WHEN THE question is raised as to where the process of ESP fits into the mental
system of the individual, the student of psychology may ask "What mental
system?" The present state of psychological knowledge does not afford any
generally accepted systematic conception of the mind. The purpose in the
discussion which follows will be to articulate with the more obvious, recognized
mental processes and to adhere mainly to objectively evident relations. As far
as the experimental results warrant, the general features of ESP will be
described, however incompletely, and the outline left for completion by further
Some General Characteristics [top]
In this section, the evidence will be reviewed to show that certain general
characteristics of ESP as a mental process are experimentally established. Some
of these characteristics will appear perhaps superficially descriptive. Perhaps
all of them might be regarded, however well established they may be, as
tentatively formulated. It is difficult to say, however, what is unimportant to
the success of further research. In fact, it is better to err on the side of
over-inclusiveness than to risk omitting fruitful suggestions.
ESP is Unconscious. The first established feature of ESP to be considered is the
fact that it is an unconscious process. There is no reliable conscious
experience of the act of perception and, as would naturally follow, no awareness
of failure or success of a trial. This has been long and widely held as an
hypothesis by experimenters in the field. From the experimental viewpoint, it is
established by the fact that the subject does not reliably know when (or
whether) he is apprehending the target card or object. This matter of general
observation has been made the subject of a special study by Woodruff and George,
who report inability of their subjects to estimate the scores prior to the
check-up. Warner and Raible found no correlation between degree of certainty of
the subject and actual success. Bender's subject expressed confidence at certain
calls, but this confidence was not significantly above the number of hits to be
expected above chance in such estimates. Riess's subject felt as much confidence
of success in the "B" series of this report, which averaged only chance, as she
did in the "A" series, which averaged above 18 hits per 25(1). Accordingly there
should be no question that in ESP performance there is no reliable consciousness
(1) This information was supplied by Dr.
Riess in conversation.
(2) Pratt reports that Rice found some success with one subject in trying to
indicate when a call was a hit. He reports that in 61 attempts, 35 were correct.
This, however, does not insure awareness of the process. Such knowledge may well
be attributed to ESP itself, i.e., a secondary ESP of the correctness of the
call. At any rate, more remarkable scores than this have been achieved by ESP.
Further evidence of the unconsciousness of ESP arises from the fact that
subjects do not agree in general as to the way in which ESP occurs. Their
attempts to tell how they receive their impressions show great variation, and
some of the most successful subjects will say they are "just guessing," meaning
that they have no awareness of the method by which they arrive at a decision.
However, none of the generalizations made in a scientific field are properly
regarded with finality; future research may enable the ESP process to be brought
into the range of conscious experience.
ESP is Erratic. A second general characteristic that is obviously established by
experiment is that ESP is erratic in its operations under the test conditions
which have been up to the present carried out. In other words, it fails to work
perfectly or steadily for any great length of time. Whether the evidence
obtained only under the most restricted conditions be considered or whether all
of it be inspected, it is uniformly manifest that there is but little, if any,
regularity about the performance of the subject in tests from run to run or from
day to day. It is true some subjects obtain more uniform scoring than others,
but even the most regular scorer is still very erratic. He does not, for
example, obtain his successes in any particular order in the run. That is, the
distribution of his hits through the run is usually erratic, though there have
been found in some instances regions of emphasis that stand out as noted by
Rhine in subject H. P.'s performance curve and in the DT U-curve. There are also
"good days" and "bad days," as illustrated in one part of the Pearce-Pratt
series, at the distance of 250 yards, in which the subject scored 12 and 10 on
the first day and 6 and 4 on the next day; the third day, he went back up to 10
and 10; the next, down to 2 and 6. This variability may be a characteristic of
the ESP process itself, but it might be attributed partly to the unconscious
character of the process. That is, if conscious control is lacking, the
resultant "blindness" of aim might be a factor in the erratic functioning of
ESP is Unstable. A third general characteristic of the ESP process that may be
said to be established experimentally is its instability; that is, the tendency
it shows to decline or disappear entirely so far as performance is concerned.
