The following investigation is based on the author's personal observations of a male chimpanzee (Joni) from the age of 18 months to four years and on records of the behaviour of the author's son (Roody) taken from the moment of his birth up to the age of four.
The observations of the chimpanzee were logged between 1913 and 1916, while the records of the child's behaviour belong to the years 1925 to 1929.
The respective notes are separated by a stretch of 12 years. It should be stated that the second chronicle is a typical “mother's diary”, with daily entries regarding all new phases in her son's behaviour. At the time of its writing, the diary was in no way intended for comparative psychological studies, and it was only at a much later date, namely in 1929, that it occurred to the writer to draw up a psychological parallel between the two subjects: man and ape.
Sorting the records, which had been collected over a period of seven years, took a full five years.
All the illustrations appended to the book are original photographs (the major portion of which is printed here for the first time) or freehand sketches made either from photos or from life. All the sketches were made under the author's personal direction and supervision. The sketches of the chimpanzee's head are schematic. These are based on observations of the chimpanzee's facial expressions and are the result of superimposing or combining a number of photographs.
Our comparative investigation of the two subjects, the human child and the infant ape, has shown the two to possess much in common with respect to many essential features of behaviour. This was, of course, by no means unexpected; even the most superficial parallel observation of a chimpanzee and a human being reveals the “human-like” features of the ape, whence one is apt to leap to the conclusion that since the ape is “almost human”, man “must evidently have originated from an anthropoid ancestor.”
And indeed, in visualizing the natural motor skills of the infant chimpanzee — his lying and sitting postures, his ability to stand upright, to move about erect, to jump, and to climb — we shall not be slow to see that the whole of this range of motor skills equally belong to the human child of the same age.
Let us now in the first place consider the instincts of the chimpanzee and those of the human child as expressed in behaviour and, in particular, let us analyze the behaviour dictated by the self-support instinct (expressed in finding food or drink, providing for sleep, and grooming). The similarity here is striking indeed.
Like the human child, the little chimpanzee, feeling hungry, will never withdraw his searching glance from the person who is in the habit of feeding him. The chimpanzee will follow his caretaker step by step and will constantly try to attract his attention with deliberate loud crying.
Again, the chimpanzee will handle raw food in a manner very similar to that of the human child. Thus, he will start clutching at the food, removing the skin of vegetables and fruit with his teeth and fingers, and flinging the kernels.
The chimpanzee easily masters the art of drinking from a cup and using a spoon (though both infants prefer to use their hands). Again, quite like the human baby, the little chimpanzee greedily attacks the food he is offered, jumps from dish to dish (in case several different kinds of food are served at the same time), and obstinately refuses to share food with anyone. In his eagerness to keep a favourite morsel to himself, the chimpanzee — quite like the child — will resort to a number of methods such as turning his back on the would-be usurper, protecting himself with his hand, or hastening to finish up the food (if someone should pretend to take the piece away). In the presence of others, or when the taking of food is accompanied by some pleasant distraction, both babies will eat with particular relish. Both children displayed an undeniably selective attitude towards food and show a marked preference in favour of a vegetarian diet — milk, sweetmeats, or fruit (even carrot juice and lemons); both likewise show a definite tendency towards the use of carbonaceous foodstuffs or those that contain lime.
Both like to sleep in immediate proximity to the person who looks after them, being particularly eager to cuddle on the latter's knees or on the same bed, where both will affectionately nestle against their protector; both try to lay their heads as high as possible on the pillow, and usually sleep on one side with arm under head and leg drawn somewhat inward towards body. In cold weather, both will draw up their blankets; in hot weather, they will put their legs wide apart and throw aside all bedclothes.
Both, when sleeping, display a tendency towards spasmodic movements and snoring. When they chance to be laid to sleep in a cot unprotected by any kind of grating, both infants frequently catch hold of the nearest firm object and continue to cling to it tenaciously even when fast asleep.
When awake, the chimpanzee and the child have no objection to being subjected to different hygienic treatments such as washing, combing, or nail trimming. They also frequently indulge in self-examination, and they are in the habit of constantly cleaning the interstices between their fingers, biting their nails, examining different parts of their skin, or fidgeting with casual pimples, wounds, pricks, or scratches that they may happen to discover on their bodies. When painlessly doctored, neither shows evidence of particular repulsion.
Both Joni and Roody are easily taught to soap their hands, to use a handkerchief, and to wipe their mouths with a serviette.
The instincts of self-preservation, self-defence and attack are strongly developed in both child and ape.
As a matter of fact, Joni and Roody were both rather great cowards. Indeed, in taking stock of all “frightening” stimuli, the question arises not so much of what they feared, but of what they did not fear.
The principal stimuli eliciting fear responses were as follows: everything unexpected; all sharply defined stimuli (light, sound, touch); large objects; everything new, e.g. new objects, new people, unusual surroundings, animals never seen before; gatherings of people; large animals (horses, cows); very tall men; loud shouting; noise; shooting; snapping; thunder; lightning; magnesium flashlights; brilliantly illuminated premises; darkness; black objects; self-propelled vehicles; live animals with sudden or jerky movements, stuffed animals and birds, or the depictions of certain animals in pictures.
The response to a fright-causing stimulus likewise finds expression in a very similar way in both Roody and Joni. When frightened, both strain to open their eyes as wide as possible, transfixed on the object of their fear; they remain motionless in the same posture as if spell-bound; from time to time they shiver, hearts beginning to beat faster, cold sweat appearing on their faces; and they do all they can to either find some suitable hiding place, to put themselves under somebody's protection, or to run away from the fear-causing stimulus.
A long-acting fear stimulus invariably causes both infants to raise a violent outcry.
Many common traits can also be observed if we examine the active self-protecting behaviour. Both Roody and Joni displayed very similar behaviour in making threatening gestures, stamping their feet, producing a rapping noise with the fist, tapping against the offending object with the palm of the hand, pinching, scratching or biting it, and occasionally even raising some object (a stone or stick) as if to hit it (in case the infant is afraid of coming into direct contact with the fear-causing stimulus).
The indications of anger were also very similar in both: in either case, the brow becomes puckered and the teeth and gums are exposed.
Both Roody and Joni are prone to shift into aggressive moods under circumstances other than those that would elicit the self-protection instinct: thus, they generally feel angry when their diverse instinctive requirements (such as those connected with food, drink, or sleep) are not properly catered to, and they likewise are apt to become disorderly when their desires — frequently altogether unreasonable ones — are interfered with, or their actions are in some way thwarted.
It is interesting to note that both the human child and the ape would easily display anger (or show a feeling of vengeance) on seeing supposedly wronged humans (especially if the latter belonged to the class of “friends”) and would do all they could to chastise the offender. Both subjects would also frequently display rancour when claims were made with respect to their alleged property or when their freedom of locomotion was in any way interfered with.
The instinct of property was strongly marked in both the human and the anthropoid child, and it found its expression not only in a manifest aversion to share a favourite object, but also in the careful safeguard of all available belongings; though at the same time their stock-in-trade was liable to be constantly replenished by all kinds of new acquisitions, some of which definitely belonged to the class of somebody else's property.
A careful study of the objects acquired by both Roody and Joni, with special-attention focused on the “favourites,” permits us to establish their predilections and even, maybe, to throw some light on their aesthetic preferences.
In the first place, it seems worth noting that both were equally eager to take possession of brilliant, transparent, and brightly coloured objects (especially when the colours belonged to the first half of the spectrum). Both shared a well-defined dislike towards dark-coloured objects, which in all probability caused fright in them.
As to the size of the preferred objects, both Roody and Joni gave special attention to miniature things, towards which the human child even seemed to feel a kind of tenderness; the preferred form was certainly that of the sphere. In the field of tactile sensations, there was a well-defined preference with respect to all that was soft, smooth, flexible and reticular; in the field of thermal sensations, there was a definite attraction towards all that was warm; among olfactory stimuli, fruit smells were invariably preferred; while all behaviour related to the sense of taste definitely suggests that both preferred sweet or sweet-and-sour foodstuffs. Both were eager to appropriate the following as playthings: brilliant or brightly coloured plates; silk, velvet, or satin rags; pieces of transparent oilcloth; glasses; lace; pieces of India rubber, etc.
Not only were both subjects reluctant to part with these toys when summoned to do so, but they were also even apt to carry them about wherever they would go. Small wooden balls appeared to be especial favourites.
Both Roody and Joni showed a definite tendency towards self-adornment, displaying particular preference with regard to brightly coloured fabrics. It may be of interest to note that both were particularly fond of hanging brightly coloured pieces of cloth round their necks like scarves. They even sometimes went so far as to bring the two ends of a scarf together near the throat, thus making themselves something like a necktie.
Both the human child and the ape were certainly freedom-seeking creatures. They hated being warmly clad or bundled up, and always began crying when locked up in the narrow confines of a room; on the other hand, they exhibited the most buoyant joy when allowed to venture abroad — to the free expanse of yard, field, or forest. Admitted to open space, they would try to extend indefinitely the range of their activity and locomotion.
Both again had the social instinct in common. This instinct, quite naturally, found its principal expression in intercourse with other children or in placing themselves under the care and protection of an adult. When friendly contact with the latter was interrupted, both little ones immediately began seeking some other source of protection, apparently fearing to remain alone without any guardianship.
Both children expressed preference towards their nurse by distinguishing her from all other people; they expressed jubilant joy on her arrival and would cry on her departure; they wished to remain day and night with their adult friend; in case of some ailment, their attachment would become particularly strong; under untoward or difficult circumstances, it was always to the preferred person that recourse was made; again it was towards this very person that all affectionate feelings and tenderness were directed; and lastly, it was none other than the nurse who was allowed to perform various hygienic and curative manipulations in case of illness or physical ailment.
Both children showed a touching sympathy for their nurse when they saw that she was ill, and each of them tried to do the utmost to comfort or cure her as best he could. Both were ready to take action in defence of their nurse — when a potentially threatening gesture was made by an outsider, or even by a member of the household.
The expression of affection was similar in both the child and the ape. When stimulated by tender feelings, both Joni and Roody would run up to their protector, huddle up close and hug her, then tenderly touch her face with their hands and slightly press her cheeks with open mouth, panting all the while. Both easily learnt the kissing movement, though the reaction appears with the human child only at a more advanced age, while with the ape it is manifestly artificial and comparatively rarely used.
Affectionate behaviour is in both cases of a well-marked egocentric character and is closely associated with jealousy; in fact, Roody and Joni both claimed monopolistic ownership of the beloved person. In all cases, when the latter attempted in their presence to show affection to others — no matter children or adults — both subjects would invariably give definite signs of hostility towards the recipient of the caresses.
Both little ones established a sharp line of demarcation between “our people” and “outsiders.” Towards the former they would display a frank and unrestrained attitude, while they would invariably be on their guard with the latter; but both were equally eager to indulge in merry play with man and animal on every possible occasion. No happening or event caused them such pain as being left alone, while there seemed to be nothing that could evoke such joy as active intercourse with other living beings.
When brought into contact with persons alien to the household, both children would show a range of responses which differed widely in accordance with the temperament of the newcomer: they would be careful and restrained with quietly-disposed visitors; stand upon their guard and remain full of reserve with the gloomy and morose; and would always be apt to display merriment when brought into the presence of persons of a lively disposition.
The imitation instinct is well marked in both Roody and Joni, both being most susceptible to impersonating the various emotions (such as fear, sorrow, joy, and even anger) displayed by the persons with whom they would come in contact. On seeing the respective facial gestures and movements or even upon hearing incoherent sounds, they were always prone to imitate them.
Especially remarkable is the considerable range of coincidence observed in the mimicry, movements, and sounds expressing the principal emotions of the two children. To this class of gesture-similarities belong: trumpet-like protrusion of lips — when excited; wrinkling forehead, closing eyes, wide-opening of mouth, crying, and weeping — when dejected or sad; smiling, haphazard movement of hands and reproduction of sounds — when pleased; pressing-in lip corners and forming quadrangular mouth-opening when disgusted; mouth wide open — when astonished; protrusion of tightly closed lips and touching objects with lips or index finger — when attention is attracted; turning back upon offender — when feelings are supposedly injured or hurt. Similar facial gestures and mimicry were also observed during the expression of suffering, anger, and affection.
Additionally, the aforementioned responses were elicited by many of the same stimuli.
When on the verge of making a tense movement calling for close coordination of hands and fingers, both child and ape would invariably stretch out their lips sideways and then tighten them.
Both children perform a number of similar imitative actions such as: sweeping the floor, using a rag for wiping a pool of water from the floor, trying to hammer nails, unlocking padlocks, grasping objects with the help of a stick, turning on electric switches, opening hooks, and drawing lines on paper with a pen or pencil.
Both children were familiar with certain uses for the following implements frequently employed by them in the course of their daily activity: cup, spoon, knife, handkerchief, serviette, blanket, broom, feather duster, hammer, key, pencil, and pen.
It is worth mentioning that both children, evidently guided by analogy, frequently substituted one instrument for another: in the absence of a pencil, both Roody and Joni would attempt scratching paper with a nail, a stick, or even a fingernail; lacking ink, both would dip their fingers into milk, broth, water, or previously ejected saliva and try making various figures on paper; when no hammer was available, they would attempt to hammer in nails with their fists, with a stone, or with any other heavy object that might come their way; pocket handkerchiefs and serviettes were not infrequently replaced by stray pieces of paper.
Their imitative actions were, however, at best, but of poor efficiency; thus, failing to see the relative dimensions of latch and key, both would attempt to fit a tiny key into a large opening and naturally fail in their endeavour.
Following the lead of adults, both subjects were prone to reproduce certain sounds, such as banging a hand, producing a clicking noise with the lips, or rhythmically tapping bent fingers against some solid material; both also had a marked tendency towards onomatopoeia, though the range of imitated sounds differed widely for each subject.
But there is indeed no other sphere of activity where the similarity of the human child and the infant chimpanzee should be so manifestly striking as in play.
Both child and ape showed the same passionate — we may even say tempestuous — zest for moving games such as is connected with running, sliding, wrestling, etc. Both were equally ready to take in new playmates such as a human being or a live animal or — in the absence of such — to amuse themselves quite alone. During long periods of time, both Roody and Joni could find complete satisfaction in self-contained motion. They would run about the rooms; make circles round the whole flat; dash from place to place or from corner to corner, then perhaps settle down for a moment on some piece of furniture, as if resting, but only in a second to renew their activity with tenfold energy, finally falling down in sheer exhaustion. “Run, run, run! Round, round, round!” Roody would shout from the age of 18 months to two years — prancing about the room — just like Joni, involving everybody he could find on the way.
No less enthusiastic were both little ones when given the opportunity to indulge in wrestling games. Again, they would seem to like nothing better then being squeezed, swung, carried about, or turned topsy-turvy, and they invariably found a tremendous source of delight in climbing upon shoulders, knees, or legs and travelling or swinging up and down on these improvised vehicles or swings.
Any toy vehicle or object in any way supposed to be suitable for “transport” was invariably welcomed with exuberant joy. Indeed, there appeared to be nothing capable of giving so much pleasure to both little ones as perambulators, toy automobiles, wooden horses, chairs, benches, baskets, pillows, and even slippers and balls, the latter of which also, by the way, appeared to be classed as a means of locomotion.
