C. E. M. Hansel portrait

C. E. M. Hansel

British psychologist. Head of the Department of Psychology at the University of Wales at Swansea. Fellow of the Committee for the Scientific Investigation of the Claims of the Paranormal.

Is ESP a Fact?

- C. E. M. Hansel -

          THE BASIC problem of parapsychology is relatively simple when compared with problems in politics or aesthetics. Either it is possible for at least some people to communicate by extrasensory perception, or else ESP does not and cannot exist because the underlying processes necessary for its occurrence do not exist. A great deal of experimental work has failed to provide a clear case for the existence of ESP, but at least two facts have been established: first, subjects when trying to guess card symbols have obtained scores that cannot be attributed to chance; second, some of those taking part in ESP experiments have cheated to produce high scores.

The first fact cannot be disputed. Results such as those obtained by Hubert Pearce or by Riess's high-scoring subject need no statistical analysis for the purpose of establishing that something was happening during the experiments other than pure guesswork. The second fact that those taking part in experiments sometimes cheat is known from admissions of trickery. The first 2 major experiments in Great Britain on the Creery sisters and on Smith and Blackburn in 1882, involved 8 subjects, 7 of whom admitted to cheating, and the other did cheat according to his partner in the act. The last major investigation in Great Britain, on the Welsh schoolboys in 1955-1957, involved 2 subjects, both of whom admitted to cheating after being caught in the act. It would be remarkable if such attempts to assist the natural course of events ceased altogether in parapsychology between the years 1882 and 1956. In fact, close examination of the most spectacular findings in parapsychology invariably points to some form of trickery as an alternative to ESP. To the skeptic, psychical research seems to have been as much a history of the manner in which the artful can mislead the innocent as it is a reflection of any more esoteric activity.

Is ESP a Fraud?

Cheating in one form or another is one of the commonest of human activities. If it never occurred, much of the expense and complication of modern life would be avoided. The paper work involved in accounting and auditing - tickets, bills, counterfoils, invoices - would no longer be necessary. Games, examinations, competitions, and numerous such activities would be simplified. On the other hand, it is unlikely that more than a small number of experiments on ESP are affected by cheating, since the investigator does his best to ensure that his subjects cannot cheat and, no doubt, usually succeeds. The majority of investigators are likely to have sufficient faith in the reality of ESP to believe that it will manifest itself without outside aid. It may then seem strange to the reader that so much space has been given here to the matter of trickery. Why in the case of each of the so-called conclusive experiments should trickery invariably emerge as a likely alternative to ESP?

One reason is that an experiment is not classified as conclusive unless the known causes of experimental error have been eliminated in its design. If a trick is used in an experiment, it might be expected to produce an impressive result having large odds against arising by chance and, if the experiment is of the "conclusive" category, trickery would be the only alternative explanation to ESP. Thus, the process by which conclusive experiments are weeded out will also bring to light experiments in which a trick has been used.

A trick also involves a trickster. The following remarks made by George R. Price are very relevant.

The wise procedure, when we seek to evaluate probability of fraud, is to try to ignore all vague, psychological criteria and base our reasoning (i) on such evidence as would impress a court and (ii) on purely statistical considerations. And here we must recognise that we usually make a certain gross statistical error. When we consider the possibility of fraud, almost invariably we think of particular individuals and ask ourselves whether it is possible that this particular man, this Professor X, could be dishonest. The probability seems small, but the procedure is incorrect. The correct procedure is to consider that we very likely would not have heard of Professor X at all except for his psychic findings. Accordingly, the probability of interest to us is the probability of there having been anywhere in the world, among its more than 2 billion inhabitants, a few people with the desire and ability to produce false evidence for the supernatural.[1]

[1] G. R. Price, Science (1955), p. 363.

There is one psychological criterion, however, that even a court of law would regard as impressive. That is the question of motive. Why should people go to all the trouble of entering into complicated conspiracies merely to deceive their fellows? It should first be noted that there are many cases of known trickery in science where the motive is not clear. The Piltdown skull discovered in 1912 that at first appeared to be an important piece of evidence in the history of man's development involved the trickster in a lot of work for little apparent gain.

However, in the case of many individuals acting as subjects in parapsychology there is often a very clear motive. Mediums at one time in the United States were said to constitute the second highest paid profession open to women, and where monetary gain is not involved, there may be the desire to impress or to gain prestige. In the case of each of the major experimental investigations to which a chapter has been given in this book, there is a possible monetary or prestige motive for trickery.

In the early 1930's at Duke University, during the Depression, students who acted as subjects in ESP experiments were paid an hourly wage for their services. If Pearce was paid to act as a subject, he had every incentive to continue in that capacity. The Pratt-Woodruff experiment was a continuation of work started by Woodruff constituting part of the requirement for a higher degree. The Soal-Goldney experiment gained Soal his Doctorate of Science at London University. Would that degree have been given for a series of negative experiments? Mrs. Stewart was paid for her services. The Jones boys earned large rewards for high scores.

