Tag Archives: Sue Savage-Rumbaugh signs

My lectures at the Minding Animals Conference

From Wednesday July 4 to Friday July 6 the second Minding Animals Conference will be held in Utrecht, The Netherlands, hosted by the Ethics Institute and Faculty of Veterinary Science at Utrecht University. Recently the two abstracts that I submitted for two lectures at the conference were accepted. They will be presented during two of the parallel sessions. Below are these two abstracts.

The first lecture is part of the theme Animal Capacities, session 2b: Higher order cognitive capacities in animals.

Have nonhuman great apes acquired a human language?

Since the beginning of the 20th century scientists have been interested to find out whether nonhuman great apes can be taught some form of human language. The first studies tried to teach spoken words to great apes, but failed to do so. From 1966 onwards, the Gardners started projects using sign language, with the chimpanzee Washoe as their first subject. These chimpanzees acquired signs and other projects soon followed: Patterson studying the signing gorilla Koko and Miles analyzing the use of signs by the orangutan Chantek. Other researchers such as the Rumbaughs used geometric symbols called lexigrams, teaching them to bonobos such as Kanzi. Most of the ape language researchers concluded that a form of human language had been acquired by their ape subjects. However, another project with a signing chimpanzee, the one by Terrace with chimpanzee Nim, obtained results that did not point to a linguistic explanation of the signing behaviour. This caused what has become known as the ape language controversy. What can we conclude about language in nonhuman great apes after these decades of research?

The field of ape language research has suffered from problems of method and interpretation. Many studies did not film the interactions between the apes and the humans, leaving room for errors of perception and memory and making it unable to examine the role of imitation in the apes’ utterances. Selective presentation of data has also been a major problem. The author analyzed the archives of all the projects with signing apes and found that particularly Patterson presented the data about Koko selectively, publishing data that seemed linguistic, but omitting the rest of the data that showed otherwise. The author also carried out a large, systematic study of the use of signs by Washoe and the other signing chimpanzees, analyzing hours of videotaped interactions between the chimpanzees and their longtime human companions. The results were that the chimpanzees mostly made 1-sign utterances, using object and action signs and request markers. Combinations of signs showed no semantic or syntactic structure, but consisted largely of stringing various signs in order to provoke their human companion into action. The communicative intentions of the chimpanzees’ sign utterances predominantly consisted of requests for objects and actions. Another systematic study that filmed all the behaviour, was carried out with Kanzi, demonstrating that he could understand hundreds of English spoken words. Unfortunately, no further reliable studies have been carried out. If we take the scientifically sound studies into account, we can draw the following conclusion about language in nonhuman great apes. The apes have demonstrated understanding of human words or symbols (an ability that has recently also been demonstrated in border collie dogs). When it comes to combining symbols into meaningful utterances like humans do, however, the apes do something different. They do not add a meaningful structure to combinations, but string symbols together in order to manipulate the humans into fulfilling their requests. With regard to the motivation for using symbolic communication, humans have a rich variety of different motivations for communication. The nonhuman apes, however, almost exclusively use symbols in order to request objects and actions from the human. Terrace called this an “acquisitive” motivation. These conclusions mean that it has not been possible to teach a human language to a nonhuman great ape and that a qualitative difference remains between human and nonhuman apes. A difference that may not have moral consequences, however.

The second lecture will be part of the theme Animal Ethics, session 4a: The moral relevance of socio-cognitive abilities.

Is absence of language in nonhuman great apes morally relevant?

The capacity for language has figured as a morally relevant ability in multiple animal ethics theories. Frey argued that language is a required capacity in order to have beliefs and desires and therefore interests. Carruthers claimed that language is a necessary ability to phenomenally experience mental states, argueing that nonlinguistic animals do not have sentience. In the Great Ape Project (GAP), set up by Singer and Cavalieri, the results from the studies with signing apes were used as an argument for equality among all great apes (human and nonhuman).