Both Roody and Joni would accost these seemingly unpromising means of transport as if they were actual carriages and would react with the greatest zest and eagerness. Both thoroughly enjoyed being conveyed in some genuine vehicle and appeared to like the rate of motion the quicker the better.
Jumping vertically up or down from some elevation was a favourite pastime with both human child and ape; no less pleasure was apparently derived from hanging onto doors and swinging about together with the door, though this kind of amusement generally lasted but for a few seconds at a time; finally, an unending source of pleasure was derived from rolling about on the floor and sliding down more or less steeply inclined boards. Both Roody and Joni were in a state of perpetual motion, ever finding new combinations of playful activities. It would take the author all the pains in the world to teach them to sit quietly, even at mealtime. Once, when told to stop dangling his legs, Roody exclaimed, “Well, with me something must always be kept going!” The statement was an avowal of the strength that was also fully and continuously borne out in the behaviour of the infant ape.
No less enthusiasm was manifest on the part of both child and ape when they indulged in gymnastical exercise, such as swinging; climbing up wooden and rope ladders; and twisting ropes into strands and subsequently letting them go with a crack that resulted in rapid untwisting and the performer merrily spinning round like a top till the rope was finally unwound. Not infrequently, both would devise the riskiest stunts, occasionally involving even serious danger to life or limb.
Both Roody and Joni seemed particularly delighted when they were given occasion to indulge in competitive exercise. Such forms of athletic competition such as races, or chasing a partner seemed to be accompanied with especial zest and it could be frequently observed that both subjects would fly into such fits of passion that the losing partner would often be on the very verge of bursting into torrents of tears or at least getting badly angered.
It seems of interest to note that both invariably preferred to run away from a stronger partner than to pursue a weaker one.
Playing at hide-and-seek was accompanied by the same manifestations. Both subjects almost always preferred hiding from a stronger playmate to seeking a weaker one.
Acting on their own initiative, both Roody and Joni would often erect obstructions to be overcome in the course of playful activity, or they would purposely introduce complications into forms of exercise such as running, climbing, or swinging. Thus, in the course of his gymnastical activity on a trapeze or simply when running about, Joni would introduce some object between his head and neck, taking all the pains in the world not to let it go during his games. Occasionally, he would grasp with his foot some rag or a bootlace with trailing shoe and would prance about the room, his progress being at every moment checked by some intervening obstacle. Now, he would be held up by a piece of furniture; or the bootlace having become entangled, his progress would be arrested in some narrow passage; but every time he would get loose — sometimes with difficulty — and continue his adventurous progress with unslackened energy and zeal. Roody would frequently make himself barriers and jump over them or else build a kind of narrow and shaking plank-bridge and carefully make his passage over it, eagerly watchful lest he should lose his equilibrium. Again, in performing feats on the trapeze, Roody would often carry in his hand a heavy plush teddy bear, being of course strongly handicapped by this rather weighty piece of altogether unnecessary ballast.
Indeed, unhampered locomotion apparently failed to give either of the little ones the same amount of pleasure as did obstructed motion. Most varied objects were taken to serve as improvised obstacles: thus, Joni liked having access to various knitted fabrics, torn baskets, ropes that he himself had previously entangled, etc. On happening to come across a rubber ring, Joni would always first introduce his finger through the opening, and then gradually begin expanding it to provide a sufficient passageway for the whole hand, next for the whole head and, then for the whole body. At last, he would drag himself all through, angrily panting and grunting all the while.
On seeing a torn net in his bed, Roody immediately recognizes that good luck has come his way and obstinately refuses to get into bed in the usual way. Instead, he drags himself through the torn net and reaches his couch only after a considerable display of effort, accompanied by loud grunting and snorting. Despite having wasted about 10 times as much time as he would have done in the normal way, from the very moment of his lucky discovery he invariably prefers the difficult crawling-in procedure.
It is but quite natural that movable objects should appear particularly attractive to both subjects. Indeed, it can in no way be considered a mere coincidence that both Roody and Joni preferred wooden and rubber balls to all other varieties of toys. Both were particularly loath to part with these, their favourite playthings, and could spend hours throwing, pushing, or catching a ball. Nearly as much entertainment was apparently derived from playing with round baskets or pushing perambulators or even roller-mounted chairs. In fact, on coming across any sort of moving object, neither infant could ever refrain from attempting to set it in motion in one way or another. Thus, they would repeatedly open and close doors, windows, and cupboards; bang piano lids; turn the wheels of sowing machines, rotate turning stools, etc.
Often, both would catch hold of stray objects that had chanced to come their way and begin scattering them all over the rooms, with the result that the whole area would soon become a scene of complete chaos bestrewed with broken, dilapidated, or discarded pieces of furniture or household utensils.
The observation of motion appeared to be in no way less stimulating. When in the city, both would eagerly watch the unfolding street traffic; they would keenly and attentively follow the progress of pedestrians, show great interest in street happenings and never remove their searching gaze from passing vehicles. So absorbed and enraptured would they become that it was sometimes hardly possible to draw them from their favourite pastime even by raising one's voice.
When in the country, both would gaze with curiosity at herds of passing cows, playing children, or any other events of rural life that might come their way. Even the progress of such slowly moving creatures as caterpillars, ants, beetles, and cockroaches seemed to intrigue our subjects. Joni would frequently take a piece of straw and start worrying a group of cockroaches that had quietly settled into the slits of his cage. He apparently found much amusement in witnessing the flight of the insects and would invariably start his little game afresh on seeing them recover from their first panic. Roody could watch ants running about for indefinitely long periods of time.
It is also quite natural that playing with larger animals should be attractive to both Roody and Joni. Deprived of the companionship of children of the same age, they seemed to feel tremendously happy when opportunities were at hand for such exploits as pursuing dogs or pigs; frightening chicks, crows or sparrows; or hunting down or frightening cats, etc.
The accompaniment of noise and loud sounds always added particular zest to playful activity. The greater the noise, bang, or uproar, the more both seemed enraptured.
There was, in fact, no greater source of delight of both than dragging about clattering chains, jingling keys, or beating or drumming against walls with metal rods, wooden balls and the like. Genuine drums or even kettledrums seemed particularly welcome. It, in fact, struck one that the more deafening was the noise the greater the pleasure thus derived.
Lacking other more varied forms of entertainment, Roody and Joni would often clap their hands, bang their fists, or stamp or tap their feet. Both enjoyed slamming the keyboard of a piano.
Much in common could again be observed in “experimentation” games involving such novel and unknown elements as fire, water, sand, and objects that were hard, transparent, or elastic.
Both were greatly attracted to fire and had to be stopped in their attempts to reach for it, lest they burn themselves. They seemed to be deeply stirred by the lighting of candles or the firing of the stove, while the switching on of electric light appeared to be a source of everlasting enjoyment.
Water seemed to be no less attractive. The sight of any amount of this element would induce Roody and Joni to devise no end of new and apparently most thrilling amusements. Joni would immediately avail himself of the opportunity for taking some water into his mouth and rinsing— this occupation often taking up quite a stretch of time; both Joni and Roody on seeing a pool of water would never miss the opportunity to splash about in it; when sitting in front of a basin of water Roody (just like Joni) would invariably take into his hands as much water as he possibly could, and then lift his hands and let it run out, only to resume the operation again the very next second. Roody liked collecting various objects and letting them float or sink in the water of a basin; on seeing spilt water both would moisten their fingers and start drawing various patterns, or else just simply splash the water about. The water held in a pedal-washstand seemed to have a particularly intriguing effect. On seeing the jet emerge, both would either attempt catching it with their mouths or try to grasp it in their fists or, again, simply smash it about, wetting both themselves and all their immediate surroundings.
Both Roody and Joni had a natural tendency towards digging in earth and sand. They liked collecting small stones and gazing at them. Oftentimes, they could be seen playing with sand, strewing it, kneading it, casting it about, or filling and emptying any handy receptacles that might come their way. The whole process was always accompanied by most eager contemplation, with many new interesting moments being apparently always found in the course of the different manipulations.
Any hard objects, such as stones, bits of glass, nails, stray pieces of wood, sticks, or matches were taken stock of and immediately utilized for play. Thus, whenever he came across a large stone, Joni would always carefully examine it, take it into his mouth, gnaw at it or scratch it, and at last throw it away in some definite and apparently preconceived direction. When seeing a smaller stone, nail, or piece of glass, his practice would consist of taking the said object into his mouth and rolling it about, sucking it, and smacking his lips; but never would he swallow any non-digestible materials.
Roody had also been found to put stones into his mouth. Special preference on the part of both was to be observed with reference to sharp objects, such as small sticks, twigs, bits of straw, etc. It is really remarkable to find that both would seem to enjoy actually pricking their hands with such sharp objects or else employ them as a peculiar kind of dilatational contrivance. Thus, Joni used to insert a stick vertically between his lips and, so arrayed, begin a number of convolutions: dangle about, begin running in various directions, start scratching himself, etc.; but he remained eagerly vigilant all the while lest his lip-extender should by some mishap fall out or become displaced. Roody used to insert a stick in the palm of his hand and never let it go even when frantically running about.
Indeed, any description of stick seemed to fascinate both Roody and Joni; on finding a stick, Joni would invariably use it for digging the ground, banging against the floor, reaching at hitherto unattainable objects, or making threatening gestures. Roody used sticks for drawing signs on the ground, or else liked to throw them over fences. He also employed sticks for chasing dogs and often found amusement in utilizing them for knocking down various objects or making them fly up high into the air. As a matter of fact, Roody could never pass a stick without saying, “Nice stick” and used to bring home tremendous amounts of long wooden objects of every imaginable description. When asked why he wanted yet another stick he would always find some new pretext to explain the purport of the latest acquisition. It has already been mentioned that both child and ape were equally fond of balls and spherical objects.
Much entertainment was similarly derived from toying with transparent objects (coloured glasses, medicine bottles, transparent oilcloth, translucent combs). On having acquired some piece of glass, Roody and Joni would both in a much similar way press it to their eyes and start looking through it at the sky, transporting their gaze from one object to another. Now they would look at the sky, then at the ground, in a moment they would dwell upon some garden flowers, only to begin staring at some human face in the very next moment. Both would cherish a tiny bit of oilcloth or a stray piece of coloured glass as if these were highly priced valuables.
Looking through a translucent yellow comb Roody would fervently exclaim, “Oh, how red the sky! Oh, how hot!” Putting a piece of yellow oilcloth to his eye and holding it with one hand Joni would begin excitedly running about the room; on coming across various objects and on seeing them “in a new light” he would invariably tap them with his free hand, as if to ascertain their real nature. Occasionally, he would lie flat on his back for quite a long time contemplating the ceiling through the oilcloth.
Long, pliable, or elastic objects, such as rubber hoses, bootlaces, and the like, were greatly cherished by both Roody and Joni. Indeed, the degree of amusement obtained as a result seemed to exceed the amount of pleasure derived from any manufactured toy. There was no end of different things the little ones would be prone to do with a hose. They would throw it high up into the air intently watching the hose uncoil in its rapid descent; they would wind it round their necks or simply slip it round their shoulders and begin drawing it from side to side; now and again, they would insert one end into their mouths and draw in air through the aperture; or they would take the end of the hose by hand and begin wildly lashing every adjacent object with the other free end.
Ropes, strings, and bootlaces were wound up or twisted into loops, offering the new and exhilarating experiment of getting through the loop — a feat which was no sooner thought of than done.
Great similarity is again observed in the kind of amusement both subjects derived from their manipulations with human hair. On having acquired himself a hair , Joni would indulge in a very peculiar pastime: time and again he would draw the thread through his mouth pressing it tightly to his tongue, but taking the greatest care not to tear it on the way. It seems most astonishing that 13 years later, Roody, acting altogether on his own initiative and in no way stimulated by any outside influence should have also become absorbed in the human hair. The human child found considerable interest in letting it gently glide between his extended fingers.
Many common traits could again be observed in their destructive games. Such forms of activity as throwing, tearing, and breaking seemed indeed to provide both subjects with a peculiar form of self-contained pleasure. In fact — most playthings would leave their hands with some trace of destructive activity, usually in the form of tooth imprints or purposeful destruction.
Nearly everyone knows that a child, on putting his finger into a hole, will try to do his utmost to enlarge the aperture as far as he can, but, with Joni, every contact with an easily breaking object inevitably ended in the complete disintegration of the item in question. It is also a well-known fact that children's playthings very soon turn into a scattered mess of dilapidated debris; but Joni possessed the destructive instinct to such an overpowering extent that the range of his devastative activities comprised virtually everything that would come his way without the slightest exception. Joni would spread havoc and ruin everywhere: he would tear wallpaper, gnaw at the walls, break apart the doors of his cage, shatter glasses, and tear up all the fabrics that were to be found in the room.
The destructive tendency in Joni's nature was, indeed, so strong and unyielding that no rebuke would prevent him from tearing pillowcases to tatters, completely breaking apart his cage, of or performing other similar disruptive actions. Joni's wilful impulses seemed to be at their strongest where destructive activity was concerned, and the less yielding the attacked object, the more energy he would expend in his attempts at demolishing it; it even seemed that handicaps stimulated his efforts. Indeed, in pursuing his goal by way of carrying out some prohibited action, or in his endeavours to get at some forbidden object, Joni would display such an amount of energy that no amount of scolding, punishment, or even physical pain would prevent him from bringing his plan to completion. Even the danger of a serious quarrel with the observer (of whom he was very fond) never stopped the progress of his destructive activities. Notwithstanding all odds, Joni would stoically, stubbornly, and relentlessly forge on towards the realization of his once established aim — the annihilation of the given object.
I often had the opportunity of noticing in the case of both the human child and the chimpanzee that a prohibition entailed a response that was entirely different from the desired one. “Forbidden fruit is the sweetest” — and the behaviour of both Roody and Joni seemed to give ample support to the truth of this saying. Both little ones would cling to prohibited actions with the greatest steadfastness.
So, on having illicitly got out of his cage in my absence, Joni was invariably found to have performed the very thing I had forbidden him to do and to have handled the very objects he knew he was never to touch. The behaviour of the human child shows practically the same tendency towards transgression of rules and opposition at any cost. I begin laying swaddles on a chair in the presence of 10-month-old Roody — he immediately starts tearing them down; I don a hat — the boy tries to remove it; I place a toy on the table — he throws it off; I start a humming top — Roody stops it; I put a ring onto a toy pyramid — he tries to remove it, grunting all the while from the effort exerted. At the age of 1 y. 6 m., he is forbidden to handle such objects as spectacles, scissors, and knives — but no sooner have I turned my back than I find him toying with the very articles he has been told never to touch; at the age of 2 y. 3 m. 8 d., when he is told not to suck his thumb — he immediately puts his entire hand into his mouth when ordered to stop; at the age of 3 y. 0 m. 11 d., he is cautioned not to play in flowerbeds — the very next thing he does is start trampling flowers; told to shake hands using his right hand — he invariably extends his left one, etc.