The discontinuance of Riess's subject to score above chance has already been
mentioned; that of Drake's subject also. A like return to the average chance
level of scoring was reported for Brugmans' subject. Rhine(3) reports the
decline of subjects A. J. L. and C. E. S. (however, in these instances by
degrees rather than by sudden cessation). In later work his principal subject,
H. P., ceased to score reliably above chance after about two years of relatively
regular performance. Pratt(4) obtained a similar result in prolonged
investigation of his subject, Mrs. M.; and as far back as the work with the Creery sisters and the Guthrie experiments, a similar outcome of prolonged
testing is reported.
(3) Rhine, J. B. Extra-Sensory Perception.
Boston: Bruce Humphries, 1934.
(4) Pratt, J. G. "Clairvoyant Blind Matching," Journal of Parapsychology,
I (1937), 10-17.
This is not to say that the actual ability is gone in such instances. It appears
more likely that the function or expression of the ability is inhibited, perhaps
by a different state or circumstance in each individual case. It is not to be
expected that the subjects themselves can furnish the correct explanation,
though, of course, what they have to say may be of interest(5).
(5) Brugmans explained his subject's decline
on the ground of pressure of medical studies. Rhine's subject, H. P., made the
announcement, before the experimental period began, on the first day of his
period of inability to score above chance, that he did not expect to be able to
do well and gave reasons (having to do with an occurrence causing him acute
emotional strain) which were quite understandable.
Not Subject to Development. A fourth general feature of the ESP process that
appears to be established within the limits of our present knowledge is the fact
that it is not (as it is now known) subject to development as an ability in
itself. That is, while there are many modifying conditions that tend to raise
and lower scoring, there appears to be no general development of the ability
itself. One line of evidence for this derives from the behavior of subjects
approaching the tests for the first time. Pratt and Woodruff found that their
subjects fell off in scoring as the novelty of the card material used declined.
Introduction of new materials (different sizes of symbols) brought the scoring
back up, but it again declined with familiarity. As just stated, Rhine reported
declines from the start in a number of his subjects (A. J. L., C. E. S., and
several minor subjects). On the other hand, he reported(6) that subject H. P.
required a period of adjustment for new test situations. The Pearce-Pratt series
gives an illustration of this, as do series reported by other investigators,
such as Riess. There is no reason, however, to ascribe this adjustment with its
incline curve of scores to the development of ESP ability itself, any more than
it would be safe to conclude from the evidence of decline that there was a loss
of the ability. It seems probable that with all the subjects mentioned, the
decline as well as the adjustment period had rather to do with accessory factors
affecting the ESP process.
(6) Rhine, J. B. Extra-Sensory Perception.
Boston: Bruce Humphries, 1934.
The case against the development of ESP capacity rests, however, mainly upon the
simple fact that with subjects who have been exposed to the test situation for
long periods, there has been almost uniformly no sign of real development;
indeed, as indicated above, quite the opposite has been preponderantly the case.
The only apparent exception is that of the subject of Martin and Stribic(7),
Mr. J. He is reported to have risen in score average during long series,
continuing through the school year, and then to drop again after vacations.
(Information available in correspondence, however, indicates that Mr. J. has not
held to his earlier level during the past year, though this may be attributed to
changes in task.) Other subjects tested for long periods, such as H. P., A. J.
L., C. E. S., and Mrs. G. (the medium), among Rhine's subjects, not only did not
develop, but actually declined. Pratt's subject, M., likewise declined. The
history of ESP has many of these cases of apparent loss of the ability, but it
has yet to reveal a case of development as reflected in a rising level of
scoring throughout a long period of trial.
(7) Martin, D. R. "Studies in Extra-Sensory
Perception: II. An Analysis of a Second Series of 25,000 Trials," Journal of
Parapsychology, II (1938), 287-295.
In Chapter XII ("Test Conditions that Affect
Performance") certain hypothetical relations were considered under the heading
of "The Cognitive Situation." These dealt with conditions that presumably were
mainly cognitive in nature, and which might affect ESP. The question raised in
this chapter under the above heading is whether there is any knowledge yet that
deals with the cognitive aspect of the act of perception itself in the ESP test.
Even a small step may be of importance.
