pipe and to various tools and mechanical appliances which I used in working about the cage, in making or setting apparatus, or solely as tests of Congo's natural response.

Her attention, to be sure, could be attracted momentarily by unusual auditory or visual stimuli, and she always was curious about strange people and objects which might possibly prove to have food value. In general, however, I found it true that she was almost unbelievably lacking in active exploratory tendency and destructiveness when faced by novel objects or with familiar objects which might readily be used as playthings or be dismembered.

One sure way to get and hold her attention appeared, and that was to eat something before her or display some object which she suspected of being edible. In this type of situation she made scant effort to control or inhibit expressions of lively interest and eagerness to participate in the activities of the experimenter. An amusing incident illustrates these points. One day as I was busily engaged writing in my notebook while seated on a box on Congo's porch, she came up beside me and before I realized her intent suddenly reached out, seized the page I was writing on, and tearing it from the book hastily made off with it. As soon as she was beyond my reach she started to stuff the page into her mouth, but finding it tasteless and probably otherwise disagreeable, immediately desisted and threw it to one side. Hugely amused by her disappointment and discomfiture, I quietly recovered my notes and proceeded with my work. It would seem that she was interested in the notebook chiefly, if not solely, because of possible edibility.

I have dwelt perhaps tediously on evidences of destructiveness and curiousity because they appear to be keys to the understanding of Congo's mental make-up. Her relatively low degree of active curiosity surely accounts in part for the slightness of her destructive propensity; and these in turn would seem necessarily to condition imitativeness and other modes of adaptation of behavior. It is a pity not to have reasonably

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accurate descriptive measures of these aspects of response, but in my hasty general survey of Congo's mental characteristics. it was impossible sufficiently well to control observational situations and often enough to repeat experiments to provide statistically reliable data, or the basis for reasonably assured generalizations as contrasted with the somewhat impressionistic general statements that I have made.

To pass, then, to the subject of imitativeness, we first of all recognize the fact that there was no opportunity for Congo during my period of observation to imitate other members of her species. The only social factors in her environment were her dog playmates, and the persons who visited her, took care of her, or studied her. Almost from the first I gave special attention to imitativeness of persons because I was struck and surprised by Congo's apparently negativistic attitude. In many of the experiments opportunity offered to record imitative responses or the absence of them, and in several it was possible to get something in the nature of measurements of imitative tendency.

Although in the use of the stick Congo eventually learned something by watching me, I am inclined to think it was far less than my notebook descriptions appear to indicate, for what she actually followed observationally was the food and the relation of the stick to it. When the stick happened to come in contact with the food she was alert and eagerly reacted to it as though it were actually a part of the food. Nothing I ever did by way of manipulating objects, whether sticks, boxes, hammer and nails, pencil and paper, pipe, or the parts of my own body, as for example by opening my mouth, grimacing, making gestures, etc., had obvious effect on the form of her response. Sometimes she appeared to be watching intently and with interest; but always her subsequent behavior gave me the feeling that she intended and perhaps preferred to do something different from what I did. This is what I have called negativism. I do not think I am exaggerating Congo's lack of imitativeness of me when I use this term; yet I fully

realize that I am going a long way beyond the simple statement that she did not tend to reproduce my acts or to be pronouncedly influenced by them in her solution of problems.

In the several stick, box, and lock problems which I attempted to help Congo with, she gained more I think by watching the result of my series of acts than by following the acts themselves and attempting to reproduce them. In the aggregate I devoted hours to the task of copy-setting, and the acts which I performed with particular intent to assist Congo in learning how to solve various problems ranged all the way from such extremely simple things as merely opening my mouth to show my teeth, to the use of a long stick to push food out of a metal pipe. Usually the copy-setting had some practical objective. Thus I did my best to get Congo to open her mouth so that I might obtain her dental formula and observe the condition of her teeth, but neither imitatively nor otherwise, except by force, could she be induced to spread her jaws widely. Or, again, day after day she saw me working in and about her cage with a pipe in my mouth; yet when this object was handed to her or placed where she could examine it at her leisure, instead of imitating my use of the object she bit at the corncob bowl as though it were a nut. Never did she give any indication of being influenced by my use of the pipe. How I literally wore myself out trying to get her to imitate me in removing the padlock from its hasp in experiment no. 11 already has been told.

