Field of Science

Do monkeys have grammar?


The short answer is "no." But a new study in PLOS One suggests that some monkey calls may be morphologically-complex. Here is the relevant passage:
Some calls were given to a broad, others to a narrow range of events. Crucially, “krak” calls were exclusively given after detecting a leopard, suggesting that it functioned as a leopard alarm call, whereas the “krak-oo” was given to almost any disturbance, suggesting it functioned as a general alert call. Similarly, “hok” calls were almost exclusively associated with the presence of a crowned eagle (either a real eagle attack or in response to another monkey's eagle alarm calls), while “hok-oo” calls were given to a range of disturbances within the canopy, including the presence of an eagle or a neighbouring group (whose presence could sometimes be inferred by the vocal behaviour of the females).
The authors take this as evidence that "oo" is a suffix of some sort that modifies the meaning of the preceding part of the call.

Maybe. Whether two words that contain similar sounds share a morpheme or not is an old problem in linguistics, and one that is actually hard to solve. I cut my teeth on such questions as whether the /t/ in swept is the same past-tense affix that we see in dropped. Notice that both words end in the sound "t" -- but, then, so does "hat," and probably nobody thinks the /t/ in "hat" is a suffix.

One crucial test the authors would need to do would be to show that this "oo" suffix can be used productively. If this was a study of humans, you might teach them a new word "dax," which refers to a chipmunk, and then see if "dax-oo" was interpreted as "warning, there's a chipmunk!"

All of which is not to say that this isn't an intriguing finding, but we're a ways from talking monkeys yet.

3 comments:

kikipotamus said...

It seems to me that the oo suffix could mean "-like situation." Krak could mean leopard; Krak-oo could mean "leopard-like situation!" or "Danger on the ground!" Hok could mean Crowned Eagle, and Hok-oo could mean "Eagle-like situation" or "Danger above the ground." But even if these are correct assumptions, I don't think teaching the monkeys Dax and then seeing if they produce a new word using the oo suffix is a very valid test. While you might succeed in teaching them the name for chipmunk, three things would probably be needed for the group to create a new word Dax-oo: 1) the existence of chipmunk-like situations 2) the need to communicate about those situations and 3) the time it takes for new words to evolve--usually generations.

josh said...

Hi Kikipotamus -- In human languages, new words appear every day. Why should it be different for the monkeys? (The fact that it *is* different for monkeys is probably very important.)

That said, the main point of my post is that the existing data are consistent with these monkeys having word combinations. The data are also consistent with the monkeys having two words that sound similar. For instance: "monkey" and "funky". The only way I know of telling the two theories apart is to look at novel "word combinations".

On a practical level, whether these monkeys can combine words is almost irrelevant; since their vocabulary is so restricted, combining words doesn't add very much to the range of things they can talk about. What the authors' hypothesis suggests, though, is that an important limitation in monkeys is not their ability to combine words, but their ability to learn words that can later be combined together (though, again, the demonstrated word combinations are extremely limited in scope).

kikipotamus said...

Ok, point taken.