Introduction

Although many of you reading this book, like myself, have few personal doubts that something like extrasensory perception is real, the effort to establish ESP as a scientific fact has been a continuous struggle the outcome of which still remains uncertain. Many subjects whose demonstrations had originally convinced researchers from the British Society for Psychical Research were later detected using bogus means to dupe these eminent scientists. Fascinated by their few successes, researchers continued undaunted in the midst of failures, criticism, and detected frauds.
 

J. B. Rhine's Early Research at Duke University

Perhaps the most publicized early experiments were those published by Dr. Joseph Banks Rhine in 1934 in a monograph entitled Extra-Sensory Perception, which summarized results from his experiments at Duke University beginning in 1927. 

Although this work was published by the relatively obscure Boston Society for Psychic Research, it was picked up in the popular press and had a large impact throughout the world. While earlier researches had been fruitful, they were generally neither as systematic nor as persistent as Dr. Rhine's studies.

These experiments used shuffled decks of ESP cards with five sets of five different symbols on them -- a cross, a circle, a wavy line, a square and a star. This method reduced the problem of chance-expectation to a matter of exact calculations. Furthermore the cards were designed to be as emotionally neutral as possible to eliminate possible response biases caused by idiosyncratic preferences. However other studies have shown that emotionally laden targets can also work without impairing statistical analysis.

Rhine describes his early work with one of his more successful subjects, Hubert E. Pearce, a graduate divinity student:

The working conditions were these: observer and subject sat opposite each other at a table, on which lay about a dozen packs of the Zener cards and a record book. One of the packs would be handed to Pearce and he allowed to shuffle it. (He felt it gave more real "contact.") Then it was laid down and it was cut by the observer. Following this Pearce would, as a rule, pick up the pack, lift off the top card, keeping both the pack and the removed card face down, and after calling it, he would lay the card on the table, still face down. The observer would record the call. Either after five calls or after twenty-five calls -- and we used both conditions generally about equally -- the called cards would be turned over and checked off against the calls recorded in the book. The observer saw each card and checked each one personally, though the subject was asked to help in checking by laying off the cards as checked. There is no legerdemain by which an alert observer can be repeatedly deceived at this simple task in his own laboratory. (And, of course, we are not even dealing with amateur magicians.) For the next run another pack of cards would be taken up.

Furthermore, was it really possible for one experimenter to maintain sufficient concentration to insure that the subject does not cheat? Experience of other researchers has sadly shown this is quite doubtful. Perhaps Rhine did utilize other safeguards. If so he could be (and was) fairly criticized for not adequately reporting his experimental conditions, although other experiments in his monograph were admittedly better controlled. Finally, there was no mention of any efforts to guard against recording errors on the part of the experimenter. One can hardly expect the cooperation of the subject, who may have a personal interest in the outcome, to be an adequate control against experimenter mistakes.

As Rhine's positive results gained more attention, arguments of this sort began to proliferate in the popular and scientific literature. It is much to Rhine's credit that he encouraged such criticism and modified his experiments accordingly. In 1940, J. Gaither Pratt, J. B. Rhine, and their associates published a work, titled Extra-Sensory Perception After Sixty Years, which described the ways in which the ESP experiments had met the thirty-five different counter-hypotheses that had been published in the scientific and popular press.

The areas of criticism Rhine and Pratt focused on in 1940 included: hypotheses related to improper statistical analysis of the results; hypotheses related to biased selection of experiments reported; hypotheses dealing with errors in the experimental records; hypotheses involving sensory leakage; hypotheses charging experimenter incompetence; and finally hypotheses of a general speculative character. In each case, Rhine and Pratt pointed to experimental evidence to counter the hypotheses.

Many prominent mathematicians in the field of probability who have made a detailed investigation have approved his techniques. In fact, in 1937 the American Institute of Statistical Mathematics issued a statement that Rhine's statistical procedures were not in the least faulty. In most experiments, both significant and chance results were reported and averaged into the data.

Between 1880 and 1940, 145 empirical ESP studies were published using 77,796 subjects who made 4,918,186 single trial guesses. These experiments were mostly conducted by psychologists and other scientists. In 106 such studies, the authors arrived at results exceeding chance expectations.

High scores due to inaccurate recording of results had been reduced to an insignificant level by double-blind techniques in which both subject and experimenter notations were made without knowledge of the scores against which they were to be matched. Errors were further reduced by having two or more experimenters oversee the matching of scores. Furthermore, original experimental data had been saved and double checked for mistakes many times by investigators. Tampering with these original records was prevented by having several copies independently preserved.

Sensory cues were impossible in many tests of clairvoyance because the experimenter himself and all witnesses did not know the correct targets. In other tests, the cards were sealed in opaque envelopes, or an opaque screen prevented the subject from seeing the cards. Often the experimenter and the subject were in completely different rooms.

Those who charged the experimenters with incompetence failed to find any flaws in several experiments (although rarely, if ever, are these early studies cited as evidential today, in an era of stricter experimental controls). In cases of inadequate reporting, Rhine indicated that further data would always be supplied upon request. In several cases, experimenter fraud would have had to involve the active collusion on the part of several teams of two or more experimenters. Critics who claimed the results came only from the laboratories of those with a predisposition to believe in ESP were also ignoring at least six successful studies gathered from skeptical observers.

Other criticisms generally claimed ESP could not exist because of certain philosophical assumptions about the nature of the universe or scientifically uninformed assumptions of what ESP would be like if it did exist. Rhine argued fo�cefully that such assumptions were scarcely sufficient cause to dismiss the carefully observed experimental data.

Of the 145 experiments reported in the sixty year period from 1880 to 1940, Rhine and Pratt selected six different experimental studies of ESP they believed were not amenable to explanation by any of the counter-hypotheses offered by critics of psi research at that time.

One of the more carefully controlled studies was the Pearce-Pratt series, carried out in 1933 with Dr. J. Gaither Pratt as agent and Hubert Pearce as subject. In these experiments, the agent and his subject were separated in different buildings over 100 yards apart. Pratt displaced the cards one by one from an ESP pack at an agreed time without turning them over. After going through the pack, Pratt then turned the cards over and recorded them. The guesses were recorded independently by Pearce. In order to eliminate the possibility of cheating, both placed their records in a sealed package handed to Rhine before the two lists were compared. Copies of these original records are still available for inspection. The total number of guesses was 1,850 of which one would expect one-fifth, or 370, to be correct by chance. The actual number of hits was 558. The probability these results could have occurred by chance is much less than one in a hundred million.
 

Criticisms of ESP Research

After the publication of ESP After Sixty Years, both the quality and quantity of criticism of ESP research declined until the mid-1970s (when a new wave of still-ongoing criticism was launched by the Committee for the Scientific Investigation of Claims of the Paranormal). That is not to say, however, that psi research met with general acceptance in the United States or in other countries. The work of the psi researchers was simply ignored by many universities and the major scientific publications. The public guardians were not then ready for ESP.

In August 1955, Science carried an editorial on ESP research by Dr. George R. Price, a chemist from the University of Minnesota, stating that scientists had to choose between accepting the reality of ESP or rejecting the evidence. Price had carefully studied the data and he frankly admitted the best experiments could only be faulted by assuming deliberate fraud, or an abnormal mental condition, on the part of the scientists. Price felt that ESP, judged in the light of the accepted principles of modern science, would have to be classed as a miracle (this judgment, as we will point out later, is ill founded). Rather than accept a miracle, he suggested accepting the position of the eighteenth-century philosopher, David Hume, who said those who report miracles should be dismissed as liars.

Similar criticisms were published by Professor C. E. M. Hansel. Regarding the Pearce-Pratt experiment, he suggests that after Pratt had left him, Pearce departed from the University Library, followed Pratt to his office and looked through the fanlight of Pratt's door thus observing the target cards being recorded by Pratt. While it is true Hansel exposed the defect in the experimental design of having left Pearce alone in the library, the structure of Pratt's office would have made it impossible for Pearce to see the cards even if he had taken the great risk of staring through the fanlight of Dr. Pratt's door. In subsequent experiments psi researchers have generally (but, inevitably, not always) eliminated such defects.

