Kanzi: The Ape at the Brink of the Human Mind (12 page)

The communication system we used with Sherman and Austin was a modified version of the computerized keyboard that Duane had developed for the Lana project. Symbols that represent objects or activities are arbitrary geometric forms, based on the Yerkish language that was invented by Ernst von Glaserfeld. Their keyboard eventually grew to 92 symbols.

Early on, we activated only a few symbols on the keyboard; as their vocabulary slowly grew we added more and more. When pressed, the key lit up, and was very obvious. To avoid the problem of the chimps simply learning the position of a key rather than the symbol on it, the symbols were randomly reassigned new positions after each keyboard use. The chimps had
to search carefully for the symbols they wanted to use. Even though Sherman and Austin have never shown any extensive comprehension of human speech, we decided from the beginning to use speech as well as symbols to get them to do things. They were evidently very sensitive to affect in the voice, and responded appropriately to emotions it conveyed.

The beginning of the journey toward true communication started with what everyone had assumed was a simple task—teaching the names of objects by association. For Washoe, Sarah, and Lana, this teaching of “names” had shared the important common procedural elements of holding up an object, an apple for example, and then encouraging and/or helping the ape to make the sign or to select the correct symbol. Once the ape could do this on its own, additional signs or symbols were introduced to build vocabulary. It was assumed that teaching words in this way was a rather simple process, if somewhat time-consuming. It was also assumed that such training basically depended on forming conditioned stimulus response associations between items and symbols. The real test of language, it was said, would come when one looked to see if apes could put together sentences from the words they had learned.

While this sort of word learning may lead to sentence production in adults who are learning a second language, it is not at all the way children go about learning their first language. However, at that time, very little research on how children actually learned words had been done. It seemed reasonable, therefore, to start by teaching apes word-symbol associations. It had also seemed to work.

Unfortunately, the process did not work with Sherman and Austin. With only one symbol available to be selected, Sherman and Austin learned relatively easily, as would be expected. If we held up a banana, they selected the banana symbol, as that was the only one available. With two, a lot more practice was required, but eventually they succeeded. Beyond two, however, the chimps became hesitant and failed to improve, no matter how much practice we gave them. The chimps were clearly puzzled as to how to proceed. I was puzzled, too, because Washoe
and Lana had encountered little difficulty in learning associations between objects and symbols or signs.

I watched videotapes of training sessions to see if I could figure out what we were doing wrong. The problem was that I had not stopped to ask why a chimpanzee who had had no previous language training would know that symbols encoded anything. I expected the chimp to make an association between the object and the symbol—and thus know the object’s name. Instead, as I learned from close scrutiny of the videotapes, Sherman and Austin were paying attention to the symbol and my subsequent action—that is, whether or not I gave them a reward.

No wonder we were all confused—humans and chimps alike. We all had different views about what was going on. As teachers holding up objects, we assumed that the object we were showing the chimp would serve as the “stimulus object” since it preceded the response. The chimps, however, were assuming that the symbol-key they selected served as the “stimulus” for us to give them food. They looked for a link between the symbol they depressed and whether or not we elected to give them food—and if so, what sort of food. They paid no attention to the “stimulus item” we displayed. Indeed, they paid no attention even when we attempted to cue them by pointing back and forth repeatedly between the stimulus item and the correct lexigram.

In hindsight, this seemed obvious. Why should they care what we were showing them? They cared more about whether we were tickling them, chasing them, feeding them, and so forth. Once it was apparent that the chimps were attentive to the consequences that followed their symbol production, rather than to the stimulus conditions that preceded it, it suddenly dawned on me that the Gardners had essentially taught Washoe “names” by giving her the object or action
after
she made the sign. Thus, if she signed
tickle
, they tickled her, if she signed
banana
, they gave her a banana. Similarly, when Lana depressed
Please machine give piece of banana
, she got a banana; when she said
Tim tickle Lana
, Tim did so—at least he did so at first while Lana was initially learning. However, this fact had not
been pointed out in articles. Instead, it had been emphasized that Washoe and Lana had learned the names of things by being shown the objects they were to name.

After it became clear that the contingencies which followed symbol use made all the difference, we switched our teaching approach. Now we showed the chimp a banana and when he selected the banana symbol, he was permitted to eat the banana.

This sort of transaction took the form, “I show you
X
, you select the lexigram that goes with
X
, and then I give you
X
,” and has been characterized as a request task. It has the superficial appearance of language, in that an ape who can make many different signs or select many different symbols when shown various objects seems to be able to ask for a wide variety of things it wants, such as foods, tickling, and so forth. What the chimp does, however, should not be confused with knowing names. Even though the ape appears to “name” something that it is being shown, it is really selecting the symbol because it anticipates that it will receive the object. This is true whether the teacher is holding up a banana, preparing to groom the ape, or getting ready to open up a door or box. In each case, the chimp is selecting the symbol or making the sign on the basis of what it anticipates will happen afterward.

The switch in training procedure produced rapid learning. Within a few days Sherman and Austin were correctly requesting a number of different foods. Now symbol-object pairings were coming as easily to them as had been described to be the case for Washoe and Lana. However, if Sherman and Austin were asked to name something when
all
expectancy of being able to receive that item was removed, they began to evidence confusion once again.

This was the first realization on my part that holding an object up and having a chimp produce the right sign or symbol did not mean that the ape knew the name of the object. It only meant that under certain conditions, the chimp knew what to do in order to obtain the object. In contrast, once a child knows words it seems able to do quite a bit more with them, even before it begins to form sentences. Certainly a child does not limit its word use to occasions set by the parent who is holding up items
and asking for their names, or waiting to open doors or tickle the child until it says the appropriate word.