ESP a "Diametric Function." In the preceding chapter, it was found to have been
established that ESP is possible with complex stimuli, as in the matching of two
unknown cards, or even two unknown decks. This indicated a response by means of
ESP to a relation between stimulus cards or (as in DT) between the stimulus card
and its position. This is, so far, entirely a behavioral observation. The
question here is: Can it be further analyzed and perhaps the underlying
cognition touched upon? Can anything be found out as to how the apprehension of
the complex stimuli is done?
The simplest supposition would be that when confronted with the task in BM: (a)
two cards are to be matched; (b) one card is perceived; (c) the other is
perceived; (d) the two are identified as similar. This is termed by Foster a
circumferential function(8), implying a going around the long way. Contrasted to
this is the diametric function hypothesis by the same proponent, which assumes
that the perceptual act cuts across from (a) to (d) omitting steps (b) and (c)
completely, and making a single act of the perception of likeness. As to which
hypothesis is correct, the diametric or the circumferential, there has been no
way to determine until Foster proposed the ESP quotient described in
XII. This permits the determination of the percentage of hits most probably
obtained through ESP in a given series, giving a basis for computing the result
expected on the circumferential hypothesis.
This concept is embodied in an article submitted by Foster to one of the authors
for examination. It is referred to with the consent of its author and will
On the circumferential hypothesis, the subject has to use his ESP ability to
identify one card in step (b) and then do the same in step (c). He has to get
both correct to make an ESP hit (for example, in BM). Just as the probability of
chance hits on both cards is squared - that is, 1/5 squared to get 1/25 for the
probability of a paired hit if separate calls are to be made so the subject's
normal ESP quotient would be squared (as a percentage) to get the expectation of
ESP hits on the circumferential hypothesis. If, as the diametric hypothesis
supposes, the subject can apprehend the relation between the two cards in a
single act, the assumption would be that it would not be necessary to square his
ESP quotient since only one step is involved. (This will be clear in terms of
illustration of the actual methods in use.)
In the OM procedure, the subject attempts to perceive only one card per trial,
as the key cards are exposed. This is comparable, in effect, to the BT
procedure. Now, if in BM tests (with the key cards inverted) the circumferential
hypothesis applies and the subject normally has an average score of 7, giving an
ESP quotient of 10 (that is, would get 10% of his trials correct by ESP alone,
using the OM or BT or GESP method), he would be expected to get, in BM, 10% of
10% or 1% of his trials correct by ESP alone; i.e., an ESP quotient of 1 and a
score average of 5.2. If the diametric function of ESP applies and the subject
perceives the relation in a single act, eliminating the necessity of perceiving
the two cards, he would be expected to obtain, other things being equal, 10% of
his trials correct by ESP alone; i.e., an ESP quotient of 10 and an average
score of 7. A similar relationship would be expected for BT (or GESP) and DT.
The square of the percentage representing the BT quotient should give the DT
quotient on the circumferential hypothesis. On the diametric hypothesis, they
should be the same.
The results of all comparable series of BM and OM and BT and DT are assembled in
Table 20. These are necessarily limited to results obtained from the same
subjects by the same experimenters in the use of two of the comparable
techniques. It will be seen that on the whole, the results clearly fall between
the two extremes expected on the basis of the two hypotheses considered. In no
series did BM or DT fall to the level supposed by the hypothesis that the
elements are separately perceived (circumferential function) and the relations
established by a separate act. In view of the uniformity of the trend of
results, the hypothesis of the diametric character of the ESP process may be
said to be indicated; that is, the apprehension of the relation between two or
more objective situations is a unitary function.
Comparison of ESP Quotients
All Comparative OM and BM Series
Woodruff & George
Price & Pegram
All Comparative GESP-BT
and DT Series
* Rhine, J. B. Extra-Sensory Perception.
Boston: Bruce Humphries, 1934.
However, the important question is still left open as to why DT and BM give
lower averages than BT and OM. This has been discussed in Chapter XII.
ESP and Volition
It has been established that the ESP process is in certain respects a voluntary
one. It is, first, voluntary in its dirigibility. In fact, if this were not the
case, it is difficult to see how an experimental demonstration of ESP would be
possible at all. The use of an experimental target upon which it may be
directed, the very nature of the ESP test procedure, brings out this point with
clarity. The naming of a particular card, the calling of the order of a deck of
cards, involves definite direction at every point. The precision of aim or the
sensitivity of this dirigibility is quite another question; but that the
capacity is subject to direction in its selection of stimulus objects, every
successful test bears witness.