Official recognition of the experimental competency of psi researchers did not come until December of 1969 when the American Academy for the Advancement of Science granted affiliate status to the researchers in the Parapsychological Association. Recent decades have shown authoritative scientific voices displaying a new willingness to deal with the evidence for ESP. In the "letters" column of Science for January 28, 1972, there appeared a brief note from Dr. Price titled "Apology to Rhine and Soal," in which Price expressed his conviction that his original article was highly unfair to both S. G. Soal and J. B. Rhine. 

Ironically, Price's apology seventeen years after his original editorial was partially premature. In 1978, psi researchers found that S. G. Soal, a British mathematician who also reported significant ESP results, had fraudulently manufactured his data.

Other criticisms relating to repeatability, fraud, statistical inferences, experimental design and interpretation of data have continued. In fact, psi researchers closely scrutinize each other's work and have often been their own most thorough critics (making it rather easy for would-be debunkers to seize upon their criticisms as grounds for discrediting the entire field). As a response to criticism psi researchers have slowly, sometimes erratically and sometimes steadily, improved the quality of their experiments while continuing to obtain data which they believe is anomalous. 

Some honest skeptics, meanwhile, while contining to reject the psi hypothesis, reluctantly acknowledge that some of the research deserves careful scrutiny from the mainstream scientific community.
 

Unconscious ESP

One of the first theories about the nature of ESP was put forward by Frederick Myers, author of the 1903 classic Human Personality and Its Survival of Bodily Death, when he associated psychic phenomena with the workings of the subliminal mind, below the limits of consciousness. Studies in which ESP signals are registered by the body's physiological processes even when the subject is unaware of the message support the concept of unconscious ESP. For example, in a series of studies conducted by E. Douglas Dean, subjects were hooked up to a plethysmograph. Increases or decreases in blood and lymph volume, resulting from emotional responses, are measured by this instrument. 

A telepathic agent in another room then concentrated on different names, some of which were known to be emotionally significant to the subjects. The results indicated changes in the blood volume which significantly correlated with the emotionally laden target messages. This finding was c

Birmed in a second series of studies conducted by Dean and Carroll B. Nash at St. Joseph's College in Philadelphia. Most of the subjects were totally unaware of the changes in their blood supply which were responding to the target material.

A similar study was conducted by Charles Tart in which subjects were hooked up to a plethysmograph, an electroencephalograph, and a device for measuring galvanic skin response. The agent in this experiment was periodically given a mild electric shock. The subjects did not know they were being tested for ESP, but rather were told to guess when a "subliminal stimulus" (sensory stimulation below the threshold of conscious awareness) was being directed to them. The subjects' hunches failed to correlate to this disguised target. However, their physiological measurements showed abrupt changes when the shocks were administered to the agent in ano@�er room.
 

Dream Telepathy

Frederick Myers noted in the early years of psychical research that the workings of the subliminal mind were most visible in such phenomena as dreams, trance states, hypnosis, and states of creative inspiration. In fact, a large proportion of the reported cases of ESP occurred while the percipient was in such altered states of consciousness.

An important series of studies on the nature of ESP in dreams was carried out by a team of researchers at Maimonides Hospital in Brooklyn, New York. Using equipment which monitored brain waves and eye movements, the investigators could determine accurately when subjects were having dreams. By waking the subjects at these times they were then able to obtain immediate reports of the dream contents. Earlier in the day, in another room, the telepathic senders had concentrated on target pictures designed to create a particular impression.

Independent judges compared the similarity subject's responses displayed to all of the actual targets in each series and found evidence for nocturnal telepathy and precognition (when targets were not chosen until the following day) of the actual targets used.,

In addition to these careful experiments, there were some interesting one-time studies. In one such test, telepathic transmission was obtained by having about 2,000 persons attending a Grateful Dead rock concert focus on a color slide projection image and attempt to send it to the dream laboratory 45 miles away in Brooklyn. Many of these individuals were in altered states of consciousness from the music and the ingestion of psychedelic drugs. This test proved successful.

Psychologist David Foulkes at the University of Wyoming, in consultation with the Maimonides team, attempted unsuccessfully to replicate the dream studies. Critic C. E. M. Hansel, a psychologist at the University of Wales in England, attributed the failure to tighter controls against fraud in the Wyoming experiments, whereas dream researcher Robert Van de Castle from the University of Virginia, one of the subjects in both the Wyoming and the Maimonides experiments, stressed the debilitating effect of the skeptical attitude of the Wyoming team.

In 1985, Yale University psychologist Irvin Child published a review of the Maimonides dream studies in the American Psychologist. Child's basic point was that this research was basically sound.

The experiments have received little or no mention in the pertinent psychological literature. When these studies were reviewed, Child claims that they were so severely distorted as to given an entirely erroneous impression of how they were conducted. Child used the example of the dream research to illustrate the general point that books by psychologists purporting to offer critical reviews of psi research do not use the scientific standards of discourse prevalent in psychology. 
 

Hypnosis and ESP

Milan Ryzl, a chemist who defected to the United States from Czechoslovakia in 1967, developed a hypnotic technique for facilitating ESP which, although it has not been successfully replicated, attracted attention and may yet prove fruitful. Ryzl's technique involved the intensive use of deep hypnotic sessions almost daily for a period of several months. The first stage of these sessions is to instill confidence in his subjects that they could visualize clear mental images containing accurate extrasensory information. Once this stage was reached, Ryzl concentrated on conducting simple ESP tests with immediate feedback so that subjects might learn to associate certain mental states with accurate psychic information. Subjects were taught to reject mental images which were fuzzy or unclear. This process, according to Ryzl, continued until the subject was able to perceive clairvoyantly with accuracy and detail. Finally, Ryzl attempted to wean the subject away from his own tutelage so that he or she could function independently. While still in Czechoslovakia, Ryzl claimed to have used this technique with some 500 individuals, fifty of whom supposedly achieved success.

Other studies have shown heightened ESP in states of physical relaxation or in trance and hypnotic states.   In fact, the use of hypnosis to produce high ESP scores is one of the more replicabIe procedures in psi research. 

A particularly notable series of experiments were described in 1910 by EmilIe Boirac, rector of the Dijon Academy in France, which produced what he described as an "externalization of sensitivity." When the hypnotist placed something in his mouth, the subject could describe it. If he pricked himself with a pin, the subject would feel the pain. The most striking experiments were those in which the subject was told to project his sensibility into a glass of water. If the water was pricked, the subject would react by a visible jerk or exclamation.

This phenomenon has been repeated by the Finnish psychologist, Jarl Fahler.

In a similar experiment performed by one of Boirac's associates, blisters were raised on the skin of a hypnotized subject, simply by pricking a photograph of the subject's hand.

Boirac, as well as Soviet investigators, have reported the ability to induce a hypnotic trance simply through telepathic concentration directed toward their subjects.,

In 1969, Charles Honorton and Stanley Krippner reviewed the experimental literature of studies designed to use hypnosis to induce ESP. Of nineteen experiments reported, only seven failed to produce significant results. Many of the studies produced astounding success. In a particularly interesting precognition study, conducted by Fahler and Osis with two hypnotized subjects, the task also included making confidence calls -- predicting which guesses would be most accurate. The correlation of confidence call hits produced impressive results with a probability of 0.0000002. 

In 1984, Ephriam Schechter reported an analysis of studies comparing the effect of hypnotic induction and nonhypnosis control procedures on performance in ESP card-guessing tasks. There were 25 experiments by investigators in ten different laboratories. Consistently superior ESP performance was found to occur in the hypnotic induction conditions compared to the control conditions of these experiments. 

Hypnosis typically involves relaxation and suggestion in an atmosphere of friendliness and trust. We do not know which of these factors, or combination of factors, accounts for heightened psi scores. Schechter himself, as well as other psi researchers, has been reluctant to conclude that hypnosis does facilitate psi performance. He noted that the studies were not designed to control for an expectancy effect. In a retrospective critique of research on altered states of consciousness and psi, St. Johns University psychologist Rex Stanford argued that many alternative explanations of heightened psi effects were not controlled for in the research studies. Stanford called for more rigorous process oriented research to determine why hypnosis and other altered states enhance psi scores -- if, in fact, they actually do. 
 

