Kanzi: The Ape at the Brink of the Human Mind

by Sue Savage-Rumbaugh

  Such personal dissections represent what Oxford University evolutionary biologist Richard Dawkins calls “the Argument from Personal Incredulity.” These arguments proceed from the individual’s personal and egocentric bias that his or her mind works in a qualitatively different manner from that of animals. Having established this private conclusion, the proponent of this theory brings into play the known and accepted principles of science for support. The trouble with this method is that not only can it be used to differentiate the animal mind from the human mind, but it also can be (and has been) used to differentiate the “criminal” mind from the “noncriminal” mind, the “male” mind from the “female” mind, the “white” mind from the “black” mind, the “Christian” mind from the “Muslim” mind, the “Catholic” mind from the “Protestant” mind, and to make any other distinction that becomes politically expedient.

  During the 1950s and 1960s the thrust of anthropology continued to emphasize human uniqueness, a view in which Leslie White, of the University of Michigan, was extremely influential. Referring specifically to language abilities, he said in 1949: “Because human behavior is symbol behavior and since the behavior of infra-human species is nonsymbolic, it follows that we can learn nothing about human behavior from observations upon or experiments with lower animals.”11 Indeed, so impressed by our mental superiority was Julian Huxley, grandson of Darwin’s champion, Thomas Henry Huxley, that he opined Homo sapiens should be removed from the animal kingdom entirely and be allotted a kingdom of its own: the Psychozoan.

  Add to this the notion that only humans use tools, only humans are conscious, and only humans elaborate culture, and a firm boundary between humans and other animals is in place. “In one way or another, policing and maintaining that boundary has been a tacit objective of most paleoanthropological model-building since the late 1940s,” observes Matt Cartmill, an anthropologist at Duke University.12

  The first bricks in this well-policed boundary wall were dislodged in the early 1960s with Jane Goodall’s observations of tool-use and tool-making in chimpanzees, at Gombe Stream Reserve, Tanzania. Goodall had the patience systematically to watch chimpanzees instead of making sweeping conclusions about what they could or could not do based on a few contacts. She saw them stripping twigs to use as probes in fishing for termites. Since then, observers have noted many additional kinds of tool-using behavior among these apes. Another brick fell in the early 1970s, with the demonstration of mirror-recognition in chimpanzees, cleverly documented by Gordon Gallup, a psychologist at the State University of New York, Albany. Many people had suspected that chimpanzees recognized themselves in mirrors, but Gallup offered conclusive proof. He applied a red dot of paint to the heads of a group of chimps while they slept. Upon waking, they were unaware of the paint, that is, until they happened to look into a mirror. At once they stopped, then turned and touched the red splotch on their foreheads to find out what it was.

  With the man/animal boundary so deep a part of the Western psyche, it is little wonder that many resist its dismantling on both a logical and emotional level, and with great confusion manifest between the two. Man’s ability to exploit the planet, to take of its resources as he needs, and to usurp entire forests and all living creatures therein, rests upon the unwritten assumption that the chasm between himself and all other creatures is impassable. All of modern man’s activities operate from the premise that the planet is his to allot into countries, states, counties, and individual plots, because he, unlike other creatures, has been given the twin gifts of reason and expression. By assuming that other animals lack these gifts entirely, man obviates any need to listen to the wishes of the creatures with which he shares the planet. He can therefore proceed comfortably by his own lights, blind to information that is perceived as nonexistent.

  To make this progression comfortable, man has wrapped his refusal to recognize the mental continuity between himself and other animals in an elaborate, ostensibly objective, scientific argument. Language, as an instrument of rational symbolic thought, has been the linchpin of that argument. By the early 1990s the boundary between man and animal was still being policed, though a few apes were fixedly gazing into the park with very deliberate expressions on their clearly humanlike faces.

  Most modern students of animal behavior, whether they work in the field or in the laboratory, count themselves as “empiricists,” meaning they accept little as meaningful data that cannot be experimentally reproduced at will. It is because of this empiricist perspective that the study of “human behavior” and that of “animal behavior” have historically been two separate fields, with few overlapping concerns or paradigms. Only a few comparative psychologists have dared to declare that a great deal can be learned about man by studying animals. It is now politically correct to view animal behavior as interesting, even important, but still irrevocably distinct from human action. This distinction is based on the empiricist view that human beings have “minds” and although we cannot know these minds nor even measure them, the minds of human beings can be revealed, one to the other, through language. Because animals lack language as we know it, students of animal behavior conclude that animals therefore cannot tell us “what is on their minds.” The empiricist doctrine relies only upon that which can be readily generated and measured at will. It is therefore forced to conclude that since animals cannot manifest minds through language, it is more parsimonious to study their behavior as though it were not generated by mind, intention, or will. However, because humans can—via language—voice expressions of mind, intention, and will, many empiricists accept these concepts as valid constructs for the study of human motivation and action.

