for both senders and receivers there is a modest positive correlation between performance and expectancy of success, [r.sub.s] (N = 20) = .188, and [r.sub.s] (N = 39) = .248, respectively. Although clearly nonsignificant, this compares favourably with Lawrence's (1993) estimate of the mean sheep-goat effect (mean r = .029). Interestingly, there is a modest positive correlation, [r.sub.s] (N = 39) = .219, between performance and receivers' having practised a mental discipline, which is not found for senders. For receivers' creativity there is a significant negative correlation, [r.sub.s] (N = 39) = -.392, which would seem to weaken the case for creativity as a predictor of ganzfeld success (contra Roe et al., 2001). However, the case for creativity is primarily based on creative populations performing better than noncreative ones, and where measures of creativity have been correlated with performance they have been relatively disappointing (see, e.g., Dalton, 1997; Morris, Cunningham, McAlpine, & Taylor, 1993; Schlitz & Honorton, 1992).

Post hoc Analysis of Magnitude of Effects

We were interested to note that the distribution shown in Figure 2 appears to be somewhat bimodal, suggesting that the target clip is either rated relatively high or relatively low compared with decoys. This brings to mind Palmer's (1997) interaction model of psi (see Eysenck & Sargent, 1993, pp. 91-93; Palmer, 1997) that treats the magnitude and direction of any psi effect as distinct. Within this model, Palmer (unpub., p. 3) argues that some factors may be associated with the magnitude of an effect (deviation from chance expectation) irrespective of its direction (above or below chance). Palmer has proposed that potential correlates of magnitude include a constellation of cognitive style factors that affect "spontaneity" (such as response set, state of consciousness, and creativity) as well as motivation to take and do "well" in the test (i.e., to confirm the participant's expectations whether this entails scoring positively or negatively). Palmer identified participant comfort as the principal factor that affects the direction of an effect. Variables that he associated with comfort include participant extraversion and (low) neuroticism, participant belief (where that concurred with the experimenter's declared belief), and experimenter variables such as friendliness. Two of the present authors have recently reported on a study that might offer circumstantial support for the model (Roe, Sherwood, Luke, & Farrell, 2002). We speculated in the current study that the magnitude of deviation from chance expectation might be affected by the experimental condition that participants completed; in other words, some conditions may be more psi-conducive than others, but for some individuals this may lead to positive scoring and for others to negative scoring. We therefore also looked at performance in terms of the mean absolute z score for the ratings.

Table 4 summarises the magnitude of effect in terms of absolute z scores, such that higher scores indicate that target ratings deviated more markedly from the average rating for the decoy clips (either positively of negatively) and low scores indicate that target ratings were similar to the average rating for decoys. Note that the overall pattern now conforms (albeit weakly) to the trends predicted, with least deviation from the mean where participants were accurately informed that there would be no sender and greatest deviation where they were accurately told that there would be a sender. Deviations are somewhat larger where the receiver believed there would be a sender even when there wasn't, compared to trials where they believed there would not be a sender when in fact there was. The effects are fairly small, however, and, given the low statistical power, there is no overall significant difference between sender and no-sender conditions, Mann-Whitney z (N = 40) = -1.135, p = .256 (two-tailed), or between receiver expectancy that a sender will be present or absent, Mann-Whitney z (N = 40) = -1.577, p = .115 (two-tailed), though the latter difference is suggestive of a greater effect when a sender is expected. There is no evidence of an interaction between actual sender role and receiver expectancy. Receiver creativity correlates positively with absolute z score, r (N = 39) = .295, p = .068 (two-tailed), which is consistent with Palmer's interaction model. None of the other correlations comes close to significance.


Overall, the results suggest that at least in the ganzfeld context, receiver expectancy might be more important than whether or not there is a sender actually present, although the small effect sizes and low statistical power, and the lack of apparent psi effects in the study mean that this remains uncertain. The presence/absence and expectation of a sender might have a greater influence on the magnitude of any psi effects rather than the direction. The results do not replicate Raburn and Manning's (1977) finding that sender trials were significantly better than no-sender trials, though the results do confirm their trend that trials in which a sender was expected were more successful than those in which a sender was not expected, particularly when considering participants' absolute rather than their directional rating deviations. It might be useful for future research to consider what the role of the sender means to receivers in order to try to tease out the nature of any possible expectancy effect. The results from this study also suggest that expectations of success in the experiment on the part of both senders and receivers are moderately associated with subsequent success, and one should note that the sample was moderately skeptical in terms of their paranormal beliefs as measured by the ASGS scale.

