Debating Psychic Experience: Human Potential or Human Illusion?
Article Type: Book review
Subject: Books (Book reviews)
Author: Parker, Adrian
Pub Date: 03/22/2011
Publication: Name: The Journal of Parapsychology Publisher: Parapsychology Press Audience: Academic Format: Magazine/Journal Subject: Psychology and mental health Copyright: COPYRIGHT 2011 Parapsychology Press ISSN: 0022-3387
Issue: Date: Spring, 2011 Source Volume: 75 Source Issue: 1
Topic: NamedWork: Debating Psychic Experience: Human Potential or Human Illusion? (Nonfiction work)
Persons: Reviewee: Krippner, Stanley; Friedman, Harris L.
Accession Number: 263250467
Full Text: DEBATING PSYCHIC EXPERIENCE: HUMAN POTENTIAL OR HUMAN ILLUSION? edited by Stanley Krippner and Harris L. Friedman. Santa Barbara, CA: Praeger, 2010. $44.95 (hardback). Pp. 236. ISBN 978-0-31339-261-0.

Whatever your prior view of the debate over psi, this book is an absolute requirement if you wish to be kept updated. The current status of differing views on scientific arguments for and against the existence of psychic phenomena is debated in this volume. The only risk is that it is easy to choose whom to believe and thereby find your own personal biases confirmed. On the other hand, should you be open-minded and hoping for a resolution, you may at first be disappointed with the stagnation. Nevertheless, I am convinced that the seeds for synthesis are actually there, although hard to find. Debates are actually not the best way of encouraging progress in a controversial subject. Inevitably, even without our biases, it is the most persuasive and eloquent debaters who are deemed the winners, whereas in this case the only winner should be science. It becomes, then, this reviewer's difficult task to try to bring fairness back to the forefront, but ultimately in a case like this impartiality is an ambitious goal. Even so, I prefer to think that I share the attitude of most serious researchers in this area: If I am being fooled, I want the critic to tell me how.

The book contains chapters written by some of the most vocal experts in this field. Dean Radin and Chris Carter are the proponents presenting the case for psi having now been established, while the critics Ray Hyman, Jim Alcock, and Christopher French take the opposing view. I am going to allow my own bias to immediately discount the chapter by Michael Shermer, the editor of The Skeptic, on the grounds that it is not science; rather, it is based mainly on his personal experiences with tarot readings, accompanied by tales provided to him by the maverick English journalist Jon Ronsson (producer of the film The Men Who Stare at Goats). The chapter does fulfill a function--as a shop-window example of what the proponents in the book complain about: arrogance, in this case assuming psychical researchers know nothing about cold reading.

I shall not attempt a summary and evaluation of each chapter, because this is more than adequately provided by the editors in the form of their own introduction. Instead, I will look at the main issues per se. Harvard psychiatrist Ruth Richards provides a fair-minded introduction to the topic, after which the major contributors present their cases. The contributors then all come back for round two, rebuttals in which they evaluate their opponents' chapters. Finally, epilogues are provided by the critic Richard Wiseman, the proponent Stephan Schwartz, and the editors themselves.

The confrontation gets heated and personal at times. Frustrated at the lack of appreciation for the enormous effort they expend to fulfill the critics' demands with the limited support available, the proponents begin to see the critics as outmoded die-hard believers in materialism. They are seen as being left behind by recent developments in quantum physics and consciousness studies. Consequently, several of the proponents label the critics now as "psi deniers," in much the same class as consciousness deniers and climate change deniers. Whatever one thinks about this labeling, it needs to be said that while much has been written on the psychology of belief in the paranormal, very little is known about the opposing polarized disbelief. Even if it causes some offence, it is therefore of value that Carter contributes a section of his chapter under the rubric "Psychology of the Dogmatic Critic" (p. 96).