The author analyzed the archives of all the signing ape projects and carried out a systematic study of the use of signs by the famous signing chimpanzees. The results of his study were that there was no evidence for a linguistic capacity in these apes. If one considers all the results from the various ape language studies (including those that examine the use of lexigrams by bonobos such as Kanzi), one can conclude that nonhuman great apes are able to understand hundreds of words or signs, but when it comes to combining symbols in a meaningful way (grammar) there is no solid evidence that the ape subjects are able to do so. Also, when it comes to the motivation for (symbolic) communication it seems that there is a qualitative difference between human and nonhuman great apes. The subjects of ape language studies use symbols more as a tool to acquire things from humans rather than use it for a rich variety of motivations as humans do. Tomasello has suggested that humans are more focused on cooperation, with nonhuman great apes focusing more on competition in their communication. Until new evidence comes forth, we have to conclude, then, that only human apes have the capacity for language.

Where does this conclusion lead to, when it comes to our morality towards nonhuman great apes? The position held by Frey and Carruthers is considered incorrect. It is not our linguistic terms for different conscious states that make them phenomenally aware, but the emotional feel of various conscious states has primacy, to which we humans then add a linguistic label. Arguing for equality among all great apes based on the capacity for language, like the GAP has done, however, is also incorrect, now that these new studies have shown that there is no evidence for the linguistic claims of the ape language researchers. Nonhuman great apes thus appear to be qualitatively different from human apes. It is, however, a matter of argument whether higher cognitive abilities such as language or rich motivations for communication are morally relevant or not. The author argues that in our morality towards humans we consider qualitative differences in cognition or motivation to be irrelevant for moral equality (cf. the argument from marginal cases). Among humans, the presence of sentience or phenomenal consciousness is considered a sufficient condition for a morally equal status. In order to avoid the risk of being speciesist by limiting equality to humans only, equality should be extended beyond humans to include all beings capable of sentience or phenomenal consciousness. Thus, equality for all great apes, nonhuman and human, is still arguable, despite the absence of language in our nonhuman cousins. Indeed, with our current scientific knowledge, equality should be extended to all nonhuman animals.

I hope these abstracts have stirred up your interest. I would like to hear from you what you think of them. You can register for the conference by clicking here. A cheaper ‘early bird’ registration is still possible until April 27. Looking forward to meeting you at Minding Animals this July!


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Great apes and their attitude towards other animals


Language research with great apes



The chimpanzee Washoe, the first great ape to learn signs




Koko and All Ball




The chimpanzee Nim Chimpsky




The chimpanzee Lucy


Sue Savage-Rumbaugh and the bonobo Kanzi using the lexigram board

The bonobo Kanzi


Tearing dogs apart and killing them





Other great apes in captivity


The orangutan Tonda and the cat TK

Eric's impression of Tonda and TK


The chimpanzee Anjana and the cubs

Eric's impression of Anjana and a white tiger cub


Killing and eating other animals



The bonobo Kuni and the starling


Great apes in the wild and other animals

Chimpanzees and baboons


Gilka and Goblina



Sexual behaviour between chimpanzees and baboons



Bonobos and other animals


Other animals as food




Big cats and great apes



Conclusion: They’re just like humans



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  10. How did human language evolve?



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My work discussed in a fascinating book on the origins of human language

