Hilyard 1Wyatt HilyardM. ScogginANTH 410April 19, 2013Overview of Studies on Human-Primate CommunicationAbstractPrimatology, a subdivision of biological anthropology, has many definitions and uses. Tosome, it is a study of primates on their own, separate from human evolution and ethology. Mostmodern and historical primatology research, however, is linked to human evolution behavioralstudies. One of the major interests of this kind of research is human-primate communication. Inthis paper I will argue that the great apes are capable of understanding and utilizing humanlanguage to some extent. The degree to which each species is ultimately able to communicatewith humans will be shown using case studies. I will also argue that both views of the disciplineare valid, but must be kept separate in order to maintain scientific integrity.A Brief History of PrimatologyBefore we talk about primate language studies, it is important to understand the history ofthe relatively new science of primatology. Many consider Robert Yerkes to be the founder ofprimatology, publishing several animal psychology works in the early to mid 20thcentury. In theearly 1920s, inspired by a recent trip to primate research facilities in Cuba, he bought twochimpanzees from a local zoo in Pennsylvania and raised them in his home. The methods he usedare viewed by many as unscientific and unethical, but there was little objection at the time. Hefounded the first research laboratory specific to primate research in 1929. Being primarily a
Hilyard 2psychologist, Yerkes most notable work was outside primatology. In the mid 1910s, he created aseries of alpha/beta tests that turned into IQ tests given to the U.S. Army, and ended up beingused to fuel the debates on immigration restriction in 1924. Yerkes claimed his tests measurednative intelligence, but the way they were formulated unintentionally relied on a certain amountof education and cultural knowledge. His personal and professional views on hereditary eugenicsand intelligence make him unpopular today. His work is often discredited due to the inherentinfluence those views had on his research and interpretation of his findings. Regardless of bothareas of politically-incorrect research, he is still viewed as a sort of pioneer of primatology. TheYerkes Regional Primate Research Center is still fully-functioning, and his name has been usedin tribute to refer to a form of symbolic primate language, Yerkish, which will be discussed laterin this paper.“Leakeys Angels” is a term used to refer to three pioneering female primatologists: JaneGoodall (chimpanzees,) Dian Fossey (gorillas,) and Birute Galdikas (orangutans.) All threerecieved a substantial amount of funding and publicity from Louis Leakey, a major figure inarchaeology and paleoanthropology. Goodall was the first of this group, and probably the mostpublicized primatologist to date. She started her field work in 1960 in Tanzania, thenTanganyika. She is often criticized by modern primatologists for her training and methodology.She had no scientific field training; she was a secretary. In her field work she greatlyanthropomorphized the individuals in the group she studied. This drew popularity to her work(people love stories of cute chimps running around and creating mischief,) but was a hindranceto the emerging science of primatology. For decades after it was impossible to get funding if yourfield work didnt have some sort of tie to human evolution. I think part of that stems from the fact
Hilyard 3that Louis Leakeys work was human evolution, and that concept was unintentionally attached tothe first major steps in popular primatology. That, coupled with anthropomorphization on the partof the scientists, hurt the disciplines reputation as a science. Although relatively unpopular, it isnow possible to do research on primates without tying in human evolution.Frans de Waal, a Dutch primatologist and ethologist, is one of the most popular currentlyactive primate behavior scientists. He has published numerous books on the subject, which focusmainly on the social lives of primates. He links the behaviors of chimpanzees and bonobos tohuman behavioral traits. An issue I personally have with de Waals bonobo field work inparticular is that it was conducted at the San Diego Zoo. Factors such as unnaturally high stresslevels are consequential to a captive environment, meaning the behavioral observations he madeare skewed. His research has contributed to the slogan “make love, not war” based on hisobservations that bonobos use sex instead of fighting to settle high-tension situations. This istrue, but due to the fact his studies were conducted in captivity, the rates he recorded are not thesame as the natural ethology of bonobos. I would have no objection if this distinction wasntoverlooked by the general media and had affected views the public now has of the species.Through my brief history of primatology, I have pointed out one common factor in thework of each of the aforementioned players: anthropomorphizing their research. De Waalsapproach is the same, and has even spoken out against its resistance, calling it “anthropodenial.”He offers the analogy of a brick wall; people in anthropodenial attempt to build a brick wallseparating humans from their evolutionary ancestors. “They carry on the tradition of RenéDescartes, who declared that while humans possessed souls, animals were mere automatons. Thisproduced a serious dilemma when Charles Darwin came along: If we descended from such