The intentional actions of both Roody and Joni are frequently marked by the features of caprice and put into effect through sheer stubbornness. Both would often suddenly (and for no apparent reason) renounce the very claims that had caused a tremendous amount of uproar but a minute ago; or else they would display complete indifference on coming into possession of the previously coveted article. Not infrequently, it appeared as if the very process of reaching for the desired object and not real necessity was the true motive of their observed behaviour.
Offence was easily taken by both Roody and Joni when they thought that their supposedly legitimate claims had not been duly complied with: both would in a much similar manner turn their eyes from the offender and refuse to take even the best-liked sweetmeats from his hand.
Roody (1 y. 4 m. 22 d.) asks for some object. He is first refused, but subsequently permitted to take it (following some afterthought on the part of the adult in question). Now, he does not any more want to take it. So, on having once eaten a pear, Roody asks for another. On cutting the fruit into two unequal halves, I told him he might have the smaller portion. The boy immediately exclaimed, “You didn't say the big one!” and burst into tears stubbornly refusing to take any of the fruit at all.
In performing prohibited actions, both Roody and Joni would try as best they could to be cunning. They would even try to trick or deceive the observer, though their naïveté frequently prevented them from displaying any considerable artfulness. To consider a typical example, we forbade Joni to gnaw a certain piece of furniture. In order to achieve his end, the ape hid behind the object in question, turned his back upon us and began gnawing; or, on another occasion, he sought shelter under a pillow trying to make-believe that he was behaving in exactly the right manner — while he was in reality steadily biting at the wood of the taboo table. Sometimes he would cover the desired item of furniture with a piece of paper and start biting through the covering. (He was allowed to tear paper.) Roody had received strict commands to the effect that he was never to put matches into his mouth — what did he do but hide behind an old armchair and perform the prohibited trick firmly believing himself to be well protected from every inquisitive glance.
When walking in the garden with his grandmother, Roody was told that he was not to pick berries; immediately, instead of proceeding ahead of his grandmother as was his usual wont, Roody (age 2 y. 3 m. 13 d.) declared that he was going to follow; on looking back, his grandmother perceived him in the prohibited act of picking berries.
On wishing to get a cracker and evidently doubtful as to whether he would actually get it, Roody says to his grandmother, “Grandma, don't follow me, for goodness' sake, don't follow me!” Whereupon he goes to the summerhouse, closes the door and takes a cracker.
I have forbidden Joni to get out of his cage in my absence and he knows very well that he must not destroy the stucco on the ceiling. On leaving the room I say to him, “Stay here and do not go anywhere” (the cage is remaining unlocked). But I have only to leave the room for Joni to get out of his cage, shut the door of the room (which I leave half-open), climb up to the ceiling, and start picking the stucco, at which point he indulges in some kind of play outside his cage. On hearing my returning footsteps he immediately returns to his place, pretending that nothing at all had happened and utterly unaware of the fact that his stucco-besmeared nose and a pool of urine on the floor unequivocally testify to his disobedience.
The behaviour of both child and chimp often resembles what may be termed “ostrich policy.” Thus, Joni, grasping objects that he knows he ought not touch, stares at the observer, never once withdrawing his gaze from the coveted object. More than that: he seeks and ultimately finds the desired article solely through the sense of touch without even once looking at it and apparently believing that if he himself does not see it, neither will others. Such little tricks were even more naive and comical with the boy. For example, Roody (age 2 y. 2 m. 6 d.) was once patently unwilling to drink his milk. I tell him, “Drink.” He hides his hands behind his back and replies, “I ain't got no hands” and “I'm afraid of the milk.” I insist on a definite answer about whether he is going to drink his milk or not. He does not breathe a word, seemingly afraid to say “no” and unwilling to say “yes.” I insist further, “Why don't you answer?” He replies, “Yes, don't answer.” I: “Why?” He: “I ain't got a tongue.”
On another occasion, when asked to shake hands, he retorted, “Don't hear.” When told to water flowers (an occupation for which he apparently cared but little), he replied (age 2 y. 2 m. 3 d.) “Don't see.”
Similar “ostrich policy” could also be observed in the way Roody used to play hide-and-seek. For example, he could be often observed to conceal himself behind a small chair, which only partly hid his figure. As for his head, he would hide that with a thick shawl, apparently believing that nobody could see him if he himself did not perceive his playmates. Or, sometimes, he would squat on the steps of the balcony covering his eyes with his hands and turning his back to the seeker, evidently fully convinced that his artful cunning had completely locked him out of the world of visual perception.
The manifestations of guilty feeling could be plainly observed in the behaviour of both subjects, but these manifestations appeared to be somewhat different in each case. On seeing that he had committed some evil doing, Joni would try to avoid the glance of the observer and stoically submit to censure, punishment, or angry words of reprimand. He apparently felt he deserved the punishment. At the same time Roody when censured would flush, stick out his lips, and appear on the verge of tears. Even the slightest slap caused an immediate outburst of tears.
Both Roody and Joni were highly mobile — not only physically but also mentally. It often seemed that their tempestuous growth constantly stirred them towards ever more buoyant activity. In whatever position or surroundings they might happen to be — eating, dressing, washing, even sitting on a highchair — unceasingly, relentlessly, they would be inventing new forms of amusement or entertainment. When they were in possession of playthings, they would constantly leap from one to another in a perpetual search for new means of amusement — often, only to return to the original plaything in the very next minute.
But the free play activity of the child and the chimp reveals not only a lack of focused attention. There is yet another and perhaps even more characteristic trait — curiosity, which found its principal expression in the fact that both subjects were invariably attracted to everything new, whatever it might happen to be: new people, things, or surroundings. The demonstration of some novel object would for instance always be an entirely sufficient stimulus for interrupting any kind of playful activity, or even for cutting short any emotion that might happen to be experienced at any given moment.
Roody's attraction to the new was well typified by his once exclaiming during a long walk, “I'd like to go on without end if I could only always see new things!” All of Joni's behaviour corroborates the opinion that he was endowed with the same disposition. In the absence of new experiences Joni would make it clear that he felt dull: he would lie flat on his back indifferently gazing ahead or he would pick his teeth and make a cracking noise with his lips. Roody would often approach me with the following request, “Now, do show me something new!”
Both subjects would invariably give signs of the most manifest joy every time they experienced new sensations. Each more or less unusual visual perception seemed to have a stimulating effect: new houses, a forest, street incidents, any novel developments in the life of the courtyard — all these and many other stimuli would cause Roody's or Joni's wandering gaze to become fixed to the intriguing phenomenon, their close scrutiny never interrupted even for a single moment. Their curiosity would become particularly keen during the course of riding in a motor car, but no less interest would be exhibited during the course of simply walking about town, when both Roody and Joni, each on his part, would invariably try to look into the windows of basement flats. Especial interest was attached to the contents of wardrobes, baskets, and cupboards: both, whenever they possibly could, would show equal zeal in trying to get inside and finding some new nondescript item which they would then start at length contemplating. All partially opened gaps seemed especially tantalizing. Under this heading came: stoves, pockets, various receptacles, human nostrils, ears, etc. The searching eye or the exploring finger would always try to penetrate the orifice; indeed there seemed to be not a single nook or recess on in the premises that Roody and Joni had not tactually or visually explored at some moment or other. In such investigatory behaviour tactual exploration usually took the lead, and in this respect Roody was in no way behind Joni — they both seemed to consider it a poor inquest if the object of interest had not been properly handled or tasted. Convex and concave objects commanded an equal degree of curiosity, manual exploration being almost exclusively resorted to when protruding or depressed shapes were being investigated.
Both Roody and Joni were often subject to erroneous visual perceptions. Thus, on seeing three-dimensional objects depicted in the pictures of a book, both frequently attempted to catch hold of them. In his unsuccessful attempts to “remove” the object in question Joni would even tear the pages, while Roody, upon seeing that all his endeavours were for naught, disappointedly exclaimed “By no means!” meaning that he could by no means take the thing (age2 y. 0 m. 23 d.).
It is only natural that lustrous, bright, or rapidly moving objects should stimulate the curiosity of both subjects to the greatest extent. On seeing articles of such description both would display very similar behaviour: thus, on first beholding the interesting item they would open their mouths wide, draw out their lips, and explore the texture of the substance with the help of the index finger.
Both enjoyed looking at picture books, and in their eagerness to consistently acquire new impressions, would rapidly turn page after page. Both would differentiate between pictures. Joni would overlook some pictures while he would intently gaze at others (notably pictures representing carnivorous wild animals with blazing eyes; or monkeys). Roody (age 2 y. 1 m. 6 d.) saw two pictures, one portraying a small bird and the other a large one, and exclaimed, “Nice!” in reference to the small bird and began kissing its picture; he then turned to the picture of the large bird and said, “Nasty!”
When touching a calendar, he used to call the red-letter days — “Good” and the others “bad” (age 2 y. 1 m. 25 d.).
The investigative curiosity of both the human child and the ape was often directed towards the facial features of human adults or towards their own bodies. All of a sudden Joni starts intently gazing at someone from the household. Though he knows the person in question very well, he starts surveying his facial features as if he were seeing them for the first time. He passes his finger over the eyes; feels the nose and ears; touches his index finger to the nostrils, mouth or ear; and pays especial attention to the mouth cavity. If the human subject under investigation happens to open his mouth or does so on purpose to comply with the inquisitive desires of the ape, Joni will smile at every movement of the mouth. He also takes much pleasure in touching human hair, spectacles, rings, or brooches. Precisely the same behaviour was observed in Roody.
Both subjects frequently indulged in self-examination. Every morning, Joni would meticulously examine every part of his body and on finding any actual or imaginary defect (scratches, specks of dirt, or soiled places) would immediately begin grooming himself, licking sore places, removing dirt, etc. When Roody was one year old, he would examine his naked body with no less keen interest. He would also often touch his navel, fingering a casual pimple, or any other intriguing spot, etc.
The reactions of both Roody and Joni to their mirror images have been observed to be strikingly similar. The following successive reactions have been found to match in every respect, viz:
perceiving own image in mirror and smiling;
touching image with hand and seeking for something behind the mirror;
spitting at image;
making rattling noises with lips, grimacing, or gesturing;
agressive lifting of hand and tools at image and hitting it.
In their examination of the surrounding objects, both Roody and Joni revealed exceedingly keen powers of observation. Both immediately recognized any new object within their range of perception and at once started scrutinizing it. Their watchful eye, fixed on the observer or some other well known human, immediately discovered any new clothing, article of footwear, scratch, pimple, or ink spot; neither did even the smallest change in the usual order of the room escape their attention. They invariably perceived such minute objects as specks of dirt on the floor, spots on the wallpaper, stray pins, needles, casually dropped nails — all miniature articles of the latter description being invariably scrutinized, touched and, if possible, collected and acquired.
Roody (age 2 y. 1 m. 24 d.) notices a tiny piece of hair sticking to a loaf of bread and exclaims, “Hairlet!” eagerly removing it before he begins to eat. When offered stewed fruit, he discovers a tiny worm and refuses to partake of this otherwise highly palatable dish. After some pictures in the nursery are moved, he immediately notices the change and enquires, “Why this picture? This not here,” demonstrating with his little finger the erstwhile location of the newly hung pictures.
But both little ones not only perceived newness: they also readily discerned similarity. In following the chimpanzee's free-play activity, we more than once had occasion to see Joni make matching colour groups out of 35 variegated plates of seven different colours. Of all the different hues Joni seemed to prefer light blue and would often select a number of light blue plates for his playful activities. At other times, I noticed that Joni, while manipulating a set of different-sized plates, would persistently select the small and round patterns; when manipulating a series of cards comprising sticks, acorns, and plates of various description (square and round, small and big), he selected all the cards of one colour and put them aside into a separate group.
The tendency to assimilate objects that possessed one characteristic in common was also strongly marked in Roody. When he was one, he would on his own initiative first point to his own ear or eye and then direct his index finger towards the same facial features of some adult in the room. Once, after pointing to the legs of a horse in a picture, he showed his own legs, thus clearly indicating that he was fully capable of assimilating like features. At the age of two (to be precise: 2 y. 1 m. 15 d.), Roody once looked at his doll, pointed to her eyebrows, said “brows-brows” then looked in turn at all the members of the family and exclaimed “Mother-brows, uncle-brows, daddy-brows,” after which he quite unexpectedly called out “milk-brows.” At the same time, he pointed to the black rim on a white milk cup, apparently implying that this was also a kind of eyebrow.
Both Roody and Joni show evidence of possessing generalized notions, which in Joni's case is expressed by the substitution of some more or less suitable contrivance for the needed instrument. Thus, he replaced sticks with pencils; ink with syrup, water, urine or milk, a hammer with a stone or his own fist; and a serviette or pocket handkerchief with a piece of paper. Joni apparently had a generalized understanding of lock and key, since he was apt to apply any key to any type of keyhole in all variety of places (doors, suitcases, etc.).
Roody, at 10 months old, had already mastered the generalized notion of “button” and when asked “Where is the button?” would invariably point to various buttons attached to many different objects and widely differing with respect to colour, size, material, and shape.
These and similar facts point to both possessing the faculty of elementary abstraction and also show that they were endowed with comparatively well-developed memory. The latter circumstance stands out in particular when we take stock of conditional reflexes.
Both the human child and the anthropoid infant easily form motor skills, no particular training being required for the purpose. These skills are principally associated with self-help behaviour, such as is expressed in drinking from a cup; or using a spoon, a knife, a serviette, a blanket or other tableware or household items.
Both subjects sometimes use a comparable gesture language. For example, “request” is expressed by extending the hand forward, “rejection of food” by turning the face and head aside, “thirst” by putting the hand to the mouth, “desire to draw attention to oneself” by tugging at the clothing.
From among other types of conditional reflexes the following has been ascertained:
Visual-gustatory-motor: when shown well-known sweetmeats such as oranges, both run up to the coveted object and grasp it.
Visual-algetic-motor: when scalded by fire or a hot stove, both immediately withdraw from the offending object.
Auricular-motor: both respond by complying to orders such as “sit down,” “lie down,” or “give me your hand”.
Auricular-visual-motor: on hearing the word “fly”, Joni looks round for a fly. When asked, “Where is tick-tock?” Roody turns his head, looks for the clock, finds it, and stares at it.
Visual-motor: the observer gathers books — a sign of forthcoming withdrawal from the room — and Joni runs up to door and bars it, preventing egress; Roody, when crossing the street, sees a bus and stops; in the past, he had to be held back by a hand under similar circumstances.
Visual-emotional-auditory: on the observer entering the room with books — a sign of prolonged sojourn — Joni excitedly and joyfully grunts; on seeing the observer gathering books, Joni begins to cry. On seeing me enter his room in a bathrobe, Roody loudly laughs; on seeing me in an overcoat, Roody cries.
Auricular-emotional-auditory: at the sound of an ascending elevator bell — i.e. a signal of arrival — Joni excitedly and joyfully grunts; at the sound of an ascending elevator and subsequent silence — a sign of the observer not having come home — Joni cries. When Roody is told, “Let us go for a walk.” He kisses hands and joyfully whimpers. But when told, “Let us go to the park,” he looks sad, even ready to weep, since he does not like to go there.
In respect of ejaculation of natural sounds we find both infants topossess the following similar vocalizations: “Ee”; “Oo-aw”; “Um”  ; “Kh-r-yu-oo” ; “Oo-hoo” ; “Oh” ; “You” Both also express very similar vocalizations when panting, sneezing, coughing, grunting, snorting, deep yawning, and to some extent crying.