And offence it does cause. Hyman claims he has always, in his role as a member of the Committee for Scientific Inquiry and through his papers in the Skeptical Inquirer, made a distinction between his treatment of parapsychology and other paranormal claims, recognizing that the former are based on scientific procedures. He is clearly offended by the allegations of unfair treatment made particularly by Carter and Schwartz. Likewise, Alcock recoils against this treatment as "ad hominem attacks" and "reviling the messenger." Naturally, many parapsychologists who have been subject to vile attacks might relish this, but Hyman and Alcock can hardly be held directly responsible for these attacks.

Hyman points out that some critics are in fact not materialists but religious--I presume he means mainly Christian. This may, however, only serve to illustrate that there is often an unholy alliance between orthodox religion and orthodox science against what is seen by both to be pre-enlightenment pagan beliefs. As Dean Radin once remarked to me, only Jesus and saints are allowed to perform miracles.

Having realized that a resolution is far from possible, the editors suggest that a detente be declared. However, given the heated and often personal nature of some the exchanges, this seems to me to be a forlorn suggestion. The editors of the Journal of Consciousness Studies made a similar effort for a truce 8 years ago when they produced the volume Psi Wars. In lieu of this, the current editors finally find a calmer haven in which to anchor the debate, in the form of the more temperate postscripts provided by the eminent psychologist Elizabeth Loftus and by the communications expert Daniel Broderick.

But are the issues as irresolvable or even intractable as this book suggests? It may be instructive to see the debate first in a larger historical context.

A similar book entitled The Debate for and Against Psychical Belief, with chapters by academic and other contemporary experts, was published 84 years ago (Murchison, 1927). In terms of the present debate, I found it particularly relevant to read the chapter by Gardner Murphy about what impressed him personally about psi research. He was impressed by what were probably the first-ever experiments in what we now call remote viewing: These were carried out by two women, Clarissa Miles and Hermione Ramsden, with rather spectacular results. But what is just as interesting, as Murphy notes, is the importance Miles and Ramsden gave to the hypnagogic state. They regarded this state as a psi-conducive state because it represents a borderline between unconscious and conscious processes (these experiments are reviewed in Parker, 2005). So here we have already a foundation for later research. But Murphy had further prescience. He was also impressed by the quantitative experiments of Coover, Warcollier, Brugmans, and Estabrooks, and he helped set the stage for what were soon to become the classical experiments of J. B. Rhine and his coworkers. This background and his own research enabled him to put his finger on what can be seen as the source of the conflict that underlies the present debate. He writes (p. 275):

Now let's move on 60 years to 1986, when Ray Hyman reviewed the first real attempt to control some of the variables for capturing psi in the laboratory in the form of the initial series of ganzfeld experiments. Hyman became very critical, if not outright disparaging, about the possible sources of errors that he found. He complains now, looking back, that parapsychologists showed little interest in finding these flaws, but Nils Wiklund and I actually spent months doing just that (Parker & Wiklund, 1987). Nevertheless, history followed Murphy's recommendation and in one of the most constructive collaborations, not just in parapsychology but also in psychology as a whole, Honorton and Hyman (1986), after evaluating the experiments, agreed in their "joint communique" on the requirements for improvement. This led to the successful autoganzfeld series and the publication by Bem and Honorton (1994) in Psychological Bulletin.

Much of this history, as reflected in this article and its immediate successors, still forms part of the current debate, and some of the same issues that appeared then are repeated here in Hyman's chapter "Parapsychology's Achilles Heel." Hyman agrees that the effect is "too large and consistent to be discounted as statistical flukes" but he presents two major criticisms he sees as damning. He objects that the effect found in the later experiments did not replicate the original findings with static (picture card) targets, because it was shown only to be present with dynamic targets. Equally damning is that the psi effect was limited to only a few experimenters.