Parapsychologists are themselves to blame for the emphasis that has to be placed on cheating when considering their work. In science generally it is likely that, at times, investigators indulge in underhanded activities, but their experiments are shown up when other scientists fail to confirm their result. In such cases it may not be necessary to hold a long post-mortem on the earlier experiment; it is just forgotten. However, parapsychologists - or at least some of the more vociferous of them - in denying the necessity to confirm experiments by repetition, make it essential to examine every experiment in detail in order to ensure that the result could not have been caused by cheating.

It is often difficult to discuss the possibility of cheating objectively. Parapsychologists tend to present their critics with a fait accompli. A similar situation would arise in orthodox science if a chemist reported an experimental result that contradicted all the previous research findings and theories of his fellow chemists, together with the statement "Either this finding must be accepted as valid or else you must accuse me of being a cheat and a liar. Do you accept it?" In such circumstances, orthodox chemists might feel diffident about openly expressing their doubts. They might, however, repeat the experiment to see whether they got the same result. If they failed to confirm his result, they would not go into a long discussion as to whether the original investigator was a liar or a cheat. They would just take with a grain of salt any further experimental reports from the same source.

The trickster has often been assisted by the investigator's overwhelming confidence in his ability to detect trickery. Observers, however careful, must be prepared to make mistakes. But in psychical research many of the investigators have considered themselves infallible. Soal claimed that boys of the caliber of Glyn and Ieuan could never hope to deceive him.

If a trick is used in an experiment, this fact might be expected to make itself apparent in the course of further research. But parapsychologists have erected a system that aids the trickster and at the same time preserves experimental findings.

Survival Characteristics of ESP

Scientists in general have been little influenced by philosophers who strive to inform them about the methodology and logic of their subject. Science has a basic methodological principle that is self-generating. It was not formulated by anybody, but it has the same empirical basis and underlying logic as the principle of natural selection in evolution. Investigators are continually producing reports of their experimental findings, which may be classified, for convenience, as good and bad. The good ones survive because they are confirmed in further research. The bad ones are forgotten because they cannot be confirmed. Science advances through a process of natural selection. New findings become targets for criticism, and a finding must be confirmed by critics under their own experimental conditions; it then soon becomes clear when it is to be rejected.

If anyone invents a pseudoscience in which this principle ceases to operate, the result soon becomes apparent, for the new "science" fails to have predictive value and leads to more and more findings and theories that are incompatible with orthodox science. This is what has happened in parapsychology. When critics fail to confirm ESP, this is not accepted as a reason for dropping the subject; on the contrary, belief in the reality of ESP is so strong that the principle of repeatability has been rejected or rendered impotent by the invoking of new processes which are claimed as subsidiary characteristics of the phenomenon. Thus, given a high-scoring subject, it would in the normal course of events be only a matter of time before every critic could be silenced, but these subjects cease to score high when tested by critics. Extrasensory perception only manifests itself before uncritical investigators. Again, Rhine and Pratt have observed, "Another major difficulty can be seen in the fact that some experimenters after a period of earlier success in obtaining extra-chance results in psi experiments have proved less effective in their later efforts. In such instances something apparently has been lost that was once a potent factor. The element most likely to change under prolonged testing would seem to be the quality of infectious enthusiasm that accompanies the initial discoveries of the research worker. Those who never succeed at all may, of course, be suspected of not ever having felt such contagious or communicable interest as would help to create a favorable test environment for their subjects."[2] In other words, experimenters fail to confirm their own results. And a further subsidiary characteristic emerges: ESP is affected by the mental state of the person investigating it.

[2] Rhine and Pratt, Parapsychology, p. 132.

If fresh characteristics are postulated in this manner, it is possible to survive almost any form of criticism. An experimental result cannot be confirmed or refuted since ESP does not operate in front of critics. After tightening up his experimental conditions, an investigator cannot disclaim the findings of his earlier work; failure in later work reveals that he has lost his enthusiasm.

Since the chief characteristic of the exploratory stage, according to the statement of Rhine and Pratt given on pages 22-23, is that the investigator carries out his work "without being burdened with too much precautionary concern."[3] Failure to confirm earlier work is likely to arise when the investigator graduates from the exploratory stage to one where he takes more care with his work. After an investigator becomes burdened with concern, his precautions will, presumably, be against error and trickery rather than against ESP. It may be assumed that any change in his experimental results is due to the effectiveness of his precautions.

[3] Ibid., p. 19.

A Revised Approach

At the present time, there are signs that the arguments put forward to support the work on ESP may be changing. Rhine and Pratt in recent writings imply that the case for ESP does not, after all, depend on conclusive experiments, but on general features that emerge from the whole mass of studies, conclusive or inconclusive; it is as if quantity can make up for quality when the latter has been found lacking. They write:

The body of fact in parapsychology is like a many-celled organism. Its strength is that of a growth-relationship, consisting not only of the compounding of one cell with another, but also of the many lawful inter-relations that emerge in the growing structure. Going back as Hansel has done, with a one-cell perspective, to fix attention on some incomplete stage of development within a single experimental research is hard to understand in terms of healthy scientific motivation.[4]

[4] Rhine and Pratt, Journal of Parapsychology (1961), p. 94.

