Different in degree or kind: Ape gestures (Introduction)

by David Turell , Tuesday, November 15, 2016, 00:16 (2931 days ago) @ David Turell

A fascinating article in which the author describes her studies of bonobo and chimp 'language gestures:

https://blogs.scientificamerican.com/not-bad-science/how-do-bonobos-and-chimpanzees-tal...

"Bonobos raise their arms, flap their legs, shake their heads, thrust their hips, just to name a few gestures. There are silent-visual gestures like waving, audible gestures like clapping, and contact gestures like slapping someone on the back. A gesture should be directed towards another individual (no random arm flailing while sitting on your own); the signaller should check that the recipient is paying attention (what’s the point in waving at you if you’re facing the other way?) and select an appropriate gesture (e.g. a tap on the shoulder if the recipient is looking away); and if the recipient doesn’t respond to the gesture, the signaller should persist or elaborate. These criteria show that the signaller has a goal in mind, something that they want to communicate, and are using gestures to achieve that goal.

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"Chimpanzees use around seventy gesture types in the wild, and they produce gestures intentionally, aiming to affect the behaviour of the recipient.

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"We found that the bonobos at Wamba have a vocabulary of 68 gesture types. The overlap with published data for chimpanzees (at Budongo research site in Uganda) was roughly 90%. Such a large overlap points toward a genetically channelled repertoire of gestures – if the gestures were all individually learned, we would expect more differences between species and even between populations and individuals. The chimpanzee repertoire overlaps around 80% with orangutans and 60% with gorillas, and so it is likely that our last common ancestor used many of these gestures.

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"This is also how I figure out what a gesture means – if Bonobo A does an “arm raise” gesture and Bonobo B responds by starting to groom the signaller, and Bonobo A seems satisfied with that response (i.e. they don’t keep gesturing), then the meaning of “arm raise” in this instance was “please groom me”. In that case, “arm raise” would be in Bonobo A’s expressed repertoire and Bonobo B’s understood repertoire.

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"For bonobos and chimpanzees, these activities include play, grooming, feeding, travelling together, and sex. At some point, it became necessary for our human ancestors to communicate about more than these immediate goals, and therein lies the mystery of language evolution.

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"By the time infants are old enough to start using gestures, they are also learning words and conventional gestures of the culture that they’re growing up in. Observation of humans is therefore inadequate for seeing which gestures are shared with other apes.

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"Our findings tell us that given the overlap of all great ape gestures, early humans likely also shared this gestural repertoire. Gestures are an important way for great apes to communicate, they use them to request food, grooming, and sex. But there are other aspects to communication as well, such as vocalisations and facial expressions. New research that looks at how great ape communication works across all of these modalities is necessary before we can start to answer the difficult questions of how language evolved. If these other forms of communication are sufficient for other species of great apes, then why language?

Comment: Yes, why language? The apes have never changed and we grew a great brain and the proper anatomy which could handle language. That reduced the need for trying to understand gestures, which are good only for immediate needs. We are different, not in degree but in kind. We can discuss anything, any concept!