The clairvoyant dog


A personal reminiscenseHondje

It must have been in 1941 or thereabouts. I was a pupil at the highschool in Veendam, a little provincial town near Groningen in the North of the Netherlands. One of our teachers in mathematics was a compact somewhat sturdy gentleman with an unruly head of hair and a five o’clock shadow, accentuated by his slightly yellowish complexion. At least, that’s how I remember him. But as you can gather, it all happened a long time ago.

This teacher was in the habit of straying from his subject, and to pose riddles or to broach areas of general interest. One of these occasions is indelibly printed on my mind: the case of the clairvoyant dog. What it boiled down to was that during his study at the University of Groningen he owned a little dog. And not one of your run-of-the-mill dogs (if dogs can ever be that). This particular dog felt when his master had almost finished his studies for the day, making it time to be taken for a walk. It was the moment to jump up, run to the door and wag its tail. Something normal dogs do as well, by the way.

This ritual was repeated for several weeks, thus confirming the clairvoyance of the dog: studies practically (but not quite) finished, dog anticipates and stands prepared. Now, you don’t study mathematics without any benefit. It sharpens your critical faculties and teaches you to approach problems in a systematical way. Covert observation of the dog did not enlighten our student. The dear animal just slept until the moment suprème. At long last it dawned upon our student: he was in the habit of lighting a cigarette as a reward for his endeavours. And he kept his cigarettes in a metal cigarette case. And closing the lid of the case . . .
The rest you can guess. (1)

(read on)

And the moral of the story? It was never explicitly stated. Here follows an attempt.

Student of mathematics

Gerard Heymans
Gerard Heymans

I won’t keep you in the dark any longer. The student’s name was A.S. van Dam. And when he studied in Groningen, the university boasted the presence of the then well-known professor of psychology, Gerard Heymans. This coincidence was to have far-reaching consequences: (I confine myself to the most important details):

During the summer of 1919 Heymans met Mr. A. van Dam, who studied mathematics and physics. Van Dam surmised himself to be endowed with the gift of telepathy, and made himself available for parapsychological research. Heymans gladly accepted this offer, and from spring 1920 till the summer of 1922 an extensive series of experiments was conducted. From preliminary investigations it became clear that Van Dam possessed a special talent for the taking in of motor-representations. […] This experiment became widely known. (2)

(Italics not in original)
This renown may have faded somewhat since then, but searching the internet still results in hits, hits that present the Van Dam-experiments as proof for the existence of telepathy. I myself was approached several times regarding this case. And the recent publications commemorating Heymans, referred to in the notes, may have revived that interest to a certain extent.

After all, the experiments were conducted under the auspices of the shortly thereafter founded Studievereniging voor Psychical Research (comparable to the Society for Psychical Research).
The first task of the society was to ascertain experimentally whether parapsychological phenomena really exist. Subsequently an inquiry was to be made into the laws that governed these phenomena. The occult was to become less occult through research. What is the role of hypnosis? Is there a link between the keenness of the senses and the emergence of telepathy? Are gifted telepathists endowed with a characteristic temperament? Heymans insisted on exact, quantative research, and he relied on the assistence of the members of the Society. The majority of the members however showed greater affinity with spiritist sceances than with statistics, resulting in the fact that Heymans’ own investigation remained the only respectable methodological experiment from that era. (2)

A sketch of the experimental set-up will suffice here. Van Dam was to be seated in front of a kind of chessboard, containing 48 partitions. The board itself was hidden from Van Dam’s view by a curtain. The experimentator concentrated his thoughts on one of the partitions, which had been determined by chance, and then endeavered to ‘send’ the position to Van Dam. The latter was to reach under the curtain and point at the correct partition. At first sight it appears that the necessary safeguards were built in to make other modes of communication unlikely not to say impossible. Which is not the same as foolproof. To that end it would have needed a James Randi, the well-known medium buster. What about Houdini?

