the Yerkes Primate Center for further study, where she died of pneumonia less than a year later. A similar experiment was conducted by scientists Keith and Catherine Hayes, who took chimpanzee Viki into their home and used intensive speech therapy, in which they manually manipulated her lower jaw, to teach her to voice four words: “mama,” “papa,” “up,” and “cup.”
Because Gua, Viki, and chimpanzees in other studies—similar experiments were carried out in laboratories—had not learned to speak, it was assumed that non-human primates either lacked the cognitive ability to learn to speak, or were physically incapable of it, which led to a modification of the experiment: instead of speech, chimpanzees were taught sign language. This technique was more successful. Chimpanzee Washoe (Hillix and Rumbaugh 2004) was born in the wild and taken from her parents by the American Air Force, initially to be used in space experiments. Beatrix and Alex Gardner took her into their home and raised her as a human child. They dressed her in human clothes, had her dine at the table with them, took her for rides in the car, and took her to the playground. Washoe had books, toys, and her own toothbrush. She soon learned to use signs, with and without direct instruction—the latter by observing humans—and invented her own: for example, she combined the signs for water and bird when she saw a swan. She could also categorize nouns and form simple sentences. When she was five, the Gardners ended the experiment and brought her to the University of Oklahoma’s Institute of Primate Studies, where she lived until her death in 2007. While at the Institute, Washoe learned to use around 350 different signs, which she also used to communicate her emotions and thoughts. She recognized herself in the mirror and showed self-awareness, as well as empathy with others. When new students came to work with her, she slowed down the speed of her signing to help them to understand her.
Chimpanzees were not the only primates used in these experiments. Gorilla Koko, who was born in the San Francisco Zoo, was taught to use over a thousand hand signs in Gorilla Sign Language (a version of American Sign Language, modified to fit gorilla hands) (ibid.). Psychologist Francine Patterson, who taught her to use sign language, reports that Koko also understands over two thousand human words. Koko signs about her emotional state and memories, showing she has episodic memory and narrative identity; she likes to make jokes and sometimes tells lies. She is also famous because she had a pet kitten, and grieved for him when he died.
Bonobo Kanzi, who was born at the Yerkes field station at Emory University, taught himself to sign by watching videos of Koko, something his trainer realized when he saw him sign with an anthropologist (ibid.). He was taught to use lexigrams, symbols on a keyboard that are used in the artificial primate language Yerkish, and he has been observed speaking human words. Kanzi likes to eat omelettes and play Pac-Man, and he is a good toolmaker. Non-human primates have been taught grammar in other language experiments. Chimpanzee Sarah, who was born in Africa, was taught to parse and produce streams of tokens that obeyed a simple grammar. Along with three other chimpanzees, she learned to use a board with plastic symbols to analyze syntactic expressions, including if-then-else (ibid.).
In these language experiments, “language” means human language, and non-human animals are used as objects of study to gain knowledge about human language. Recent research in biology and ethology shows that many other non-human animal species have their own complex and nuanced species-specific ways of communicating with members of their own and other species. These studies ask us to reconsider the cognitive, social, and linguistic capacities of other animals, and to reconsider what language is. In the first chapter of this book, the focus was on the critical part of this investigation, tracing the relation between defining language and excluding non-human animals. In this chapter, I focus on non-human animal languages, studying language and the question of how to define language. I draw on recent empirical research into non-human animal languages on the one hand, and Ludwig Wittgenstein’s proposal to view language as a set of language games on the other, to develop a non-anthropocentric way of thinking about language and studying animal languages. My aim is not to provide a full theory of non-human animal languages; humans are only just beginning to learn about many non-human animal languages, so it would be empirically impossible to provide a full description or theory of animal language. This would also be undesirable for political reasons, because rethinking language should not be a human endeavor, and it is not up to humans to define what represents meaningful communication for others. We need to learn about language in interaction with other animals in order not to fall into the trap of repeating anthropocentrism. The following investigations are meant as a first step in this process. Even though my aim is not to provide a full theory of language, I do want to show that the question of whether or not other animals use language is legitimate, point to the complexity of their expressions, and demonstrate the similarities between non-human and human languages. I also want to offer a starting point for a different way of thinking about and studying language in an interspecies context.
If we are to adequately study non-human animal languages and develop a non-anthropocentric view of language, we need to move away from seeing language as exclusively human. Wittgenstein’s (1958) proposal to view language as language games offers a good starting point for thinking about non-human animal and interspecies languages, as well as for studying language in an interspecies context. Wittgenstein argues that, because of the way in which language works and its interconnection to social practices, we can never give a universal definition of language as a whole, or fixed definitions of separate concepts. Instead, we should investigate the meaning of different language games by exploring how and where they are used. This method of studying language allows us to acknowledge non-human animal agency in language and recognize how non-human animals co-create meaning in relation to members of their own and other species, including humans. Existing human concepts can offer guidelines for understanding the meaning of certain practices and for illuminating relations between human, non-human, and interspecies language games, without pre-determining what counts as language for other animals. Before discussing different non-human animal and interspecies language games in more detail, I now first turn to this movement from seeing language as exclusively human, and studying it as such, to viewing it as a set of animal language games.
From Human Language to Animal Language Games
Studying Human Language in Other Animals
Although writers and philosophers have always speculated about non-human animal behavior and animal minds—or the absence thereof—animal cognition was not taken seriously in science until the end of the nineteenth century, when Charles Darwin (1872) began writing about animal behavior and animal minds (Bekoff 2002, 2007; Slobodchikoff 2012). Darwin emphasized the continuities between species, and he saw the differences between human animal minds and the minds of other animals as differences of degree and not of kind (Darwin 1872). His approach to animal cognition was anecdotal and drew upon his personal observations, as well as stories about non-human animal behavior, which led to criticism regarding their scientific value. In order to avoid this criticism, and to improve the study of animal cognition, the psychologists Thorndike and Pavlov took their research on animal cognition into the laboratory, where they could study the reactions of non-human animals to stimuli in repeatable experiments (Allen and Bekoff 1999). In this way, they studied operant conditioning and classical conditioning respectively. The design of their experiments was heavily influenced by behaviorism, both in research questions and methods, and became the standard for most research into animal behavior until the 1960s. Behaviorism is a philosophy behind the study of behavior that uses methods from the natural sciences and focuses on functional connections between acts and environment, aiming to predict and control behavior. In behaviorism, human and non-human animal minds are studied as black boxes of which the content is not relevant; only outward reactions that can be measured have scientific value. Description of behaviors or interpretations of acts should be avoided. In the 1960s, a cognitive revolution in the study of human minds took place, which also influenced thinking about the minds of other animals. Mental processes that were not immediately observable became part of the study of animal minds, and other animals were increasingly seen as agents with a level of cognitive complexity. The rise of ethology and animal psychology as scientific disciplines also helped to instigate this process. However, the methods used by Thorndike and Pavlov were, and still are, widely used in animal research, and the view of animal minds as black boxes has continued to influence research methods and objectives to the