As regards imitative sounds, few can be produced here that have the two subjects in common, yet both were able (albeit with differing skill) to imitate a dog's bark. The better accomplishment certainly belonged to Joni, which is no wonder, since the bark was his natural sound.
Both the child and the chimpanzee reproduced such sounds as the stamping of feet, the banging of hands, and the smacking of lips.
With such material it would seem that the similarity between the infant chimpanzee and the human child was in many respects, doubtless, strikingly vast and many-sided.
But if we deepen our analysis and bring the behaviour of the two subjects into even greater focus based on the full range of our observational evidence, we shall certainly be as likely as not to discern other traits that clearly testify to dissimilarity and divergence.
Speaking first about the sitting postures of ape and man, we must say that previously we looked primarily at sitting postures of an artificial or atypical character (on a bench or other elevation, sitting on the knees of the observer); but the typical or natural sitting posture of the chimpanzee, which can be seen from a number of our photographs, is altogether different: it consists of the ape sitting on his rump with legs bent and closely adhering to body, and the trunk being firmly supported on downcast arms. Now, this very posture seems to be entirely unnatural to the human child and may only be observed in the five-month-old baby when he is learning to sit. On the other hand, I never had occasion to observe the chimpanzee in that very typical infantile sitting posture, which consists of squatting or sitting down on the heels.
Standing postures may be said to be quite as dissimilar.
True, the chimpanzee — just like the human child — is capable of standing vertically erect, but when he does so, in order to keep up his equilibrium, he always leans against one side of the sole of his foot or at least on one of his feet. Moreover, he is in the custom of standing with legs wide apart and even then lacks the necessary stability to preserve a standing posture for more than a short interval of time, and even then, the ape is prone to seek some suitable support with his hand lest he should lose his balance. At such a moment, the chimpanzee closely resembles the human child when learning to stand, who, while clinging fast to some handhold, will also set his legs somewhat akimbo and fall down to one side a little. The typical posture of the chimpanzee is: standing on all fours with the body slightly inclined; it is only in this manner that he can manage to stand for indefinitely long periods of time. At the same time, the typical way in which the three-year-old human will stand is vertically erect with legs brought tightly together, his only support being the full spread of his foot.
But the erect walking of the chimpanzee arouses yet greater doubts. On the whole, it is possible to speak about this mode of the ape's locomotion in a somewhat conventional manner: the infant chimpanzee is able to walk upright no more than three or four steps at a time and at that he constantly balances his arms to keep up equilibrium. The chimpanzee will only then adopt the vertical way of walking when he wants to survey his immediate neighbourhood or if he is in need of finding his bearings in a new or seemingly dangerous locality. His clumsy gait proceeds only with difficulty and he is at any moment likely to abandon it in favour of more familiar modes of locomotion such as walking or running on all fours (with a slightly inclined body). When thus proceeding ahead, the infant chimpanzee will in his rapid and resilient gait not only by far overtake a human child of the same age but will also even surpass an adult.
I was never able to observe any genuine “all four” locomotion with regard to my own child. Even when crawling (at eight to nine months old), he would always support himself on the palms of his hands and on his knees. Never would he lean upon the soles of his feet or support himself on bent fingers, as is the case with the chimpanzee.
In order to facilitate locomotion, the chimpanzee will every now and then put his hands to the ground, even when led by the hand. And, if in observing the gait of a nine- or 11-month-old child, we can still see some balancing of the arms in addition to a slightly inclined posture, the three-year-old child almost without exception walks freely about in a completely upright posture, his uninterrupted erect locomotion lasting from 1½ to two hours without tiring.
The fact that the human child does not utilize his arms at all in the course of locomotion permits him to carry various objects, which he freely bears, drags. or brandishes about at will when walking or running. But, when the chimpanzee wishes to take hold of something, he usually prefers to carry the object in his mouth or drag it along with the help of his foot.
Mention was already made of the climbing activities of both subjects. It is perhaps in the manner and in the perfection of climbing upstairs or up trees that we see the greatest dissimilarity of all. While Joni always ascended stairs on all fours and got down in exactly the same manner (upside down), Roody was able to descend a staircase or climb down from an armchair in this manner only after the age of about 18 months, the descent being nearly always accomplished with legs forward. But at the age of three, the human child was already fully capable of ascending stairs fully erect without any need for using his hands.
On the other hand, the human child aged three to five years has the greatest difficulty in climbing up a small tree and can hardly hold onto the branches with his weak little hands. When sitting on the branch of a tree, his face betrays a pitiful grimace and he seems at every minute to be in danger of helplessly tumbling down to the ground. In direct contrast to this, the infant chimpanzee dexterously, assuredly, and easily climbs aloft using both hands and legs and not only reaches the tops of trees but sometimes even climbs over steeply inclined roofs and bravely perches himself on the very ridge. The descent involves no greater handicap than the upward movement. The little animal will in some time even make so bold as to climb down columns and nearly perpendicular inclines, leaving far behind even the most skilled human stunt performer.
The chimpanzee's foot as compared to the respective human appendage not only possesses much greater flexibility, but the chimpanzee is also characterized by far larger mobility in the pelvis joint: thus Joni was able to throw his leg so high up that it practically formed an obtuse angle with the other leg. Such a feat was entirely beyond Roody's capabilities, being, as is well known, usually only accomplished by specially trained professional acrobats.
“Jumping for joy” without moving from the spot is a trait common to both the child and the chimpanzee; but it is only the human child who can jump on one foot, while the chimpanzee has been frequently observed to leap from his legs to his hands and vice versa.
Let us now turn to divergence in behaviour, which is particularly evident in the instinct of self-support and self-help. While the human child was prone to perform all the acts pertaining to daily routine (such as eating, drinking, dressing, washing, combing, etc.) with the greatest precipitancy as if wanting to finish as soon as possible, the infant chimpanzee indulged in such processes as eating, drinking, grooming, and so on with the highest degree of preoccupation, attention, and minuteness.
Prior to swallowing a piece of food — even a variety he was accustomed to consuming— Joni would invariably smell it, bite off some small morsel as if to taste it, and would only then begin slowly eating the food, finding particular delight in consuming his favourite bits. When offered some milk at a temperature below that to which he was accustomed, Joni would refuse to drink it, or else he would slowly rinse his mouth with it until the temperature was warmed to the desired point and felt he could at last swallow the liquid.
Joni would never swallow hard, useless objects (such as fruit stones, etc.), however Roody was often observed doing so.
The ape thoroughly disliked adding butter or meat (especially chicken) to his food, but would apparently find insects quite palatable, occasionally eating even the fleas he had caught on his own body. In contradiction to Joni, Roody thoroughly enjoyed butter and meat, but was so squeamish with regard to insects that he would refuse to even taste food into which a small fly or worm had by some ill chance found its way. In the course of eating some particularly highly-prized treat Joni would loudly grunt, the grunt occasionally passing into a deep short cough. Under similar circumstances, Roody used to deliver a specific grumbling sound, much resembling the ejaculations of a suckling bear cub.
While the human child, in beginning the various activities connected with his daily routine, would dislike any intervention on the part of adults, eagerly shouting “Out!” “Let me alone!” or “Myself, myself, myself!” and displaying a clear desire to acquire an independent, self-taught command of such every-day contrivances as cup, spoon, towel, clothing, etc.; the chimpanzee was by no means averse to receiving assistance and displayed no tendency whatsoever to find a clue through his own independent activity. It was but clumsily and reluctantly that Joni would drink from either cup or saucer and, in proceeding to his meals, he would frequently hold the vessel not only with his hand but also with his foot.
It goes without saying that Roody's dexterity in this respect by far superseded what could be qualified as Joni's acquired motor skills.
Elsewhere, we have already mentioned the subjects' common dislike of sharing their food, but here we must point out an exception and say that, while Joni altogether refused to share anything (even with the person towards whom he otherwise showed the greatest affection); Roody, on being asked to share, would generally apportion some small bit to the supplicant, and would occasionally even go so far as to give a whole piece of food if he happened to be in the possession of two. Notwithstanding this, the fact is clear that Joni, in contrast to Roody, always displayed a tremendous degree of extravagance and would constantly throw about or otherwise waste a tremendous amount of edible material while partaking of his food.
In the process of catering to his bodily wants, the chimpanzee not only indulges in self-examination and cleaning, but also takes care to doctor any minor afflictions. He readily removes a splint, or licks a wound. Sometimes, notwithstanding all the pain caused by such a procedure, he will suck the blood from a wound, shuddering all the while at the aching sensation he is inflicting upon himself. The human child, on the other hand, on seeing blood or getting a splinter in his finger, becomes frightened and immediately requests the assistance of some adult, appearing to be afraid to touch the painful spot himself. Similarly, while Joni would readily submit to any kind of doctoring administered by the observer, Roody not infrequently attempted to thwart similar manipulations, or else submitted to them only through bitter tears.
Close observation of the manner in which both prepare for sleep points to considerable dissimilarity.
The ape is in the habit of preparing his bedding himself. He makes his sleeping quarters as soft and cosy as possible and will fidget about with his bedclothes till he at last he manages to arrange himself something of a nest. He will never be satisfied with even the most carefully made bed and invariably tries to modify its layout in accordance with his wont: for example, softer covers were usually distributed along the periphery of the bed, while some elevation is always provided for the head. Quite the reverse of the ape, the human child makes use of his bed, revealing no particular tendency to rearrange it in accordance with his taste. It is worth noting that, while Roody invariably enjoyed being tucked up to the neck and would even then occasionally (despite remonstrances) make a “dive” under the blanket, Joni never (not even during cold weather) permitted his bedclothes to reach higher than his waist, offering definite resistance when attempts were made to raise the blanket.
When asleep, Roody would frequently talk, wave his arms, or cry but we never had occasion to observe anything of the sort with Joni.
We might venture to suggest that Joni's opposition to having his arms covered up was dictated by an instinctive desire to keep the upper appendages of his body free for self-defence in case he were to be attacked during sleep, when one is most vulnerable. Such an inference is apparently corroborated by the fact that Joni was firmly against wearing any pyjamas of any kind — even the lightest jerseys. No less reluctance was revealed when attempts were made to tie bandages round his neck. Even the light dressing of a cut finger would be most energetically countered — something never observed in the case of Roody.
Roody seemed to have a definite desire to master the art of dressing on his own and deliberately, if slowly, improved in his skill. Joni refused to use any kind of clothing except a blanket.
We may also surmise here that the instinct for liberty is much more strongly developed in the anthropoid infant.
It seems characteristic that when allowed abroad, Roody would run far and wide, while Joni had an apparently insatiable desire for negotiating great altitudes. Up he would go at any cost and could soon be seen loftily perched upon some neighbouring roof where he would sometimes spend as many as several hours at a stretch. (It is perhaps worth noting that climbing aloft always preceded his stomach and bladder voidings).
Privation of liberty was much more acutely sensed by Joni than by Roody, which may possibly be accounted for by the fact that the ape, when confined, would generally be locked up in his cage while the child almost always remained within a human environment.
Again, there was a marked divergence in the attack and defence instincts. One could even claim that there was a great difference here not only in the outward signs of fear each exhibits, but also in the provoking stimuli.
While Roody, when frightened, would flush slightly and draw his hands to his chest, Joni would, on the contrary, grow pale, bristle up, and make something of a safeguarding gesture with his hand, usually bringing it to his eyes as if to protect them from an eventual assault. When experiencing a fit of terror (caused by stimuli such as a shot, a loud discharge, or a magnesium flashlight), Joni would fall prone upon the ground hands crossed above the head. It is perhaps needless to say that such tantrums were often accompanied by violent defecation.
I never noticed Roody becoming frightened on hearing loud light or sound stimuli, but Joni was invariably quite terrorized under such circumstances. Joni was particularly afraid of reptiles (even of the tiniest turtles and grass snakes) and of some animals' fur coats (particular fright was evoked by the spotted skin of a panther). Olfactory stimuli left Roody on the whole indifferent, while they caused a definite fear response in the infant ape. One could say that Joni was generally more easily frightened than Roody. It is all the more wonderful then that Joni could spontaneously overcome his fears with much greater rapidity than was the case with Roody; accordingly, the ape could on the whole be said to be braver than the boy.
To further illustrate this point, I will say that I had on several occasions observed that Joni, having had some frightening experience would, on his own initiative, arrange a second encounter with the frightening stimulus, as a result of which he gained better understanding of the bugaboo and came closer to completely overcoming his fear. Roody, when frightened, would seek the companionship of some grown-up and would master his terror only as a result of receiving either encouragement or assistance on the part of the protecting adult.
Joni was certainly more capable of self-protection than Roody. The alarmed chimpanzee could often be seen in a threatening posture with hair bristled up and looking nearly double his normal size. Standing on all fours, he would stare intently at the fear-provoking stimulus. Every now and then, he would perform a little jump from one foot to the other as if ready to assail the enemy, and would indeed leap at the offending stimulus at the critical moment. In doing so, he would stand erect, show his teeth, turn down his upper lip, and make a kind of clamouring noise. At last he would seize the victim in his teeth and start tearing and worrying it. If prevented from doing so, his paroxysm of helpless rage would sometimes go as far as to cause him to start biting his own body.
It seems hardly necessary to say that Roody never displayed anything like Joni's tantrums when stimulated by the same “intimidating” objects (stuffed animals, animal pelts). When in a state of anger, Roody would frequently clench his fists, while Joni would do the same with his feet.
It seems also worth mentioning that one of Joni's greatest fits of rage was observed when he was shown the stuffed specimen of a small chimpanzee (at six months old), while a similar object shown to Roody (at 2½ years old) 13 years later seemed to evoke the boy's most tender feelings. Acting altogether on his own initiative, he began hugging the stuffed animal saying, “Poor little Joni.”
Roody generally had not even a trace of that cruel hateful or scornful attitude towards small animals that was so characteristic of Joni. It was, in fact, apparently a pleasure for Joni to torture, worry, or even kill various small and harmless living beings such as frogs, crawfishes, beetles, cockroaches, etc.
Contrastingly, Roody seemed to possess a feeling of particular tenderness towards animals. Whenever some small beast got into trouble, he would invariably try to render it all the possible assistance he could. For example, he would try to extricate flies from Tanglefoot Paper, and would shed bitter tears on seeing the insects flutter their wings in helpless attempts to disengage themselves. He would also cry with compassion on seeing ill-treated dogs and make all kind of attempts to protect them. On seeing a bleeding animal, he would try to heal its wounds and was most emphatically opposed to the catching of mice in traps. When coming across smaller children, he always tried to render them whatever services were within his power.
Elsewhere we have already briefly dwelt upon the feelings of affection and sympathy that both subjects displayed towards their adult protector. But it should be pointed out here that only Roody wept with compassion on seeing his adult friends show signs of sickness or other bodily suffering. At the same time, it seems characteristic that the writer never had occasion to see the ape relinquish his egocentric tendencies or make any attempt towards sharing his welfare with somebody else. For example, Joni would never —not even when entreated to do so — give up even the slightest morsel of his food; true, he would sometimes act in protection of his human friends, but he would immediately retreat if he felt he was in real danger himself, leaving his companion to extricate himself out of the difficulty as best he could. Thus, when some object causing considerable fear to Joni was brought up, or in case of a pseudo-attack by some person of whom Joni was afraid, the chimpanzee cared only about escaping peril himself.