The results were astounding. Under the severest of control conditions Van Dam scored 32 out of 80! Heymans concluded that ’the existence of thought-transfer under circumstances that completely (sic!) precludes other modes of communication has been proved beyond all reasonable doubt by these experiments’. A very conservative conclusion, as Heymans figured the chances of obtaining this result by guesswork as one to ten to the power thirty. (3)

Draaisma reports that a certain Schouten and Kelly ’translated’ this into the these days more current notion of significance. They not only confirmed the findings of Heymans, but while they were about it also scotched the idea that Van Dam might have utilised a systematic irregularity in the generation of a random series which determined the square to be pointed at. As only one of the experimentators was responsible for this irregularity, Schouten and Kelly apparently reckoned with the possibility that Van Dam was endowed with sheer inhuman, be it ‘normal’ gifts, compared to which the tour de force described in footnote 4 was child’s play.

Understandably, Heymans was very disappointed that Van Dam’s gifts diminished in the course of time.

Some ‘personal’ memories

Isn’t there a credibility gap between the happenings in the early twenties, a few years before I was born, and my experience with Mr. Van Dam in the early forties? Let me state here that I knew Van Dam also outside the school setting. That I even was to a certain extent his confidant, if he had confidants at all. In addition I shall rely on the experiences of my much older brother, who also had had Van Dam as a mathematics teacher. And in his case not only as a mathematics teacher, but also as a Scout Leader in the Scout Movement.

As regards the parapsychological experiments I wish to point out a few aspects. Why the chessboard with ’targets’ was hidden from Van Dam’s view is not clear to me. I suspect that the experimentors pulled the wool over their own eyes. (4)

Were they sufficiently competent in the rest of the arrangement of the experimental setting?

The experiment was conducted under two different conditions. Under the close-up setting the experimentator stood at a distance of approximately one meter from the testee, under the remote setting the experimentator resided in a room above the room with the testee. In the floor between the two levels a square hole was cut, closed with two sheets of glass. The report of the experiment states that ’the penetration of sound through the sheets of glass was muffled to such an extent that even when shouting one could not make oneself understood in the other room’. Carington, a visiting researcher of parapsychology who came to have a look at the experimental conditions says of the floor that it was ‘of a most uncompromising solidity’. (1)(5)

It is truly remarkable that the close-up experiments showed less result than the remote experiments, for the controls for unintended clues in the close-up condition were sloppy to say the least. For this anomaly (my word) I can offer no explanation. On the contrary, on the basis of my understanding of the background to the Van Dam puzzle I would expect the opposite.

This is not to say that in my view the remote experiments did not allow of (unintended) communication. Double glazing does indeed act as excellent sound-proofing. But what about the floor? Carington’s words regarding this aspect, (‘of a most uncompromising solidity’) carry a meaning that might be unintended by him. Such a floor is effective against acoustic transmission of sound, but (due to its solidity!) not effective against contact transmission of sound. In this connection I wish to remind you of the application of so-called ‘floating floors’ in newer housing estates, to counteract noisy neighbours living one floor up. Shuffling of feet might well have been audible. (And the additional conclusion of Schouten and Kelly just mentioned, that Van Dam had not made use of the irregularity in the random series also raises a question: Van Dam could only have done so if he had been kept acquainted in each instance of his hits and misses. And wasn’t communication from floor to floor impossible?)

The question remains, whether this calls for hypersensitive ears? This is the moment to call upon my brother:

During a summer scout camp our Scout Leader gave a demonstration of his telepathic powers. He let himself be blindfolded, then told us to hide an object, just anywhere. We thought to be very inventive, and hid a book in a duffle bag in one of the tents. Full expectation we then surrounded our Scout Leader. After some hesitation he started to walk in the right direction, closely followed by the troupe. Etcetera etcetera, until he triumphantly pulled the book from the duffle bag.
After keeping us in uncertainty as regards the way he had fooled us (clairvoyance was not an option for clear-headed scouts), he came with his explanation: all he had done was to listen to our collective breathing and how it changed if he appeared to be on the right track . . .

Which still does not provide the decisive answer the question whether Van Dam had extra acute hearing at his disposal. Now this is the point at which some readers might conclude that Van Dam only pretended to be guided by his ears, to camouflage his true gifts. Those readers need not read any further.

Still there? It is my contention that most people are not inclined to test the extremes of their human potentialities (6). For many it may come as a surprise that we can hear our own blood circulation. This would constitute a handicap in our daily life, reason why we have a built-in mechanism that normally lowers the sensitivity by a few decibels. (At last something that literally resides between the ears.)

