It’s rather fortuitous that the article I’m about to discuss popped up right after my last post, a discussion of how critters’ need for audio-specific brain adaptations depends in part on the complexity of their vocalizations.
The piece of work I’m referring to is a relatively brief description of research on the putty-nosed monkey (figure 1). The finding is that these animals use two types of calls, so-called “pyows” and “hacks” in a combinatorial way: they string together these two words (if you will) to form longer phrases1.
The authors demonstrate that different combinations (pyow hack pyow pyow, vs. hack hack pyow pyow, or something to this effect) can code for distinct predators (leopard vs. hawk). Further, they indicate that novel combinations of the sounds elicit different group behaviors, and that the animals behave differently when the certain calls come from a within-group male rather than a stranger.
This smacks of the beginnings of language to me, in part because one feature of our sentential grammar is iterative construction. Noam Chomsky and others pointed out this method of building up of new sentences with new meaning by tacking extra bits onto the old ones.
1. Arnolda, K & Zuberbühler, K (2008) Meaningful call combinations in a non-human primate. Curr. Biol; 18(5):R202-R203