J. B. Rhine

Joseph Banks Rhine

Widely considered to be the "Father of Modern Parapsychology." Along with his wife Dr Louisa E. Rhine, Dr J. B. Rhine studied the phenomena now known as parapsychology at Duke University in Durham, North Carolina. He coined the term "extrasensory perception" (ESP) to describe the apparent ability of some people to acquire information without the use of the known (five) senses. The Rhine Research Center in Durham still continues to be a thriving center for parapsychological research.

The First Serious Criticism (of the Duke Experiments)

- J. B. Rhine -

          AT THIS stage of the story nobody should take the existence of extra-sensory perception on faith. What the two preceding chapters have done is to describe certain experiments with cards, tell about the scores which some subjects were able to make with them, and quote the odds against guesswork or chance as the explanation. The tests as a whole, or in their natural subdivisions, gave results that are clearly beyond the best that could be expected from the so-called laws of luck. A figure of over a thousand digits would be required to express the unlikelihood of that solution. Some other factor was causing our results, and so far it has been called "extra-sensory perception" in a noncommittal way.

In explaining the results of these tests a mere abstract citation of mathematical odds against chance as the explanation of our findings is not sufficient. People want every question and doubt answered before they are convinced, and indeed it is sensible to look over again and again every possible alternative before accepting such a revolutionary explanation as our hypothesis of extra-sensory perception. Then, too, the tests on which it is based are so incompatible with certain widely accepted points of view that even though we have found many subjects who can produce high scores there is perhaps a flaw in the method itself or in the way of handling the results. Is chance really excluded by the mathematics used? However conclusive the figures appear, is there not a possibility that the mathematics used in deriving them is faulty or is wrongly applied?

Now, of course, my associates - particularly Mr. Stuart, who is mathematically trained - and I have been asking ourselves these questions from the very beginning. We have had others doing it in other places. We have been in touch with mathematical people all along the way, but most readers have not. For their sake I shall take up these questions here and see if I can show whether we have adequately excluded chance as a possible explanation. This is important because, if there is doubt at this crucial point, the rest of this book will not be even interesting.


To begin with, let us take a simple, commonsense view of the results of the tests. On that basis there are two things to be compared: (1) the scores a subject gets by actually calling the cards through a long series of runs and (2) the scores secured in tests where no subjects called the cards at all simply cross-matching one deck against another. As we have already seen, thousands of these tests have worked out to an average of almost exactly 5.0, and when you reflect that mechanical shufflers have been employed in some of these control tests, as they are called, it is impossible to believe that they did not exclude the faculty or condition, or whatever it was, that made the higher scores of the human subjects possible. But that is not all the precaution we have taken on this point. Thousands and thousands of other matchings have been made to cross-check calls by the subjects themselves. This is easily done by using a different pack from the one against which he made his calls - say, the order of the deck in the run before or the run after. Thus, the records of the subject's calls in his second run are compared with the actual order of the cards in his first or his third run. This, too, ought to exclude extra-sensory perception because the calls were never intended for the cards against which they are checked.

One of the very first things that was done in the evaluation of Pearce's scoring was to take his first thousand ESP trials and compare them with a thousand card records taken from the same pack of cards when no extra-sensory perception was involved. In other words, a thousand of his calls were checked against cards that he did not intend them to match. The cross-check series of 1,000 approximated 5 very closely, giving 5.1 as a result, while Pearce's first thousand trials averaged 9.6 hits per 25, almost double the amount. Various other kinds of cross-checks have been made, as well as the simple matching of one pack of cards against another, and in no case has there been any important departure from the theoretical chance average of 5.0. It is just as easy, then, for one to judge by common sense that something is shown where the results average 9.6 as it would be to look into one's account book and find that there was a profit if the average sale amounted to $9.60 and the cost was $5.10.

For a long time one of my friends, who did not understand the mathematics of probability very well, kept repeating, "But sometime you may find your subjects going just as far in the other direction as now they are going above chance."

In reply I used to appeal to his common sense and say, "For two years now Pearce, to say nothing of the others, has been coming in here several days a week and has been leaving every day a positive deviation. He never goes below chance unless we ask him to. When we do ask him to go below chance and deliberately try to miss the cards, he can do so, sometimes scoring zero. The fact that he can go low at will and can regularly go high for so long a period must be the answer to your claim that we are having just a run of luck. Such voluntary scoring is the very opposite of chance. This man can get a score of 9 or 10 if I ask him for a high score; if I ask him to run low, he can get a 1 or 0; can go back up on the next run if I say 'high' and down on the run succeeding that if I say 'low.' If this is a matter of chance performance, then the rise and fall of that steam shovel I see out the window is a chance performance. And even if the subject does reverse later, and go regularly below for two years? A man may make money on his sales every day for two years; then he may turn round and sell at a loss for the next two years and lose it all again. Is that to say that the whole performance was merely chance?"


Most striking to the people who want the point made as simple as possible are the long unbroken stretches of successive hits. Even 5 successive hits represents odds of more than 3,000 to 1 against a chance occurrence. But when one gets up into 9's, 15's, and finally 25's, one need only know the multiplication table to follow through and find out what the chances are of such an event's being due to nothing but random factors. Or you can even dispense with the multiplication table. Actually, all we have to convince us of the occurrence of things in life is simple repetition in unbroken succession. Apply the simple, everyday rules of common sense to these long stretches, and few people would be likely to say they were accidental.

