The argument that language began as gesture picked up some more ammunition last week, although this blog remains dubious. An article by Amy Pollick and Frans de Waal appears in the May 8 issue of the Proceedings of the National Academy of Sciences (abstract here and supporting data here) reporting that gesture has become a serious candidate for the origins of expressing “symbolic meaning in early hominins,” and “the present study supports the gestural origin hypothesis of language.” Their most important observation was that gestures can have different uses in different contexts.
This blog has often reported that our closest evolutionary relatives, chimpanzees and bonobos, appear to be smart enough to use language. They can reason and learn names. Now it appears that they can also take context into account when interpreting gestures.
Most of the gestures apes use are associated with one specific social context, but that one-to-one relationship is not always true:
For example, a chimpanzee stretching out an open hand toward a third party during a fight signals a need for support, whereas the same gesture toward a possessor of food signals a desire for a share. [p. 8184]
The neutral language of scientific papers is often amusing. Here it is downright misleading. A photograph of the chimpanzee gesturing “toward a possessor of food” to signal his “desire for a share” makes the story more clear. An older chimpanzee has stolen food out of a juvenile’s hand and the younger chimpanzee puts out its hand—wailing or demanding?—wanting the food back. The article makes the gesture sound like some sort of proper communication in an orderly society, while the truth seems to be it is the angry response to a local bully.
One matter not discussed in the article is the reaction of others to these gestures. Does the bully relent and return at least some of the stolen food? Or does he go merrily on his way hogging the whole thing? It cannot be called communication unless it produces results. In an e-mail Dr. de Waal confirmed that the researchers did not require a response for a gesture to count as a gesture; however, in a separate e-mail Dr. Pollick reports, “We certainly observed gesture ‘dialogues’ and sequences as well. But we did not analyze these in our study. Anecdotally, an example would be one individual reaching out his hand to solicit play, which is followed by the receiver slapping the ground to begin the play bout.”
The article specified the behavioral categories that produced gestures which I have listed below. I have added the human gestures that seem similar in spirit.
- Affiliative (e.g., greetings): Invitation for amiable body contact. Hugs and handshakes are typical human greeting gestures.
- Agonistic (e.g., threats but also consolation): Chasing, biting, and fleeing are examples of agonistic actions. There can also be reconciliation and supportive gestures in which one of the individuals seems distressed, frightened or hurt. Humans, of course, have a wide variety of threatening gestures — e.g., shaking a fist, raising a hand — and also a variety of supportive gestures — hugs, pats, and touches.
- Food (e.g., begging): Apes tend to feed themselves, although there is a surprising amount of stealing (dominants from subordinates, adults from juveniles). A begging gesture can be touching the lips or chin of the chewing individual with the beggar’s hand(s). The beggar might also touch its own lips to the chewer’s hand. They can also simply take a keen interest in another person’s food. Humans can beg with an outstretched hand, usually accompanied by speech (“please,” “help me,” etc.) although begging for food seems something more common among children than adults. I have seen children react to food by showing keen interest, raising eyebrows, coughing, etc. This category is the closest one to having a topic — food — but the signal is still personal (gimme). It seems to me that most cultures have developed ways of handling eating situations to avoid this kind of behavior. In many societies the idea of eating in the presence of another who is not eating is scandalous and requires sharing. Even very young children in some societies already know to share their food.
- Groom: Invitations to grooming can be initiated by staring, approaching, or signaling. Humans, of course, do not groom, and some suggest conversation is the way we have replaced grooming. Conversations allow more than two individuals to interact at one time, permitting a more efficient bonding within a large group than a series of one-on-one interactions can. It makes sense, however, conversations have topics while grooming does not. Examples of topicless social interactions among humans include singing, making music, and perhaps joking (although joking presupposes language).
- Play: Apes invite one another to play by running to or from the other or by making gestures. Play among apes and humans is favored by youngsters more than by adults. Human children might invite a game by suddenly touching someone and crying, “You’re it,” but it seems to me that more formal activities like playing a game, even a game that is mostly just running about, begins with a verbal agreement of the “let’s play cops and robbers” sort.
- Sex: The sexual gestures of apes are the kind of thing that can get a person arrested in the USA or beaten up in other parts of the world. Ape sexual invitations include exhibiting genitals, spreading legs, or presenting hindquarters.
- Locomotion: Apes can gesture to invite another to come closer or to signal move back. Humans can also beckon with the hand or signal halt, stay back.
This list provides a powerful reminder that social situations are stereotypical enough for stereotypical signals to suffice. The peculiarity of language’s function—directing attention to an outside topic—explains the peculiarity of language’s structure—it’s capacity to support an infinite number of statements. Without that larger interest a set of gestures will serve, especially when you have a species intelligent enough to take the context into account.
The Pollick-de Waal article suggests that its findings support the theory that language arose from gestures, but I find the results ambiguous in that regard. The article states:
Gestures seem less closely tied to particular emotions, such as aggression or affliliation, hence possess a more adaptable function. Gestures are also evolutionarily younger, as shown by their presence in apes by not monkeys, and likely under greater cortical control than facial-vocal signals. [p. 8187]
These observations, however, do not require that speech flowed from gesture. I was particularly struck by the way many of these types of gestures persist among humans today, suggesting an evolutionary continuity that has not been altered by the introduction of a complex new function. I can imagine just as easily that with so much of the stereotypical communication having been transferred from vocalizations to gesture, vocalizations became available for the evolution of a new function.