(This post is more a more or less verbatim replica of a post from April this year in a discussion board which I was intermittently spending way too much time on; if I were to write it now, I’d at least include a reference to Whiten (2011) (Whiten, A., Hinde, R. A., Stringer, C. B. & Laland, K. N. (2011). Culture Evolves. Phil. Trans. R. Soc. B 366, 938-948.), and maybe somewhat qualify that the dichotomy between cumulative human and non-cumulative chimpanzee culture may be based on relatively minor and gradual differences in underlying transmission mechanisms. This post was in response to another participant asking whether signing apes would “talk to researchers on their own” and what we could learn about their ways of thinking from them doing so.)
If by “talk to researchers on their own” you mean initiate a conversation untriggered by an immediate need, or by an object present in the immediate environment, the answer is no. This is in and of itself a very interesting result, though. It means that we have to be cautious when attributing differences in outcome between chimpanzees and humans to limitations on chimpanzees’ cognitive abilities – it may be that the most decisive difference underlying the presence of cumulative cultural evolution in humans (senso Tennie et al. 2009) and its absence in chimps isn’t in what chimps can’t do, but in what they won’t do. In short, chimps lack humans’ propensity for co-operative goal-directed behaviour (Jensen et al. 2007). This is certainly connected with the species’ qualitatively different learning strategies: While humans and chimps are both social learners, only humans show tryadic interactions between adults, infants and objects, while chimps learn by observation alone (cf. Matsuzawa 2007 cited above) which has implications for how cultural evolution in humans accumulates innovations (the “ratchetting effect” of Tennie et al. 2009) but not in other apes. Tomasello (1999) goes further than that in claiming that even language is primarily if not exclusively a cultural tool and its emergence among humans but not other apes (in the wild) the product of this uniquely human (at least among apes) drive to communicate and co-operate in a qualitatively different fashion, which would imply that much current linguistic and “biolinguistic” research is fundamentally misguided in that it focusses on finding elements of our capacity to form abstract concepts and to compositionally build sentences with them (i.e. our conceptualising and hierarchical structuring skills) as the root of human language. I believe that is too strong a claim, and the failure of signing apes to unambiguously acquire any syntax appears to argue against Tomasello, but it’s certainly a healthy reminder not to think about grammar alone when we think about language and why we have it but chimps don’t.
Fitch (2011) proposes to introduce the term Mitteilungsbedürfnis as a terminus technicus for this particular human drive to communicate, summing up much of the above discussion:
Our communicative capacity rests on two different bases. One is the sheer capacity to produce signals of the requisite complexity, and map them onto thoughts. […] Another component, however, has less frequently been singled out for attention: our propensity to use this capability in honest, informative, information exchange. Biologists interested in animal communication have long recognized that there are serious evolutionary problems in getting co-operative signlaing systems off the ground. […] recent work on chimpanzees has made it clear that ape cognitive skills seem highly biased to perform well in competitive situations rather than in cooperation (reviewed in Hare&Tomasello 2004), while work on young human children demonstrates just the opposite (Tomasello 1999). These data suggest that, even if chimpanzees had the capacity to encode and decode arbitrary thoughts into and from signals, they might simply avoid using this ability except in specialized circumstances[…].
Humans, of course, have an irrepressible habit of sharing their thoughts with others. […] Perhaps this propensity to talk has escaped detailed consideration in the literature on language evolution because English lacks a specific word for this drive to share our thoughts with others. Fortunately, German has the perfect term: Mitteilungsbedürfnis. Mitteilen means ‘to share’ and bedürfnis [sic!] means ‘a need’ or ‘drive’ but the composite term refers specifically to verbal communication and the basic human drive to talk and share their thoughts and feelings with others.
I suggest that human Mitteilungsbedürfnis (MtB) is a crucial component of linguistic communication. […] Because it sharply differentiates us from our nearest living relatives the chimpanzees, and is difficult to explain from the viewpoint of evolutionary theory, the human MtB deservews far more attention than it traditionally recieves.
(pp. 141f, or via Googlebooks (search inside for “Mitteilungsbedürfnis”: books.google.at/books?id=2gBIrBzf2A4C)
On a less serious note, this is, of course, related to Ford Prefect’s Problem (Adams 1979)
One of the things Ford Prefect had always found hardest to understand about humans was their habit of continually stating and repeating the very very obvious, as in It’s a nice day, or You’re very tall, or Oh dear you seem to have fallen down a thirty-foot well, are you alright? At first Ford had formed a theory to account for this strange behaviour. If human beings don’t keep exercising their lips, he thought, their mouths probably seize up. After a few months’ consideration and observation he abandoned this theory in favour of a new one. If they don’t keep on exercising their lips, he thought, their brains start working. After a while he abandoned this one as well as being obstructively cynical.
Adams, Douglas 1979. The Hitchhiker’s Guide to the Galaxy. London: Pan Books.
Fitch, W. T. (2011). “Deep Homology” in the Biology & Evolution of Language,” in The Biolinguistic Enterprise: New Perspectives on the Evolution and Nature of the Human Language Faculty. Eds. A. M. Di Sciullo, and C. Boeckx. Oxford:Oxford University Press. pp. 135-166.
Hare, Brian and Michael Tomasello 2004. Chimpanzees are more skilful in competitive than in cooperative cognitive tasks. Animal Behaviour 68, pp. 571-581.
Jensen, K., Call, J. & Tomasello, M. (2007). Chimpanzees are rational maximizers in an ultimatum game. Science, 318, 107-109.
Matsuzawa, Tetsuro 2007: Comparative cognitive development. Developmental Science 10:1, pp 97–103.
Tennie, C., Call, J. & Tomasello, M. (2009). Ratcheting up the ratchet: on the evolution of cumulative culture. Philosophical Transactions of the Royal Society of London B Biological Science, 365, 2405-2415.
Tomasello, M. 1999. The Cultural Origins of Human Cognition. Cambridge, MA: Harvard University Press.