orangutan goals and communication

A report on the orangutan communication caught my eye. When orangs have a goal in mind (below, getting a human experimenter to deliver a particular type of food), they can gauge the level of understanding of the human and adapt their gestures accordingly. Orangs don't strictly need theory-of-mind (understanding of the human's understanding) to do this, but it does strongly hint at that. Chimps adapt their communication as well. Thinking about these findings makes it really easy to empathize with these apes, highlighting that they have strong representations of things they want, and can communicate it - with the same problems, because we have trouble getting across what we want all the time.

Orangutans Modify Their Gestural Signaling According to Their Audience's Comprehension. Erica A. Cartmill and Richard W. Byrne. Current Biology

When people are not fully understood, they persist with attempts to communicate, elaborating their speech in order to better convey their meaning [1]. We investigated whether captive orangutans (Pongo pygmaeus and Pongo abelii) would use analogous communicative strategies in signaling to a human experimenter, and whether they could distinguish different degrees of misunderstanding. Orangutans' behavior varied according to how well they had apparently been understood. When their aims were not met, they persisted in communicative attempts. However, when the interlocutor appeared partially to understand their meaning, orangutans narrowed down their range of signals, focusing on gestures already used and repeating them frequently. In contrast, when completely misunderstood, orangutans elaborated their range of gestures, avoiding repetition of failed signals. It is therefore possible, from communicative signals alone, to determine how well an orangutan's intended goal has been met. This differentiation might function under natural conditions to allow an orangutan's intended goals to be understood more efficiently. In the absence of conventional labels, communicating the fact that an intention has been somewhat misunderstood is an important way to establish shared meaning.

This work is part of an increase in the number of highly visible primate research these days - a Science paper every month, etc. The Economist catches on and features two studies (and human study) in this week's edition. In the first, Marc Hauser's lab shows that chimps discount food rewards over time less than humans. This is remarkable, considering how much theoretical weight is thrown about on the role of the human PFC in regulating "limbic" areas that want immediate rewards - himps have a relatively small PFC! (...well, maybe, we aren't sure yet). The other piece, in Science, shows that chimps are much more rational (though consequently less "fair"), accepting small ultimatum game offers that humans reject.

And yet another piece in Current Biology demonstrates the endowment effect in chimps! This might help weed out the theories on this effect that rely on particularly human things (e.g. market prices).

Also, nyt has a piece on the great work on baboon social cognition by Cheney and Seyfarth.

I love non-human primates. Maybe more than human primates. The UN estimates the orangutan may be extinct in the wild in 5 years. God save the apes!