Van Dam himself reported that he could enter the (according to him) needed ‘state of passivity’ at will. And a relaxed state of mind can go hand in hand with a heightened alertness for extraneous stimuli (7).

Temperament (?)

Which brings us to Van Dam’s ’temperament’. He was known as a very intense type of person, which now and then tended to work on people’s nerves. Not exactly a relaxed type as such. But also as somebody who did not avoid exploring human capabilities. Let me give some examples.

Van Dam was an officer in the Dutch army reserves. En route to the summer camp mentioned above the scouts were trained in quickly dismounting from their bicycles and hiding in a ditch on the cry: “Enemy planes attacking”. Allright, so the Scout Movement was founded by Baden Powell, himself an officer. . . .

What about this one: there exists a method of mental arithmetic which makes use of the squares of numbers. Van Dam had memorized them to at least 1002, but I seem to remember even to 2002. So what! you may well remark, surely not unusual for a teacher of mathematics. Do you know of one? (8)

The best is however another of his free discourses in the classroom. He was in the process of having a house built for himself. During one of his frequent (and irritating) tours of inspection, he came across a carpenter who, standing on a scaffolding, had to cut a beam that extended to the left. But the carpenter was right-handed. So Van Dam took the saw and cleared the job. But Van Dam was also right-handed. Only, he had taught himself to handle a saw with the left hand as well. Just in case. And, typically for Van Dam, he was of the opinion that a carpenter worth his salt should do the same.

Ergo: it does not appear too farfetched to me to assume that Van Dam had on occasion experimented in picking up minimal clues.


Before coming to a kind of conclusion we should take into account the course of affairs that led up to Van Dam being singled out for the laboratory experiments, something that is usually missing from the enthousiastic retelling of the story.

Van Dam had originally, as freshman, taken part in a game to match the feats of a stage mentalist who, blindfolded, recovered objects that had been hidden on the stage by the public. This performer had most likely made use of the involuntary movements most people make when concentrating on the direction one should take to recover the hidden object, so-called muscle reading. Van Dam had no difficulty in replicating this feat, though to me the reports sound here and there a bit too good to be true.

And now we can at last choose between various possibilities as regards the phenomenon Van Dam:

a) Van Dam was aware of the modus operandi, and took part in the later experiments as a student’s prank. I should remark here that Van Dam’s brand of humor, which depended on putting the listener on the wrong track, leaves some room for this possibility.

b) Van Dam was aware of the modus operandi, but reasoned that it was covered by the terms of the experiment. Didn’t it specify an investigation into ‘a special talent [ ] for taking in motor-representations’? This could be taken as covering his performance. He studied mathematics after all, not psychology.
For the experimentors this leeway is unacceptable however. The research addressed modes of communication by methods other than through the senses known to us. The use of the expression ‘representations’ leaves no doubt.

Let’s not judge from the present perspective. At the time it was a valid field for psychological research.

Refer for example to Parapsychology.

c) Van Dam was unaware of the modus operandi.

d) And as a gesture to those who are still with me, though forewarned: Van Dam possessed paranormal gifts. They should face the fact that more than 100 years of parapsychology has not resulted in a theoretical model for telepathy that could stand the test, nor has it come up with a practical case that could be replicated under controlled circumstances.

I maintain that I have made clear that the controls in the case of Van Dam left something to be desired. This on top of Van Dam’s ‘confession’.

Whatever the case may be, it seems plausible to me that Van Dam at a certain moment decided that enough was enough. Either he forefelt (yes, you read correctly!) that his chances of being unmasked were becoming too great, or he could not spare the time any longer.

Or he had become convinced that his gifts were not in the field of telepathy. With some assistence of his little dog? Let me add that it does not have to come as a surprise that he did not openly confess to have cooperated in creating a myth. It would have made a laughing stock of Heymans. And the case of Conan Doyle, the creator of supersleuth Sherlock Holmes, makes clear that such a step is not lightly taken (9). Not to mention that Van Dam himself would have appeared naive, stupid or manipulative, if not all three.

No, then it is more elegant to simulate that your ‘gifts’ are leaving you. But you later on give a covert warning to your pupils (and to a bunch of boy scouts). How sensory leakage can mislead yourself and others.