Exceptional ESP Laboratory Performers

Western researchers who travelled to Prague to personally investigate Milan Ryzl's hypnotic training program were able to test one of his better subjects, Pavel Stepanek. During a long period of experimental investigations, Stepanek proved to be one of the most successful subjects ever tested. More than twenty studies with him have now been published.

What we still do not know is whether Stepanek always had this ESP ability or whether it developed as a result of Ryzl's training. There was a period of time during which Stepanek's scores did drop down to chance levels and then jumped up again after a hypnotic session with Ryzl.

In a book titled How Not To Test A Psychic, skeptic Martin Gardner reanalysed the tests with Stepanek, offering detailed hypotheses as to how the results obtained for over a decade by several independent experimental teams may have resulted from cheating by Stepanek. 

In a study with an exceptional subject, Bill Delmore, confidence calls were made using a deck of ordinary playing cards as the target. The technique used was a "psychic shuffle" in which the experimenters randomly select a predetermined order which the subject must match by shuffling the target deck. In each of two shuffle series, with fifty-two cards in a series, Delmore made twenty-five confidence calls -- all of which were completely correct. The probability of such success is only one in 5250. Other studies with Delmore have also produced extraordinary results.

Delmore does not seem to use an altered state of consciousness as a means of gaining psychic information. In fact, the research in altered states seems to point to other variables which are really more significant. For Delmore, a congenial atmosphere is important.

Skeptical statistician Persi Diaconis, who observed some informal tests with Delmore which amazed a group of Harvard faculty and students, hypothesized that the results were due to a set of complicated maneuvers that would be familiar to magical practitioners. 
 
 

In 1974, Harold Puthoff and Russell Targ at SRI International (then Stanford Research Institute) in Menlo Park, California, reported on experiments conducted with the Israeli psychic performer Uri Geller. Their results, covered studies taking place over an eighteen month period:

In the experiments with [Uri] Geller, he was asked to reproduce 13 drawings over a week-long period while physically separated from his experimenters in a shielded room. Geller was not told who made any drawing, who selected it for him to reproduce or about its method of selection.

The researchers said that only after Geller's isolation -- in a double-walled steel room that was acoustically, visually and electrically shielded from them -- was a target picture randomly chosen and drawn. It was never discussed by the experimenters after being drawn or brought near Geller.

All but two of the experiments conducted with Geller were in the shielded room, with the drawings in adjacent rooms ranging from four meters to 475 meters from him. In other experiments, the drawings were made inside the shielded room with Geller in adjacent locations. Examples of drawings Geller was asked to reproduce included a firecracker, a cluster of grapes, a devil, a horse, the solar system, a tree and an envelope. 

Two researchers -- not otherwise associated with this research -- were given Geller's reproductions for judging on a "blind" basis. They matched the target data to the response data with no errors, a chance probability of better than one in a million per judgment....

In another experiment with Geller, he was asked to "guess" the face of a die shaken in a closed steel box. The box was vigorously shaken by one of the experimenters and placed on a table. The position of the die was not known to the researchers.

Geller provided the correct answer eight times, the researchers said. The experiment was performed ten times but Geller declined to respond two times, saying his perception was not clear.

Because of the publicity which these studies received, they have been highly criticized by skeptics. These criticisms are largely speculations as to how Geller might have cheated. The SRI researchers have responded by maintaining that the experimental conditions were such that the alleged cheating could not have taken place. Nevertheless, psi researchers in general are reluctant to defend Geller.
 

Ganzfeld Research

A very thoughtful approach toward investigating ESP was reported in 1974 simultaneously by investigators in New York and Texas., These researchers hypothesized that the reasons why high scoring occurred in altered states (e.g., the Maimonides Hospital ESP dream research) was that the normal, waking mind was less active at these times; thus there was less mental "noise" covering up the signals coming through the subliminal mind. To test this theory, they utilized a ganzfeld technique of covering the eyes of their subjects with halved ping pong balls so that the visual field was seen as solid white. A constant auditory environment was provided by either a white noise generator or a tape of the seashore. Under these conditions, with a constant sensory input, psi signals were expected to be easier to perceive. Subjects were put into this condition and asked to free-associate out loud while their responses were put on to magnetic tape. In another room, the telepathic sender chose, at random, a set of slides to look at and try to send to the subject. After the experiment, the subject was asked to guess which of the view-master reels, of a group of four, had been the target. The subject's taped responses were also independently judged. The qualitative results of this procedure were often striking and statistical results also proved impressive. 

In 1985, a meta-analysis of 28 psi Ganzfeld studies by investigators in ten different laboratories found a combined z score of 6.6, a result associated with a probability of less than one part in a billion. Independently significant outcomes were reported by six of the ten investigators, and the overall significance was not dependent on the work of any one or two investigators. Moreover, in order to account for the observed experimental results on the basis of selective reporting, it would have been necessary to assume that there were more than 400 unreported studies averaging chance results. Part of this problem was addressed by British psychologist Susan Blackmore's survey of unreported ganzfeld studies. Seven of these 19 studies (37%) yielded statistically significant results. This proportion was not appreciably lower than the proportion of published studies found significant. 

In evaluating the ganzfeld database, Harvard psychologists Monica Harris and Robert Rosenthal compared it in quality to research in biofeedback. This is not to say, however, that the studies were flawless. Several critics found methodological problems with these studies.,, In fact, for every ganzfeld study reporting significant evidence of psi communication, there has been at least one critical review or commentary.

By their nature, ESP studies must eliminate opportunities for sensory cueing. An exception occurred in some ganzfeld studies when the subject was asked to choose which target picture had been "sent" by another person or agent. When slides held originally by the sender were shown to the receiver, finger smudges or other marks could theoretically have served as cues. Honorton has shown, however, that ganzfeld studies which eliminated this type of cue yielded at least as many significant psi effects as the studies with poorer controls.

In response to the various criticisms which had been addressed to the ganzfeld studies, Honorton and seven associates reported on a series of eleven new experiments at the 1989 convention of the Parapsychological Association. These studies were conducted using an automated testing system which controled random target selection, target presentation, the blind-judging procedure, and data recording and storage. Targets were recorded on videotape and included both video segments (dynamic targets) and single images (static targets). In all, 243 volunteer receivers completed 358 psi ganzfeld sessions. The success rate for correct identification of remotely viewed targets was statistically highly significant. The likelihood that these results could have been obtained by chance was less than one in ten thousand. The results were consistent across the eleven series with eight different experimenters. 

A number of other interesting correlations were noted. The success rate for sessions using dynamic targets was significantly greater than those with static targets and accounted for most of the successful scoring. Significantly stronger performance occurred with sender/receiver pairs who were acquainted than with unacquainted sender/receiver pairs. Furthermore, comparison of the outcomes of these eleven automated ganzfeld studies with a meta-analysis of the original 28 direct hits ganzfeld studies indicated that the two sets were consistent on four dimensions: (1) overall success rate, (2) impact of dynamic and static targets, (3) effect of sender/receiver acquaintance, and (4) impact of prior ganzfeld experience. 

This new series of eleven ganzfeld studies provides a model for psi research in that it combined exacting methodological rigor with a consideration of the humanistic considerations essential for psi performance. Participants were all informed that they were free to bring a friend or family member to serve as their sender. Additionally, the researchers encouraged participants to reschedule their session rather than feel they must come in to "fulfill an obligation" if they were not feeling well or were experiencing personal problems.

Researchers greeted participants at the door when they arrive for their session and attempted to create a friendly, informal social atmosphere. They offered coffee, tea, or soft drinks. The experimenter and other staff members engaged the participant in conversation during this period. If the session involved a laboratory sender, time was taken for the sender and participant to become acquainted. The experimental protocols included many other details to help subjects feel comfortable using psi faculties.