On the other hand, Roody seemed to experience particularly strong vengeful and wrathful feelings on such special occasions when he would, for instance be trying to save small animals from the attack of larger ones. For example, on seeing a big dog fight a smaller one, he would do all he could to break up the pack, and in his efforts to save the “underdog” he would even go as far as to entirely forget all personal danger. More than once we had occasion to see the boy discontinue some kind of clamorous amusement at the slightest hint of somebody being unwell in the house. Once he refused point blank to eat a piece of marmalade with the imprint of a hare, stating that he was sorry for the “little hare” and “that he could not eat him up.” All our attempts at proving to him “that this was not a real hare” led to nothing and he stubbornly refused eating the food, in spite of the fact that it was one of his favourites and there were no other sweets in view.
As early as at the age of three, the child's behaviour already appears to indicate spontaneous manifestations of such feelings as ethics, altruism, a sense of justice, and grasping right and wrong. But there does not seem to be even the slightest hint of this on the part of the chimpanzee. The utmost that I had occasion to observe in this respect with Joni was a case of inhibited anger when I once happened to cause him pain in treating his nose with ointment. Joni caught my hand in his mouth, but let it go at the last moment without biting.
The affectionate behaviour of both is again marked with a tremendous difference in the strength of the feeling. Roody expressed his affection with characteristic utterances: “Dear mother — love.” “I don't want to give you up to anybody.” “I want to always be with mother — day, evening, and night.” “I do love mother, every day do I love my mother.” The child wanted to be in the complete and everlasting possession of his loved ones. For example, he asks, “Mother, will you ever die?” and getting no answer expresses his own secret desire, saying, “I'd like mother to never die!”
In our observations of other phases of social behaviour, we must first point to Joni much more rapidly establishing contact with human adults than Roody; it may also be said that his relations with a newcomer were to a much greater extent tinged with familiarity or something of the “hail fellow well met” attitude; but in his playful behaviour Joni invariably tended towards a commanding role and would always show a definite unwillingness to submit. The smaller and the more defenceless Joni's playmates, the more commandeering, despotic, and even cruel he would become.
The social behaviour of the human child as illustrated during play is radically different: he readily acquiesces to adult leadership and gladly performs any assignment he is given. The companionship of his equals causes him to display something of a brotherly fellowship, while the society of younger children, animals, or toys evokes a kind of fatherly or protective attitude.
We may now revert to the question of emotional manifestation. In the preceding treatment of this subject, we mentioned some basic similarities in the principal emotions (fright, sorrow, excitement, joy, anger, disgust, curiosity, astonishment, and tender behaviour) as well as a similarity in many of the corresponding stimuli.
Now, in order to throw our comparative study into still bolder relief we must point to yet another feature viz. the manifestation of emotions as expressed in mimics, pantomime, and vocalization, which is considerably more pronounced and accentuated in the case of the ape. The expressiveness, strength, and duration of the ape's emotional manifestations are indeed such that opportunities are afforded for in-depth, close observation of all the successive stages in which the respective emotions are unfolding. Nothing similar can be observed in the case of the human child, the behaviour mirroring of whose emotions is incomparably paler and less sharply defined.
In a state of excitement Joni's hair bristles up, he stands vertically erect, and emits a modulated “oh-oh-ing sound”; next he clenches his feet into fists and begins expressively gesticulating with both hands. The only outward expression of excitement with Roody consists of his heavy breathing.
When overpowered by despair or completely woebegone, Joni starts a resounding outcry; then stretches out his hands, then throws them about his head, and lastly falls prone on the ground, where he commences a number of somersaults. In the course of these convolutions, the ape's face slightly darkens, but with no evidence of tears. Mild forms of depression find their expression in the protrusion of lips and whining.
If particularly sad, Roody starts to weep, shedding abundant tears, which drop right upon the floor. But his shouts are of course nothing compared to Joni's wild outcry. Also, his gesticulation is by far less sharply pronounced, the most frequent gesture consisting of rubbing his eyes with his fist. Joni's mimicry is naturally devoid of this gesture, since he sheds no tears. Roody expresses a very mild form of depression  by turning his upper lip down.
Tearless crying, similar to that of the chimpanzee, is observed in the human infant only up to the age of 1½ months.
While the human infant's joy finds expression in loud laughter accompanied by other loud, shrill sounds (such manifestations occurring as early as the age of three or four months and becoming consistently stronger afterward), the chimpanzee lacks the ability to vocalize laughter and even when tickled will only pant and broadly grin, though his eyes glitter and all his face expresses full satisfaction. The absence of vocalized laughter in the anthropoid seems to be compensated for by the emission of other loud sounds. For example, the joyful excitation of the ape is first signalled by a series of oh-oh-ing outcries, pitched in a major key that later turns into a resounding bark accompanied at every second by a real whirlwind of diverse bodily movements and gestures. Mention was already made of the fact that the frightened human infant gets pink in the face and cries out, pressing his hands to his chest. Under similar circumstances, the chimpanzee becomes pale, his hair bristling up, and emitting a short and dull o-o sound. When in a tantrum of rage, the chimpanzee turns up his lip, shows his gums, opens his mouth and begins banging against the offending object. The angered human child clenches his teeth and fists and stamps both feet without moving from his place.
The child expresses his affection by kissing or rubbing his face against that of his friend; the chimpanzee by touching the object of his affection with the lips of his open mouth (a similar gesture is observed only in the child under 2½ years) or by using his tongue in the same way (which is not to be observed in the case of the child).
The astonishment of the human child is accompanied by a deep sigh, while the astonished chimpanzee emits not a single sound. The child's disgust is expressed by a kind of grunting or coughing sound. The chimpanzee under similar circumstances emits no vocalization whatsoever.
All three emotions — astonishment, fear, and excitement —frequently cause the chimpanzee's hair (on his face as well as on his body) to stand on end.
If moved by curiosity, the chimpanzee nearly always sniffs the object of his interest, another form of behaviour never to be observed in the human child.
But the intentness of the human child is characterized by a special kind of mimicry altogether alien to the ape and consisting of the protrusion of the tongue and the coordination of arm movement .
Passing over to the range of emotional stimuli, we are again liable to see tremendous differences. Indeed, in considering the three principal emotions — excitement, sadness, and joy — we see that the former actually takes the lion's share in the ape as compared with the latter two, while this emotion is but feebly and rarely manifest in the human child. In direct contrast to Roody, Joni was often found to respond almost passionately to environmental changes, but his responses somehow seemed to lack colour, or, to put it another way, appeared insufficiently differentiated.
As a matter of fact, one got the impression that Joni was at first unable to decide whether the new stimulus was favourable or not. It was as if he, himself, felt uneasy as to what kind of response might follow: whether it would be joy or sadness, and whether the given stimulus dictated self-defence or attack.
A wealth of observations shows the child's reaction to be incomparably more rapid and precise: the human child either rejoices or grieves and either feels fear or anger, but knows none of these intermediate excited mind states when things have not yet made themselves sufficiently clear and no definite attitude or frame of mind can accordingly be adopted. It appears as if the human child at once grasps the biological purport of every new stimulus and hastens to respond accordingly.
The range of every description of emotions — pleasant, unpleasant, affectionate, astonished, and curious — is indeed incomparably broader with the human child. Suffice it to remember the acute sensation of pain felt by the child crying at even the smallest hurt; or we might remember the tears he sheds in sympathy with his elders and the many other afflictions of the higher order that he is prone to experience, for instance when thwarted in his creative, constructive, or reproductive activities, if disappointed in his ambitions, etc.
None or at best very few of these emotions are shared by the chimpanzee. Of course, a much vaster range of pleasure- and joy-inducing stimuli also move the human child. It is at a very tender age that his ontogenesis reveals him to possess a special form of perceptive joy — the sense of the comical — which not infrequently comes into play as soon as the child perceives a new or unexpected combination of well-known stimuli; the availability of the sense of the comical shows us indeed that the child is capable of perceiving any breach of the norm and, what is more, finds a source of amusement in the element of novelty and even rejoices in it.
The human child is just as depressed by a case of ill luck as he is happy upon reaching a desired goal and this again tends to vastly increase the range of his pleasant emotions.
There seems indeed not to be the slightest doubt that such emotions as curiosity, attention, and astonishment are of an incomparably wider scope in the child — a fact that is well borne out by the speech reactions of the human.
Our comparative investigation into the emotions peculiar to the two subjects plainly reveals their external expression — with the single exception of affectionate behaviour — to be much more obvious in the chimpanzee. We have already seen that his expressions of anger, sorrow, fear, etc. are extreme.
Our general impression is that with respect to the caricature-like expressiveness of his feelings, the chimpanzee is much like the insane, with their extravagant and exaggerated facial expressions and pantomimes.
Regarding the range of emotions — or the latitude and multiplicity of emotion-causing stimuli — our observations show a rather well-defined division between the two subjects: while the chimpanzee tends towards a broader range of feelings such as general excitement, fear, and anger, the human child is affected by a far greater number of stimuli, which are apt to produce joyful, sad, or affectionate responses. Feelings associated with cognition, such as curiosity, astonishment, and concern, are experienced similarly.
Roody was also much more likely to imitate adult behaviour, and his imitative behaviour was by far more efficient and versatile. While Joni could only imitate separate actions, Roody appeared to be capable of reproducing a whole series of them. The boy liked to impersonate professional men and tradesmen and would often mimic doctors, automobile drivers, newspaper vendors, museum curators, firemen, photographers, fishermen, and soldiers. On the whole, he was able to pull it off rather successfully. He liked to attire himself in the respective uniform and had a penchant for mimicking voices and gestures.
Moreover, his mimetic behaviour comprised the imitation of grunting, snorting, and singing. He even went so far as to attempt the reproduction of certain animal cries, like the crowing of birds and the squeaking of guinea pigs, or the sounds emitted by inanimate objects, like the ticking of watches, the cracking of curtain rods, the roar of airplane propellers, etc.
It's been said that the entire mechanism by which a child masters speech may be based upon first subconscious, and later conscious, imitation. When told to reproduce such words as papa, mama, baba (grandmother), or nyanya (nurse), Roody (age 1 y. 5 m. 22 d.) enthusiastically shouts them out, but is unable to pronounce an unknown word and mixes up the syllables, which he puts in the wrong order. However, in some three months, following an adult's lead, he is fully able to articulate even entirely novel and unfamiliar sound combinations, though sometimes errs in the successive order of the component syllables.
At 2½, Roody is already able to reproduce three-word sentences and later remembers even long poems from picture books. It stands to reason that Joni lagged behind the boy considerably in this respect — his vocal imitation being confined to mimicking the barking of dogs and the vocalization of his own natural sounds when the observer purposely uttered the same. The little ape seemed to find particular delight in the latter form of imitation.
Moving on to imitative behaviour connected with the use of implements and constructional play, we again see the incontestable superiority of the human child.
How each handles the pencil and hammer may be considered good criteria for comparison here. Despite all his efforts, for example, Joni never succeeded in hammering a single nail into place, while Roody was able to accomplish this feat already at the age of 2 y. 1 m. 10 d.. Notwithstanding Joni's constant fidgeting with a pencil, his accomplishments in the field of drawing never went beyond tracing several intersecting lines, while Roody (at two or three years old) could already master some elementary sketches of nearby objects. Our analysis of the boy's drawings, as well as his concomitant statements , shows him to possess a distinct tendency to identify his drawing with the object drawn . His drawings also reveal his ability to grasp more features  than the chimpanzee. Thus, the child compares his drawing with the model and attempts to correct his work; if he is unable to do so, he supplements his shortcomings with a vocal description — a fact that confirms the free play of imagination. None of these specifically human traits could ever be observed in the chimpanzee.
Next, let's compare the egocentric instincts of the two infants, and their instinctual desire for property. In this section, the first thing that should be mentioned is that the chimpanzee has a far more aggressive way of protecting and safeguarding what he believes to be his lawful property. He also shows greater dexterity, cunning, and skill in acquiring prohibited objects. At the same time, Joni had no capacity for utilizing his property. He would strive to get the desired object, doing his utmost to become its sole owner, then frequently not know what to do with the new acquisition. Unless it was some practical object like bedding, for instance, he would often let it go and appear to forget all about it within moments of procuring it. Once an object was in his possession, however, should anyone attempt to take it away Joni would bristle up in defence and behave as though it were the most precious of his belongings. It sometimes seemed as if the very process of acquisition and not the object itself were his final goal. As a matter of fact, Joni usually showed complete indifference to most of his possessions; but only up to the moment when the danger of losing them arose. As soon as Joni's belongings begin to attract someone else's attention, he would start a desperate fight to retain the object in question.
Now, Roody would certainly accumulate belongings with much greater avidity than the ape, but he was much more likely to amass his collections in a peaceful, quiet manner. He particularly liked little trifles such as sticks and stones and was of course eager to safeguard them, but never displayed the same passionate fervour in opposing somebody's desire to remove them from his possession. He was likely to differentiate between his and other people's belongings, and would never be particularly averse to parting with objects about which he did not particularly care. For example, when another child asked him for some plaything, he would not infrequently give it away, adding, “Well, why do I really want it?” illustrating that the object in question was of little if any value to him. At times, he would show special preference towards some disabled old plaything and seemed altogether loath to part with it, while a new or recently acquired toy would rank comparatively low in his esteem.
It is quite natural that Roody should have found a much more efficient way to use his belongings than did Joni. Even waste material was “reclaimed” and put to good use in the playful activity of the human child; true, when asked to explain the exact need for this or that small stick or stone, Roody was not always able to give a fully explicit or satisfactory answer; but there always came a time when it would find itself a suitable place in some new structure. Though, again, there were many occasions when the child put the item to immediate use.
The aesthetic and colour preferences of the two subjects are at considerable variance. Joni preferred blue plates, Roody chose red ones. Roody had a much greater tendency towards self-adornment and enjoyed looking at himself when attired in some new garb.
It may generally be said that the child draws his inspiration from the world of real objects and carries it into the realm of cognition. Thus, we know him to possess a definite predilection in favour of some pictures and we are aware of his preferring some books to others. The child moreover exercises choice and judgement in his selection of stories. He prefers the fantastic, the humorous, and the lively. He understands imagery and in listening to adventure stories is fully able to give free vent to his powers of imagination.
Nothing similar is observed in the chimpanzee. His mind dwells solely upon the concrete. It may be that the ape's imagination enters into the picture only when he is playing with some part of his own body, or when he purposefully erects obstacles to overcome during play.
The sex instinct was, on the other hand, certainly much more pronounced in Joni. Emotional behaviour was invariably accompanied by sexual irritation, which could be observed particularly often when he was wrestling with a football or some other soft object. Roody never displayed even a trace of excitement under similar circumstances.
In summing up our analysis of instinctive behaviour, we find that nearly all instincts find a much sharper and stronger expression in the ape. This applies to such instincts as self-support, self-protection (both defence and attack), the pursuit of freedom, ownership, and social and sexual instincts. There appears to be only a single instinct, namely imitation, in which the manifestations of the chimpanzee fall short of those of the human child.