In 2008 MIT Press published Michael Tomasello’s book Origins of Human Communication, which was based on lectures that Tomasello gave in Paris in 2006. The book is a fascinating account of how human language may have evolved out of ape gestures. Based on the latest scientific knowledge on the use of gestures by apes and language development in human children, Tomasello makes a quite plausible and elegant argument that human language has had its origins in great ape gestural communication. This is because ape vocalizations are not learned. The vocalizations are used inflexibly, tied to the emotions that give rise to them. Great ape gestures, however, show much more flexibility and the use of gestures is learned during development. Great apes also use their gestures intentionally, they wait for a response from their conspecifics and will repeat or adjust the gestures if there has been no response. Though Tomasello has of course no clear-cut story of how exactly human language may have evolved, the argument for a gestural origin is solid, given these differences between great ape vocalizations and gestures. Tomasello divides great ape gestures into attention-getters and intention-movements. A gesture such as a mother asking her child to climb on her back, is an example of an intention movement: the movement of the gesture shows the intention that the mother wants to take place. The use of gestures by great apes is, however, limited to making requests to and demanding actions from others. In contrast, human communication includes motives for helping and sharing, which results in three basic motives of human communication: requesting (requesting help), informing (offering information) and sharing emotions and attitudes (bonding). These motives have come about because unlike nonhuman great apes, who have a comprehension of individual intentionality only (they know what the goals are of separate individuals), humans have skills for what is called shared intentionality: human individuals have a common conceptual ground, they have shared goals and attention and communicate with cooperative motives. These skills and motives arose in a context of mutualistic collaborative activities. Originally starting with pointing and using iconic gestures (pantomiming), humans experienced a “drift to the arbitrary,” eventually resulting in the linguistic conventions that we now know. Even grammar thus originated in human cooperative communication, because the human motives for informing and sharing needed the possibility to communicate about events displaced in time and space and to share further information about events and people that can only be expressed by certain aspects of grammar. mark the particular roles of participants and to relate events to one another as in stories and narratives. Grammatical constructions would have come about by a conventionalization process and there would thus be no need to infer a universal grammar such as Chomsky proposed: grammar is learned, not innate. The fact that grammar is part of every human language is because it is functional and necessary for our particularly human way of cooperative communication, not because grammatical rules are hard-wired in our brains.

I know this is a very short summary of Tomasello’s argument for the gestural origin of human language, so I advise you to read the book in order to understand his full argument. The book is written in a very clear and convincing style and is understandable for most lay persons with some academic background.

Chapter 6 is about the possible evolution of grammar and it is here that Tomasello gives ample space to discussing my work with the signing chimpanzees. He mentions that there has been a controversy about the lack of grammatical structure in the use of signs or lexigrams by the great apes in the language projects, because of a lack of systematic and quantitative data. My work with Washoe and the other signing chimpanzees has been exactly that: a large systematic analysis of the way the chimpanzees use their signs. My study is then presented by Tomasello on a par with the study of Sue Savage-Rumbaugh and Patricia Greenfield (published in 1990) of the way the bonobo Kanzi used his lexigrams. Both studies are the only ones in ape language research that systematically analyzed the videotaped behaviour of these ape subjects. Tomasello discusses the results of my study in several pages, presenting my conclusions on the communicative intentions or functions of the apes’ signed utterances and the lack of grammatical structure in the sequences of signs that the chimpanzees produced. He presents the only ordering that I found in the apes’ sign combinations: the chimps used object and action signs first, and a point (to the requested object or to the human) and signs that functioned as wild cards (pleasing the human) last. He quotes my 2005 conclusion in the Journal of Comparative Psychology:

“The object and action signs are produced first because these are the more important or salient signs of the (usually request) utterances, specifying what is requested. The request markers THAT/THERE/YOU/GOOD/HURRY are produced last because they are less important (not specifying what is requested) and function to add emphasis or to spur the human into action.” I feel great my work is being discussed in this great book and I’m grateful my hard work is now of use in theories and conclusions about ape communication and the evolution of human language.”

Michael Tomasello (1950) is a psychologist who originally worked at Emory University, Atlanta (where he did a lot of research on the apes at the Yerkes National Primate Research Center). Since 1998 he is professor at the Department of Developmental and Comparative Psychology of the Max Planck Institute for Evolutionary Anthropology (of which he is co-director) at Leipzig University, Germany. His research staff continues to do important studies on all four great ape species’ communicative behaviour and social cognition. The Koninklijke Nederlandse Akademie van Wetenschappen (Royal Dutch Academy of Sciences) has rewarded him the 2010 Dr. A.H. Heineken Prize for Cognitive Science.

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Filed under Animal Communication, Language research with animals, Publications

Ape language videos on YouTube


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Filed under Animal Communication, Language research with animals