  The empiricist takes the model of physics as the starting point for the study of behavior. This model suggests that behavior can be reduced to “units” similar to protons, electrons, and neutrons and postulates that only by reducing behavior to its elemental units will we be able to understand its structure. However, unlike physics and chemistry, there is no agreement on what these units should be, nor, indeed, how we should go about looking for them. Nonetheless, the field of animal behavior has long been dominated by a premise called Morgan’s Canon. This canon states that animal behaviorists should always seek to explain behavior in terms of the simplest possible processes. Thus, if a dog appears to be hungry, it is thought to be appropriate to define that hunger in terms of percent of normal body weight (that is, a dog that is 80 percent normal body weight is said to be hungrier than one that is at 100 percent normal body weight) or in terms of time since the last food intake. By looking to factors such as “time since last food intake” or “normal body weight,” we can avoid attributing eating behavior to “mental states” such as hunger. Of course, as humans who have experienced the state of hunger, or having a desire to eat, we are all quite aware that such a state can, at times, have little to do with either our body weight or the amount of time since we have last eaten. Students of human behavior often view such “irrational urges to eat” as conditioned “bad habits.” However, few would deny that a state of hunger in human beings is indeed a mental state and that it can be alleviated by food, as well as by many other activities.

  By 1976, the discrepancy between the ways in which animal and human behavior were being investigated became so great that the well-known biologist Donald Griffin began to plead for acceptance of what he called a “common-sense view of animal mind.” In a series of three books, published in 1976, 1984, and 1992, he collected reports of animal behavior, not unlike those amassed before him by Darwin and Georges Romanes. Don Griffin echoed their argument that such observations implied awareness and cognition. Since that time, a few researchers have acknowledged that science may well be underestimating the capabilities of animals and have undertaken new techniques for the study of what has come to be called “animal consciousness” and “animal mind.” For example, Christophe Boesch, who is studying wild chimpanzees in the Taï forest, has begun to ask questions about the intentional teachin
g of offspring, particularly as regards the complex skills utilized by this group of apes in nut cracking with hammers and anvils. Robert Seyfarth and Dorothy Cheney have begun to ask questions about whether or not vervet monkeys are explicitly and intentionally attempting to tell each other specific things with their calls, and if so, whether the monkeys themselves are actually aware of what they are doing. Gordon Gallup, a pioneer in the field, whose work predates that of Griffin’s, has attempted to determine whether or not various animal species have a concept of self. And of course the language-training efforts of David Premack, Beatrice and Allen Gardner, Duane Rumbaugh (with chimpanzees), Penny Patterson (with gorillas), Lynn Miles (with an orangutan), Lou Herman (with dolphins), Ron Schusterman (with sea lions), and Irene Pepperberg (with a gray parrot) have all suggested that animals must have competencies far greater than currently acknowledged. None of these efforts has yet had a major impact on the way we study human or animal behavior, nor have these two disciplines yet become linked within the field of psychology in the seamless manner that characterizes biology.

  In a book written in 1863 entitled Evidence as to Man’s Place in Nature, Thomas Henry Huxley recognized the close anatomical relationship between the African apes and man. The orangutan, an Asian ape, was said to be more distantly related. Huxley concluded that the African apes and man should be placed in the same taxonomic family. Although Huxley’s recommendations were ignored at the time, a century later, Morris Goodman of Wayne State University confirmed them at the molecular level. Goodman, like Huxley before him, proposed a reclassification of man and ape at a Wenner-Gren conference in 1962. Goodman, again like Huxley before him, was roundly rebuked for suggesting that the biological data indicate that man and the African ape should be placed in the same family, which would make them as closely related as, for example, the spinner dolphin and the bottle-nosed dolphin.

  In the three decades since Goodman’s pioneering work, a vast flood of molecular biological evidence has confirmed his—and Huxley’s—conclusions. Pressure is consequently mounting to reclassify humans and great apes in a way that reflects evolutionary and biological reality. Humans and the African apes differ in about 1 percent of their DNA. This means that apes are far more closely related to us than they are to monkeys. Yet many people still have difficulty even telling the difference between an ape and a monkey. Monkeys have tails, apes do not. Apes are built very much like us; monkeys have a wide variety of anatomical types, but in general their shoulders, hips, and torso all articulate in a manner similar to other quadrupedal mammals and very different from apes. Apes, like ourselves, are built on the “upright plan,” which means that we, and they, tend to orient toward each other in an upright position much of the time. The upright position may be achieved by being suspended from a branch, by sitting, or by standing.

  There are differences between ourselves and apes, of course. The most striking is that the size of our brain is three times that of an ape. And then there are the behavioral differences. None championed these more strongly than Huxley himself, even though he argued that man and ape belonged in the same taxonomic family. “No one is more strongly convinced than I am of the vastness of the gulf between … man and the brutes … for he alone possesses the marvelous endowment of intelligible and rational speech [and] … stands raised upon it as on a mountain top, far above the level of his humble fellows, and transfigured from his grosser nature by reflecting here and there, a ray from the infinite source of truth.”13 Huxley’s views are widely echoed today. Simply put, they state that language makes it possible for we humans to transcend our biology and thus enter a state of being so different from that experienced by any animals as to render a complete discontinuity between their life experiences and our own.