The first objection seems now adequately answered in the rebuttal chapter by Carter, who points out that included among the static targets was a set of halfway dynamic targets--View Master stereoscopic slides. As these gave significantly better results than the purely static targets, modern dynamic targets in the form of movie clips can be seen as an extension-replication of these View Master slides. But leaving Carter's point aside, surely common sense says one should look at the context. Participants in psychology experiments are not like objects in physics experiments. In psychology, the use of vintage equipment in an experiment is bound to influence the participant's expectancies. Art prints are today no longer as engaging as they once were to students. I have found that even showing the same film clip to students on an old video player, compared to showing it as DVD, produces markedly different reactions. Using overheads instead of a power-point presentation is guaranteed to provoke a groan from today's students.

The second objection, concerning the experimenter effect, is now the major issue for Hyman. Indeed, he writes in his rebuttal (p. 146): "I now believe that my original critique of the ganzfeld experiments, as well as my unpublished follow-up, were misguided.... I should have made it clear that the striking experimenter effects in the database indicated a failure to replicate."

These internal effects are claimed by Hyman to have violated the basic requirement for homogeneity and rendered the meta-analyses invalid. I would disagree with Hyman on the homogeneity issue (and even checked this with an expert in meta-analysis for pharmacological research). Meta-analysis is used to discover hidden effects that may not be apparent in one set of data. When differences are seen across numerous experiments, they are nearly always found to be the effect of some specific variables; indeed, it is the purpose of meta-analysis to identify these. The effects in this case, of the type of target and of the experimenter, are of course important and can guide further research. To then argue that this invalidates the findings, Hyman is not so much shifting the goal posts as turning them round such that the net now faces inwards.

Of course, it is important to know just how many successful experimenters were responsible for the effect, and Hyman is right to raise this issue. It was particularly poignant in the first meta-analysis, when there were only a very few successful experimenters and the questionable work of Carl Sargent was in the forefront. Carter, in his rebuttal, provides the reader with a table showing the later replications, but the data in his table still contain only a few successful experimenters, namely, Dick Bierman, Kathy Dalton, and myself.

A much more promising updated picture is provided in a publication by Lance Storm and coworkers in Psychological Bulletin (Storm, Tressoldi, & Di Risio, 2010). This important paper was published too recently to be discussed in the present book. Ironically, given its importance, it received little interest in the media compared to Daryl Bem's (2011) paper "Feeling the Future," to which the critics seem to react as if it were the first-ever successful series of ESP experiments carried out and published in a mainstream journal.

As well as presenting meta-analyses suggesting that the work on psi and altered states gives, in general, replicable and highly significant effect sizes, Storm et al. (2010) updated the ganzfeld meta-analysis from 1992 to 2008 and found a further 30 studies. The overall hit rate and effect size were highly significant and showed superiority for participants selected for psychic experiences and/or meditation practices. Most important, however, is that the number of experimenter/laboratory groups was seven, and there were no significant differences in effect size between the groups.

Of course, it could still be argued that even the contemporary ganzfeld experiments have potential flaws; what occurs is a replication of errors rather than psi. To my knowledge, there is no recent analysis of the quality of the replications in terms of potential flaws in relation to the outcomes. Surprisingly, critics do not seem to have picked up on this.

An objection related to participant selection is raised by Richard Wiseman in his chapter "Heads I Win, Tails You Lose." It concerns how a ganzfeld experiment is defined. Although the early work did not often specify selection criteria, one meta-analysis did find that selection criteria were important. Wiseman objects to how in a reanalysis of the nonsignificant results of the smaller meta-analysis by Milton and Wiseman (1999), Bem, Palmer, and Broughton (2001) used judges to re-evaluate the data but also defined subject selection criteria. By defining the ganzfeld experiments this way they were able to find an effect size within the expected range.