The possibility of sensory cueing was eliminated by the use of the automated target selection system. Both sender and receiver were kept in separate sound attentuated chambers during each experiment. Only the sender was aware of the target's identity. The use of a videotape display system prevented potential cues that might result from manual handling of target pictures. Dozens of details in the experimental protocols addressed every criticism which has been made of the experimental procedures. All electronic circuits, for example, were carefully monitored to exclude the possibility of even subliminal sensory leakage. All of the data from every test with every subject was reported using statistical tests which were specified in advance.

The use of a large number of subjects and the significance of the outcome using subjects as the unit of analysis, rules out subject deception as a plausible explanation. The automated protocol had been examined by several dozen psi and behavioral researchers, including two well-known critics of psi research. Some participated as subjects, senders, or observers, and all expressed satisfaction with the handling of security issues and controls.

In addition, two experts on the simulation of psi ability have examined the system and protocol. Ford Kross has been a professional mentalist for over 20 years. He is the author of more than 100 articles in mentalist periodicals, and has served as Secretary/Treasurer of the Psychic Entertainers Association. Mr. Kross has stated: 

"In my professional capacity as a mentalist, I have reviewed Psychophysical Research Laboratories' automated ganzfeld system and found it to provide excellent security against deception by subjects." 

Similar comments were made by Daryl Bem, Professor of Psychology at Cornell University. Professor Bem is well-known for the development of self-perception theory in social and personality psychology. He is also a member of the Psychic Entertainers Association and has performed for many years as a mentalist. He visited PRL for several days and was a subject in one series. In a book review of Advances in Parapsychology, Vol. 5 published in Contemporary Psychology, Bem made the following statement about the Honorton-Hyman debate over the psi ganzfeld studies:

For what it's worth, I find Honorton's conclusion that there is a significant and nonartifactual effect in the Ganzfeld data more persuasive than Hyman's more pessimistic conclusion. Apparently parapsychological data will remain a projective test for all of us.

Skeptic Ray Hyman and psi researcher Charles Honorton stated in a joint communique regarding the status of the ganzfeld studies:
 

...the best way to resolve the controversy...is to await the outcome of future ganzfeld experiments. These experiments, ideally, will be carried out in such a way as to circumvent the file-drawer problem, problems of multiple analysis, and the various defects in randomization, statistical application, and documentation pointed out by Hyman. If a variety of...investigators continue to obtain significant results under these conditions, then the existence of a genuine communications anomaly will have been demonstrated. 

The automated ganzfeld studies show an overall success rate slightly in excess of 34%. A power analysis by University of California statistician Jessica Utts shows that for an effect this size, the investigator has only about one chance in three of obtaining a statistically significant result in an experiment with 50 trials. Even with 100 trials, which is unusually large in ganzfeld research, the probability of a significant outcome is only about .5. 
 

The Experimenter Effect

For some time psi researchers have been suggesting that the failure of some investigators to repIicate their findings was due to attitudes and expectations, conscious or unconscious, which were communicated through subtle sensory or psychic channels to their subjects. A number of psi research projects have been designed to study on the factors that Harris and Rosenthal identified as contributing to the experimenter expectancy effect. 

For example, one project compared the effects of a warm and cold social climate on ESP scores. All of the subjects had the same instructions and the same long ESP task. For half, there was a friendly, informal conversation with the experimenter for a quarter of an hour before the orientation began, and the experimenter made encouraging remarks during the breaks. The other half were treated formally and rather abruptly. The experimenter began the orientation immediately and also made discouraging remarks during the breaks. Results clearly confirmed the hypothesis. ESP scores of subjects treated warmly were significantly higher than mean chance expectation; scores of subjects treated coldly were significantly below mean chance expectation.

Judith Taddonio followed Rosenthal's classic expectancy effects design in an experiment with two series. Her experimenters were six undergraduates with previous practice in conducting psychological experiments. All felt neutral toward ESP but agreed to help her when she told them that a particular ESP method needed checking out. Three were told that prior findings with this method could not fail. The other three were told that Taddonio's colleagues were worried because the method seemed to elicit only psi-missing. All experimenters used the same materials and method.

Both in the first series and in the second, subjects of experimenters with high expectations made ESP scores above chance and subjects of experimenters with low expectations made ESP scores below chance. In each series, the difference was significant.

A study conducted at the University of Edinburgh in Scotland suggests that the attitude of the exerimenter regarding the existence of ESP correlates the results of that person's research. Ironically, one of psi researcher's least successful experimenters is from the University of Edinburgh, psychologist John Beloff.

Beloff is a respected researcher who has consistently failed to confirm several psi experiments that have done well elsewhere.,, Yet, in spite of his inability to confirm psi studies in his own laboratory, Beloff has remained convinced of the legitimacy of the research conducted by others. If he is a psi-inhibatory experimenter, it is not likely that his belief system is the inhibiting factor.

In 1988, psychologist Gertrude R. Schmeidler conducted an analysis of psi research studies testing for expectancy effects. Her conclusions were:

Psychological research on the experimenter effect has shown higher scores with a warm than with a cold experimenter climate and with an experimenter who expects high rather than low scores. Eight experiments, comprising 12 series, tested for the experimenter effect in psi. Nine of the 12 series had significant results, all in the predicted direction. Six other experiments tested a related hypothesis: that psi experimenters would be self-consistent in obtaining results like their prior ones. Four of these had significant results, all in the predicted direction. 

However, the psi experimenter effect actually has revolutionary implications for normal psychological research. The following study was reported by Professor Hans KreitIer and Dr. Shulamith Kreitler of the Department of Psychology at Tel Aviv University in Israel:

The first experiment dealt with the effect of ESP on the identification of letters projected at subliminal speed and illumination. The second experiment dealt with the effect of ESP on the direction of perceived autokinetic motion (i.e., of a stationary point of light in a dark room). The third experiment dealt with the effect of ESP on the occurrence of specific words and themes in the stories subjects tell to TAT (Thematic Apperception Test) cards.

In all these three experiments the subjects did not know that ESP communications were "sent" to them, the "senders" never met the subjects and "senders" were naive in the sense that they were not particularly interested in parapsychology, were unselected, and did not get any training for the experiments. The precautions undertaken against any sensory contact between "senders" and subjects were highly complex and included the spatial separation of "sender" and subject (they were in two different soundproof rooms with another room between them), the decentralization of information about the experiment among different people, strict randomization of all stimuli and sequences, the use of experimenters who were disbelievers in ESP, etc.

The results show that in every experiment there was a significant effect due to the ESP communication....The effect...was particularly pronounced with regard to responses with an initially low probability of occurrence.

The Sheep-Goat Effect

The hypothesis that the attitude the experimenter takes can effect ESP scores also applies to ESP subject attitudes. Dr. Gertrude Schmeidler, working at Harvard University and at the City College of New York, divided her subjects into "sheep" who believed that ESP might occur in their experiment and "goats" who did not.

Her studies, which were conducted over a nine year period and have since been replicated, showed an unquestionable difference between the "sheep" whose scores fell above chance expectation and "goats" who scored below chance levels. The phenomenon of psi-missing is thought to be a psychological effect in which psychic material is repressed from consciousness.

In a review of 17 experiments testing the hypothesis that subjects who believed in ESP would show superior ESP performance compared to subjects who did not believe in ESP, psychologist John Palmer found that the predicted pattern occurred in 76% of the experiments, and all six of the experiments with individually significant outcomes were in the predicted direction. These findings suggest an overall statistical significance for this effect.

It is important to realize, however, that the sheep-goat studies do not necessarily distinguish those who believe in ESP from those who do not. In most studies, the "sheep" were not "true believers"; they merely accepted the possibility that ESP could occur in the test situation. On the other hand, many of the "goats" were willing to accept that ESP could occur between people who loved each other, or in certain times of crisis; but they rejected all possibility that ESP would manifest for them in their particular test situation.
 

Psi-Missing

One would expect that if a person had ESP the level of performance on an experimental ESP test should be higher than chance expectation. Some individuals (and some groups in specific experiments) on the other hand have been found to score significantly below chance. This is termed psi-missing. It is important to note that this does not necessarily indicate a lack of ES since that would be associated with nonsignificant scores. Rather, psi-missing can be viewed as an expression of psi in a way that produces a result different from one's conscious intent. The percipient shows sensitivity to the targets' identity but tends to make calls at odds with this sensitivity.