Hilyard 4automatons, were we not automatons ourselves? If not, how did we get to be so different?” (deWaal, “Are We in Anthropodenial”). According to this analogy, a brick is pulled from the walleach time one of these questions is asked. He attributes our “anthropodenial” to parsimony, “thatwe must make as few assumptions as possible when trying to construct a scientific explanation”(de Waal, “Are We in Anthropodenial”). Personally, I agree with this idea, and liken it to thelegal concept of “innocent until proven guilty.” The reason behind a given behavior must betested, not immediately explained by our own reason for similar behavior. And this sort of testinghas been applied in certain circles of scientists, but isnt over yet.When we anthropomorphize in field work, it invites a set of assumptions that may clutterthe data. In the subfields of archeology and paleontology, for example, it is a well-acceptedpractice that every piece of data be collected with as little assumption as possible. This allows fora wider range of possible conclusions during lab analysis. If we record that a particular behavioris anything other than the behavior itself, it muddies the results. Research that uses otherprimates in order to better understand ourselves isnt the only research that is being carried out.Inferring meaning is admissible when dealing in that realm of study, but harms the data whenstudying the ecology of a species on its own. As far as Im aware, fields like ichthyology andornithology dont have this problem. Our evolutionary proximity shouldnt come into the picturewhen studying species ecology for conservation and rehabilitation uses.Language Studies of the Great ApesWhen it comes to experiments dealing with apes abilities to learn and understand humanlanguage, there have been a few different approaches: sign language, physical tokens withsymbols, and an asymmetric form of communication that utilizes drawn symbols. Each has its
Hilyard 5own theoretical and methodological advantages and setbacks. The degree to which thecommunication is two-way is important, as well as the ability for the ape in question to retain thetaught information.SigningThe most famous sign language experiment has to be Koko the gorilla, who has gotten anincredible amount of media attention over the years. She is currently 41 years old, and issomewhat of a pop culture phenomena. She is thought to be able to sign over 1,000 words, andunderstand more than 2,000 words of spoken English. Project leader Dr. Francine “Penny”Patterson has documented Koko inventing new words for objects on her own (The GorillaFoundation). Knowing sign language and understanding spoken language is all well and good,but what she does, while impressive, is not full communication. She does not use sentences, butrather strings together words that suggest her implied meaning. She does not know how to applygrammar, and uses signing for mostly self-serving purposes; it is not necessarily what I wouldcall a conversation. Another objection is the way her handlers interact with her, especially intraining. In a psychological process known as operant conditioning, Koko is rewarded forproducing a sign. Some issues with proper word use have arisen with her training, for examplethe use of the word “dirty.” To train the concept, the researchers associated the word with herfeces. Once learning the word, she referred to people and even events as “dirty” (Candland).All of Kokos behaviors and abilities have been anthropomorphized to some extent. Herpaintings have been viewed by the public and art critics, and both have praised her abilities. Shehas adopted pets, and is said to still mourn her first kitten. Her keepers see her as an individualwho is completely capable of emotional feeling and expression. Im sure she innately has somedegree of emotional depth, but Im skeptical of the way in which it is expressed. Of interest is the