The lack of association between sender variables and task performance is disappointing, but perhaps not surprising given the small number of sender trials. However, we plan to examine the same relationships again, using the same measures, once we have obtained data from two further studies. We also plan to look at the different sending strategies reported by our senders to see if some are more successful than others. Perhaps there might be a difference between active versus passive strategies; for example, it is interesting to note that Kanthamani and Khilji (as cited in Kanthamani & Palmer, 1993) found that the use of subliminal sending in the ganzfeld resulted in suggestive psi-missing. We also plan to continue our investigation of the different roles within the ganzfeld context by looking at the experimenter effect in terms of his/her interactions with participants, and participants' perceptions of it, before the ganzfeld session begins to see whether these variables are related to subsequent task performance. In future studies we also intend to recruit more participants with previous psi experiences from New Age rather than student populations, given Parker, Grams, and Pettersson's (1998) finding that the former populations performed better than the latter in a ganzfeld task.


We would like to thank the Perrott-Warrick Fund for their kind support of this project. An earlier version of this paper was presented in 2003 at the Parapsychological Association 46th Annual Convention, Vancouver.


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The Parapsychological Association 37th Annual Convention, 429-438.

Centre for the Study of Anomalous Psychological Processes

Division of Psychology

University College Northampton

Boughton Green Road

Northampton NN2 7AL, UK


(1.) Previously we had stated that we planned to run 60 trials in this study (Roe & Sherwood, 2001). Because of time constraints, this was revised to 40 trials in the final planning stage, prior to conducting any pilot sessions.

(2.) This was a computerised PK task in which participants were to attempt to affect the outcome of each of a series of greyhound races in which the movement of greyhounds was determined by an REG. This task was chosen because it was thought to be engaging but rather simple thematically (obviously, no target clip involved greyhounds or races) but still involved a parapsychological topic so those "unused" senders would feel that they had actively participated in a parapsychology study.

(3.) There were no significant differences between senders and receivers on measures of general paranormal belief, expectancy of success, experience of paranormal phenomena, practice of a mental discipline, extraversion, or creativity (all p > .05).

(4.) Despite being instructed otherwise, on two or three no-sender trials the sender did listen in to the judging phase after having completed the alternative task. Of course, at this stage they were still blind to the nature of the target.

(5.) This prediction was originally one-tailed, but in the opposite direction to that found. The two-tailed probability is given for information only.

(6.) Univariate analyses are rather simplistic, and ideally we would go on to conduct multivariate analyses to further consider the possible interaction between variables. With a sample of only 23 sender trials, this would not be appropriate here, but it is planned for the end of the project when more data will be available.


 1 2 3

Sender 6 (26.1 %) 3 (13.0 %) 5 (21.7 %)
No sender 4 (23.5 %) 8 (47.1 %) 0 (00.0 %)
Overall 10 (25.0%) 11 (27.5 %) 5 (12.5 %)



Sender 9 (39.1 %) 63 57.5
No sender 5 (29.4 %) 40 42.5
Overall 14 (35.0 %) 103 100



 1 2 3

Sender expected 6 (33.3%) 3 (16.7%) 2 (11.1%)
No send. Expected 4 (18.2%) 8 (36.4%) 3 (13.6%)
Overall 10 (25.0%) 11 (27.5%) 5 (12.5%)



Sender expected 7 (38.9%) 46 45
No send. Expected 7 (31.8%) 57 55
Overall 14 (35.0%) 103 100


 Sender role

 Sender No sender
 M SD Count M SD Count Mean

 Sender -.09 1.11 9 .03 1.08 9 -.03
 No -.21 .97 14 -.07 .74 8 -.16
Column -.16 1.00 -.01 .91


 Receiver Sender
 (Max N = 40) (Max N = 23)

ASGS belief score .013 .169
 (.939) (.464)

Believe able to .248 .188
demonstrate psi in a (.127) (.428)
controlled experiment

Prior experience of the .094 .090
paranormal (.573) (.699)

Practised a mental .219 (.110)
discipline (.181) (.634)

Extraversion (.033) (.045)
 (.847) (.847)

Creative (.392) (.127)
 (.014) (.582)

Note. Reported significance levels may differ between receiver and
sender correlations of the same magnitude as the latter consists
only of those trials on which a sender was actively involved.


 Sender role

 Sender No sender
 M SD Count M SD Count Mean

Receiver Sender 1.00 .36 9 .95 .40 9 .97
 No .86 .42 14 .57 .43 8 .75
Column .92 .39 .77 .44
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Title Annotation:general extrasensory perception
Author:Roe, Chris A.; Sherwood, Simon J.; Holt, Nicola J.
Publication:The Journal of Parapsychology
Geographic Code:1USA
Date:Sep 22, 2004
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