For the accuracy of my story you’ll have to take my word.
And I may have been taken in. Maybe Van Dam never had a little dog.

Unless a dog called White Lie? (10)


1.  Van Dam’s dog had many animal predecessors. Famous was Clever Hans, a horse that in the early 20th century astounded the public with his gift for performing simple arithmatical calculations. It tapped the correct answer to sums by scraping the ground with a hoof. Until the psychologist (sic!) Oskar Pfungst showed that Hans simply reacted to unwitting nods of approval. A successor to Hans, the blind horse Berto, most likely used his ears.

2. The data regarding Van Dam during his stay in Groningen were derived from:  “De parapsychologie”, the contribution of D.Draaisma to D.Draaisma et al.: Gerard Heymans. Objectiviteit in filosofie en psychologie. A publication of Het Wereldvenster, Weesp (1983) and from:
“De witte kraai van Heymans. De Groninger telepathie-experimenten”, the contribution of D.Draaisma to:
Douwe Draaisma (ed.): Een laboratorium voor de ziel. Gerard Heymans en het begin van de experimentele psychologie. A publication of the Historische Uitgeverij/Universiteitsmuseum, Groningen (1992).

Both with permission of the author, for which I hereby express my appreciation.

3. More precisely the probability of 32 (or more) correct guesses in 80 exeriments is 2 times 10 to the power -31. (Note of the editor.)

4. Was this precaution taken to avoid that Van Dam ‘consciously’ would point to a target upon telepathically received instructions? For didn’t Heymans specifically direct his investigation towards ‘a special talent for the taking in [ ] motor-representations’? How this professor of psychology imagined this feat to be accomplished without the intervention of the brain escapes me.

Not that ‘blind’ pointing at at specific target is beyond human capabilities. I refer to “The road to En-Dor” by E.H.Jones, originally published in 1919, reissued as a Pan Book in 1955. A few officers, prisoners of war of the Turks during World War I, fooled first their fellow officers, subsequently their captors and finally themselves by performing on a Ouija board. They could spell any message at will, though blindfolded. Also when their skeptical colleagues rotated the board at random. They simply reoriented themselves by a few notches they had cut in the outer edge.

A fascinating story with an almost fatal ending. Recommended reading for those who are fooled by messages from the beyond, spelled out by a sliding drinking-glass.

5. Walter Whately Carington (1892–1947). He had the surname Carintong only after 1933. (Editor’s note)

6. To wit: to stick a needle through your cheek, a feat performed by ‘fakirs’. To convince his public that he is endowed with magical powers, preferably brought forth by hypnosis? Just try it. You’ll hardly feel anything! Tip: disinfect that needle first.

And now that the subject has been mentioned, do you believe that there exists a special faculty that enables somebody to hypnotise others? In this case: experiments not recommended.

7. Refer for example to: Robert E. Ornstein (1972) – The psychology of consciousness. Penguin Books. For readers who are conversant with the Dutch language: P. Vroon (1976) – Bewustzijn, hersenen en gedrag. Baarn: Ambo

8. To calculate the product of two numers of the same parity: square their  average, and subtract the square of half their difference, for example 52 x 38 = 45-squared minus 7-squared (=2025 – 49 = 1976). In case of unequal parity change one of the factors, and correct afterwards. Mathematicians knowing many squares beyond 21 are rare. (Editor’s note.)

9.  For the story of the Cottingley Fairies, see the Wikipedia-article. Conan Doyle was taken in by this, shortly after he had been convinced by Oliver Lodge’s book Raymond (1917) of the reality of spiritualist claims. Conan Doyle wrote in his Foreword to the 1929 edition of The complete Sherlock Holmes long stories: “Having endured a severe course of training in medical diagnosis, I felt that if the same austere methods of observation and reasoning were applied to the problems of crime some more scientific system could be constructed.” He should have applied his lofty intentions to the productions of two little girls. A piquant note: Conan Doyle was an intimate friend of the famous magician Houdini, who abhorred all things paranormal. And note also that one of the girls only at age 84 confessed that they had been too embarassed to admit the truth. (Note corrected by the editor.)

10. This article is a slightly edited version of this article with the same title on the site factorfiction of the author. It is copied with permission. The editor is Jan Willem Nienhuys.