Hilyard 6fact that, after the first year of the project, the zoo Patterson was working with was uneasy withthe her work because they believed Koko was becoming “less of a gorilla than a human-tamedanimal” (Candland.) To me, the use of the word “tamed” implies there is little self-awareness ofher behavior, it is strictly a reward system. All behavior is taught by mimicry, but the individualmust eventually understand deeper levels of meaning implied in the communication, and Im notsure shes there yet.SymbolsDavid Premacks primatology work dates back to 1954 when he joined the YerkesNational Primate Research Center. The opening note in his paper “Animal Communication”nicely summarizes his approach on the topic of human-primate communication: “This mighthave been called animal language, but purposely it was not. In fact, the difference between thenature of language and communication in man and animals is the basis of an ongoing theoreticaldiscussion among researchers in behavioral and biological sciences.” His approach is morescientific than Pattersons, and poses a series of research questions that attempt to answer whatlevel of communication other primates are capable of. Instead of sign language, he usedmagnetic-backed plastic symbols, each standing for a word or concept.First working with Cebus monkeys in 1959, he published a paper on reinforcement, whatis now known as Premacks Principle. He postulates that the more probable behavior willreinforce less probable behaviors. For example, students will often execute a less favorable taskif they know a more favorable one will be next as a result. One experiment Premack conductedon children used eating candy as the reinforcing activity, and playing pinball as the instrumentalactivity. He found that the children who prefered candy over pinball would perform the secondactivity for the joy of eating the candy afterward. As stated in his 1959 paper, “Toward Imperical
Hilyard 7Behavior Laws. I. Positive Reinforcement,” his theory outlines six conditions:1. Reinforcement is a relative property. Responses A, B, C have a descending rank order of probability. A willtherefore reinforce both B and C. C will reinforce neither. This suggests that reinforcement is an absoluteproperty. However, B corrects this view. B will reinforce C, but not A. B is both a reinforcer and not areinforcer. Reinforcement is therefore a relative property.2. Reinforcement is a reversible property. When drinking is more probable than running, drinking reinforcesrunning. When the probabilities are reversed, running reinforces drinking.3. Historically, consummatory responses, eating and drinking, have served exclusively as reinforcers, butconsummatory responses are, like any other response, subject to reinforcement.4. Reinforcement and punishment, traditionally contrasted as opposites, are in fact equivalent except for sign.If response A leads contingently to B, and B is more probable than A, A will increase in frequency(reinforcement); conversely, if A leads contingently to B, and B is less probable than A, A will decrease infrequency (punishment). The major contrast is not between reward and punishment; but between rewardand punishment as contrasted with freedom. Freedom is the condition in which stimuli are freely (notcontingently) available to an individual.5. When motorized running is more probable than lever pressing but less probable than drinking, then runningreinforces lever pressing and punishes drinking. In other words, the same response can be both a reinforcerand a punisher - at the same time and for the same individual.6. The equivalence of reinforcement and punishment is further suggested in this interesting fact: rats are eithersensitive to both reinforcement and punishment, or insensitive to both; they are never sensitive to one butinsensitive to the other.All six conditions are consistent with what we generally think of as the reward system. I think itsimportant to include his theory here because it applies to the other two case studies, Koko andKanzi/Panbanisha. Premacks work in the field of primatology has been mostly withchimpanzees, and while he has shown that they can mimic certain facial expressions and usesymbols to communicate, it is not full communication. His studies showed a lack of ability forsyntactical understanding, which is a key part of the English language.LexigramsThe names Kanzi and Panbanisha dont quite elicit the same response from the generalpublic as Koko, but they are also very well-known apes in this field. The project they are under,the Great Ape Trust, is lead by Sue Savage-Rumbaugh, whose approach is very controversial.She believes great apes, specifically bonobos, can exist in a world where they are partly bothape-like and partly human-like. Her approach for communication uses boards of lexigrams, a“language ”called Yerkish in a nod to Robert Yerkes which is comprised of colored pictographic