A second generalization may be made regarding volition and ESP, this time as an
indicated one, namely, that the use or application given to ESP is likewise
voluntary. Most striking perhaps is the high aim vs. low aim experiments. That
the subject can successfully call the cards or the agent's experiences correctly
is, of course, the main burden of this summary, but he can likewise call the
cards incorrectly and secure lower than chance average scores. This was first
pointed out by Rhine(9) with subjects H. P. and C. E. S., was later confirmed
by Pegram(10), and again by Price(12). There is, of course, no a priori reason
why it should be difficult to call a card wrongly if it can be called rightly,
or to match it opposite the wrong card if matching it against the right card is
(9) Rhine, J. B. Extra-Sensory Perception.
Boston: Bruce Humphries, 1934.
(10) Pegram, Margaret H. "Some Psychological Relations of Extra-Sensory
Perception," Journal of Parapsychology, I (1937), 191-205.
(11) This work is the investigation of
psychotic patients at Ohio State Hospital referred to above. The tests were all
done with screened cards; the average deviation for low aim was 0.44 and the
average deviation for a high aim was 0.53.
As Thouless(12) indicated, given the same ESP ability, a smaller deviation
would be expected on the negative side from low aim than would be expected on
the positive side with high aim. In fact, according to Foster's ESP quotient
formula, which is based on logic similar to that of Thouless. the positive
deviation should be four times that of the negative for the same order of ESP
ability. It is suggested (a) that the fact that the negative deviation that has
been obtained in these instances is larger than would be expected on the basis
of the positive deviation may be due to the fact that the low-aim tests are
commonly conducted as diversions from the normal high-aim procedure and offer
perhaps more interest and challenge. They are, of course, novel and have the
suggested advantage of that effect. Or it is suggested (b) that the subjects may
approach the low-aim tests (after working at high-aim) with a level of
aspiration which they think of in terms of an expected deviation, and that their
performance is somewhat a function of their expectations.
(12) Thouless, R. H. "Dr. Rhine's Recent Experiments
on Telepathy and Clairvoyance and a Reconsideration of J. E. Coover's
Conclusions on Telepathy," Proceedings of the SPR, XLIII (1935), 24-37.
Other illustrations may be given of the applicability of conscious direction to
the ESP process. The adaptation of the ESP function to situations with which
there is no previous acquaintance is established. In all of the work of the
first rating summarized in Chapter VI, the subject had not previously attempted
experiments under exactly similar conditions. In each case, there was a definite
adaptation to a set-up requested by the experimenter. Obviously the voluntary
efforts of the subject in adapting his abilities to each of the experiments
brings this capacity in line with the more recognized cognitive processes.
There is one more generalization referring to the voluntary control of the ESP
process that may be regarded as established, viz., that gross differences in the
rate of response
may be voluntarily adopted by the subject. In the Pratt and Woodruff series the
rate of response was increased to something more than one trial per second by
preference of the subjects. In the long distance pure telepathy tests, the
periods ranged from three to five minutes, the highest results having been
obtained at a rate of from one to five minutes per trial. In the Pearce-Pratt
series, as in the Riess series, the time per trial was one minute. However,
subject H. P. of the Pearce-Pratt series was reported by Rhine to respond with
normally high scoring at a rate of about one second per trial, a speed adjusted
to. the needs of recording by the experimenter. The relationship derivable from
these observations may be stated either as one of volitional control of rate or
as one of independence of effect of reaction times within the limits tested(13).
(13) This must not be regarded as
contradicting the findings of Stuart (see "The Effect of Rate of Movement in
Card Matching Tests of Extra-Sensory Perception," Journal of Parapsychology,
II (1938), 171-183) that when the subject's response was
timed to the metronome he was successful in getting extra-chance deviations only
when the metronome was set at his normal and preferred rate of movement. In the
above experiments, the subject either set his own pace or voluntarily agreed to
the rate suggested. There was no compulsion; whereas in Stuart's test the rates
were fixed by schedule and regularly indicated by the metronome.