  How did humans come to possess so remarkable a means of communication? Is language a highly developed extension of the communication systems already in use by other primates, or does it represent a complete break, a way of communicating that is so different from that of other species that it makes a completely new form of thought—rational thought—possible? The rationale of ape-language research, of course, is that the cognitive foundations of modern human speech are likely to be found in the great apes, our closest evolutionary relatives, and perhaps in other higher mammals as well. Much of modern linguistics is dominated by the opposite view.

  Since the late 1950s, Noam Chomsky, of the Massachusetts Institute of Technology, has argued forcefully for the complete and singular independence of language from all other forms of communication and thought. According to this view, it is the syntactical structure underlying language that, in effect, makes language possible. Without this structure, Chomsky argues, we would be limited simply to expressing linear unrelated concepts and to reacting to single events, one at a time. According to Chomsky, this underlying structure, once it is fully understood, will be found to be identical across all languages and all cultures; that is, it will manifest the universal properties of human intelligence. The ability to relate world events in a causal-linear manner is thought to derive from this structure, and consequently to be as innate a portion of our biology as are our eyes, our hands, or our internal organs. According to Chomsky, “the child approaches the task of acquiring a language with a rich conceptual framework already in place and also a rich system of assumptions about sound structure and the structure of more complex utterances.” In Chomsky’s view these assumptions “constitute one part of the human biological endowment, to be awakened by experience and to be sharpened and enriched in the course of the child’s interactions with the human and material world.”14

  Chomsky argues that one should study language “exactly the same way you’d study an organ, say, the heart.”15 To Chomsky, this means that we need to open up the “language module” and understand its structure, just as we have done with the heart. Just as we have learned that blood flows from the heart to the lungs and back again to be pumped to the rest of the body, we need to understand how syntactical rules regulate the flow of our speech.

  When the 1990 Wenner-Gren conference began, therefore, it was with the boundary between humans and nonhumans still being policed and maintained by the scientific community at large, with Chomsky as their guardian.

  Kathleen Gibson set the stage for the conference, briefly sketching the intellectual questions we were to address. She reminded us that while paleoanthropology had progressed in understanding the evolution of the physical form of Homo sapiens, the origin of the mind was still swathed in mystery. Perhaps this should not be surprising, as neuroscientists also have found it difficult to answer a basic question about how the brain functions: Are cognitive skills such as reasoning, language, music, and art controlled by discrete modules within the brain, or by the interrelated agents of a distributed system? Evidence has been adduced for both positions, but nothing is conclusively settled.

  Until the structure-function relationship of the modern human brain can be described accurately, any understanding of the dynamics of the evolution of the mind must rely on indirect evidence, such as behavior (that of modern humans compared with African apes, and that preserved in the archeological record). Psychobiologists, such as myself, don’t often sit at the same conference table as archeologists, but that lofty aim was why we were in Cascais. We each had a view of the value of our own contribution, as I was soon to learn. To me, it seemed obvious that studies of chimpanzees, humans’ closest evolutionary relative, offered us our best insights into the emergence of human mind.

  I was therefore incredulous when, on the very first morning of the conference, Iain Davidson, an archeologist from the University of New England, Australia, began to speak, saying, in essence, “Humans are different from apes, and all the ‘chimpology’ in the world won’t tell us anything of interest; chimps [aren’t] representational thinkers, therefore we [can’t] learn anything useful about language by looking at apes; training chimps to do tricks might be interesting in itself, but it is irrelevant to events in the past
; and if you want to learn anything about language origins, the only place to look is at the archeological record; psychologists behave as if prehistoric evidence doesn’t matter; finally, the archeological evidence suggests that human language arose very recently, within the last 100,000 years—so much for chimpology.”

  Iain should have been aware that a word such as “chimpology” would grate on those of us at the conference who had devoted our lives to the study of apes. His assertion that nothing of interest could be learned from chimps about the nature of human language made me feel that an immediate response to such a totally homocentric position was sorely needed. I therefore vigorously objected to the idea that Kanzi had been trained to do anything, observing that Iain obviously hadn’t had much opportunity to learn what chimps were like. I noted that they easily handled symbolic representation, but I had to stop short of explaining the data that permitted these conclusions. My response had to be brief as Gibson and Ingold were careful to let others have an opportunity to respond, too.

  I sat back thinking, “Oh no, another Chomskian! Another scientist whose mind is closed to what chimps can tell us about the human mind.” As others spoke I was amazed at the anthropocentric views of many around me. The reaction to language in apes was even more negative than I had feared. For some, Kanzi and other speaking apes were seen as little more than the ghoulish constructions of publicity-hungry scientists who sought to distort the natural order of things by creating apes who could talk. The idea that an ape might desire to learn to talk, for the purpose of communicating his or her thoughts to another species, was not one that many seemed interested in or able to grasp. The idea that we humans might learn something about the origins of our language and minds by observing how apes can go about developing these capacities seemed too remote to hope to present.