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7 Hypnotic Hyperaesthesia

As the causal memory becomes more perfect in the primates, so the senses degenerate. The accumulation of individual memories is quite clearly of far greater value in the animal's struggle against its environment than the acutest senses could ever be. Selection would therefore tend towards the development of the new mentality rather than towards the development of the senses. Degeneration of the senses would keep pace more or less with the evolution of individual causal memory.

In the primates the senses become more perfect the lower one descends in the scale of evolution. In man sense-degeneration has reached an extreme point. Hypnosis proves, however, that this degeneration in man is not organic, or even functional in the generally accepted sense of the term. The organs are still capable of a very high degree of sensitiveness, and under hypnosis they may actually become functional. This sensitiveness must, therefore, be inhibited by the high mentality, and when this mentality becomes dormant under hypnosis the inhibition is removed. In the chacma, as one would anticipate, this inhibition has not progressed very far. Its sense-acuteness comes midway between that of normal man on the one hand and of the higher mammalia on the other.

The following record of experimental comparisons between man under hypnosis and the normal chacma will prove how nearly, in respect of the senses, the human hypnotic mentality approximates to that of the normal chacma.

Tactile Sense

Subjects:

J.B., an 18-year-old Boer girl; poorly educated but naturally bright and intelligent; neurotic temperament and heredity.

Old male chacma; age unknown; time in captivity unknown, intelligence low; hereditary environmental instincts above the average; nervous, vicious and bad-tempered.

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During hypnosis the girl was blindfolded and touched on the forehead with the poles of a large steel horseshoe magnet. She was told, ‘This is the north, and this is the south,’ as each pole touched her skin. She was thereafter, supposedly, able to distinguish the north and south poles infallibly if touched on the forehead or hands. She could name each pole without a mistake when it was dragged rapidly across the palm of her hand. When the magnet was wrapped in two folds of a thick tablecloth, she could tell the north from the south by lightly touching the extremities of the covered magnet with her finger-tips.

There was some excuse, perhaps, for the original hypothesis that during hypnosis the subject was sensitive to magnetism, and this conviction was strengthened by her own explanation. When the memory of her sensations was fixed by post-hypnotic suggestion, she explained that where the north pole touched her she felt a ‘comb of rays’ (kam van strale) beating into her body to the left, and to the right when the south pole touched her, and that the sensation was the same no matter where on the body she was touched. Notwithstanding this explanation, a doubt arose as to whether she actually experienced any sensation due purely to the magnetic force. This doubt was created by the fact that her sense of touch, tested in many different ways, proved acute enough to be able to distinguish the two poles without any aid from magnetism.

She was, for instance, tested in the following manner: In her absence twenty shells of the giant African snail, practically identical in shape, size and weight, were numbered on the inside from one to twenty and placed in that order on a table. The girl, carefully blindfolded, was then brought into the room and allowed to touch the shells, closing her hand over each one in succession without lifting or moving it. She was then taken from the room and in her absence the order of the shells was arbitrarily changed. Brought back still blindfolded, she replaced the shells in their original order, without very much hesitation, and without ever making a mistake.

It was then found that when a soft-iron or brass horse-shoe was used in place of the steel magnet in the first experiment and it was suggested to her that one extremity was south and the other north, she was able to distinguish them as with the steel magnet and still, post-hypnotically, described her sensations as ‘comb of rays’ to the right and left respectively. Further investigation brought to light that the ‘comb of rays’ was no more than an unintentional suggestion conveyed to her during the experiment. Before she was hypnotised someone had tried to explain magnetism to her and had used the very words ‘comb of rays’ to describe the parallel lines of the force.

Blindfolded, she was able to distinguish the steel magnet from its soft-iron replica when both were wrapped in several thicknesses of the same cloth by touching the two extremities with her finger-tips.

[p. 1170]

The chacma was taught to associate the presence of the steel magnet with an imitation snake of which he was afraid. Both snake and magnet were hidden in a bag of thick cloth.¹⁶ An identical bag contained a soft-iron replica of the steel magnet and was associated with the presence of a plantain at the bottom. A bag was always so placed that in order to ascertain whether it contained the snake or the plantain the chacma had to draw it towards him and was compelled to touch through the cloth either the magnet or the soft-iron imitation. As soon as the memory was fixed in his mind, he never once made a mistake. The slightest touch was sufficient to indicate to him whether the bag contained the magnet or the replica.

Taste

Subjects:

J.B. (as above).

Male chacma about three years old, bred in captivity; artificially reared; very high intelligence.