What is the point of presenting conclusive experiments for the consideration of the scientific world if they cannot be criticized? How can an experiment be criticized until it has first been isolated? If experiments are to be considered en masse, will not data be confused with results such as those obtained with the Creery sisters and Smith and Blackburn? But as soon as criteria by means of which experiments are selected or rejected are set up, it becomes necessary to isolate each experiment to see whether it satisfies those criteria.

Moreover, what precisely are the "lawful inter-relationships" within the body of fact in parapsychology to which Rhine refers. To date, not a single lawful inter-relationship appears to have been established. How, for example, does distance affect extrasensory perception? The relationship between scoring rate and distance is completely chaotic, apparently dependent on the investigator, the subject, and the experimental conditions. If it were possible to give a standardized test for ESP to different groups of subjects, systematically varying factors such as age, nationality, intelligence, previous practice, distance, and so on, some lawful inter-relationships might eventually be expected to reveal themselves. But each of the reported investigations yields a result that has little relationship to any of the others.

Extrasensory perception is not a fact but a theory put forward to account for observations consisting of high scores obtained during the course of experiments. Parapsychologists have made such observations under a diversity of research conditions from which a number of facts emerge. If these facts can be related to one another by a theory that enables any one to be deducible from knowledge of the others, that theory has some value and plausibility. By means of it predictions might be made of what will happen in further experiments so that it can be put to further test. However, a theory that fails to account for a variety of facts and that cannot predict what will happen in further tests is of no value.

If some facts gleaned from the literature on ESP are assembled, they might appear as follows:

1. Subjects, when attempting to guess card symbols, have obtained scores that cannot be attributed to chance.

2. Some of those taking part in ESP experiments have indulged in trickery.

3. Subjects who obtain high scores cannot do so on all occasions.

4. Subjects tend to lose their ability to obtain high scores. This loss often coincides with the termination of an experiment.

5. A successful subject is sometimes unable to obtain high scores when tested by a critical investigator.

6. Some investigators often observe high scores in the subjects they test; others invariably fail to observe such scores.

7. A subject may obtain high scores under one set of experimental conditions and fail to do so under other experimental conditions.

8. No subject has ever demonstrated his ability to obtain high scores when the test procedure is completely mechanized.

Fact 1 is directly applicable to a hypothesis of the existence of ESP. Fact 2 is not relevant to such a hypothesis. Facts 3 and 4 are not predictable but could be said to provide further information about ESP; that is, it appears to be spasmodic and temporary. The remaining facts (5-8) are not predictable, and in the case of any other supposed process investigated by psychologists, would throw doubt on its authenticity. These facts can only be explained by invoking subsidiary characteristics of ESP.

Again, fact 1 is directly applicable to a hypothesis predicting trickery. Fact 2 demonstrates that such a hypothesis is correct in the case of certain experiments. The remaining facts (3-4) are all predictable from what is well known about trickery.

Lawful relationships can readily be seen among the facts when they are interpreted in accordance with the hypothesis of trickery. Thus, for example, from fact 7 it might be predicted that those experimental conditions that eliminate the possibility of trickery will also be the ones in which high scores do not arise. This is confirmed by fact 8, and also by examining the experimental conditions under 7 in which high scores have and have not been observed.

Thus the set of facts given above display lawful inter-relationships when interpreted in terms of the hypothesis of trickery, but they are difficult to reconcile with a hypothesis based on the existence of ESP.

A number of other facts could be added to the above list to which neither a hypothesis of ESP nor that of trickery would be applicable. This is to be expected, since a great deal of research both in parapsychology and elsewhere has revealed the manner in which high scores can arise through experimental error.


During the past 85 years, a large number of investigations have been reported, the majority of which no responsible parapsychologist would claim as having been designed or intended for the purpose of providing conclusive evidence for ESP. Only a small number of studies were begun with the intent to provide such evidence.

The aim of this book has been to isolate the conclusive experiments and then to indicate that other explanations than ESP can account for their results. In the case of each of these conclusive experiments, the result could have arisen through a trick on the part of one or more of those taking part. In addition, closer examination of the experiments to see how far the hypothesis of trickery is consistent with information concerning the experiments in no case invalidates the hypothesis and in some cases strengthens it.

It cannot be stated categorically that trickery was responsible for the results of these experiments, but so long as the possibility is present, the experiments cannot be regarded as satisfying the aims of their originators or as supplying conclusive evidence for ESP.

A great deal of time, effort, and money has been expended but an acceptable demonstration of the existence of extrasensory perception has not been given. Critics have themselves been criticized for making the conditions of a satisfactory demonstration impossible to obtain. An acceptable model for future research with which the argument could rapidly be settled one way or the other has now been made available by the investigators at the United States Air Force Research Laboratories. If 12 months' research on VERITAC can establish the existence of ESP, the past research will not have been in vain. If ESP is not established, much further effort could be spared and the energies of many young scientists could be directed to more worthwhile research.


The article above was originally titled 'Conclusion' and was taken from C. E. M. Hansel's "ESP: A Scientific Evaluation" (London: Charles Scribner's Son, 1966).

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