On the other hand, it is just as important to find out what is involuntary.
There can be no question of the fact that the precise temporal control of ESP is
a relatively involuntary function, and this, too, may be rated as established.
However successful the subject may be, as for example in the Riess series, there
is no given point at which the subject can, in advance and with fixed certainty,
determine that the next trial will be a success or that he will score above
expectation in the next run(14).
(14) This goes a step further than to say, as
above, that ESP is erratic. It might be erratic to the extent that only 2 per
cent of the trials give ESP hits, yet these 2 per cent might be awaited, and
taken advantage of. But because it is unconscious, too (and perhaps for other
reasons), ESP cannot be awaited and thus controlled. Or again it might be mostly
erratic, yet at intervals - when possible - be volitionally evocable. But if so,
the subject does not know it, and cannot consciously command his performance
("not at present" should, of course, be added to all negatives).
As above indicated, volitional control is exercised in the general undertaking
of direction of the capacity: to the cards or agent in question; to the
particular card at the moment; to the kind of response that will be made; and to
the direction of deviation. But when it comes to the point of determining
exactly when the process shall work, the control falls. All of the available
data indicate this effect clearly, and the observation is important in the
general attempt to describe the ESP process.
Sensory and Extra-Sensory Perception
Certain general relations have been observed between sensory and extra-sensory
perception, and most of them appear to be established. Most of these relations
have to do with the aspect of perception which in sensory perception (SP) is
called stimulation - the relation between the object and the sensory end organs.
In almost every instance the relation found between SP and ESP is one of sharp
When other aspects or phases of perception are considered, the difference
between SP and ESP largely disappears. Perhaps the outstanding difference lies
in the fact that the ESP stimulation cannot as yet be brought above the
threshold of consciousness; whereas, of course, in the case of SP it can and
more commonly is. To what extent the characteristics of the ESP identification
or judgment can be duplicated in SP experiments with stimulus intensity reduced
to a point well below the threshold of awareness of the subject, is an area for
large experimental inquiry. There is no reason to anticipate fundamental
differences between SP and ESP in this respect. Bender(15) and Williams have
both done pioneer work in this field.
(15) Bender Bender, Hans. Zum Problem der
Aussersinnlichen Wahrnehmung. Leipzig: Johann Barth, 1936.
It is suggested that the erratic and unstable character of the ESP test response
is not due to any fluctuation in the supposed stimulation phase of the ESP
process. Nor is it likely that there is any great variable in the act of
identification or judgment in view of the fact that the identifications are
often repeated and are very simple to begin with. Rather it would appear that
the enormous fluctuations in scoring, ranging from chance average to 25 hits per
25 trials, is to be found to be closely associated with the variable commonly
called attention (and variously used and defined - most commonly, however, as the
selective action of motivational components of the subject). It would appear
that the shifting activity of this conative selection, operating without benefit
of consciousness, would be capable of producing unpredictable oddities of
scoring with which this field is familiar.
Stimulation in SP and ESP. It is in the stimulation phase, and perhaps there
alone, that the uniqueness of ESP phenomena stands out against the background of
1. Among the established relations referred to above is the fact that a wider
range of stimuli is possible to ESP than to SP. In the work having fullest
precautions, the types of stimuli are not numerous, but the range is very wide.
ESP cards and playing cards were used in the main, but in the long distance PT,
the "stimulus" was the experience of an agent purportedly trying to experience a
mental image of one of the ESP symbols. Whatever is taken to be the actual
stimulus in this case - whether cerebral process patterns of physical character,
or something of an order less physical in the accepted usage - the target is
clearly beyond the range of direct sensory perception. Going further afield into
the work of earlier periods and of less elaborate precautions, we encounter
among the successfully used stimuli which are less accessible to the senses the
use of pain localization and the transfer of suggestion by ESP by Janet.
2. So far as the sensory analogy goes, the range of stimuli extends into the
invisible (to anyone) as well, as exemplified in the sealed opaque envelope test
and the DT test in which the symbols are presumably completely concealed from
3. The size of the target which, within a certain range, is highly important to
success in SP of the visual mode, has not as yet been found to have any limiting
effect upon ESP. Sizes used have ranged from 3 1/2 inches to 1/8 of an inch in
the tests by L. E. Rhine and from 2 1/4 inches to 1/16 of an inch in the Pratt
and Woodruff series. (This size range, however, is not enough to present a
fundamental distinction between ESP and SP on this point.)