Recalling the natural love of the captive chimpanzee to use for its own amusement, and apparently imitatively, such things as tooth brushes, hair brushes, scrubbing brushes, brooms, wash cloths, I gave Congo similar opportunity, especially with broom and brush; but her interest and response were limited to fingering the objects for a few seconds, smelling or biting at them and pushing them out of the way as though they were not useful parts of her world.

Were it not for my experience in trying to teach Congo to eat unaccustomed foods I should have to say that she almost

entirely lacked tendency to imitate me, and that I saw no convincing evidence of imitation of other persons or other animals. But the story of her response to edible things is as different from the above as well could be. When I arrived on the scene, I learned that Congo's diet was very limited, primarily because of her refusal to eat most of the things that were offered her. She was diligently specializing on baked banana, baked sweet potato, orange and apple, and skimmed milk heavily watered. Lettuce, celery, carrots, eggs, bread, meats and various other things which had been offered she had regularly cast aside either with a casual taste or merely a sniff. Knowing that her health and growth might at any time demand a more varied diet I promptly decided to try to teach her to eat other things. This offered an excellent opportunity for copy-setting and I fully availed myself of it.

Our first experiment looking toward a liberalized diet may be described in detail. With Congo chained to one of the big oaks after her morning's experimental work, I seated myself on a box just beyond her reach and producing two graham crackers proceeded to eat one ostentatiously and with gusto. She watched intently for a few seconds, then turned away to the tree. I continued to munch my cracker. Shortly she approached and watched me eating. I held out a piece of cracker to her and she took it, smelled it, then dropped it to the ground. Now she went again to the tree while I continued to enjoy my cracker. Very soon she came back, picked up the piece of cracker which she had dropped, and carrying it to the foot of the tree broke off a small piece and nibbled at it. Soon she climbed to her favorite resting place in a crotch of the tree and settled there with her back toward me. When a little later I walked around to the opposite side of the tree so that I could see her, I noted that she was nibbling at the cracker. My notes at this point record this reflection: Congo's apparent negativeness and obvious reluctance to accept suggestions from or to imitate me may prove to be a valuable clue to her psychology.

Some two minutes later, attracting Congo's attention, I took another cracker from the box and taking a bite of it myself held the remainder toward Congo saying, "Don't you want some cracker, Congo?" She came for it spryly and somewhat to my surprise took it from my hand eagerly and retired with it to her tree crotch where a moment later I discovered her eating it with apparent relish although slowly. I can but wonder whether taking a position in the tree in which she was hidden from me and could not be seen eating the cracker was a part of her negativism.

My note record of this observation concludes: Even if Congo cannot be driven to eat things she may be led by imitation! I fancy one new article of diet a day is enough, so here endeth the first lesson in catholicity of diet.

Subsequently several other articles were added to Congo's meal by similar procedure. She was induced to eat cereal and milk and to use a spoon in feeding herself by observing me. Apparently my act gave her confidence in the edibility of strange substances; and whereas if I merely offered food to her without taking some myself she often would throw it away or push it to one side, she usually could be induced at least to give it a fair trial if I acted as though I liked it. This behavior probably indicates important tuitional relationship between parent and young. Indeed it is more than likely that most of the new foods which in nature are gradually added to the young gorilla's dietary are eaten first in the presence of the parents, and probably in face of their imitative copy, and possibly also their effort to induce the young to imitate.

Entirely consistent with Congo's limited imitativeness of human beings is her social independence. She is interested in persons mainly as sources of food or desired attentions. During my observation of her she paid relatively little attention to strangers, but I am told that her attitude has changed and that she now takes very considerable satisfaction in acting for the entertainment of a "gallery." To those of us who attended

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