As a baby the chacma had developed the habit of sucking its thumb. The thumb became raw and painful and all the means commonly resorted to in the case of human babies failed to cure it of the habit. Eventually the lady who had charge of it placed on the thumb a glove finger saturated in quinine. As the chacma grew up, it retained a deep and perhaps not unnatural aversion to quinine. After some preparatory instructive experiments it was found that this baboon could in darkness - to exclude the possibility of visual identification - detect by taste the presence of sulphate of quinine in a solution of one milligram in four litres of water.

Another chacma who had once accidentally eaten a poison fruit could detect by taste similarly infinitesimal quantities of the juice in water or fruit.

The hypnotised girl, without any instructive preparation, could detect the drug in the same solution as the chacma. If there was any difference in threshold value, it seemed slightly lower in the girl than in the chacma. The weakest solution used in either case was one mg. to four litres, and the chacma appeared occasionally to be in doubt, and there was reason to believe that he sometimes had to taste the liquid two or three times before he was quite sure. The girl was never in doubt. It was only necessary for her to place a single drop on her tongue and the moment she closed her mouth she knew whether the liquid contained quinine or not.

The same chacma could in strong light detect the presence of the drug in a slightly weaker solution - equal to 1 in 800 000 of water. The hypnotised girl

[p. 1171]

showed doubt and hesitation and her errors amounted to 40 per cent. When the strength of the solution was raised to 1 in 600 000 she became infallible. When normal she could detect the quinine only in a solution four times the above strength.

Sight

In distant vision the superiority of the chacma seemed greater still. A young captive male could at a distance of six miles, over a landscape flickering with mirage, recognise without fail among a group of people a human friend to whom he was greatly attached. At that distance in such atmospheric conditions no normal human, even with a good pair of binoculars, could distinguish human beings from cattle. Our observation of wild troops convinced me that even this perhaps does not represent the limit of chacma vision. Among hunters the chacma has the reputation of being the most far-sighted of wild animals living in Africa.

The hypnotised girl even at half that distance failed to recognise an acquaintance, and approached infallibility only with a good pair of binoculars, though this would, in her normal state, have been impossible.

Smell

Subjects:

M.B., a 21-year-old Boer girl; fairly well educated; sister to J.B. (above); neurotic.

Several male and female chacmas.

Twenty different people, the majority unknown to the girl, each handled a different small object and then placed it in a receptacle. The girl, blindfolded, took out one object after another and by smelling the object and the hands of the different people handed each object back to the person who had handled it first without a mistake. By smell she could identify any number of acquaintances sitting in a room, walking past each one at a distance of one yard and sniffing the air. Still blindfolded, she could find a grain of musk hidden anywhere in a room. When a small fragment of asafoetida tied to a thread was dragged over a table in an irregular course, half an hour later she could trace out its path by holding her blindfolded face a few inches from the surface of the table.

Investigations with a number of chacmas made it apparent that although their sense of smell is far inferior to that of many species of mammalia, and con-

[p. 1172]

siderably below that of the hypnotised girl, it is, nevertheless, greatly superior to that of the average normal human being. A blindfolded chacma could not recognise an acquaintance standing within a yard. But when the baboon could touch the person, it invariably made use of the sense of smell to aid it in determining identity. Its nose would be thrust up against the clothes of the person examined and it often seemed as if there was considerable hesitation and doubt. A full-grown male was unable to trace the course of as strongly scented a fruit as a pineapple after it had been dragged along the ground, and was unaware of its presence when it was hidden in a bag three yards away.

Hearing

Subjects:

M.B. (as above).

Several captive chacmas.

Of a number of experiments which definitely established the superiority of hearing in the hypnotised girl I will describe only the following: A sound of constant volume imitating the hiss of a snake, and in the case of the chacmas associated with the presence of an imitation rubber snake, could be clearly heard by the hypnotised girl at a distance of 230 yards. The distance at which average normal human beings could hear the sound lay between 20 and 30 yards. The chacmas could hear it at a distance of between 50 and 65 yards.¹⁷

The difficulty of arriving at anything like an exact comparison between the respective threshold values of these stimuli will be appreciated, but where we are dealing with values so inconceivably low when judged by a normal human standard I do not think that a very exact comparison is necessary in order to prove at least a convincing correspondence - or the reverse. And that this correspondence does exist it is hardly possible to doubt. It will be seen that in two senses, hearing and sight, there seems to be a considerable difference, but, taken generally, there is undoubtedly a closer agreement between the hypnotised human being and the chacma than between the hypnotised and normal human beings. And it seems to me a fair presumption that if hypnosis could be induced in the chacma and its behaviour in that condition controlled and directed, it would be found that its hypnotic sense-acuteness approximated that of many of the lower mammalia.