4. Size is relative to distance in SP and it is on this point that the case more
particularly rests. The ordinary ESP cards at a distance of a hundred yards or a
city block would, of course, be beyond the range of vision by an unquestionable
margin. Yet, under such circumstances, the ESP process is able to function,
presumably at its best so far as score measures go.
5. Another sharp distinction between ESP and SP lies in the easily recognized
localization of reception in sensory experience in general(16), whereas no locus
of reception of ESP impressions has as yet been reported by any experimenter.
Bodily orientation is clearly not essential. In the Pearce-Pratt series the
subject and cards were on approximately the same level in two buildings located
about 100 yards and 250 yards (in different sub-series) from each other. In the Brugmans series, the subject was immediately under the agent and experimenter.
Again, in the Warner series, the subject was below, but not directly under, the
experimenter who held the cards. Rhine reported that subject A. J. L. tended to
turn away from the cards; subject G. Z. preferred to work with his back to the
experimenter; and Gibson's most successful subject walked about the room,
evidently in deep absorption.
(16) Warner rightly points out in this
connection that the location of receptors of equilibrating sensation were not
discovered by introspection.
6. A continuation of this contrast between ESP and SP leads clearly back to the
preceding chapter, which deals with the relations of ESP with the physical
world. There, it will be recalled, it was pointed out that so far as evidence is
available, the angle at which the stimulus object used in ESP tests lies with
respect to the percipient may be varied without inhibiting the effect. On the
sensory analogy, presumably there would be the least effect obtained when the
pack of cards, for example, lies with the edge toward the percipient; yet some
of the better series (e.g., Pearce-Pratt) were obtained under this condition.
It was also pointed out in the preceding chapter that embedding the card in a
pack of similar cards does not, in spite of the close proximity of card to card,
over 100 to the inch, prevent perception by the mode here under consideration.
The fine discrimination required (especially with distance) has not a comparable
It was concluded after the discussion of physical relations that, according to
the results available and so far as knowledge of the physical world has
advanced, there is no known energy which could fill the need for an explanatory
principle intermediating between the percipient and the object in the ESP tests.
In view of the fact that in sensory perception the intermediating energies are
relatively easily intercepted and measured physically, this contrast serves to
set off most sharply the distinction of extra-sensory from that of sensory
perception. Whether the dilemma of ESP causation is solved by the discovery of
other physical processes involving unknown energies, or whether perception may
be found to occur without intermediating energy of any kind whatever. the
contrast with sensory perception is still a striking one.
ESP, considered as a psychological process, shows
certain well-defined characteristics:
1. It is entirely unconscious; that is, it is not thus far found reliably
available to introspection in any way or degree.
2. In its effect upon performance in the tests, ESP is erratic; i.e., variable
and undependable in its functioning, insofar as present tests measure it.
3. It is a most unstable ability, as it is at present known. disappearing
suddenly or gradually, often without recognized causes.
4. As a capacity, ESP does not seem to be subject to development through use
(again, according to present knowledge), as are most other specific capacities.
5. Although the direction of ESP is subject to voluntary control, the immediate
activation of the process is apparently spontaneous and involuntary.
6. The ESP process is diametric in its function, encompassing more than a single
object in its scope and apprehending relations as a unitary act.
7. In all but the stimulation aspect of the process, ESP and SP appear to be
much alike as far as comparative knowledge is at hand. On the other hand, when
compared as to the relation to the stimulus object, there is vast difference:
ESP is apparently responsive to a wider range of stimuli and of conditions of
stimuli than any known sense modality; it is independent of bodily orientation
to the stimulus; it does not permit introspective localization of reception; and
it functions under conditions for which no known stimulating energy could
The article above appeared in "Extra-Sensory Perception After Sixty Years: A
Critical Appraisal of the Research in Extra-Sensory Perception" (1940, Henry
Holt and Company, New York) by J. B. Rhine, J. G. Pratt, C. E. Stuart, B. M.
Smith and J. A. Greenwood.