What seems clear from the debate is that the ganzfeld does not work consistently enough to satisfy the critic. The fact that it does not succeed with all participants should not, however, present an insurmountable problem. The effect size is such that sample sizes must be larger than 100 participants to favor significance. Having come this far causes Carter, Schwartz, and Radin to argue in their chapters that parapsychology has implicitly fulfilled all the requirements for replication and that the critics are an "Antique Road Show" (the title of Schwartz's chapter) showing "Persistent Denial" (the title of Carter's chapter). Hyman would still maintain there is something weird afoot in the form of the experimenter effect, and he may just be right. Hyman requires that for parapsychology to be a true science it should be able to specify how to get positive results, and this inconsistency and lack of prediction is its "Achilles Heel"--part of his chapter title.

A general recipe for success can be and has indeed been proposed (Parker, 2000b). Yet, to be fair to Hyman, it has not been found to work all the time. Anneli Goulding, as part of her doctoral thesis at Gothenburg, followed this recipe and found a significant negative effect using the conventional analysis (Goulding, Westerlund, Parker, & Wackermann, 2004). In the most recent study, Bjorn Sjoden and I used a complicated and cognitively demanding series of comparisons between subliminal primed and nonprimed targets. This time we obtained no psi effect whatsoever (Parker & Sjoden, 2010). Nevertheless, what I still find remarkable in these last results is the complete absence of the so-called real-time hits that objectively earmarked our successful series. If our first results had all been due to artifacts, then these artifacts should still be present, causing us to subjectively validate the same spurious real-time correspondences: This time, neither the hits nor the misses showed this. But even leaving these hits aside, what strongly suggested to us that we were dealing with apparently causal effects in the earlier studies was what happened when I surreptitiously, without telling anyone involved, suddenly introduced a change in procedure. In this case, I unexpectedly brought a friend of the receiver into the sender's room to take over the role of sender. This action immediately evoked the following remark from the receiver, which was recorded as a real-time match: "Where have you been?"

What is the explanation then for the inconsistency of replication? Hyman refers to what he sees as the more esoteric explanations of Jim Kennedy (2003) in terms of a cosmic "intelligent mischief" or of Walter von Lucadou (2001) in terms of a conservation principle in natural law that interferes with psi, so as to make it impossible to capture it in the laboratory. Hyman uses these notions to discredit the field as too esoteric. But less farout explanations may be possible and even plausible, even if they might need to be extended to include the experimenter's own psi. It is surely the ambience of the experiment that is crucial and difficult to replicate. In the case of the above-mentioned Goulding at al. (2004) experiment, there had been a strong dispute at the time over whether the participants themselves or a judge should carry out the evaluation, and this may have spoiled the positive atmosphere. In the case of our last experiment, the shortage of funding and the radical and unexpected change in the research climate in Sweden meant that I frankly no longer had the spirit and zeal needed to obtain positive results.

Now having said that, I can almost hear my friend Alcock protesting that this is all contrived post hoc attribution. Of course he may well be right, but in a frontier field, speculation can be a valuable tool which may stimulate creativity in research. The experimenter effect is, despite Mcock's objections to its use in parapsychology, firmly established in psychology. I would also assert that there is sufficient evidence provided in the classical literature reviews of Rhea White (1976a; 1976b; 1977) to substantiate the occurrence of such effects in psi research. And if this is not enough, an excellent example of the role such factors play is one of psychology's most cherished effects, the conformity effect. This effect is actually found in Alcock's own coauthored Textbook of Social Psychology (Alcock, Carment, and Sadava, 1998).

Much of the current debate in the book centers on the ganzfeld, but Dean Radin's initial chapter presents an iconic review of the history of psychical research and parapsychology, in much the same manner that his book Entangled Minds (Radin, 2006) does. Likewise, Stephan Schwartz in his chapter attempts to place psi as a natural phenomenon in the wider context of creativity and altered states. Damien Broderick describes this in his postscript as a "nonlocal apprehension of a larger reality."