Hilyard 8symbols that stand for words or concepts. The boards emit the spoken word when the lexigram ispressed, as well as the trainers speaking the word for reinforcement of the symbol. Savage-Rumbaugh says Kanzi picked up the use of symbols when he started repeatedly drawing asymbol in sand on the floor. I believe the system the Great Ape Trust uses more fully resemblescommunication, as the apes are able to communicate more deeply than Koko or historical cases.Other primates simply do not have the vocal cord range that we do, and this system somewhataddresses that by having the board speak the word on behalf of the individual.In their 1985 paper entitled “The Capacity of Animals to Acquire Language: Do SpeciesDifferences have Anything to Say to Us?” Savage-Rumbaugh et. al. begin by attempting totackle the public and academic notions of what human-primate communication is or should looklike.Thus, it must be recognized that the real issues involved in ape-language go far deeper than words andsyntax. They involve the very nature of inter-individual relationships as we as human beings know andexperience them, for a most distinctive human characteristic is that we do “tell” each other things, whetherit be in words, gestures, or pictures drawn in the dirt. We do knowingly, and with intent “tell” each otherthings that allow us to transmit indirect experiences from generation to generation, to produce myth fromfact, to build and maintain unique cultures, and to know other human minds in ways that we do not knowthe minds of other species on this planet. It is no small thing, therefore, to assert that apes are “telling”people things, or that they are “telling” each other things.Unlike the objections Ive had to the previous cases, they acknowledge the issue of syntax but gopast it, going deeper into what communication actually means. In the conclusion to their paper,they fully agree that the symbols and sentences Kanzi uses are learned, but assert that theacquisition was not through conditioning or “training any more than the words and the symbolsused in this paper are so conditioned.” His understanding of the symbols on his lexigram board
Hilyard 9seems to be bolstered by spoken language. Savage-Rumbaugh claims he had difficulty findingthe symbol for “apple” but as soon as the word was spoken, he seemed to immediatelyunderstand and touched the appropriate symbol.Some critics of her work have said the researchers use subtle facial gestures, such ashinting with the eyes, to aid the bonobos in understanding what is being said. To counter theseclaims, she wore a welding mask and asked Kanzi to “get the ball that is outside and bring it tome.” Kanzi immediately goes outside, passing by another ball on his way out, and brings her therequired ball. Tasks such as “take off Sues shoe” and “put the keys in the refrigerator” were alsosuccessfully completed, with the welding mask on the researcher. The extent to which Kanzi andPanbanisha understand spoken English is still being tested, but what we know at the moment ispretty impressive. However, this is still not full communication, two-way communication.Continuing Issues Within the FieldSince this paper assesses the capacity for the great apes to learn human language, it wouldseem these two viewpoints, “anthropodenial” and anthropomorphization, are contradictory whenargued in the same paper. I think both aspects have their place and it is vital that they remainseparate. In terms of public perception, the de Waal camp is certainly predominant. However, ifother taxonomic studies like ornithology and ichthyology are more or less free of these conceptsthat alter scientific perceptions, why cant there be a section of research carved out forprimatology that is ideally un-anthropomorphic?That is probably the largest problem with these kinds of behavioral experiments,choosing a theoretical side. Being categorized under anthropology, there is an inherentanthropomorphic viewpoint to primatology. The extent to which you mix that with the
Hilyard 10methodologies of “hard science” will determine what kind of primate behavior research you do,as well as the kind of criticism you receive from both academia and the public.ConclusionDue to basic biological differences, the great apes are not able to reproduce the sounds ofthe human vocal range. However, it is Savage-Rumbaughs mix-and-match approach that mostclosely resembles “communication” to me. A thread that runs through all of the human-primatecommunication studies, and most of the current primate research, is anthropomorphization. It issometimes very difficult to know what the appropriate situation is to allow ourselves toanthropomorphize, but it depends on the kind of research being done. As a general rule, I believethat if the research is centered around the ecology of a primate species, then the practice ofanthropomorphization should be avoided. If there is some connection to humans, an attempt tounderstand ourselves better, then it is more admissible but care should be taken to maintainscientific integrity.
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