Communicating with Bonobos

On November 6, 2012, the world lost one of the most linguistically accomplished non-humans on the planet.  Her name was Panbanisha and she was a bonobo (Pan paniscus).  Panbanisha grew up in aHomo sapiens/Pan paniscus hybrid culture at the Language Research Center (LRC) in Georgia (Armstrong & Botzler, 2003).  Her entire life was a language experiment that taught us a great deal about the behavioural continuum separating humans from our closest living relatives.

When Panbanisha was born, language research with bonobos had already commenced with studies on Kanzi.  However, researchers knew more experiments needed to be conducted.  They wanted to understand how a young bonobo would develop linguistically with a linguistically competent bonobo present (i.e., Kanzi) and they wanted to see how bonobo and chimpanzee linguistic development differed (Armstrong & Botzler, 2003).  In order to test bonobo/chimpanzee linguistic difference they raised Panbanisha with a chimpanzee named Panzee.

When research started, Kanzi had already learned 256 symbols using a lexigram.  Therefore, Panbanisha and Panzee were exposed to complex communications from the very first weeks of life.  As a result, they acquired language much quicker than did Kanzi (e.g., Krasnegor et al., 1991).  The effects of Panbanisha’s early exposure to language seemed to have a significant effect on her subsequent development.  Both Panbanisha and Panzee understood and used words through direct linguistic training and also through passively listening to human-human conversation.  Their competency was best displayed in a series of tests to see how well they could understand unique sentences.  At the age of 7.5, Kanzi, Panbanisha and Panzee could respond correctly ~75% of the time to unique sentences that required more than a yes or no response.  In comparison, an intelligent two-year-old child can accomplish the same task with a ~65% success rate (Hillix & Rumbaugh, 2003).  However, PET scans revealed that both Panbanisha and Panzee had superior information-processing skills when compared to Kanzi, which increased their ability to process verbal material.  This demonstrated that rearing may be a more powerful variable than species (e.g., bonobo/chimpanzee) when it comes to comprehending and using language (Armstrong & Botzler, 2003).

Conversation with Panbanisha also revealed that she connected deep meaning to the words she was using.  Here is an excerpt from a conversation she had with one of her trainers in the early 2000s (Hillix & Rumbaugh, 2003):

Panbanisha: Milk, Sugar

Liz: No, Panbanisha, I’d get in a lot of trouble if I gave you milk with sugar.

Panbanisha: Give milk, sugar.

Liz: No, Panbanisha, I’d get in so much trouble.  Here’s some milk.

Panbanisha: Milk, sugar.  Secret.

Panbanisha’s understanding of the word, “secret,” provides evidence of incredibly complex thought.  Still there were obvious limitations.  Geoffrey Pullum, a linguist at the University of California stated, “I do not believe that there has ever been an example anywhere of a nonhuman expressing an opinion or asking a question.  It would be wonderful if animals could say things about the world, as opposed to just signaling a direct emotional state or need.  But they just don’t” (Raffaele, 2006).  Furthermore, neither Panbanisha nor Panzee developed the ability to communicate using human-like sounds.  ThePan vocal tract is different than the human vocal tract because they lack a descended larynx.  The human larynx descends shortly after infancy allowing us to make a seemingly infinite number of vocalizations (Hillix & Rumbaugh, 2003).  However, the Pan vocal tract does permit for the production of more sounds than they do produce, which could mean that both chimpanzees and bonobos lack the neural connections necessary to fine-tune the vocal apparatus and produce human-like sounds and language (Hillix & Rumbaugh, 2003).

Despite this, Panbanisha showed us that bonobos can and do participate in meaningful discourse interactions with humans (Benson et al, 2004).  She communicated her emotions, feelings and developed strong linguistic bonds with three species (i.e., chimpanzees, bonobos and humans).  She also learned how to make and use stone tools, which also sheds light on the mental capacities necessary for complex tool construction.

Did Panbanisha prove that nonhumans can use language?  This research may have shown us that this question is too simplistic.  There is clearly a linguistic continuum.  There are several aspects of human language that Panbanisha never displayed.  However, she was able to understand English sentences and respond meaningfully to them.  She could not express ideas or opinions, but she could express her feelings and desires.  She could not use language vocally, but she could master language symbolically.  This research also showed that when it comes to language, early development is crucial.  Without exposure to language at an early age maximal linguistic potential can never fully develop.

Whether Panbanisha used language is also subject to definitions.  If language is any means of communication between two entities, then clearly she was quite advanced on the continuum of linguistic competency.  If language means creating meaningful units from meaningless units and combining them according to certain rules and then turning those units into meaningful phrases and sentences, then Panbanisha did not break the language barrier, and no other nonhuman ever has either (Hillix & Rumbaugh, 2003).

Panbanisha’s life taught us a great deal, not only about what separates our species, but also what makes us unique.  Although she died too young (26), she leaves behind one surviving offspring (Nyota) at The Great Ape Trust in Des Moines, Iowa (The Stone Age Institute, 2012).  Future research into the origins of language, language acquisition and interspecies vocal communication will continue to build on what we were able to learn from her accomplishments.

Panbanisha lexigram Panbanisha (Pan paniscus) (November 17, 1985 – November 6, 2012)

References

Armstrong & Botzler.  2003.  The Animal Ethics Reader.  Routledge.

Benson et al.  2004.  Mind and brain in apes: a mathodology for phonemic analysis of vocalizations of language competent bonobos.  Language Sciences, vol. 24, 543-660.

Hillix & Rumbaugh.  2003.  Animal Bodies, Human Minds: Ape, Dolphin and Parrot Language Skills.  Springer.

Krasnegor, et al.  1991.  Biological and behavioural determinants of language development.

Raffaele, P.  2012.  Speaking Bonobo.  Smithsonian Magazine.

The Stone Age Institute.  In Memorium – Panbanisha: 1985-2012.

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About Cadell Last
I am a science educator, freelance science writer, and founder of The Advanced Apes based in Toronto, Ontario. In the past my academic research focused on the evolution, ecology, and behaviour of non-human primates (i.e., chimpanzees, gorillas, ring-tailed lemurs). Currently, my official blog, The Ratchet, can be found via The Advanced Apes and Svbtle. I enjoy exploring recent research in human evolutionary sciences, as well as biology, ecology, astronomy, physics, and computer science. My work has been featured in Scientific American, American Humanist, Richard Dawkins Foundation for Reason and Science, and Jane Goodall Institute of Canada. I am also exploring science popularization in new mediums in collaboration with PBS Digital Studios with an animated YouTube channel. You can contact me on Twitter (@cadelllast) or via email: cadell.last@gmail.com

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