Psi-missing is thought to be in part a consequence of negative elements in mood and attitude or aspects of personalty; these elements may cause psi-missers to focus their ESP inaccurately. While observations of psi-missing are much less common than those of psi-hitting, the former are sufficient numerous to suggest there is an effect here to be explained.

Critics argue that the occurrence of so-called psi-missing confirms their view of reported data as statistical freaks. These below-chance scores are seen as nothing else than the negative tail of the normal distribution of random guessing scores. Two points count against this interpretation. First, under this "normal curve" model the incidence of psi-missing data should be the same as that of psi-hitting results, yet in fact the former is much lower than the latter. Second, the occurrence of psi-missing seems to be correlated with certain psychological variables; this should not be the case if properly controlled ESP tests entail purely random guessing.
 

ESP and Personality Traits

Beginning in the early 1940s numerous attempts have been made to correlate experimental ESP performance with individual differences in subjects' personality and attitudinal characteristics. A series of studies with high school students in India by B. K. Kanthamani and K. Ramakrishna Rao has given further insight into the personality traits associated with psi-hitters and psi-missers. 

The following adjectives summarize the results of their work.
 

These particular traits are not suprising, in that people who frustrate themselves in the course of their other affairs are quite likely to behave the same way with regard to psi. It is much harder to define the personality of someone who expresses no ESP ability and whose scores will always approximate chance. For example, many people who indicate a fair amount of spontaneous ESP experience, and even professional psychics (whom I would assume have at least some ability) often do not score well in a laboratory. 
 

Extraversion/Introversion

Extraversion is a personality type in which one's interests are directed outward to the world and to other people. This is contrasted with introversion in which one's interests are more withdrawn and directed toward the inner world of thoughts and feelings.

Gertrude Schmeidler, building on earlier studies by John Palmer and Carl Sargent, reviewed 38 experiments involving the relationship between ESP performance and standard psychometric measures of introversion/extroversion, found that extraverts scored higher than introverts in 77% of these experiments. In twelve of these studies, the difference between introverts and extraverts was statistically significant.,
 

Effects of Different ESP Targets

Robert L. Morris who holds the Arthur Koestler Chair of Parapsychology at the University of Edinburgh in Scotland has proposed that each target be viewed as having both physical and psychological characteristics.

The psychological characteristics seem to be more salient for psi research subjects than the physical. Morris has also suggested that researchers consider not only the targets themselves, but also the systems to determining and displaying the targets.

The nature of the test situation and the target material itself is likely to affect ESP scores. Some people prefer material which involves other human beings on a feeling level. Other subjects who do well with ESP cards show little psychic skill outside of the laboratory. The technical name for scoring well on some kind of targets and not on others is the differential effect and seems to follow a trend relating to emotional preferences, attitudes, and needs.

For example, in a test conducted by Jim Carpenter at the University of North Carolina, Chapel Hill, with male college students unknown to the subjects, some of the ESP cards had sexually arousing pictures drawn on them. The subjects showed a greater ability at guessing the ESP symbols on these cards than on the regular cards. In another study with a female patient in psychotherapy, an ESP test was given using words which were emotionally potent for her. Half of them were of a traumatic nature and half of them were of a pleasant nature. In this test, she showed psi-missing for the traumatic words and psi-hitting on the emotionally-positive targets. This test was conducted by Martin Johnson at Lund University in Sweden.
 

Psi Mediated Instrumental Response

One of the most ingenious theories regarding the role of psi in everyday life was developed by Rex Stanford, who is currently teaching in the psychology department of St. John's University in Jamaica, New York. 

Stanford developed the concept of the psi-mediated instrumental response (PMIR) to explain non-intentional psychic experiences. For example, there is the story about a retired army colonel who found himself unconsciously getting off of the subway in New York at the wrong exit and then running into the very people he was intending to visit. Is it possible that his response of getting off the subway was triggered by ESP?

To test this hypothesis, experiments were designed to see if subjects would use ESP in a situation in which they would be rewarded for it, although they did not know they were being tested. In one such experiment, students in a psychology class were given an essay-type exam with the answers to half the questions sealed in opaque envelopes which were handed to them with the exam. They were told that the envelope contained carbon paper which would make copies of their answers. The experimenters thought that the students would use ESP as well as other means in order to do well on the examination. In fact, the students did better on the questions which were answered in the sealed envelopes. Furthermore, in a study where sealed answers were incorrect, the students did poorer on the corresponding questions. This study was conducted by Martin Johnson at Lund University in Sweden.

Another study has indicated that subjects who use the PMIR to avoid unpleasant situations and to encounter favorable situations, also score better than average on tests of conscious ESP.

The PMIR model and research program have not been addressed by outside critics. However, Stanford himself has abandoned the model because he found its "psychobiological" or cybernetic assumptions to be untenable. Other psi researchers, such as John Palmer, feel that the PMIR model need not be abandoned, although modifications are necessary.
 

Stanford's Conformance Behavior Model

Stanford calls his new approach the "conformance behavior" model of psi. He challenges the "psychobiological" or "cybernetic" assumptions of PMIR, which assume that psi abilities are similar to other sensory-motor functions. Stanford questions whether ESP is analogous to normal perceptual or cognitive processes, since it occasionally manifests itself through unconscious motor behavior (such as when one misses a subway train and then encounters the person one is going to see in the first place). For this reason, Stanford sees psi as "dispositional" in character. He no longer assumes any communication of information across a channel.

As further support for his view, Stanford cites evidence that psi success is independent of task complexity. If psi were akin to normal sensory-motor skills, Stanford argues, one would expect deterioration in psi performance when doing a multicomponent task. 

As evidence of the complexity independence of ESP, Stanford cites a 1940 study showing no deterioration in performance when a subject had to integrate information from two extrasensorily perceived targets from that obtained when the information was contained on a single target. Had the subject been cheating, and thus relying on normal senses, one could anticipate deteriorating performance in the more compl
p task.

Stanford interprets psi events as the conformance behavior of "random event generators" (such as quantum mechanical REGs or human brains) to the needs of a "disposed system" (typically, the subject in a psi experiment, or the agent or percipient in a spontaneous case). In order for such conformance behavior to occur, the REG must produce events that are "unequally attractive" to the disposed system. Further, labile systems characterized by a great deal of random fluctuation should produce more conformance behavior than more deterministic systems.
In principle, the concept of conformance behavior, does away with the distinction between ESP and PK. As some support for this view, it is interesting to note that studies have shown no decrease in PK success when the PK target is a complex, multi-process REG as opposed to a simple, single-process REG. However, we are getting ahead of our story.
 

Precognition

ESP is generally divided into telepathy, i.e., extrasensory communication between two minds; clairvoyance, i.e., extrasensory perception at a distance, without the mediation of another mind; and precognition, which is ESP across time into the future. There is still some controversy as to whether telepathy actually exists, or whether it is simply another form of clairvoyance. However, precognition, a most unusual ability in terms of our conventional notions of time and free will, is a rather well-established ESP phenomenon. In fact precognition tests afford some of the best evidence for ESP, since sensory leakage from a target which has not yet been determined is impossible. For example, in early studies with Hubert Pearce, the subject was able to guess what the order of cards in a pack would be after it was shuffled at the same high rate of scoring (up to 50% above chance levels) as in clairvoyance tests.

While many people tend to reject ESP because it seems to contradict the classical laws of science, precognition is even harder to swallow for exactly the opposite reason -- it seems to imply a completely mechanical, predetermined universe. Ironically, it is this determinism which violates the sensibilities of twentieth-century science. In fact, precognition is very difficult to prove; although its alternatives are not exactly palatable.

For example in the precognitive card guessing studies, one might say that the subject psychokinetically caused the order of the cards to conform to his guesses. Or perhaps, more reasonably, the experimenter, using his clairvoyance subconsciously, determined the subject's guesses and (with possible PK influence) shuffled the cards accordingly. It is impossible for precognitive experiments to rule out the possibility of contamination by other forms of psychic interaction. The methodological difficulty in distinguishing different types of extra-sensory transmission and reception had led researchers to use the more general term psi.