The least divergence between the two subjects is to be observed during playful activity and especially games that involve motion.
Roody liked games that might be termed “pseudo-locomotion.” Accordingly, he would often set up a long train of toy vehicles, fill them with his dolls or toy animals, and pretend he was off on a railway journey, playing the role of the conductor himself.
When indoors, Roody found particular pleasure in pretending that he was skating or skiing: he would take some kind of plank, place his slippers on top, and begin a series of sliding movements, making believe he was engaged in winter sports.
Nothing even remotely resembling such “pseudo-locomotion games” was ever observed in Joni.
But, while little three-year-old Joni was able to swing about on a door for quite a long stretch of time, Roody could master this feat only at the age of four and, at that, very soon became tired and discontinued the game. It goes without saying that Joni performed every kind of gymnastic exercise (climbing, hanging, swinging, jumping, etc.) with much greater ease and dexterity and with a much more considerable number of bodily movements, a fact which is of course readily explained by the much greater strength and tenacity of the ape's arms and legs. Roody could remain suspended on the door for no more than two to five seconds, while Joni could hang on for several minutes at a time. More than that, Joni could remain suspended upside down for two or three seconds — a feat that Roody could never achieve. Joni showed no signs of fear when jumping from an altitude of two to three meters and even higher; the maximum height Roody could negotiate was never in excess of ¼ meter. Joni would boldly climb up steep ladders to the second floor of houses; Roody seemed already afraid when reaching a height of two meters, etc.
Our analysis of competitive games reveals the following points of divergence.
Joni's “enthusiastic” disposition led him to a display a much greater zest in competitive games and he flew into veritable fits of passion whenever wrestling, playing catch, or taking something away was concerned. No less passionate behaviour could be observed when he indulged in such competitive pastimes as catching a tossed object, seizing it from its lawful owner, sneaking out of his cage, or fleeing pursuit.
Upon failing to be the victor of a contest, Joni would never cry, but would rather show anger with respect to his opponent; Roody, on the other hand, would very frequently start weeping under similar circumstances. Roody's favourite competitive game was wrestling, a game in which he would always try his best to win.
Our observation of playful behaviour with obstacles provided shows that Joni preferred to burden his mouth and legs (of which he made free use for carrying cargo); Roody carried everything in his hands. When Joni overloaded himself with objects (carried in his mouth and between his legs), he seemed to enjoy negotiating the difficulties involved and to take pleasure in stealing objects, climbing through holes  etc., Roody, on the other hand, found an unending source of merriment in jumping over barriers, walking and riding a bicycle or in a toy motor car, etc. He seemed to especially like various forms of leg exercise, and was particularly keen to negotiate various risky obstacles that involved retaining his equilibrium (walking over narrow bridges, beams, etc.)
It is interesting to note that Joni, upon hurting himself, would stoically endure the pain, while Roody always tried to avoid painful stimuli and in doing so would exercise principally his dexterity and sense of boldness. Thus, the human child is inclined towards intellectual skill, while the ape principally towards bodily skill.
Playing at hide-and-seek again shows Joni to find far superior places of concealment than Roody.
In his games with live animals, we see Joni play the despot and try in every describable way to torture, pursue, beat, worry, and even kill his inferior playmates; the human child, on the other hand, does what he can to involve the animal (toy or live) in his games and makes an effort to set up organized play, in which he reproduces a successive series of relevant and logically consistent events that deal principally with such events of adult life as fire, hunting, travel, and the like.
The animistic attitude of the child towards his toys, as well as his powers of imagination is particularly manifest in his games. Here, Roody would repeatedly attribute his own feelings to a toy — a cat, cock, hare, or doll — and exclaim, “See the cat cry,” “Poor cocky, weeping like anything!” “Rive [the doll] has got something wrong with his throat!” etc. It is clear that the child does not take his own animistic utterances for the truth. He understands that his doll and stuffed animals are “not quite real people,” but he nevertheless thinks them to be “like people.” For example, Roody once gave his wooden horse a book and told it “to read.” In order “to encourage the horse to read,” he began himself reading “like a horse” i.e. uttering a series of meaningless and incoherent syllables. On another occasion, he made his doll utter nonsensical statements (apparently “doll-like”?). Evidence like this tends to prove that in his games the child does not substitute one form of reality for another, but rather consciously rises above reality to indulge fantasy and imagination. We see the child create new imaginary realities, but this owes neither to a complete identification with myth or fact, nor to a complete rejection of reality.
The child's creativity consists of the virtual remodelling of reality. It would seem that in this instance at least some similarity can be found with the ape.
But the infant chimpanzee, in his struggles with bogus enemies and in his purposeful erection of obstacles, displays such extraordinary passion, rage, and enthusiasm that one gets the definite impression that he considers real objects either mere puppets (which would amount to a virtual blending of his ego with an alternate reality) or that he perhaps perceives the obstacles in a “matter of fact” way (meaning that no mental substitution is taking place), believing them to be nothing more than tangible items.
In those games that involve both animate and inanimate playmates, the human child frequently adopts the role of both leader and protector and, while acting this part, he makes every attempt to appear magnanimous, generous, and brave (the latter quality which he may be somewhat lacking in everyday life) and exerts every effort to appear merciful and kind to the game's lowly and oppressed (being in this respect a complete contrast to the ape).
As for the problem of response to pleasant auditory stimuli, we find that Roody was eager to find amusement in self-emitted vocalized sounds already at three or four months old (first came incoherent vocalizations, then muttering, shouting, and lastly verse and singing); Joni never exhibited even the slightest trace of pleasure in the utterance of vocalized sounds, and this despite his strongly marked tendency towards making various kinds of noise, such as smacking lips, noisily pulling eyelids, banging hands against various objects, rattling a stretched piece of rubber, etc.
In playful activity of the experimental kind, such as the exploration of novel stimuli, like water, fire, sand, and various other eye-catching objects (sharp-edged, transparent, soft, elastic), the writer was able to note the following principal differences:
Roody actually experiments with his environment and not only does he attempt to gain awareness of his surroundings, but he also actually tries to understand the very root of things. His interests are primarily directed towards finding a satisfactory explanation for the appearance and disappearance of certain elements. For example, at the age of 2 y. 5 m. 27 d., Roody found amusement in extinguishing a candle and on having blown out the flame, and exclaimed in amazement, “Now, where is the fire?” Next, he began looking for the “lost fire,” searching for it under tables, chairs, and other furniture .
It is quite the opposite with Joni. He extinguishes a candle with not a single sign of astonishment or dismay. The disappearance of the flame is taken for granted and no inquisitiveness is aroused. In Roody's case, experimenting behaviour was particularly evident when he had occasion to come across a pool or some other body of water. At the age of 2 y. 10 m. 9 d., the boy was already performing actual experiments such as throwing various articles into a pool in order to see which of them would float and which would not; here are some of his comments: “This little lid floats alright” (eagerly following the drift of a small wooden object); “And what about this one?” (before launching another one); “Why does iron not float? Yes, it sinks” (on putting an iron container into water and seeing it become submerged); “A stone does not float” (on seeing it sink to the bottom) “… and my bear floats” (the toy in question was made of wood).
At the age of 2 y. 3 m. 25 d., Roody was observed to have become particularly interested in the tripod of a camera. By gradually lessening the distance between the supports, he seemed to be trying to gauge the smallest range at which they could be set without interfering with the equilibrium of the structure. Every time the distance was reduced, Roody would say to himself in amazement, “Will it go on standing?” At last the tripod tumbled down and the boy concluded, “Won't stand any longer!” On another occasion, upon being given a small watch, he brought it close to his ear and began eagerly listening to its ticking. Then, he began raising the watch to his head, pressing it to the eye, etc., as if trying to find out which conditions were more or less favourable for listening.
The human child gladly reclaims all kind of waste and refuse material and puts it to good use in his games, a trait never observed with Joni.
In playing with hard or sharp objects, Joni was a great deal bolder than Roody: for example, the latter would never dare attempt putting nails into his mouth, something Joni had been observed doing on more than on one occasion. Similarly, Roody never stretched his mouth by inserting sticks, as was Joni's wont, and he confined himself to merely putting twigs in the extended palm of his hand. This again shows how very afraid of painful sensation is the human child. Speaking of the use of sticks, branches, and other elongated objects, it seems worth mentioning that while Joni would at best utilize a stick as a tool for reaching remote objects (e. g. for frightening cockroaches out of their holes, or for getting at a suspended chandelier), Roody found sticks and twigs to be highly suitable structural materials and would invent for them no end of useful applications such as making whips, toy airplanes, boats, wells, etc.
Playful behaviour of a destructive nature occupied a much greater share of Joni's free time and was invariably accompanied by far greater gusto, as well as efficiency. Destruction for its own sake seemed indeed to be the source of the ape's greatest pleasure, and his sharp teeth and strong hands would usually make short business of the luckless prey. Roody was manifestly unable to destroy things with anything like the same speed or totality as were characteristic for Joni. True, he also seemed to find a peculiar pleasure in demolition, but his naturally weaker hands never afforded him the same opportunities in this respect and he often happened to resort to various “tools” for the purpose in question, preference being generally given to stones, sticks, and the like. He also never contented himself with demolishing what was nearby, but extended his destructive activities to what was even beyond his direct reach; as compared with the ape, the human child could also much more frequently be seen throwing a stick or a stone at a definite target. Also, he sought to produce the maximum effect by combining destruction with construction. He would make himself bows, wooden forks for shooting, pebbles, toy swords, etc., and found pleasure in firing from toy guns or pistols. Once Roody even made himself a peculiar kind of projectile resembling a shell with poisonous gases. He put some dust into a jug and started throwing it up and down. The tumbling down of the jug apparently gave him the illusion of an explosion, while the escaping dust was intended to represent a cloud of smoke.
It is highly typical that Joni's imitative behaviour should be more effective in destruction, Roody's — in construction. Roody used tools or instruments for creating or building something. He used to do his best to build airplanes, boats, railway trains, zoological gardens, houses, telephones, wells, cages, etc., the completion of every new structure invariably greeted with the most exuberant joy. Cf. also Figure D.24, “Independent structures made by the child in imitation of an airplane” (The child builds a reproduction of an airplane without help).
The child made rapid progress  in the design and construction of every new item of his construction projects (cf. the illustrations showing the houses built by Roody at the age of two, 2½, and 4¾ years, respectively).
Contrastingly, Joni succeeded much better in extracting nails than hammering them in; in tearing a trapeze down from its hook vs. hanging it in place; in unlocking a padlock vs. locking it; in untying a knot vs. tying it, etc.
There was a time when both little ones had ninepins at their disposal. These ninepins were of a sort that could be taken apart and put back together again. While Joni could find a great deal of pleasure in disassembling the plaything, mutely appealing to me to put the parts back together every time he had separated them, then immediately beginning the process of dismantling anew; Roody would continuously exercise his ingenuity in both putting the pins asunder and putting them together again, an activity that had not once been observed in Joni.
The tendency towards constructive play is very prominent in the human child and in contrast to the ape leaves destructive behaviour far behind. Mention, however, should be made here of two strange attempts at imitation that Joni did manage to make on two separate occasions. These were an imitation of a string musical instrument and a kind of rattle. The two instances occurred as follows: on one occasion, I saw the chimpanzee draw aside a rubber ring that he had previously placed round his head. A clicking sound followed. Evidently finding pleasure in the sound, Joni fastened the ring to his tooth and began playing on it with his fingers as if it were a musical instrument. Another time he put sawdust into a small bottle and started shaking it, evidently waiting to hear some kind of rattling sound.
On reaching his third year, Roody began engaging in even more building activity. At this stage, one could hardly find any household or other object that he would not want to reproduce in his structures. Of course, relative to real-life structures, the child's buildings must be qualified as coarse, inadequate, and inefficient. But the child takes no heed. He clearly sees the proper place for everything, but instead of putting it there, he jumps into fantasy. He is also extremely creative in describing his games.
Imagination, the ability to take the humdrum canvas of reality and weave on it a multicoloured vista of imaginary events is essentially a human gift, and we find but a poor surrogate on the part of the chimpanzee.
Now that we are nearing the close of that part of our analysis which deals with playful activity, it seems necessary to say that among all the kinds of play in which he indulges, the infant chimpanzee most often chooses amusement of the competitive or gymnastic kind. The ape passionately indulges in forms of playful activity that are connected with overcoming obstacles, destruction, killing, or worrying smaller animals, but imitation and construction are altogether beyond him, being as it were, the specific prerogatives of the human mind. True, both seem to find nearly the same degree of pleasure in playing with objects that move or make noise, but experimental play as such is incomparably more developed in the human child and bears the definite stamp of being one of the leading forms of activity that tend to shape the human intellect. In such forms of play, the child, far from being a mere spectator or simple onlooker, takes on the role of the investigator and makes good use of the experimental method, looking into natural phenomena and tracking down explanations. We might even perhaps go as far as to say that the playful activity of the three-year-old child already exposes the very features that will in time permit him to become in manhood the lord and master of nature.
The initiative displayed by the human child also gives weight to the argument. As already stated, both showed a definite tendency towards imitative behaviour, but the human subject displayed much greater daring and attempted to reproduce not only what he actually could, but also what was beyond his still weak and inadequate capabilities (c.f. what has been stated elsewhere about Roody's imitation of adults).
The behaviour of the chimpanzee reveals yet another important and distinguishing characteristic: viz. scattered attention. Our observations of his playful activities indeed show an entirely fragmented psychic pattern made up of separate and disjointed elements. His actions may be said to be “mosaic-like:” they begin with a start and are suddenly discontinued, but only to commence again the next moment without any clear reason.
The highly organized play of the human child offers in this respect a striking contrast to the playful behaviour of the ape. In most cases, the play of the human child is found to consist of a consecutive series of entirely relevant and mutually interconnected actions (cf. his play with dolls and live animals discussed elsewhere).
Both subjects are endowed with natural curiosity, but it is only in the human child that curiosity extends to the sphere of cognition and it is only with reference to man that we can say that curiosity actually passes into inquisitiveness.
We may now move to a general discussion of the intellect of ape and man (as expressed in inquisitiveness, powers of observation, recognition, identification, generalization, abstraction, comparison, making logical inferences, memory, and imagination). But we must in the very first place make the following important stipulation:
Had we started with evidence based on direct observation, but excluded speech, we would have been obliged to confine ourselves solely to evidence that dealt with the similarities between the two subjects. Considering our subject in this manner, we should indeed have been obliged to place the ape and the human child on almost the same footing.
But would such conclusions be consistent with the true state of things? Have we the right to leave out the child's utterances, which are such a potent a factor that they permit us to unearth a whole wealth of data on child psychology? We would indeed be passing up a hidden treasure. Certainly, it is our duty to dig it out, assess, and take proper stock of all the contents and only then shall we be in a true position to adequately gauge the entire personality of this most interesting and unique creature — the human child.
Having concluded that it is necessary to ponder the speech evidence, let us now consider a number of traits that we will call human par excellence, since they find no counterpart in the mind of the ape.