Fortunately for the skeptics of common sense, the mathematics which applies to these cases has been in use for many years and has been recognized over and over again by the authorities in the field of special determinations of probability. It was first applied to these problems back in the [eighteen] eighties and nineties by the physiologist, Professor Richet, and it was then used essentially as today*. It was used again by Coover (who, you will recall, mistook his evidence to be against nonsensory perception), by Estabrooks, and by several others, including the experts called in to evaluate the results of the widely publicized Scientific American tests for telepathy. It has had the endorsement of the leading authorities of Britain and America. To my knowledge no question of its validity has been raised by any professional statistician or mathematician of probability.

* This article was written in 1937.

Granted, then, that the mathematics is sound and appropriate to these results. have we somehow made a mistake in the way we have applied it? There is a good test for this too: we may know reliably that we have not made such a mistake because we get only figures appropriate to chance when we apply the mathematical tests in the same way to experiments carried out under conditions identical in every point with the test experiments, except that, since no human mind has made any of the calls in the series, ESP has been so positively excluded that only chance factors can possibly be operative. From these non-ESP experiments we get the same results to be anticipated from mere chance data. At the moment of writing, a group of papers is going to press for the Journal of Parapsychology reporting such parallel experiments. In every case chance conditions give figures that would be expected. In every case the ESP tests, differing only in that extra-sensory perception was allowed to operate if it could, show that something beyond chance is at work. There is logically no criticism left to level at the use of the mathematics in the case.

So much for chance. We have had it as our ever-present competitor. We have always been alert to its claims. But as a theory for these results it "hasn't a chance"!

But suppose the subject has personal preferences and calls twice as many circles as other symbols. Might this not favor him? The answer is "no" since, even if he called all 25 of the cards circles, the most he could get would be 5. The more circles he calls the greater chance he has, of course, of getting a good proportionate score among the five circles in the pack, but a proportionately small chance is left for his getting the other twenty cards right. Preference cannot help him on his total score.

A shuffling box to insure mechanical shuffling. The lid is to put on and the box slowly tipped, one end up and then down, not less than five times. Five ESP cards are displayed against the lid of the box.


Can any method of shuffling the cards or any natural sequence of cuts give peculiar upcurves or downcurves in the scoring of these control series? The many practical test checks that have been made on just this point furnish the best answer. They average close to 5, with no long-drawn-out stretches of runs that would yield significant deviations.

For years one of the most common objections that we encountered was: "But might not the subject use reasoning, as in card games? Suppose he has called all the symbols five times over except one let us say, star, and he has two calls to make. Will he not reason that these now must be stars because he has called all the others?" Obviously, as I have suggested already, he has no way of knowing whether or not the other calls have been correct, so it would be most unfounded reasoning to conclude that the last two must be stars. Only if he knew the correctness of the cards already called could reasoning help him, and this he does not know. Therefore, the chances remain the same on the twenty-fifth call as on the first, since he is just as ignorant about what that card is.

"Might not a subject use some system of advantage to him?" How can he, if he has nothing to go on? If he does not know whether his calls are correct or incorrect, no system could work. A system without a basis in fact would be nothing but a delusion.

A curious question has been raised and vehemently urged in one or two places. It is supposed that all our investigators in this research might be stopping at some strategic moment - say, after some high scores have been made and just before a series of low ones might be made. The very essence of this question is to assume that we can tell somehow by previous runs what the next ones are going to be. If our results are due to chance, this could not be done. What we mean by the term "chance" is the very absence of a fixed order and predictability. However, to settle the matter, one of my critical colleagues, who believed this was a weakness in our work, tested out the supposed principle in actual experimentation and found no evidence of it.

At times we have been told that perhaps something is wrong with our using a pack of 25 cards, and we have been urged to try packs of 100 or 1,000. There are no adequate mathematical grounds available for such insistence, and even from a common-sense point of view it is difficult to see what difference it would make. However, some of our best work has been done without adhering strictly to a pack of 25. It will be recalled that Pearce's twenty-five straight successes were made by calling one card, checking it at once, returning it to the pack, and cutting. In this way the pack was an unending one. It might have been a hundred or a thousand or any other number. Considerable later work has been done with packs of 50, and on some occasions of even larger size.

After weighing all the criticism we have been able to get in seven years' time, I have come to feel as much security in the general soundness of the research as is good for an investigator in science to have. Reflecting upon the enormous amount of work that has been done here and elsewhere, it seems to me that no inferential scientific conclusion has ever had so much evidence in its support; that is, in excluding a chance hypothesis. The mathematics has been questioned, yes, but not by a single mathematician. Two psychologists have written a total of four articles criticizing it, but the author of three of them has become satisfied that his criticisms do no apply now that he has what he feels is sufficient further information. A third psychologist has more recently published a review of the criticisms, and he asserts that the statistics used in this research are substantially correct.

Among mathematicians the best authority is with us. Confirmatory mathematical checks have mounted by tens of thousands, not only in this laboratory but in a number of other places. It is difficult to see what further mathematical criteria can be applied to evaluate the results of our tests.

Thus far, it would appear, we have been on sound territory. Whatever we have claimed to be beyond chance has stood the tests and is safe. But our experiments are still going on. They are going on into yet more meaningful, more revolutionary lines. The strain upon this mathematics of probability will be increasingly great with every advancing step along the lines we are at present following. With the enormously greater burden anticipated for this technique of evaluation, it is high time that we secure the last word, both in criticism and in support. We shall need it.


The article above was taken from J. B. Rhine's "New Frontiers of the Mind" (1937, Farrar & Rhinehart).

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