Sacred Texts  Parapsychology  Index  Previous  Next 
Buy this Book at

Extra-Sensory Perception, by J. B. Rhine, [1934], at


Some General Biological Considerations

There are a few general points of interest that do not belong in the more special departments of the preceding chapters and they justify, I think, a brief one of their own.

One of the questions of some importance not yet considered is that of family strains and E.S.P. Does the ability "run in the family"; is it heritable? This is a difficult matter to answer but an impression may be

p. 154

of interest. This impression cannot be clearly supported by adequate evidence as yet but we do have a few data in its favor. It is also in line with the popular notion, so far as there is one. My impression is that there is some heritable basis for marked E.S.P. ability. When I learned that the mother of a certain individual had possessed "mediumistic" ability, I rather expected to find a good subject in him and this judgment proved to be correct. All my major subjects, except one, have a parent or aunt, and often both, who are reported to have had at least one definitely parapsychological experience. And the one exception states that the mother is "very intuitional", which, as she used it, means "clairvoyant" in small daily things. In five of the other seven cases, there is more than one relative that has been parapsychic. These are all (with one exception) on the same side of the family, too (that is, always blood relations), but are of both sexes. The reader may better judge in how far these are applicable to the general rank and file of humanity if some of the details are given. Since some of these details are confidential, I shall give the subjects arbitrary numbers and refer to them all as masculine. No. 1 states that his mother and her uncle were both parapsychic. The phenomena consisted of premonitions, mind reading and character reading. Instances have been related to me. No. 2 had a parapsychological family on the father's side, with only a minor experience by the mother, and this was co-incident with the father's experience. The joint case was of a prophetic dream, experienced on two successive nights by both father and mother, of an unexpected event. The other experiences, by the father's side only, consisted of detailed prophetic dreams and monitional experiences connected with death. The father's father, too, was reported to have been parapsychic. No. 3 has a very parapsychic mother, who had strong clairvoyant power, believed she was in touch with spirit agencies and that through them she could give parapsycho-physical manifestations. The subject testifies to having witnessed these himself, under good full light conditions, and remains convinced that they occurred, although doubtful about the explanation given. Brothers of the sensitive also possessed some ability of the sort; on these, however, there are no further details given. No. 4 states that his uncle has experienced different para-psychical occurrences, chiefly of clairvoyant and previsionary character, and has had, in general, much the same sort of experience as he, himself. His own have included hearing a deceased relative's familiar footsteps, hauntings of hallucinatory sounds that did not disturb others, previsionary clairvoyance, etc. He and his uncle are said to be much alike in personality. At least 4 members of the family have been awakened by apparent "haunting" phenomena. No. 5 says his mother has had many premonitional dreams and monitions of the death of friends. She occasionally

p. 155

warns the children of a coming danger and often knows of their unexpected danger when they are at a distance. She is generally clairvoyant but it is a casual sort of thing with her. No. 6 informs us that his mother had one veridical spontaneous psychic experience, a visual hallucination of a brother being wounded in France and carried off the field, with close time and fact coincidence. Her sister was given, in life, to veridical dreams concerning relatives particularly. Although No. 7 himself has had an hallucinatory experience of his deceased grandfather's voice, he can credit his mother only with being unusually "intuitional"; the mother says playfully that she is clairvoyant. No striking experiences can be related, however. No. 8 has an aunt and grandparent on the mother's side who have had parapsychic experiences in connection with religious experiences. The mother herself is very intuitive, especially on character-judgment. It must be emphasized strongly that these subjects are all normal, healthy, intelligent young men and women, not peculiar in any way and without pathological heredity, so far as they know.

