Michael Tomasello is perhaps the consummate product of contemporary sociobiology. A tenet of sociobiology is that we can understand the behavior of a species by comparing and contrasting with closely related species, and with species that have found similar means for solving their social problems. Tomasello offers us deep insights into human communication and learning by comparing and contrasting our behavior with that of our nearest evolutionary relatives, the great apes.
Tomasello is not only a creative and incisive scientist, but also a learned intellectual, who is at ease bringing philosophical issues to bear on complex questions in behavioral science. In this book, we not only find out about human communication, but also are rewarded with an appreciation of the philosophy of the great Ludwig Wittgenstein. Wittgenstein is a difficult philosopher because he writes in quasi-aphorisms and follows something like the Socratic Method in asking questions rather than answering them. A good example is the quotation from the Philosophical Investigations with which Tomasello's book starts: "Point to a piece of paper. And now point to its shape---now to its color---now to its number... How did you do it?" Wittgenstein's point is that gestures as a form of communication are primary and part of our essence as humans. They are not translations of verbal linguistic structures into visual form. As Wittgenstein says in his unpublished notes (The Big Typescript, 2005[1933]), "What we call meaning must be connected with the primitive language of gestures."
Tomasello takes Wittgenstein literally: we share with chimpanzees and other apes the capacity to communicate by gesture, so it is likely that this was a capacity possessed by our most recent common ancestor. "My central claim," Tomasello writes (p. 2), "is that to understand how humans communicate...using a language...we must first understand how humans communicate...using natural gestures. Indeed, my evolutionary hypothesis will be that the first truly human forms of communication were pointing and pantomiming." Tomasello does not prove this thesis (if it can be proved at all), but rather uses the differences between gesture in apes and humans to develop a story of why humans catapulted so far beyond the apes in the use of communicative tools.
Tomasello's hypothesis from a careful study in contrasts between the role of gesturing in human and non-human primate societies is that "there must be some fairly specific connections between the fundamentally cooperative structure of human communication...and the especially cooperative structure of human, as opposed to other primate, social interaction and culture in general." (p. xi). Humans communicate because they want to help one another, he asserts, and a highly flexible system of communication is more helpful than a series of pants and grunts.
Tomasello gives a number of compelling examples contrasting human and other primate communication. Here is one: "When a whimpering chimpanzee child is searching for her mother," he writes, "it is almost certain that all of the other chimpanzees in the immediate area know this. But some if nearby female knows where the mother is, she will not tell the searching child, even though she is perfectly capable of extending her arm in a kind of pointing gesture" (p .5). Human communication, he argues, is a fundamentally cooperative enterprise, dependent upon deep commonalties in the consciousness of humans, including a common conceptual ground and cooperative communicative motives.
This human commonality is what Tomasello calls "shared intentionality": "The proposal is thus that human cooperative communication...is one instance...of a uniquely human cooperative activity relying on shared intentionality." At this point Tomasello relies on Gilbert and Searle, who are fine philosophers but whose theory of "collective intentionality" I think is completely without merit. Neither the conceptual arguments nor the empirical examples provided by these philosophers (and other of this school of thought) are compelling, and I believe that a combination of game theory, gene-culture coevolutionary theory, and the psycho-social theory of norms is a better starting point to understand how individual intentional agents succeed in coordinating their activities so as to produce human cooperation.
The problem with the theory of collective intentionality is that it depicts cooperation as a process in which all participants have no motives except for that of accomplishing the "team goal," whereas in fact this is rarely even remotely the case. The triumph of human cooperation is that people manage to coordinate their activities even though they generally have highly heterogeneous motives. For Tomasello, humans developed language because they want to help one another. However, it is not clear what fitness benefit comes from helping others, and the notion that we developed huge brains, complex voice boxes and its associated aural production physiology because we "want to help each other" is implausible. Indeed, among the more prominent predilections of humans is to lie, cheat, and attempt to free-ride on the prosocial behavior of others.
I find it more plausible to posit that human language flourished when humans became sufficiently adept at punishing social miscreants (gossip, shunning, beating, ostracizing) that it became plausible that communication would be truthful, on balance, and the detection and punishing of untruthful utterances could occur with high probability. Once the veracity of communication was ensured, it became possible to coordinate much more complex activities (e.g., warfare, conflict adjudication, hunting strategy, complex verbal agreements of intention), and individuals with the best command of language were afforded special privileges, including more and higher quality offspring, thus justifying the costs of developing the communication physiology.
I am not saying that Tomasello is wrong in stressing the humans have an inordinately highly developed propensity to help each other for purely altruistic reasons. They clearly do, and the predisposition towards prosocial behavior is one of the preconditions of human cooperation. However, the notion that language developed because people like to help each other and have a collective, or shared, intentionality is not a plausible basis for a theory of human communication. Human society is just more complicated than that.