The Logic of Language Evolution

Cooperation is the key to team sports, as when one baseball player makes an out at second base and throws the ball to first base for a second out. The ape world has no equivalent to the Tinkers-to-Evers-to-Chance relationship.

Human language is “cooperative communication.” It emerged from ape gestures that became collaborative pointing and pantomiming. Later cooperative communication switched modalities to become vocalized. That thesis is the heart of the evolutionary process presented in Michael Tomasello’s new book, Origins of Modern Communication. His account may be the most logical and detailed that I have seen.

Tomasello’s first step in the transformation of apes into humans is the rise of a collaborative species. He performs a detailed analysis of chimpanzee hunting in the wild and concludes that it is not collaborative. The members do hunt as a group and different members play different roles, but they do not synchronize their activities and there is no evidence of the shared goal of getting food for the group. Instead, each individual’s goal appears to be to get as much of the meat for itself as possible, recognizing that getting it all is not likely. “They have neither the skills nor the motivations to form with others joint goals and joint attention or otherwise participate with others in shared intentionality” [p. 179]. They understand their own goals from a “first-person perspective” and that of their fellow hunters from a “third-person perspective.” They lack the ability found even in human infants to “understand joint activity from a ‘bird’s-eye view’” [181].

Tomasello does not tell us where human’s got this bird’s-eye view along with the skills and motivations to form joint goals and pay joint attention (and I’ve complained about that in an earlier post, here), so let’s just move along with the scenario. Once they had begun to collaborate, they could request things based on mutual interest. Apes already make requests, so this development seems plausible. What’s more (as discussed in yesterday’s post) request do not require an elaborate syntax, so early Homo could make collaborative requests by using simple gestures.

Requests involving mutual interests might not require the full collaborative infrastructure, if our ancestors managed to develop greater tolerance for one another’s company, especially during feeding. As it is now among apes, they insist on their space when eating, and indeed that is a general rule among mammals, including hunting packs and prides. The human custom of sharing a meal is unusual. Since mutual assistance is, by definition, beneficial to both parties, evolutionary pressures could favor it.

Once mutual assistance through requests becomes common, it seems a small step to helping others by informing them of things. The benefits of this communication are based on reciprocity—I inform you today; you inform me tomorrow—and indirect reciprocity—by informing you of something, I improve my own reputation as a good person to have around. Although basic informing can be done simply, say by pointing to an object another is seeking, it often requires true, albeit basic, syntax. At this point language (probably still gestural) begins to evolve its grammatical form.

Requests carry little risk, as in it can’t hurt to ask. Informing however does carry a risk for both parties. The informer loses if there is no reciprocity and the informee suffers if the information is a lie. Thus, it as at this stage that biological sanctions as well as cultural ones begin to evolve. To promote reciprocity, the human lineage develops an urge to share information. To promote truth telling, the human lineage develops a distaste for liars.

The next step, narrative accounts, is more complicated yet, and depends on group selection. (Technically: multi-level selection.) Narratives are part of what hold a culture together, while simultaneously keeping the group separate from other groups that are ignorant of the narrative. Tomasello is very leery of citing group selection although he seems plainly to believe in it, but he does make the interesting case that “if groups are indeed possible units of selection in evolution” we would be much closer to understanding why there is no one, universal language throughout the species. Language differences keep each group together and aware of itself, while simultaneously marking others as different.

It is a provocative suggestion and makes me reconsider the fact that after about twelve it becomes difficult (impossible?) to learn a language without speaking in an accent. Perhaps the learning window evolved as a way of easily detecting non-native speakers whose loyalty to the group is suspect.

Language began as a series of collaborative gestures, but at some point it switched to vocalization. “Our proposal … is that in the beginning the earliest vocal conventions were emotional accompaniments, or perhaps added sound effects, to some already meaningful action-based gestures” [233].

That scenario is the main outline of Tomasello’s account of language origins. I’m quite sure much of its logic will be reflected in future posts, but I have some hesitations.

1. He skips too easily over the critical change in which somehow we become more tolerant of others and generous with our food. Pass that mystery and everything flows logically, but it would be nice to know where this mystery came from.
2. He is too cautious about introducing group selection, although the idea grew much more respectable between his initial lectures on the theory and publication of the book. I can understand why in 2006 he wanted to be careful about that one. But you can’t be a semi-virgin. If he was going to introduce it, he did not have to wait until so much had happened.
3. His dogmatism on gesture only, when so much is unknown, seems arbitrary, especially when there is the well-known vocal phenomenon of infant babbling.

It turns out, by the way, that a revised scenario is possible if you address all three of those objections as a unit. I think Tomasello's suggestion that our earliest vocal conventions were emotional is quite plausible. Babbling (point 3) does allow for emotional expression and eases emotional bonding as well. Thus, if some ape troops babbled, they could (point 1) express contentment and the absence of a threatening mood, making it easier for others to be tolerant of their presence. Over time, this tolerance could lead to collaborative groups (point 2) that could be selected evolutionarily. Then cooperative communication in the form of speech accompanied by gestures could arise.

Obviously, this speculative scenario is not close to proven, but I like it because it overcomes my objections to Tomasello’s outline while making full use of his three great contributions to the subject:

• a clear account of the infrastructure that distinguishes language from ape communications,
• a strong account of the functional evolution of grammar, and
• a logical scenario about what happened once the human lineage developed collaborative groups.

Comments

[JoseAngel]

You are right to point out the importance of group selection, which becomes all the more important when a group has developed technologies (including language technologies) which give it a definite advantage over other groups. Bows and arrows and stone axes too. I suspect much "group selection" in human history has taken the form of genocide, the extermination of neighbouring tribes or ape-like cousins who did not quite speak "in the right way" or interact profitably with the dominant group. To coin a phrase: the history of human evolution is a history of genocide. And a shared language is a key element in this tale. So, cooperation within the group goes hand in hand with competition with neighboring groups; it may actually hone the edge of competition.
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BLOGGER: Long ago I was partial to the genocide idea myself. It is melodramatic and decisive, but I have changed my mind. There is no good evidence that it has been as important as the more familiar mechanisms we see in history: the stronger move in and push the weaker aside, either by shoving them off into highland or desert margins, or by dominating the older group and taking a region's wealth, or by absorbing the weaker so that they become part of the new power.

[JoseAngel]

Well, call it "soft" genocide then. How do you "push" someone to the margin, in fact? Of course I agree all kinds of domination strategies are influential- including extermination through infectious diseases, which according to Jared Diamond also tends to wipe out less 'globalized' peoples. But we are not lacking in evidence for more or less deliberate genocides in recent history (take for instance the case of all-white Argentina or Australia). A story along that line has long been a matter of speculation as regards the spread of Homo Sapiens, of course: for instance in William Golding's "The Inheritors".

[Michael]

Regarding Your Criticism #1, I think there is some interesting work done by Michael Tomasello and his colleagues at the MPI, which shows that tolerance and personal relationships between individual apes are a necessary precondition and a triggering factor for co-operation.

Here's the link to the 2007 Science story: Greg Miller - All Together Now, Pull!:

http://www.sciencemag.org/cgi/content/full/317/5843/1338?ck=nck

[watercat]

Manual babbling would arise naturally once gestural communication developed the forms of language. This would facilitate the collaborative groups you posit, but it would not provide any pressure toward speech, in fact just the opposite. What's more, in the absence of spoken language there would be nothing to provide a source for vocal babbling.