More of the subjects have parapsychic relatives, apparently, than do people in general, but a general questionnaire and statistical study would be needed to evaluate these cases. It will be better, however, to do this when the number of subjects becomes larger, since an extensive study would be required for final decision. There is, then, only the general impression that there is perhaps some inheritance of a general parapsychological sensitivity which is represented by the E.S.P. we are measuring. Casual inquiry among friends who may or may not have marked E.S.P. ability does not reveal the high percentage of psychic family connections given in these 8 subjects. The four of the poor E.S.P. subjects who have been asked have not been able to claim any parapsychic relatives; of course, this number is not regarded as large enough for a basis of judgment. 1

The very biological question of the comparative range of the E.S.P. capacity among the species does not enter into the work here reported, directly. This interesting question has, however, already its own literature. Our own work with the filly, reported in 1929 2 has convinced us of the E.S.P. capacity in at least one horse and the work of Bechterew on telepathy in dogs seems quite satisfactory as reported. Further than this, I feel disinclined to venture. There are claims for telepathy in the more social animal species but there is not the rigid experimental proof required for so important a conclusion. The point was made in Chapter 11

p. 156

that the drug and fatigue data seemed to indicate that E.S.P. may be a higher, more complex development than sensory perception, and, the suggestion follows logically, is probably a later development in mental and cerebral evolution. This is unfavorable to the view held by some without even this amount of facts to support it, that E.S.P., in man, is an atavism.

The extent and level of E.S.P. in our own species constitute points of importance. We cannot say how large a percentage of people are capable of E.S.P. until we have tried larger numbers under good conditions. There is no ground for a decision, as we now can see, in a few tests given in a classroom, or under any other conditions preventing abstraction. Even our best subjects cannot succeed under such conditions after months of experience at the work. Negative results are never final. It is impossible, with our present knowledge, to know if the conditions are adequate for judgment. But some small notion of the number of good E.S.P. subjects existing 1 may be gained from the facts on our own departmental students. Of the 14 graduate students in psychology present in the last two years, 6 have shown E.S.P. ability that is statistically significant. One other has been reported to have done work appreciably significant but I do not have his results. There are 7 others remaining. These have never been tested, to my knowledge. But even allowing for no ability in the remaining half, we have 50%. Will some one say that psychology students are a select lot? Estabrooks said he found them singularly poor as subjects; they were too introspective.

Very few subjects have run very long without scoring above chance, to some extent. Of course, initial failure soon discourages many. And about them we never really know. With persistence, they might succeed! My impression is, on this, that most people can run at least a little above chance, with patient persistence and interest, under favorable conditions of quiet, isolation and abstraction. Stuart's work, and that of Dr. Lundholm and myself, carried out with all the subjects who came (a total of 77 subjects), all back this up. Then, too, whether the poorer are really weak in E.S.P. or whether there are merely obstacles in its way, we cannot yet determine. The better subjects may simply be better able to abstract or they may be better able to retain patient interest. For aught that may be said to the contrary, E.S.P. may be as widely distributed a natural capacity in the species as is that highest mode of cognition, reasoning. Even this requires conditions for success—purpose, degree of integration of effort, not too much distraction to permit attention. Very possibly the delicate nature of E.S.P. and the complex

p. 157

conditions required may conceal it from our tests—even without preventing its functioning in the freer circumstances of daily life.

Among the better subjects there is what may well be a kind of "species level". They mostly score on an average of between 8 and 11 per 25, both P.T. and P.C., if conditions are good. See column 3 of Table XLII. All 8 subjects do this, except when a disturbing factor enters, as illness, drugs or a decline of E.S.P. capacity (as with Linzmayer and Stuart). If we take the total normal scores of the 8 major subjects (before they began to decline in the cases of Linzmayer and Stuart) and leave out drug, illness, D.T. and other special data that do not represent the regular function of E.S.P., we get only one exception. This is Zirkle, who is unusually high on P.T. and not significantly above chance on P.C. If we include the P.T. work done during his long, mild illness (2,700 trials), his score average drops within the range indicated, 10.7, but this would, of course, not be justifiable.


Normal E.S.P. Averages of Major Subjects



per 25





1st 600 trials before decline.




1st 500 trials before decline.




All B.T. trials up to 4-1-33.




All E.S.P. trials to 4-1-33; no decline.

Miss Ownbey



B.T. and P.T. trials; no decline.




P.T. only; health good; no decline.




Includes his illness data.

Miss Bailey



B.T. and P.T.; no decline.