But of course the critics will have none of this. In particular, Mcock re-presents his 13 reasons for rejecting parapsychology and psychical research. Some of these reasons concern the lack of lawful relationships, of predictability, of accepted theories to integrate the area with normal science, and the speculative nature of research projects. These criticisms are obviously to some extent valid, but they are equally valid for many areas of frontier psychology, and they will remain so as long as there is virtually no funding for major research on understanding psychic phenomena. So Alcock is merely illuminating the vicious circle that he and other critics helped to create and could actually help break. Other reasons given by Alcock, such as parapsychologists' disinterest in normal explanations, are not entirely true and certainly not for me (Parker, 1999; Parker, 2000). Many parapsychologists, including myself, have taken an active interest in magic tricks; in my own case, these were actually inspired by Alcock's own skills in this area.

Alcock's only remaining reason concerns assuming causality from correlations and the role of attribution. Concerned that we derive causal explanations where there is only chance coincidence at play, he reiterates the criticism from his Psi Wars publication (Alcock, 2003) that we should "give the null hypothesis a chance." Clearly there is good reason to be skeptical about attributing psi to the claims of most spontaneous cases. On first opening this book, I was struck by the first illustration accompanying the chapter by Krippner and Friedman, which is titled "Cradle Song." I was amused by the thought that Krippner's name is derived from his Norwegian ancestry in the form of Kribbmakare, which means crib maker. The occurrence may, of course, have been intentional or coincidental, but in either case such attributions are part of normal life and may express a biological preference to seek out such meaningful relationships in our environment.

However, when these events concern parapsychology, we can actually turn to the laboratory for their validation. Parapsychology is then surely not anomalous psychology, but rather a controlled study of normal experiences that challenge our view of reality. The ganzfeld, especially the real-time version we developed at Gothenburg, is specifically designed to reproduce the contingencies for psychic experiences in the laboratory, and the causal conclusions from statistics are usually clear. It becomes then almost self-contradictory that in "giving the null hypothesis a chance," both Alcock and Hyman in their chapters appear to downgrade the value of statistics and meta-analysis in drawing conclusions about phenomena and their causal relationships in the real world.

Richard Wiseman in his chapter also refers to the history of the field in an attempt to show how researchers are constantly, as he describes it, changing ships and cherry-picking new procedures. He finds a notable quote from Gaither Pratt about how from 1882 onward a succession of practices for getting replicable results has-fallen in and out of fashion, without any tangible, replicable results. Yet one should not overly exaggerate this. Carter reproduces a table from Honorton showing that the frequent claim by critics that Rhine's work was never replicated by other psychologists is actually false. Moreover, it can be argued that the ganzfeld procedure is a natural and systematic evolution from earlier methods and findings. This is shown in the flow diagram adapted from Honorton in Parker (2005, p. 74).

Of course, Wiseman is correct that some methods seem at first to mysteriously work and then decline. But this may have to do with the ambience of the laboratory, as mentioned earlier. In his joint chapter with Harris Friedman in the book, Stanley Krippner gives us an account of such a positive ambience. It concerns the successful Maimonides series of dream telepathy experiments. The attempts he mentions to meet the criticisms were extensive, and the Maimonides work (if seen generally) has continued to enjoy consistent replication. It is noteworthy that no mention of these experiments is made by any of the critics in this book, whether it be Alcock, Hyman, Wiseman, or French.

So where are the seeds for future dialogue? French suggests breaking down the barrier between critics and proponents and concentrating on collaborating to develop a specific standard and repeatable design. But is this so easy in practice? The collaboration between French and Sheldrake on telephone telepathy experiments, which was heavily supported by the Perrott-Warrick Fund, seems to have been in all respects a dismal failure, at least as far as hands-on cooperative willingness was concerned (Skeptiko, 2009).