Above all the human child is inquisitive. Already, at the age of 2½ years, he is imbued with the desire to “inquire into everything” and bombards adults with neverending questions. Eager to know the name of every new thing, to understand the meaning of every word, and to grasp the import of every picture, Roody would from the beginning of his third year persistently inquire, “What is it?” However, upon reaching 2½ years, the scope of his questions becomes more extended and, no longer content with knowing the mere names of objects, he poses questions such as: “Tell me all about...” (bread, potato, grapes); “Where does the zebra live?” “Where does the giraffe come from?” “Whys” and “wherefores” are constantly on his lips: “Why have you not got a beard?” “What are clouds?” “Where do they go?” “Can we catch them?” “Why not?” “Can we make the little stars come down?” and so on, and so on, to infinity. Everyone knows that a single answer to a child's “wherefore” often entails a series of consecutive and logically connected further “whys.” The child always wants to get back to basics, and sometimes goes so far in this respect that adults are actually thwarted in their attempts at explanation.
The child shows keen powers of observation. Once, upon seeing a small line drawn on the floor with an indelible ink pencil, Roody (age 3 y. 0 m. 6 d.) exclaimed, “How it glistens: Why does it glisten? See, I go off and when I am far away it still glistens!” On another occasion (age 2 y. 10 m. 9 d.), he sees two faces on a small rattle; one seems jovial, the other not, Roody exclaims, “The one laughs and the other one does not!” etc.
The child easily finds and identifies various objects in pictures. At the age of 2 y. 9 m. 16 d. Roody knew the names of 85 different objects depicted on the cards of a lotto game. All the easier does he identify concrete objects. At the age of 2 y. 6 m. 13 d., Roody could already distinguish between 45 different animals depicted in his picture book.
At the age of 1 y. 9 m. 18 d., Roody was already able to recognize a whole by its component parts. For example, when I cut some toys into several parts, he told me exactly to what particular toy a given piece belonged. Self-recognition by photograph was first noticed at 1 y. 10 m. 20 d.. Very soon after, Roody recognized his father, mother, nurse, doll, and horse in photos, stating the names of each when asked to do so. He even recognized the writer in a photograph taken 20 years earlier.
Roody possessed a well-developed capacity for generalization, making analogies, and organization by colour, shape, size, or texture of material (elasticity, transparency, etc.).
An example of Roody's generalizations is as follows: from the age of one year to 18 months, Roody called all men “uncle,” all young women “Gaga” (after the housekeeper), all elderly women “granny,” and all children “Katia” (after a female playmate).
We select from among the considerable data in our records a few examples typical of the child's powers of organization (these are illustrated in Figure D.17, “Analogization by colour” — Figure D.22, “Identification of twigs and branches with different objects”).
|Classification by colour: By comparing a piece of yellow oilcloth with cod-liver oil, the child describes it as “oil.”.
|Classification by colour and form:
|Classification by form only:
|Classification by the property of transparency:
|Classification by the property of elasticity:
|Classification by size:
Roody did not always draw comparisons according to the main characteristic. However, very often he did identify a basic trait and abstracted it from the secondary characteristics.
Let's look, for example, at Roody's relationship to airplanes, which had apparently made a deep impression on the child's mind. Even before he could speak, Roody indicated airplanes with the “gh” sound (for the sound made by the propeller).
Once (age 1 y. 6 m. 27 d.), while playing with some wooden shavings, he discovered a shaving that apparently reminded him of an airplane. He lifted it up into the air and exclaimed: “gh”.
Later, the image of an airplane would come back to him whenever he saw anything resembling two surfaces intersecting one another at more or less right angles.
We produce a number of pictures that graphically illustrate 38 cases when an airplane was compared with different objects. The exact age to which every comparison refers is given below the respective figure.
The child thus drew analogies between 38 objects widely differing with respect to texture, shape, colour, and size. (Figure D.18, “Analogization by form. Identification with “airplane”” — Figure D.19, “Analogization by form. — Identification with airplane”).
We sometimes had occasion to see that one and the same object (e. g. a bitten-off piece of cheese) would elicit a number of different associations, linked to the original stimulus in various ways. Here is a brief list covering the association-responses to a piece of cheese made between the ages of two to three: carriage, axe (2 y. 17 m. 9 d.); automobile; wood-pecker (2 y. 8 m.); fish (2 y. 11 m. 24 d.) crow (2 y. 7 m.); airplane, seal (1 y. 11 m. 24 d.) rooster (2 y. 0 m. 6 d.); Pl. Figure D.19, “Analogization by form. — Identification with airplane”. Analogies such as these by no means come to the child's mind in a haphazard fashion. For example, if after his statement that the piece of cheese reminds him, say, of a crow, he is asked to point to its head or tail, the child immediately demonstrates with his index finger the particular spot which, in his opinion, ought to stand for the respective part.
The tendency of the child to draw analogies substantiates the theory of the well-developed imagination of the child, which appears particularly salient if the comparisons connected with the perception of plants are analyzed.
Leaves, flowers, fruits, and twigs are not only seen as real, tangible objects — they also serve as the starting point for a vast number of analogies. (Cf. Figure D.21, “Identification of plants with different objects”, Figure D.22, “Identification of twigs and branches with different objects”).
See below some examples of parallels drawn by the child, between the ages of two and three.
|Stimulus||Statement made in response|
|Dry leaf||“gh” (airplane)|
|Pine and lime-tree twigs||“caterpillar”|
|Fir-tree bush||“looks like a crayfish”|
It seems certain that in the course of drawing analogies, the child actually compares the stimulus and the respective image in his mind.
Sometimes the child is able to identify instances of similarity and dissimilarity on his own. He also possesses the necessary faculty for qualitative appreciation. On seeing a rather unlucky family portrait made by an ill-suited artist he (age three) exclaims, “Father! Mother!” But straight away adds, “Father not like this! Mother not like this! I not like this!” He even volunteered the explanation, “Mother has a nasty face. Father has a nasty face. I have nasty hair. I am very nice really.”
On examining picture books, Roody (age 2 y. 6 m. 7 d.) very keenly perceived similarities between the people in the book and his acquaintances.
Both subjects liked gazing at their mirror image, but only Roody (age 1 y. 6 m.) associated the reflected image with reality, as for instance on an occasion when he looked back upon seeing the reflection of his grandmother and began looking first at her and then at her image in the glass.
The reactions to the mirror are of considerable interest. On first seeing his image in the glass (age 1 y. 4 m. 27 d.), Roody (just like Joni) spat at it and began banging it with his fist. When asked, “Who is there?” and upon seeing the author and himself in the mirror, he replied, “Mother, uncle” (he called all male humans “uncle”). Obviously he failed to recognize himself in this instance. But soon (age 1 y. 9 m. 19 d.) he began to identify himself with the image and gave an altogether different response. On bringing his face quite near the mirror, he kissed the image. And upon being asked, “Who's there?” he immediately gave his nickname and even added on his own initiative “Nice boy.” Joni got used to the mirror after some time and made no more threatening gestures, but he could never be observed to kiss or otherwise proffer endearments to his image, and whether or not he actually identified himself with the reflection remains yet an altogether moot question.
On another occasion, I saw Roody make the following interesting comparison. On seeing three white enamelled nails in his bed — two of which were small and one of a larger size — and on further noticing that one of the smaller nails had a little black spot on it, Roody said, “Mother, [the big nail] has no coal [no coal — no black speck]; child — coal, other not.” He evidently meant that one of the smaller nails or “children” had a black spot on it, while the other one had not. This utterance was made when Roody was 2 y. 0 m. 23 d. old.
At the age of 2 y. 6 m. 21 d., he was once being read to. The text was as follows: “Two boys hold a wild hairy cat.” At the time of the reading, Roody was shown a picture in which a boy is holding a cat. Roody immediately remarked, “And the other one does not” (meaning: does not hold the cat).
Examining an automobile at close quarters, Roody makes a comparison with his own toy motorcar at home and says, “Father, it has not got a steering wheel, has it?” Then, coming nearer and scrutinizing the machine, he remarks, “Father, what a funny wheel. We've not got such a wheel at home. They have notches on it, and ours has none.”
The child has a well developed memory.
Once (age 3 y. 1 m. 13 d.), Roody happened to break a porcelain cup. On the cup, there was an illustration of a boy in a green hat and mauve-coloured trousers with a flower in his hand. He immediately burst into tears. In order to comfort him, he was given a similar cup on the very same day. The new cup differed from the original only with respect to some minor details (notably, the boy was wearing a blue hat rather than a green one). Everybody was sure that the boy would notice no difference, and he was told that an identical cup had been bought. No sooner had he seen the cup that he exclaimed “Green hat!” I erroneously thought he had either forgotten or mixed up the colours and asked him, “What about the pants?” He answered, “Pants and this (pointing to the flower) are like!” (They were the same). Then I again asked, “What colour is the boy's cap?” And he answered correctly, “Blue.” His first remark meant that he remembered the colour of the boy's hat on the broken cup, and that he had an altogether clear recall of all the colours in the original depiction.
Once, at the age of 2 y. 9 m. 20 d., the boy remarked, “A chip of wood is hanging from the dog's mouth” (it was in fact some hair). Next day on seeing the dog in full order he inquired, “Why hasn't he got anything in his mouth?”
The child's spontaneously formed conditional reflexes number at least 100. Roody left the ape far behind in this respect, especially in auditory-auricular reflexes (e.g. his reciting verse and prose from memory). The gesture language of the chimpanzee relative to that of the human child is incomparably poorer, and in contrast with that of the child appears much more closely connected with the emotions, whereas in the case of the human child gesticulation essentially reflects the thinking activity of the mind.
The incontestable advantage of possessing the gift of speech goes of course without special mention. It is notably through the faculty of speech that we perceive the child to be the full master of logical thought, permitting him to make inferences, draw conclusions, and understand phenomena within his immediate environment.
On the other hand, it is the very lack of the speech faculty that prevents us from making any definite non-experimental conclusions as to whether the ape really possesses any of the intellectual processes that are so easily revealed in the human child.
Hereunder are several examples illustrating the child's independent thinking. Each example is an utterance corresponding to a definite intellectual process.
Judgment or supposition. On seeing a sleeping man on the boulevard (evidently drunk), Roody (3 y. 0 m. 25 d.) inquires: “Why has uncle's head gone down? Perhaps he's got a headache.”
Practical generalization: Roody asks, “What is the little duck made of?” (The material was cellulose). Answer: “I do not know.” Roody: “And I do. It's made of eggshell.” (Deduction based on two characteristics: colour and brittleness).
Conscious understanding of speech: After the boy had been ill for a certain time somebody said, “How thin he has grown! Quite worn out!” He retorts, “Am I so worn out? And where are the holes then?”
Logical inference: “You must not throw your galoshes about. You'll break them!” Roody: “But what are they made of?”“Rubber.” Roody: “But rubber won't break, will it?”
Deduction: Roody: “May I eat eggshells?” His father: “No, only birds eat it.” Roody (some time later): “Father, am I a bird?” His father (having forgotten what he had just said and perceiving no mischief), “Yes, you are my darling, little birdy!” Roody: “Well, then I am going to eat eggshells.”
Attempts at humour. One of the members of the household: “This is no joke.” Roody: “What is a joke?”“When somebody says something funny on purpose.” The boy starts uttering the meaningless word bandyuk (corrupted from the Russian: indyuk — a male turkey). On being asked why he persists repeating the word he laughingly replies, “It's a joke, isn't it?”
Such utterances give some insight into the as yet poorly understood psychic processes that are involved in the depths of the child's mind.
We might compare the spoken words of the human child to the rays emitted by a genuine diamond, which gathers diffused light, refracts it, and returns an amazing shower of glistening rays to our wondering eye; its brilliance permits us to judge both the quality of the stone and of its cutting.
Just so a child's speech — its imagery, its colourful play of halftones, its wonderful many-sidedness, all this lays bare the human mind and permits us to see how beautiful, unique, and above all progressive is the human soul!
Quite different is the impression derived from our analysis of the chimpanzee's mental capacity.
Taking our comparison further, we might liken the chimpanzee's dim, groping mind, not to a genuine diamond with its wonderful play of colours or to an unpolished gem with all its tremendous promise, but to grey, ordinary graphite.
As soon as we decide to take stock of the child's speech, we shall be obligated to disregard all evidence that indicated equality between the minds of the three- or four-year-old child and the chimpanzee of the same age. This evidence will now be replaced with other markers that favour the human child. But even the strongest evidence that points to the incontestable quantitative superiority of man seems so feeble that one feels tempted to exclaim, “No, not only more — better! Qualitatively different! Without comparison!”
Now, let's move from analysis to synthesis.
What, after all, is the contemporary chimpanzee? Not only is it impossible to say that he is “almost human,” but we must also go even farther and state quite definitely that he is “by no means human,” — and this on the grounds of the following evidence:
Similarities between the human child and the infant chimpanzee do exist in many spheres, but it is possible to speak about general similarity only when the subjects are casually and superficially observed. Common features are actually found in some types of playful behaviour (mobile games, experimental play), in the expression of certain emotions, in conation (particularly destructive behaviour), in some conditional reflexes, in a few intellectual processes that the two have in common (curiosity, recognition, identification), and in certain undifferentiated sounds. But as soon as we deepen our analysis and attempt to understand where to mark the two “equal,” we at once behold the sheer impossibility of doing so, and feel obliged to mark “unequal,” now the chimpanzee, now the man.
On the whole, it is possible to say that, the more biologically significant the functions we examine, the greater the ape's primacy over man. But, on the other hand, the higher and more intellectually refined the psychological attributes we review, the more we feel convinced of the supremacy of Homo sapiens.
Our analysis further reveals man to possess many traits that the chimpanzee lacks altogether. Comparative studies obviously become irrelevant here and must stop short. In the category of functional biological features, we can classify erect walking and carrying objects by hand; in the category of instinct, emitting purely human sounds such as loud laughter, singing, and the reproduction of words; with respect to egocentric instincts, the chimpanzee knows not what to do with acquired property, while his social instincts are not sufficiently developed to allow for organised peaceful interaction with inferior living beings; as for emotions, the chimpanzee is completely lacking moral and altruistic feelings, as well as a sense of the comical (which is developed from a comparatively early age in man); in the category of play, the chimpanzee seldom indulges in the kind of creative or building games in which man excels; as for the higher conduct of the mind, we find in man faculties such as imagination and logical speech; our analysis of habit-forming shows that it is only the human child who is capable of flawlessly acquiring useful practical habits; lastly, our analysis of habit forming shows that it is only the human child who is capable of perfectly acquiring practically useful habits.
On the other hand, it is quite remarkable that we should fail to find in the chimpanzee even a single psychological trait that would not also belong to man at some stage of his development.
Even such manifestations as would seem to be inherent to the chimpanzee only, such as walking on all fours (motor skills); sniffing or licking food, making threatening gestures, biting (instincts); general excitement gestures (emotion); playing with sharp instruments (play); specific gesture language (conditional reflexes); providing improvised obstacles (conation) — all these varied forms of behaviour find themselves a pretty close counterpart in the manifestations of the human child.