B.T. and P.T.; no decline.

Miss Turner



B.T. and P.T.; no decline.

The averages shown in Table XLII run remarkably close together, in view of the wide range of differences to be expected in such a group or any other delicate or complex mental endowment. Any complicated task we could propose might be expected to show greater differences, I think. These eight subjects represent, by the very fact that we have worked with them so much, the more successful subjects. But in most mental tasks the more one selects the better subjects, the greater the diversity and peculiarity between them. It is not common to find a "species wall" as a limitation. Yet here such a limit is suggested. And this makes E.S.P. capacity appear more like native species endowment perhaps, since we would not expect acquired abilities to stop thus in their development, at a common level; that is, this appears somewhat more like an innately given

p. 158

perceptual range, like the species range of sound or light perception. This is, of course, speculative analogy, representing a beginning of inquiry rather than a conclusion. The subjects can all "jump" this "species wall" for short periods, as in the occasional very high scores, even ascending to 25 consecutive successes, but for the averages and the long runs, the "species range" of from 8 to 11 seems to be (excepting Zirkle) the natural level. Of the two conditions, the P.C. remains the more stable. P.T. varies more widely; it has two human variables and two E.S.P. elements probably at work.

We have yet to explain the curious decline of Linzmayer and Stuart, or, as more experienced parapsychology students would put it, the curious failure to decline on the part of the others. It has been the great misfortune of so many workers to find that their telepathic subjects have lost their ability after a period of very good results. From the Creery sisters, on down to Van Dam (in Bruggmann's laboratory) and Lady, the filly, in our own experience, this disappointment has been an all too common one. (It may explain the tendencies of some subjects in the past to have recourse to deception in their later work, when they have achieved a reputation that has to be maintained—as they see it—at all costs. Or it may well be that they have "rationalized" the earlier telepathic results from a later viewpoint of incapacity and have decided they must have been cleverly deceiving, without realizing it perhaps; this would make it "reasonable", at least, and might be the only way for them to make it so.)

The decline of Linzmayer began in June, 1931, with my urging him to work against his obvious wish to leave. He ran below chance then, as I had expected and hoped he would do. This was, however, a great strain for him, and perhaps the ruthlessness of the method permanently injured his capacity for E.S.P. by inducing strained or unwholesome memories and attitudes. He is still interested, but I think that possibly he can never really feel the same toward the experimenter and his plans; he has also a strong negativism of which he is hardly conscious (but which is apparent in hypnotic tests), which may be activated to cause a certain conflict and oppose the abstraction necessary for high scoring. Failure is very discouraging to Linzmayer, and he has become more and more chagrined by his inability to return to his original level. This makes it still harder for him to "concentrate" and so the "vicious circle" of decline goes on. His "decline curve" is given in Graph No. 6, representing the four periods of work he has gone through, omitting the purposively planned low-scoring period mentioned. For the fuller data see Table XII in Chapter 5. The averages per 25 trials dropped as follows: 9.9, 6.9, 6.8, 5.8.

Stuart declined slowly over a long period of about a year, rose again and, a few months later then, he declined once more—this time much

p. 159

more promptly, in less than two months. The first 500 trials were within the 8-to-11 range, which I have come to think may be typical of most normal E.S.P. subjects at their best over long periods. But, while this first 500 gave an average per 25 of 9.0, the next 500 dropped to 6.6 and the next still lower. The decline, as shown by dividing the 7,500 into

Graph No. 6. Decline of E.S.P. ability in Linzmayer. The curve represents scoring-rate for 4 major periods of work.
Click to enlarge

Graph No. 6. Decline of E.S.P. ability in Linzmayer. The curve represents scoring-rate for 4 major periods of work.

[paragraph continues] 5 groups of 1,500 runs each, is as follows, in averages per 25 trials: 7.1, 6.1, 5.7, 5.9, 5.4. See Graph No. 7, A. On the return to scoring, while the graph shows the B curve starting higher than the A, Stuart really did not rise in the second period to the level of the original 500. 7.3 was the highest he made for as many as 400 trials. For about the same number of trials he held up above 7.0, both times and then dropped to around 6.0.