When I had funding available, I suggested a joint project with Jim Alcock, but his preference was to remain an armchair critic. It is evident from this book and his previous writings that he is influenced by the failure of a physicist colleague, Stan Jeffreys, to obtain positive results. However, if Carter is correct in his rebuttal, then this is no longer the case. Likewise, French denies having ever found any evidence of psi, despite the efforts of his students. Here we go again. If the recent report by Suitbert Ertel (2010) is also correct, then this is not so. Moreover, I know personally that Chris French was very impressed by the performance of the British medium Diane Lazarus. Even Wiseman, who is famous (some might say infamous) for his categorical statements of never having encountered any evidence of the paranormal, was one of the joint authors of the security setup for the successful ganzfeld experiment with Kathy Dalton (Dalton, Morris, Delanoy, Radin, Taylor, & Wiseman, 1996) and succeeded with Marilyn Schlitz (Schlitz, Wiseman, Watt, & Radin, 2006) in replicating their experimenter effect findings in two of three studies. He has also been able to follow the occasional successes of his partner, Caroline Watt (Watt & Ramakers, 2003).

It would therefore be ideal if both proponents and critics could avoid categorical statements such as there is "no scientific evidence for ESP" or "ESP experiments are consistently replicable." Indeed, considering the above, it might be considered disingenuous to continue this polarity.

It is clearly also important to maintain a dialogue. Elizabeth Loftus, who is a major figure in mainstream psychology, provides a postscript chapter where she admits being impressed by Ray Hyman's contributions, although she is a supporter of meta-analysis, which he nowadays is less than enthusiastic about. She also freely admits that replication is a problem in psychology as well as parapsychology. Naturally, her own research on false memory has led her to doubt the eyewitness reports in psychical research. These effects may not, however, be entirely in the direction that Loftus might suppose. There is some evidence that, depending on a person's belief system, extraordinary events are not exaggerated but tend instead with the passage of time to become downplayed and normalized. Obviously, this would be a fruitful area for collaboration. Having attended and received a favorable impression of the Meeting of Minds conference organized by Dean Radin, Loftus expresses a desire for future meetings. I hope her wish is fulfilled.

Given its funding, parapsychology has apparently come as far as it can as regards replication, and it has to await the solution to the critics' other major objection: a theory integrating it with normal science. This was also the view of one of the great optimists in the field, Ed May, expressed in his farewell speech to the Parapsychological Association in 2008.

In view of the above, it is interesting that Carter cites (p. 165) another paper written by Gardner Murphy, this time published in 1969, in which he urged parapsychologists to become better acquainted with the findings of modern physics. The June 2011 issue of Scientific American concerns how entanglement effects have been found at a biological level. If their presence is confirmed in the brain, maybe the critics will be demanding that for our worldview to make sense, psi phenomena must be acknowledged to actually occur. If so, real collaboration can then begin on understanding more about what these phenomena mean.


Alcock, J. E. (2003). Give the null hypothesis a chance: Reasons to remain doubtful about the existence of psi. Journal of Consciousness Studies, 10, 29-50.

Alcock, J. E., Carment, D. W., & Sadava, S. W. (1998). (Eds.) A textbook of social psychology. Scarborough, Canada: Prentice Hall.

Bem, D.J. (2011). Feeling the future: Experimental evidence for anomalous retroactive influences on cognition and affect. Journal of Personality and Social Psychology, 100, 407-425

Bem, D.J., & Honorton, C. (1994). Does psi exist? Replicable evidence for an anomalous process of information transfer. Psychological Bulletin, 115, 4-18.

Bem, D.J., Palmer, J., & Broughton, R. S. (2001). Updating the ganzfeld database: A victim of its own success? Journal of Parapsychology, 65, 207-218.

Dalton, K. S., Morris, R. L., Delanoy, D. L., Radin, D. I., Taylor, R. & Wiseman, R. (1996). Security measures in an automated ganzfeld system. Journal of Parapsychology, 60, 129-148.

Ertel, S. (2010). Psi in a skeptic's lab. A successful replication of Ertel's Ball Selection Test. Journal of Scientific Exploration, 24, 581-595.

Goulding, A., Westerlund, J., Parker, A., & Wackermann, J. (2004). The first digital autoganzfeld study using a real-time judging procedure. European Journal of Parapsychology, 19, 66-97.