From these early experiences I learned three important lessons. First, chimpanzees do not necessarily learn object-symbol associations easily through practice and repetition, as had been supposed. Second, I did not have to worry about cuing Sherman and Austin into giving erroneously positive results; cuing, if it was happening, was clearly ineffective as a means of teaching. Third, the simple relationship that was assumed in the object-symbol association was not simple at all; such associations could be of several types, each with a different implication for inferred language competence.

Also from these experiences flowed a means of communicating wishes, which Sherman and Austin unexpectedly developed on their own. Our technique required either me or another teacher to put some item of food in a dispenser linked to the keyboard. The chimp’s task was to hit the key that corresponded to the food, and thus receive it. Very soon the chimps began to pay close attention to the food I was about to select, and would become impatient if they thought I was too slow. Before long they began to hit a key
before
I selected the food. Were they trying to control my behavior, getting me to select foods they liked? It seemed so. They were very attentive, and if they hit a symbol for a food they knew was in the refrigerator, they would stare at the refrigerator after hitting the key, apparently waiting for me to respond appropriately. As they always chose favorite foods, like M&M’s or juice, and never water or chow, the behavior did have the appearance of intention about it.

Initially I discouraged this behavior, but then I realized it was indeed communicative and as such was important in our overall goal. We therefore incorporated it into our teaching regime. Once the chimps learned to use specific symbols for specific foods in this way, their progress improved dramatically. We were pleased with the chimps’ headway, and added more and more symbols, including some nonfood items, such as “tickle” and “out.” The value of communication as a motivator to the chimps’ learning was plain, and I often reflect on the
benefit of abandoning strict experimental procedure when an opportunity for an unexpected breakthrough offers itself, as it did in this case.

The ability to request is just one of three elements that must combine to produce true communication between individuals. The other two are (1) the ability to name objects and (2) a comprehension of symbols as referents of objects. We were unsure of the precise learning path we needed to take to have Sherman and Austin communicate symbolically with each other, but we knew they would need to be able to use their symbols without expecting some particularly beneficial contingency to follow each time. After all, if Sherman was to do something as simple as to ask Austin to give him a banana, Austin would have to understand that “banana” meant the specific fruit, even though he was giving one rather than getting one. Separating “names” of things from the contingencies associated with the learning of those names proved to be more difficult than we had anticipated.

Knowing how to use the symbol “banana” as a way of getting someone to give you a banana is not equivalent to knowing that “banana” represents a banana. (It is not obvious that this distinction had been seriously dealt with by other ape-language researchers.) Full communication would require that the chimp be able to use the symbol “banana” without expecting to receive one. We hoped we might simply reverse the request task to achieve this understanding on the part of Sherman and Austin. We held up a food item and lighted the “?What this” symbols. We didn’t expect them to know immediately the intent of what we were saying, but we tried to make it clear by nonverbal means. If the chimps replied correctly, we gave them another food item as a reward.

Initially, both chimps selected the appropriate symbol when we held up specific food items, but they then reached out for the food, expecting to receive it. They were puzzled when they were given something else instead, and continued to gesture for the original food item. Eventually, they became upset at what
was happening, not because they were being deprived of food—they weren’t—but because their expectations were being violated. Soon they stopped producing the appropriate symbol for the food item being displayed.

We pondered how we might make the distinction between requesting things and naming things more obvious to the chimps, and decided to make the food items we displayed nonedible. We did this by coating the food with plastic resin (the sort you see in the windows of restaurants in Japan). We hoped that by removing the possibility of consuming the food, we would also remove the chimps’ expectation that they would receive it when they selected its name.

This procedure proved to be futile as well. When Sherman first saw me hold up the plastic-coated M&M’s, he hurried to the keyboard, said “M&M,” and held his hand out to receive the candy. When I gave him one, he popped it into his mouth, got a strange look on his face, and spat it out. He then asked for another one. I gave him another one and he did the same thing. After a few more trials, he looked at me and said “banana” instead. When I gave him a piece of plastic-coated banana, he did not even bother to taste it before throwing it on the floor and stomping on it. This didn’t help because there was no way to “open” this banana. When it became apparent that none of these plastic-coated foods was going to be edible, Sherman refused to use his keyboard to name or request them. Austin deemed the task equally meaningless and both started pointing at the refrigerator and the door to communicate their wishes to me in a more direct manner.

Sherman and Austin finally learned to name things independently of any event that followed naming by a procedure known as “fading.” It begins like a request regime, with a food item being held up and given to the chimp after he lights the correct symbol. Fading refers to the fact that the size of the food item given to the chimp gradually diminishes, while the size of the item he is being shown does not change. At the same time, we lavish great praise for correct answers, and give a sizeable portion of a reward food item. For example, if the food we wanted them to name was “sweet potato,” we gave them a
smaller and smaller piece of sweet potato each time they did so, along with a large piece of some other food, to indicate we were still pleased. This additional food was the same whether the food they were asked to name was a sweet potato, an M&M, or soycake. The procedure worked. After 102 trials for Sherman and 201 for Austin, they both could reliably name these three food items without error through thirty trials. Thus if I held up sweet potato, M&M’s, or soycake, Sherman and Austin could easily select the appropriate lexigram, regardless of what happened afterward—even if I gave them nothing.