The explanation of these declines is not easy and at most an hypothetical suggestion is offered. Stuart worked alone and would likely get

p. 160

the full monotony of the procedure in that way, certainly so in the course of many thousand trials. He was working without any other motivation than his own interest; at least, without pay, and without any urging or suggestion on my part. What wonder if the motivation of his own interest should weaken somewhat after so much work that is so exhaustive of time and patience! This is my preferred hypothesis—he lost interest,

Graph No. 7. Decline of E.S.P. ability in Stuart. A, first period, 1931-32. B, second period, Summer, 1932. Average scoring-rate is shown for each period, in each case subdivided into five parts, by number of trials.
Click to enlarge

Graph No. 7. Decline of E.S.P. ability in Stuart. A, first period, 1931-32. B, second period, Summer, 1932. Average scoring-rate is shown for each period, in each case subdivided into five parts, by number of trials.

became a little tired of the business and needed a rest from it. Let the reader try 7,500 trials, if he doubts the need for a rest and change of scene. This view may not be correct, but it is both an adequate hypothesis and a probable situation. At the end of the 7,500, when he complained of low scoring and I suggested he might be bored with the business, he admitted that he might need a change. Only a few months later he returned to a level of 7.3 but has not yet come back to 9.0 in 25.

While, then, there may be a "species level" at the top—at least, it is favored by the facts so far—there is none at the bottom. Subjects can be made to decline, either indefinitely, as if by a fixed limitation, or, perhaps, just until a rest is had or a new interest aroused, as illustrated by Linzmayer and Stuart, respectively. Several of our minor subjects, too

p. 161

[paragraph continues] (Miss Weckesser and Pratt, for example), have declined to a "chance level", how permanently we do not yet know. But the majority of the major subjects are holding up very well, with no serious signs of decline. (Just at the moment of writing this I am informed that Pearce, who has worked more than any other subject, has scored 11 and 9 in two runs of P.C. with the cards in one building and himself in another, 250 yards away. A few days ago he finished a series at 100 yards with 13, 13, 12. He is evidently not in danger of running down.) This is important not only in its experimental convenience and not merely as a further fact in the psychology of the E.S.P. processes, but in the general biology of E.S.P., with which we are at the moment most concerned.

For E.S.P. is a biological phenomenon and one that might obviously be of tremendous value to the species. To the hunter, the warrior, the seaman—in fact, to most all life situations—E.S.P. might serve in many ways to give man an important margin of advantage over his enemies and his environment in general, so that the question of its permanence is most serious. Were it characteristically to flit in and out of functioning, its biological significance would be reduced almost to nothing. But if it does, as we find, only relatively rarely decline (if, indeed, it has not merely declined for our particular experimental situation), we can regard it as having biological survival value to any species possessing it. In homing, migration, food-seeking, mating and all the processes where cognition is a primary essential this mode of perception might be of value, if it exists and functions in the species. The fact, however, that it has not been more clearly observed in the many observations made on animals would seem to exclude it from any considerable importance to animal existence. Or could it be that it has not been seen because it has not been looked for?

In our own species, however, extra-sensory perception occurs and may be demonstrated in many normal people in undeniable fashion. In the light of the foregoing observations, it seems to be a fairly dependable and persistent capacity, when it is given proper conditions for its functioning. These are facts which any comprehensive biology must face and study, if it is to treat faithfully of the natural history of our species.


155:1 Another instance of relation between E.S.P. ability and general parapsychology has been found recently. Mr. Finan, another of our graduate assistants, stated to Mr. Stuart that he came from a "psychic" family. Stuart forthwith tested him at B.T. and he scored 8. Finan asked to go to another room alone and, thus remote from the cards, he next got 12, a very unusual start. His later work has been poorer, but he still shows some E.S.P. ability.

155:2 See page 22, Chapter 2.

156:1 I now have more subjects than I can myself work with; the experimentation needs institutionalizing; i.e., needs special endowment and special assistants. No one individual can manage it adequately.

Next: Chapter 15. Summary and Concluding Remarks