The only specific trait of the chimpanzee with apparently no analogy whatsoever in human behaviour is the modulated grunting “oh-oh” sound ending in a bark (accompanying general excitation), and perhaps also the howling and rattling sound of anger and vexation. I never heard Roody make any sounds of this description, but I am certain that he might have been able to reproduce the latter two, provided he had been given suitable time for training.
We reached a peculiar set of conclusions in connection with the foregoing.
If we plot the principal mental and physical characteristics of a three- to four-year-old chimpanzee against the consecutive ontogenetic periods of human life, we obtain the following analogies:
Judged by his wrinkle-furrowed face, the three- or four-year-old chimpanzee reminds us of a kindly old man of at least 60 or 70 years of age.
With respect to the development of running and climbing, as well as the senses (sight, hearing, etc.), both our own investigations and others put the ape on a level that even surpasses that of an adult in the full bloom of his vitality (24 to 35 years of age).
The strength of the ape's hands and teeth outstrips that of a well-developed youngster (16 to 18 years of age).
The development of the chimpanzee's vitally important instincts (self-support, self-protection, property, social, etc.) surpasses that of a seven-year-old child.
The strength and expressivity of his emotions are comparable to that of the mentally ill, whose behaviour bears a striking semblance to the restless excitement and plaintive hand movements of the troubled chimpanzee.
The playful behaviour of the chimpanzee insofar as destructive, mobile, competitive games are concerned puts him on par with a human child of the same age (18 months to four years), this being the only point of tangency in our parallel.
At the same time, our analysis of the playful behaviour of the chimpanzee as expressed in games involving creative (and building) activity does not permit us to place him any higher than at the level of the one-year-old to 18-month-old child.
He remains on about the same level or even lower (corresponding to a six-month-old to two-year-old child) when we consider his ability to form conditional reflexes.
With reference to gesture language and vertically erect walking, we cannot put him on any other level but that of a nine-month-old to 18 month-old-child.
In those vocalizations that show any resemblance to the sounds emitted by the human child, e. g. coughing, snorting etc., the respective level is reduced even further, to the first day of the human child's life to two or three months of age.
And lastly, no comparison with the child whatsoever can be drawn with respect to articulate sounds (such as voiced laughter, singing, speech).
Almost all of the 25 sounds that we have on record and that Joni was capable of emitting when moved by various emotional stimuli have a definite counterpart in Roody's vocalizations. At the same time, as early as eight months, Roody was already capable of reproducing a four-letter word while he freely indulged in spontaneous word building at the age of one. By the time he was 1 y. 2 m. 20 d. old, he had already started using words for calling things by name, rapidly enriching his vocabulary with every subsequent day. In so doing, he could be seen to display a fervent desire to accumulate an ever-increasing supply of new words and eagerly asked to be told the names of surrounding objects. At the age of 1 y. 5 m. 10 d., he began uttering sentences, first using only two words, growing to three words by the age of 1 y. 8 m. 2 d., and to four words by 1 y. 11 m. 2 d.. Thereafter, the child invariably accompanied all his daily activities with unceasing chatter and unrestrainedly poured forth the full contents of his mind, permitting the observer to readily witness all the intricacies of the hitherto concealed intellect with all its keen powers for observation, identification, abstraction, and logical inference.
Now it seems particularly opportune to stress the fact that the infant chimpanzee, though possessed of the rudiments of quite a number of purely human traits, altogether fails to exercise the respective faculties, and will not even do so if apt to gain definite advantages there from.
Thus, the chimpanzee is fully capable of taking a few steps in a vertically erect posture and will always stand erect when trying to find his bearings in open or unknown country, but never had I occasion to see Joni spontaneously exercise a vertical gait.
The chimpanzee frequently wants to carry some object, but can invent nothing better than to drag it with his foot, often losing the article on the way and always impeding his progress by the clumsily hauled burden. But this fact will never prompt him towards the vertical posture  or induce him to start carrying objects in his hands.
The infant chimpanzee constantly hears human vocalizations, responds correctly to spoken directions, uses his own natural sounds for expressing his emotions, and acquires complex conditional reflexes for the mimetic expression of his desires. But never once has there been any evidence that the chimpanzee would try to imitate the human voice or to master even the most elementary words, with which he could have facilitated interaction with his master.
More than that, the experiments conducted by Professor R.M. Yerkes have plainly shown that no amount of training will ever teach the chimpanzee to acquire the command of human speech.
The chimpanzee is more than keen to experiment with various objects, or explore them; he is also highly eager to acquire this or that coveted article and he is apt to become very competitive when it comes to rights of ownership. But no sooner has he received the desired object, than he begins destroying it or, at best, leaves it to lie idle.
The few scribblings by the chimpanzee in the possession of the author fail to give even the slightest indication that the ape had made progress in either drawing or penmanship. It would even seem that the main pleasure derived by the chimpanzee from handling pencils, chalk, or pens consists not so much in the drawing of a certain pattern as in the very act of handling the respective drawing instruments.
When brought into a human environment, the chimpanzee lacks any desire at all to learn the correct use of various household utensils (such as containers, spoons, forks and the like), though he would actually be able to do so if he only cared. He never gets tired of being waited on, in which respect he offers particularly striking contrast to the human child.
Ardently as the infant chimpanzee clings to other living beings, strong as may be his wish to interact with them, never will he adopt any other attitude towards an inferior creature but that of persecutor and killer. At the same time, if he had not made comrades of the lower animals, he would have at least made playmates of them.
To sum up: 1) In the functional biological field: the chimpanzee fails to walk erect and thus free his hands for carrying burdens; 2) In the sphere of imitation: the chimpanzee is devoid of imitation insofar as human sounds are concerned and generally fails to extend or improve his imitative behaviour; 3) With respect for emotional, altruistic, and social behaviour: the chimpanzee fails to understand the advantages of friendly and sympathetic interaction with creatures on a lower biological level than himself; 4) With regard to habit-forming: the chimpanzee does not improve in motor skills associated with the use of tools and household implements; 5) In the sphere of playful behaviour: he does not indulge in creative building play.
It seems difficult to predict how far the chimpanzee might go by way of acquiring essentially human features, but one thing seems certain, and it is that the chimpanzee — this strong, sanguine, strong-willed, and very active animal — actually fails to possess any inherent tendency towards progressing in the above directions, his failing being especially plainly marked where he is handicapped or thwarted by nature.
All the stronger is the contrast with the human child, who boldly dares to overcome his mental and physical deficiencies.
To illustrate this point even further, let us remember that the human child, with his weak little hands, is naturally unprepared for climbing, but he nevertheless does climb. He will tumble down, hurt himself, and start crying, but will at last learn to ascend a tree or roof (true, with perhaps less dexterity than the chimpanzee). Years will go by and he will don spiked boots and a mountaineering costume and rise to greater elevations than the chimpanzee had ever dreamt of. The human child lags far behind the ape in running, but after the age of three he jumps onto his skis or skates and leaves the chimpanzee far behind on snow and ice. Later, in some 20 years or so, he will break world records in motorcars and high-speed electric trains. In contrast to the chimpanzee, the child is afraid of jumping from any considerable elevation and cannot leap from tree to tree as the chimpanzee will, but he is possessed with a frantic desire to fly; so at the age of three, he runs about the room with outstretched arms crying, “Let's fly!” Soon, he will board airplanes and conquer the air in high-altitude flying machines and dirigibles.
And so in everything: the weak jaws of the child are made stronger by the use of tools, as when he rapidly breaks with a stone the same kernel that the ape had been gnawing with his teeth, or, when he may resort to an axe, vice, or hammer instead of using his arms and hands as would be the wont of the chimpanzee under similar circumstances. And then it is revealed that the very weakness of man is the source of his strength. Man's power breaks forth from the very fact that he has overcome natural impediments and obstacles.
It may even be that this very process of mastering physical shortcomings was responsible for making man's primordial ancestor what he has become: the genus Homo sapiens.
Thus, it was the natural weakness of the human body — notably the weakness of teeth and arms — that prompted primeval man to toil, use tools, and become technician and inventor.
The poorly developed vital egocentric instincts of man (such as self-support and self-protection) had to be compensated by a strengthening of his social and altruistic behaviours, which later took the form of organised interaction.
Great emotional vulnerability (the wide range and considerable intensity of painful sensations) led on the one hand to the development of the feeling of compassion (which borders on morality and altruism), and on the other hand brought about a particularly pleasant state of mind (the sense of the comical), which may have sprung up as a kind of antidote to the feeling of dejectedness.
The insufficient expressivity of man's facial expressions may have stimulated the wider use of the vocal organs, resulting in numerous and varied vocalizations.
At the same time, the existence of organized interaction was persistently claiming more differentiated forms of mutual understanding than stereotyped facial expressions and so it happened that articulated speech came into being.
It may be that a remote ancestor of man, placed as he was in a hostile or barren environment, had constantly to gain greater skill in his struggle for existence and, in order to get possession of the necessities of life, was obligated to endure a fierce struggle that ultimately resulted in the conquest and subjugation of nature. But his conquest of nature involved creative effort and creative effort is intrinsically bound up with imagining that which is not yet there, but has to be either obtained or in some way devised. And so it was that the lack of necessities or the difficulty of procuring them led to a vision of the things that ought to be, thus giving rise to fantasy and eventually to its shadow — art.
Such appear to be the main prerequisites for genesis of the seven specifically human attributes: labour, inventive faculty, organized intercourse, moral feeling, sense of humour, speech, and art.
“Forward and upward!” seems to be the subconscious motto of man long ere he recognized the thinking being in himself. It appears as if man, in the course of evolution, has been continuously adding more and more talents to the one or two that nature had at the beginning given him.
On the contrary — the child chimpanzee — inasmuch as we know him — does not seem to be in any way inclined to augment his talents; one even gets the impression that the ape has buried the one talent he had.
All this brings us to understanding the chimpanzee as a creature obdurate in its limitations, regressive as compared with man, and unable or unwilling to go any further in its development.
“Was ein Haeckchen werden will krummt sich bei Zeiten” (a hook becomes bent beforehand) — and if the infant chimpanzee fails to progress relative to the man even at the most tender age, there are but few chances that he should be able to go much further in later years, when his mind has become fully formed.
And now, as I come to the end of my comparative study, it seems as if the bridge by means of which I had all the time been endeavouring to span the gulf between ape and man has all gone to pieces...
Day in and day out, with infinite care and patience, steadily checking on the strength of each structural component, did I construct this bridge. All the time, it seemed to me that I was nearing the completion of a stupendous structure, which was to link up the previously disjoined — and all of a sudden what came, but complete collapse!
I thought that I might take my two little ones, each from his own side, and bring them to the middle of the bridge so that after their long and arduous journey they might here at last shake hands.
But what did I find?
If in the beginning of my task (in the morphological and biological part), my bridge had but few gaps, which might easily have been ignored and against which my two subjects but occasionally stumbled — a yawning abyss opened itself in the culminating point of the structure when I came to its end. The crown of the bridge, the meeting point of intellect and progress, nay, the very spot from whence the chasm seemed the most bottomless and terrifying — that very spot indeed — suddenly collapsed and into it, head first, full speed ahead, down went the chimpanzee, leaving his human counterpart high, high above, bewildered, perplexed, and wondering where had gone the one to whom he was just a second before been quite ready to fraternally extend his hand.
Would I ever be able to bring the chimpanzee up to the level of man, and perhaps with new trials find in him the kind of human-like features that the primitive Paranthropus would have needed to possess in order to become Homo sapiens? I hope to find the answer in the third part of my experimental study: Ability of the chimpanzee to distinguish form, size, quantity, and number; and his capacity to ascertain likeness and dissimilarity, forming analysis and synthesis.
Only after having made a complete and exhaustive comparison between the mental capacities of the child and the ape shall we be able to delve into the problem of genealogy and finally learn to what extent the two are true congeners.
 I wish to express my acknowledgment to Professor Brandes (Dresden); Prof. R. M. Yerkes (Yale), the Director of the Florida Anthropoid Laboratory and to three Laboratory scientists (Dr. C. F. Jacobsen, Dr. O. Z. Tinklepaugh, Dr. J. G. Yoshioka) for determining the age of my chimpanzee, Joni.
 My child learnt to kiss only at the age of two years.
 Roody was able to swing on a door only at the age of four years but not before.
 In his desire to get a hair to play with, the chimpanzee often went as far as to tear a human hair from someone's head.
 This process was described at length in my book “Poznavatelnye Sposobnosti Shimpanzee,” State Publishing Department of the USSR, 1924. N. Kohts Untersuchungen uber die Erkenntnisfahigkeiten des Schimpansen, Moskau. Zoopsycholgisches Laboratorium des Museum Darwiniarum. 1924.
 Observed in Roody as early as the age of five months.
 Observed in Roody at the age of eight to nine months.
 Observed in Roody at the age of seven months.
 Observed in Roody at the age of 0 m. 1 d..
 Observed in Roody at the age of 0 m. 5 d..
 Observed in Roody at the age of 1 m. 27 d..
 Observed in Roody at the age of 2 m. 3 d..
 Observed in Roody at the age of 3 m. 32 d..
 Observed in Roody at the age of 6 m. 30 d..
 The last seven sounds are listed in decreasing order of similarity.
 Both subjects had been placed in similar environmental conditions. Any kind of ill treatment with respect to smaller animals was strictly forbidden and efforts were made to encourage feelings of sympathy and compassion. Yet, our endeavours in this respect met with a degree of success only in the case of Roody, whilst they may be said to have been completely frustrated as regards Joni. All evidence points to the fact that whatever pedagogical devices might have been used with Joni, they would invariably have proved futile, with no apparent probability of making the ape show any degree of sympathy towards lower forms of animals.
 Especially when the stimulus is unexpected.
 For example, the child protrudes his tongue under circumstances similar to the following: when handling objects that he is afraid of letting fall down, when carrying too-heavy burdens, during his first attempts at donning a cap, etc.
 For example, when asked what he has drawn, the two- to three-year-old child answers, “airplane” or “uncle.” Sometimes, when drawing, he determines the contents of his sketch: “wheel,” “snake,” “horse.”
 At the age of three, Roody made a sketch of something more or less resembling a human being (see Figure D.25, “Samples of scribblings of chimpanzee and human child”, fig 5). Having finished his drawing, he saw he had omitted the hands and exclaimed, “And now where are the hands?” Thereupon he added two lines, which apparently stood for the missing members.
 Once, at the age of 2 y. 7 m. 29 d., he made two sketches in rapid succession, both depicting airplanes. On finishing, he pointed to the first airplane and said, “This airplane is not like a real one” then pointed to the second, “This airplane is a good one.”
 He seemed to find particular enjoyment in picking up this or other object and then dragging his body through some narrow bottleneck aperture, both head and body often becoming entrapped in the narrow opening.
 It was only on a single occasion that I was able to observe similar behaviour in Joni. Upon having once rubbed him with turpentine and after the chemical had begun tickling him, I saw the ape start looking about as if in search of the invisible enemy who was causing him the unpleasant sensation. However, the chimpanzee's curiosity on this occasion was stimulated by painful sensations and was in no way aroused by cognitive tendencies.
 We of course speak of spontaneous improvements achieved during free play activity and not of improvements acquired by learning.
 Which is physiologically quite possible, since there are several cases on record when anthropoids kept in zoological gardens did walk about fully erect.