There is evidence to suggest that precognition actually does occur -- with all of its ramifications regarding time and free will. Among the most sophisticated tests for precognition were those designed by Dr. Helmut Schmidt, a physicist now associated with the Mind Science Foundation in San Antonio, Texas.

Subjects in his experiments were asked to predict the lighting of one of four lamps which was determined by theoretically unpredictable, radioactive decay. Schmidt gives us the following description of his apparatus:

The target generator consists of a radioactive source (strontium 90), a Ceiger counter, and a four-step electronic switch controlling the four lamps [see illustration]. The strontium 90 delivers electrons randomly at the average rate of ten per second to the geiger counter. A high frequency pulse generator advances the switch rapidly through the four positions. When a gate between the-Geiger counter and the four-step switch is opened, the next electron that reaches the Geiger counter stops the switch in one of its four positions (whichever one it happens to be in when the electron registers) and illuminates the lamp corresponding to that position.

A subject presses a button recording a guess on one of the automated 
testing devices developed by Helmut Schmidt. There is a probability of 
1 in 4 that the subject will score correctly by chance alone. 
(Courtesy Foundation for Research on the Nature of Man)

In precognition experiments, the subject makes her guess before the apparatus makes its random selection of a target. The results of these experiments were automatically recorded and the device was frequently subjected to tests of its true randomness. The instrument can also be modified for experiments in clairvoyance and psychokinesis. In all three modes of psi testing with the Schmidt device, significant results have consistently been obtained.  Many other studies also show precognition.

Schmidt's studies have come under close scrutiny by skeptics. In 1981, psychologist C. E. M. Hansel suggested that Schmidt's experimental designs were not adequate to prevent cheating by Schmidt himself. Fellow skeptic, psychologist Ray Hyman responded to Hansel's critique by pointing out that a charge of possible fraud is "a dogmatism that is immune to falsification." Both points have some merit, and Schmidt himself has in some subsequent studies (to be covered in the forthcoming discussion of psychokinesis research) collaborated with other researchers to minimize the possibility of experimenter fraud. Perhaps the most cogent critique of Schmidt's research is that randomization checks on the instrumentation could have been conducted in a manner which more closely simulated actual experimental conditions. There is no data to suggest that this methodological weakness actually contributed to artifactually inflated psi scores. There is also, unfortunately, no way in which such control tests can be designed to be immune from possible psychic influences!

In 1989, Charles Honorton and Diane C. Ferrari reported a meta-analysis of forced-choice precognition experiments published in the English language between 1935 and 1987. "Forced choice" experiments are those, such as Schmidt's, in which the ESP percipient is asked to select among a limited number of choices -- as opposed to "free-response" experiments in which the percipients' responses are not limited. These studies involve attempts by subjects to predict the identity of target stimuli selected randomly over intervals ranging from several hundred milliseconds following the subject's responses to one year in the future. 309 studies reported by 62 investigators were analyzed. Nearly 2 million individual trials were contributed by more than 50,000 subjects. Study outcomes were assessed in terms of overall level of statistical significance and effect size. There was a reliable overall effect with chance probability less than 10-25. Thirty percent of the studies (by 40 investigators) were statistically significant at the 5% level. A ratio of 46 unreported studies averaging null results would be required for each reported study in order to reduce the overall effect to non-significance. No systematic relationship was found between study outcomes and eight indices of research quality. Effect size has remained essentially constant over the survey period, while research quality has improved substantially. 

Four moderating variables were significantly associated with study outcome: (1) Studies using subjects selected on the basis of prior testing performance show significantly larger effects than studies involving unselected subjects. (2) Subjects tested individually by an experimenter show significantly larger effects than those tested in groups. (3) Studies in which subjects are given trial-by-trial or run-score feedback have significantly larger effects than those with delayed or no subject feedback. (4) Studies with brief intervals between subjects' responses and target generation show significantly stronger effects than studies involving longer intervals. The combined impact of these moderating variables appears to be very strong. A nearly perfect replication rate is observed in the subset of studies using selected subjects, who are tested individually and receive trial-by-trial feedback.

An interesting study comparing real-time ESP tests with tests of precognition was conducted by Charles T. Tart, a psychologist at the University of California, Davis.

Using a measure of information rates, Tart analyzed 53 studies of present-time ESP and 32 studies of precognitive ESP -- all of which used a forced-choice test model. A striking and robust performance difference was found: present-time ESP worked up to 10 times as well as precogntive ESP in forced-choice tests. 

Tart suggested three possible explanations for this finding. (1) Real-time ESP may be emotionally more acceptable than precognition. (2) Perhaps present-time ESP and precognition are two basically different processes, with inherently different characteristics. And (3) something about the nature of time itself attenuates ESP performance that extends into the future.

A study on a single individual, Malcolm Bessent, who has a history of success in laboratory precognitive tasks suggests that that the barriers to precognition may, indeed, be psychological. Bessent completed 1,000 trials in a computer-based experiment comparing precognition and real-time target modes. A diode-based electronic number generator (RNG) served as the target source. Target mode was randomly selected at the outset of each 10-trial run and was unknown to Bessent until the completion of each run. Bessent's task was to identify the actual target from a judging pool of four graphic "card" images represented on a computer graphics display.

Based on Bessent's prior research history, two formal hypotheses were tested by researcher Charles Honorton: (1) Bessent would demonstrate statistically significant hitting in the precognitive target mode, and (2) his precognitive performance would be significantly superior to his performance on real-time targets. Significance criteria were specified in advance. Both hypotheses were confirmed. Bessent's success rate in the precognitive target mode was 30.4%. This is reliably above the 25% chance level. Real time performance did not exceed chance expectations.

As is customary in psi research, various rival hypotheses including sensory cues, faulty randomization, data-handling errors, data-selection bias, multiple analysis, and deception were assessed. Honorton found them to be inadequate explanations of the beyond chance result.

This was the fourth precognition experiment with Bessent, each involving a different methodology and each yielding a statistically significant outcome. The combined result is highly significant with a chance probability of less than one in a billion.

An ingenious experiment, designed and conducted by Dean Radin, using himself as subject, attempted to explore the hypothesis that precognition entails the ability to see probability wave, to see probable rather than actual futures. 

Radin designed a computerized Random Event Generator that would, in effect, change the probabilities of the various targets with each trial. A conventional precognition hypothesis would suggest a greater than chance number of hits for the correct target (regardless of a priori probability). Radin suggested that if precognition involved probable futures, the incorrect responses might still match the targets which were given a high a priori probability of being selected by the computer on a given trial -- even if they were not ultimately selected. This hypothesis was confirmed.

How unfortunate that, while the hypothesis would seem to have enormous ramifications for our understanding of precognition, there is no known way to distinguish the outcome of Radin's experiment from the possibility that he simply used his own psi abilities, if they exist, to confirm his favorite hypothesis.

One of the most rigorous and successful series of precognitive studies has been conducted by Brenda Dunne and colleagues at the Princeton Engineering Anomalies Research program. The Princeton group used a a free-response, remote-viewing procedure which was developed by physicists Harold Puthoff and Russell Targ at SRI International (working in conjunction with research subjects Ingo Swan and Pat Price). 336 experimental trials have been conducted in which randomly selected targets are not chosen or visited until the percipient's responses have been recorded. 

The targets are real-life locations that are actually visited by an experimental agent acting something like a telepathic sender. The experimental subjects or percipients are asked to report any and all imagery which comes to them during the testing period. Then percipients are asked a series of thirty questions about the target which are to be answered "yes" or "no." These questions include such items as whether the target was outside, was it man-made, does a single object dominate the scene, are animals present, is it colorful, are there any loud sounds, etc. A statistical analysis then compares the subjects responses both to the actual target and to the descriptor ratings for all the other targets in the target pool. The results are summarized:

Effects are found to compound incrementally over a large number of experiments, rather than being dominated by a few outstanding efforts or a few exceptional participants. The yield is statistically insensitive to the mode of target selection, to the number of percipients addressing a given target, and, over the ranges tested, to the spatial separation of the percipient from the target and even to the temporal separation of the perception effort from the time of target visitation. Overall results are unlikely by chance to the order of 10-¹⁰.
 

