Monday, April 15, 2013

Rare Primates May Be Speaking to Each Other

While studying geladas, a baboon-like primate that lives only in the highlands of Ethiopia, evolutionary biologist Thore Bergman kept having the feeling that someone was talking to him only to realize, as he says in the Los Angeles Times, that it was “just the geladas.” As Bergman, a researcher at the University of Michigan, relates in a just published study in Current Biology, the geladas make lip smacks and other sounds that not only close resemble human speech but offer clues about how human speech originated.
Geladas are able to smack their lips by moving their lips, tongue and the hyoid bone beneath them together.  They also vocalize while doing this, thereby producing sounds resembling human speech. In contrast, most monkeys communicate in one or two syllables that are mostly in flat tones.

Bergman refers to the geladas’ vocalizations as “wobbles” and is now in the process of analyzing these, to see if they produce any rhythms resembling those of human speech. That is, words are only one aspect of human speech; the rhythms and tones of our voices also also play a part in helping us express ourselves. (My teenage autistic son uses only a very few words to communicate at a time but also produces streams of sounds that are definitely communication, just not sounds we readily think of as language.)
For all that the geladas’ sounds resemble human speech, it is not yet clear what purpose their lip-smacks and wobbles serve. Bergman does note in Wired that geladas have a “very complex social situation” and live in groups that remain together for many years; females have especially long relationships.  Gelada groups can include several hundred individuals. As Bergman points out, “These very large group structures may be linked to vocal complexity. There’s some evidence across primate that bigger groups make more sounds.”
As he also comments, “Language is not just a great tool for exchanging information; it has a social function.”  While we certainly use language to share ideas, express our beliefs and much more, we also talk as a way to interact with other. “Small talk” is one such example as is the use of words like “hi,” “bye,” “please” and “thank you” — in fact, autistic individuals like Charlie must often be taught how to use such words and for the appropriate social interactions.
Lip-smacking has also been identified in macaque monkeys and, says Wired, found to have an “intriguing correspondence to the universal rhythms of human language“; the macaques’ lip-smacking is different from their mouth movements in eating.
The discovery of the geladas’ unique vocal abilities — lip-smacking plus those “wobbles” — also raises intriguing questions about the origins of human language. Was it that we were first able to produce complicated sounds in different rhythms and patterns and then found that, with this greater array of sounds at our disposal, we could communicate more? Or was it that, as Bergman asks, that because we had more to say and to communicate, “we developed an ability to produce a greater variety of sounds”?
Perhaps you could put the question this way: do we speak because we need to express ourselves, or was it only in the process of making the sounds we call “speech” that we realized all we have to say?