Hyman, R. (1985). The ganzfeld psi experiment: A critical appraisal. Journal of Parapsychology, 49, 3-49.

Hyman, R., & Honorton, C. (1986). A joint communique: The psi ganzfeld controversy. Journal of Parapsychology, 50, 351-364.

Kennedy, J. E. (2003). The capricious, actively evasive, unsustainable nature of psi: A summary and hypotheses. Journal of Parapsychology, 67, 53-74.

Milton, J., & Wiseman, R. (1999). Does psi exist? Lack of replication of an anomalous process of information transfer. Psychological Bulletin, 125, 387-391.

Murchison, C. (1927). The case for and against psychic belief London: Oxford University Press.

Parker, A. (1999). Imaginal experiences and perceptual defence. British Journal of Medical Psychology, 72, 447-448.

Parker, A. (2000a). An experimental study of the influences of magical ideation and sense of meaning on the attribution of telepathic experience. Journal of Mental Imagery, 24, 97-110.

Parker, A. (2000b). A review of the ganzfeld work at Gothenburg University. Journal of the Society for Psychical Research, 64, 1-15.

Parker, A. (2005). Psi and altered states of consciousness. In L. Storm & M. Thalbourne (Eds.), Parapsychology in the 21st century (pp. 65-89). Jefferson, NC: McFarland.

Parker, A., & Sjoden, B. (2010). The effect of priming of film clips prior to ganzfeld mentation. European Journal of Parapsychology, 25, 76-88.

Parker, A., & Wiklund, N. (1987). The ganzfeld: Towards an assessment. Journal of the Society for Psychical Research, 54, 261-265.

Radin, D. (2006). Entangled minds. New York: Paraview.

Schlitz, M., Wiseman, R., Watt, C., & Radin, D. (2006). Of two minds:

Sceptic-proponent collaboration within parapsychology. British Journal of Psychology, 97, 313-322.

Skeptiko. (2009). Retrieved from Skeptics/2009/10/Skeptiko-Sheldrake-v-French

Storm, L., Tressoldi, P., & Di Risio, L. (2010) Meta-analysis of free-response studies, 1992-2008: Assessing the noise reduction model in parapsychology. Psychological Bulletin, 136, 471-485.

Von Lucadou, W. (2001). Hans in luck: The currency of evidence in parapsychology. Journal of Parapsychology, 65, 3-16.

Watt, C., & Ramakers, P. (2003). Experimenter effects with a remote facilitation of attention focusing task: A study with multiple believer and disbeliever experimenters. Journal of Parapsychology, 67, 99-116.

White, R. A. (1976a). The influence of persons other than the experimenter on the subject's scores in psi experiments. Journal of the American Society for Psychical Research, 69, 133-166.

White, R. A. (1976b). The limits of experimenter influence on psi test results: Can any be set? Journal of the American Society for Psychical Research, 70, 335-369.

White, R. A. (1977). The influence of the experimenter's motivation, attitudes and methods of handling subjects in psi test results. In B. B. Wolman (Ed.), Handbook of parapsychology (pp. 273-301). New York: Van Nostrand Reinhold.


Department of Psychology

University of Gothenburg

Box 14158

40020 Gothenburg, Sweden
The attempt to control all sources of error at the
   beginning is not only futile because of the impossibility
   of foreseeing all sources of error, but prejudicial to
   obtaining the kinds of occurrences that one is out to
   observe. Tenseness, distrust, and apathy are but three
   of many ways of becoming negatively conditioned to
   a long series of laboratory experiments.... The task
   before the investigator is not a polemic one: It is simply
   the task of steadily improving the quality and quantity
   of experimental work, the task of controlling more and
   more of the variables involved and working towards
   a thorough understanding of the physiological and
   psychological factors which underlie the phenomena.
Gale Copyright: Copyright 2011 Gale, Cengage Learning. All rights reserved.