. A survey published in New Scientist, on January 25, 1973, indicate that 25% of scientists polled considered extrasensorimotor phenomena "an established fact." Another 42% opted for "a likely possibility." 

. Harry Price, Fifty Years of Psychical Research. London: Longmans, Green & Co., 1939, pp. 73-74. Price, who founded the National Laboratory of Psychical Research in London, was involved in exposing many fraudulent "psychics."

. Joseph Banks Rhine, Extra-Sensory Perception. Boston: Society for Psychical Research, 1933, pp. 73-74.

. B. H. Camp, [Statement in notes.] Journal of Parapsychology, 1, 1937, 305.

. J. Gaither Pratt, James Banks Rhine, et al., Extra Sensory Perception After Sixty Years. New York: Henry Holt & Co., 1940. This book was a bible, in its day, for card-guessing researchers.

. Rhine and his associates borrowed a German term and designated their experimental work parapsychology. This was done both to distinguish it from t`! earlier term psychical research which was generally a non-experimental field, and to denote an inquiry which was closely related to psychology.

. Rhine, Extra-Sensory Perception.

. George R. Price, "Science and the Supernatural," Science, 122, 359-367.

. C. E. M. Hansel, ESP: A Scientific Evaluation. New York: Scribner's, 1966.

. Ian Stevenson, "An Antagonist's View of Parapsychology. A Review of Professor Hansel's ESP: A Scientific Evaluation," Journal of the American Society for Psychical Research, 61, July 1967, 254-267. Stevenson points out that Hansel based his conclusions on an inaccurate diagram of Pratt's office.

. Betty Marwick, "The Soal-Goldney Experiments with Basil Shackleton: New Evidence of Manipulation," Proceedings of the Society for Psychical Research, 56, 211.

. In the absence of experimental consistency and theoretical underpinnings, some psychic investigators feel it is premature to claim that even the best experiments support a psi hypothesis. Perhaps, in the future, researchers and critics working together will uncover conventional explanations for the existing data. Therefore they prefer to refer to the existing data of psi research as anomalies. See John Palmer, "Have We Established Psi?" Journal of the American Society for Psychical Research, 81, 1987, 111-123; K. Ramakrishna Rao & John Palmer, "The Anomaly Called Psi: Recent Research and Criticism," Behaviorial and Brain Sciences, 10, 1987, 539-551.

. E. Douglas Dean, "The Plethysmograph as an Indicator of ESP," Journal of the Society for Psychical Research, 41, 1962, 351-353.

. E. Douglas Dean & Carroll B. Nash, "Plethysmograph Results Under Strict Conditions," Sixth Annual Convention of the Parapsychological Association, New York, 1963.

. Charles T. Tart, "Possible Physiological Correlates of Psi Cognition," International Journal of Parapsychology, 5, 1963, 375-386.

. Montague Ullman, Stanley Krippner, & Alan Vaughan, Dream Telepathy. New York: Macmillan, 1973. A valuable feature of this book is that, as in ESP After Sixty Years, the authors invited contributions from known critics of their work.

. Naturally these findings caused some scientists to echo the thought of Shakespeare that "we are the stuff that dreams are made of." This notion may eventually take on some rather precise physical and mathematical coloring, as the Pythagorean tradition finds renewal mathematical theorists (see Appendix).

. Stanley Krippner, Charles Honorton & Montague Ullman, "An Experiment in Dream Telepathy with The Grateful Dead," Journal of the American Society of Psychosomatic Dentistry and Medicine, 20(1), 1973.

. John Palmer, An Evaluative Report on the Current Status of Parapsychology. Alexandria, VA: U.S. Army Research Institute for the Behavioral and Social Sciences, 1985.

. Irvin L. Child, "Psychology and Anomalous Observations: The Question of ESP in Dreams," American Psychologist, 40(11), November 1985, 1219-1229. 

. Milan Ryzl, "A Method of Training in ESP," International Journal of Parapsychology, 8(4), Autumn 1966.

. Charles Honorton, Significant Factors in Hypnotically-Induced Clairvoyant Dreams," Journal of The American Society for Psychical Research, 66(1), January 1972, 86-102.

. Edward A. Charlesworth, "Psi and the Imaginary Dream," Seventeenth Annual Convention of the Parapsychological Association, New York, 1974.

. Gertrude R. Schmeidler, "High ESP Scores After a Swami's Brief Instruction in Meditation and Breathing," Journal of The American Society for Psychical Research, 64(1), January 1970, 101-103.

. Karlis Osis & Edwin Bokert, "ESP and Changed States of Consciousness Induced by Meditation," Journal of The American Society for Psychical Research, 65(1), January 1971, 17-65.

. Emille Boirac, Our Hidden Forces, London: Rider, 1918.

. D. Scott Rogo, Parapsychology: A Century of lnquiry. New York: Taplinger, 1975, p. 238.

. Boirac, op. cit.

. Ibid.

. Shiela Ostrander & Lynn Schroeder, Psychic Discoveries Behind The Iron Curtain, Englewood Cliffs, N.J. Prentice-Hall, 1970. pp. 37-40.

. Charles Honorton & Stanley Krippner, "Hypnosis and ESP: A Review of the Experimental Literature," Journal of The American Society for Psychical Research, 63, 1969, 214-252.

. Ephriam Schechter, "Hypnotic Induction vs. Control Conditions: Illustrating an Approach to the Evaluation of Replicability in Parapsychological Data," Journal of the American Society for Psychical Research, 78, 1984, pp. 1-27.

. Ephriam I. Schechter, personal communication, September 12, 1989.

. Rex G. Stanford, "Altered Internal States and Parapsychological Research: Retrospect and Prospect," in D. H. Weiner & D. I. Radin (eds.), Research in Parapsychology 1985. Metuchen, NJ: Scarecrow Press, 1986, pp. 128-131.

. J. Gaither Pratt, ESP Research Today, Metuchen, NJ: Scarecrow Press, 1973. pp. 84-100.

. Martin Gardner, How Not to Test a Psychic. Buffalo, NY: Prometheus, 1989.

. H. Kanthamani & E. F. Kelly, "Awareness of Success in an Exceptional Subject," Journal of Parapsychology, 38(4), December 1974, 355-382.

. Persi Diaconis, "Statistical Problems in ESP Research," Science, 201, 1978, 131-136.

. Stanford Research Institute, news release, October 1974. See also Harold Puthoff & Russell Targ, "Information Transmission Under Conditions of Sensory Shielding," Nature, October 18, 1974.

. Martin Gardner, "How Not to Test a Psychic: The Great SRI Die Mystery," Skeptical Inquirer, VII(2), Winter 1982-83, 33-39.

. Charles Honorton & James C. Terry, "Psi-mediated Imagery and Ideation in the Ganzfeld: A Confirmatory Study," Seventeenth Annual Convention of the Parapsychological Association, New York, 1974.

. Lendell W. Braud & William G. Braud, "The Psi Conducive Syndrome: Free Response GESP Performance During an Experimental Hypnagogic State Induced by Visual and Acoustic Ganzfeld Techniques," Parapsychological Association Convention, New York, 1974.

. Charles Honorton. "Meta Analysis of Psi Ganzfeld Research: A Response to Hyman," Journal of Parapsychology, 49, 1985, 51-91.

. Susan Blackmore, "The Extent of Selective Reporting of ESP Ganzfeld Studies," European Journal of Parapsychology, 3, 1980, 213-219.

. Monica J. Harris & Robert Rosenthal, Interpersonal Expectancy Effects and Human Performance Research. Washington, DC: National Academy Press, 1988.

. Susan Blackmore, "A Report of a Visit to Carl Sargent's Laboratory," Journal of the Society for Psychical Research, 54(808), July 1987, 186-198.

. Adrian Parker & Nils Wiklund, "The Ganzfeld Experiments: Towards an Assessment," Journal of the Society for Psychical Research, 54(809), October 1987, 261-265.

. Ray Hyman, "The Ganzfeld/Psi Experiment: A Critical Appraisal," Journal of Parapsychology, 49, 1985, 3-49.

. Charles C. Honorton, Rick E. Berger, Mario P. Varvoglis, M. Quant, P. Derr, George P. Hansen, Ephriam Schechter, D. C. Ferrari, "Psi Ganzfeld Experiments using an Automated Testing System: An Update and Comparison with a Meta-Analysis of Earlier Studies." Proceedings of Presented Papers, the Parapsychological Association 32nd Annual Convention, San Diego, August 1989, pp. 93-109.

. If the participant choose not to bring a friend, a Psychophysics Research Laboratory staff member served as sender. 

. These courtesies and considerations may seem either obvious or trivial. Experience suggests, however, that they should not be taken for granted. The emotional tone is noticably different where researchers are hostile to the possibility of positive psi results and are suspicious that subjects will engage in fraud.

. This statement, cited in Honorton, et al., 1989 is attributed to correspondence received in May 1989.

. This quote is cited in a news brief titled "Psychologist for Psi," in Parapsychology Review, 20(5), September-October 1989, p. 14.

. National Research Council, Enhancing Human Performance: Issues, Theories, and Techniques. Washington, DC:National Academy Press, 1988, p. 175.

. Ray Hyman & Charles Honorton, "A Joint Communique: The Psi Ganzfeld Controversy," Journal of Parapsychology, 50, 1984, 353-354.

. J. Gaither Pratt � M. Price, "The Experimenter-Subject Relationship in Tests for ESP," Journal of Parapsychology, 1938, 84-94.

. Charles Honorton, M. Ramsey, & C. Cabibbo, "Experimenter Effects in Extrasensory Perception," Journal of the American Society for Psychical Research, 69, 1975, 135-149. 

. Judith L. Taddonio, "The Relationship of Experimenter Expectancy to Performance on ESP Tasks," Journal of Parapsychology, 40, 1976, 107-114. 

. Adrian Parker, "A Pilot Study of the Influence of Experimenter Expectancy on ESP Scores," Parapsychological Association Convention, New York, 1974.

. John Beloff & I. Mandelberg, "An Attempted Validation of the 'Ryzl Technique' for Training ESP Subjects," Journal of the Society for Psychical Research, 43, 1966, 229-249.

. John Beloff & J. Bate, "An Attempt to Replicate the Schmidt Findings," Journal of the Society for Psychical Research, 46, 1971, 21-30.

. John Beloff, "The 'Sweethearts' Experiment," Journal of the Society for Psychical Research, 45, 1969, 1-7.

. Gertrude Schmeidler, Parapsychology and Psychology. Jefferson, NC: McFarland, 1988.

. H. C. Berendt, "Parapsychology in Israel," in Allan Angoff & Betty Shapin (eds.), Parapsychology Today: A Geographic View. New York: Parapsychology Foundation, 1973. p. 68.

. Gertrude R. Schmeidler & Robert A. McConnell, ESP and Personality Patterns. New Haven: Yale University Press, 1958.

. John Palmer, "Scoring in ESP Tests as a Function of Belief in ESP. Part I. The Sheep-Goat Effect," Journal of The American Society for Psychical Research, 65, 1971, 373-408.

. John A. Palmer, "Scoring in ESP Tests as a Function of Belief in ESP. Part I: The Sheep-Goat Effect," Journal of the American Society for Psychical Research, 65, 1971, 373-408.

. Gertrude R. Schmeidler, personal communication, September 18, 1989.

. J. E. Crandall, "Effects of Favorable and Unfavorable Conditions on the Psi-Missing Displacement Effect," Journal of the American Society for Psychical Research, 79, 1985, 27-38.

. K. Ramakrishna Rao, "The Bidirectionality of Psi," Journal of Parapsychology, 29, 1965, 230-250.

. Harvey J. Irwin, An Introduction to Parapsychology. Jefferson, NC: 1989. This is an introductory text, suitable for college classes. In particular, see the discussion on "The Bidirectionality of ESP: Psi-Missing."

. B. K. Kanthimani & K. R. Rao, "Personality Characteristics of ESP Subjects," Journal of Parapsychology, 36, 1972, 56-70

. John A. Palmer. "Attitudes and Personality Traits in Experimental ESP Research," in B. B. Wolman (ed.), Handbook of Parapsychology. New York: Van Nostrand Reinhold, 1977, pp. 175-201.

. Gertrude Schmeidler, Parapsychology and Psychology. Jefferson, NC: McFarland, 1988.

. Robert L. Morris, "The Concept of the Target," in L. A. Henkel & R. E. Berger, Research in Parapsychology 1988. Metuchen, NJ: Scarecrow Press, 1989, pp. 89-91.

. Martin Johnson, "A New Technique of Testing ESP in a Real-Life, High Motivational Context," Journal of Parapsychology, 37, 1973, 210-217. This study, however, was not actually designed to test Stanford's PMIR model.

. Rex G. Stanford & Gary Thompson, "Unconscious Psi-mediated Instrumental Response and its Relation to Conscious ESP Performance," Parapsychological Association Convention, Charlottesville, Virginia, 1973

. John Palmer, An Evaluative Report.

. Rex G. Stanford, "Toward Reinterpreting Psi Events," Journal of the American Society for Psychical Research, 72, 1978, 197-214.

. A. A. Foster, "Is ESP Diametric?" Journal of Parapsychology, 4, 1940, 325-328.

. This works both ways as many PK experiments can be interpreted as evidence of precognition.

. Helmut Schmidt, "A Quantum Process in Psi Testing," in J. B. Rhine (ed.), Progress in Parapsychology. Durham, NC: Parapsychology Press, 1973, pp. 28-35.

. Helmut Schmidt, "A Quantum Mechanical Random Number Generator for Psi Tests," Journal of Parapsychology, 34, 1970, 219-224.

. Helmut Schmidt, "Precognition of a Quantum Process," Journal of Parapsychology, 33, 1969, 99-108.

. Helmut Schmidt, "PK Tests with a High-Speed Random Number Generator," Journal of Parapsychology, December 1973, 105-118.

. C. E. M. Hansel, "Critical Analysis of Schmidt's PK Experiments," Skeptical Inquirer, V(3), Spring 1981, 26-33.

. Ray Hyman, "Further Comments on Schmidt's PK Experiments," Skeptical Inquirer, V(3), Spring 1981, 39.

. J. E. Alcock, A Comprehensive Review of Major Empirical Studies in Parapsychology Involving Random Event Generators or Remote Viewing. Washington, DC: National Academy Press, 1988.

. Charles Honorton & Diane C. Ferrari, "Future Telling -- A Meta-Analysis of Forced Choice Precognition Experiments, 1935-1987," Proceedings of Presented Papers, the Parapsychological Association 32nd Annual Convention, San Diego, August 1989, 110-121.

. Charles T. Tart, "Information Acquisition Rates in Forced-Choice ESP Experiments: Precognition Does Not Work as Well as Present-Time ESP," Journal of the American Society for Psychical Research, 77(4), October 1983, 293-310.

. Charles Honorton, "Precognition and Real-Time ESP Performance in a Computer Task with an Exceptional Subject," Journal of Parapsychology, 51(4), December 1987, 291-320.

. Dean I. Radin. "Precognition of Probable Versus Actual Futures: Exploring Futures That Will Never Be," in D. H. Weiner & R. L. Morris (eds.), Research in Parapsychology 1987. Metuchen, NJ: Scarecrow Press, 1988, pp. 1-5.

. Harold E. Puthoff & Russell Targ, "A Perceptual Channel for Information Transfer over Kilometer Distances: Historical Perspective and Recent Research," Proceedings of the Institute of Electrical and Electronics Engineers, 64, 1976, 329-354.

. Brenda J. Dunne, York H. Dobyns & S. M. Intner, Precognitive Remote Perception III: Complete Binary Data Base with Analytical Refinements. Technical Note PEAR 89002. Princeton, NJ: Princeton University School of Engineering and Applied Sciences, 1989.

. Ibid., pp. i-ii.