More monkey language

The New York Times is running an article trying to pull together recent work on primate communication, including the paper I blogged about last week.

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.

Monkey language -- better every year

For many years we've been saying that monkey calls were non-decompositional. That is, you can't break them into parts, each of which has its own meaning (as you can do with this sentence, for instance).

New research suggests that this monkey calls are more complex than we thought. Click here to learn more.

Scientists create mice with human language gene

Scientists at the Max Plank institute in Germany recently announced that they had successfully knocked the human variant of the FOXP2 "language" gene into mice.

The FOXP2 gene, discovered in 2001, is the most famous gene known to be associated with human language. There has been some debate about what exactly it does, but a point mutation in the gene is known to cause speech and language disorders.

Part of the interest in FOXP2 stems from the fact that it is found in a wide range of species, including songbirds, fish and reptiles with only slight variations. Also, FOXP2 is expressed in many parts of the body, not just the brain. Previous research had found that removing the gene from mice decreased their vocalizations...and ultimately killed the mice.

In the new study, scientists created a new mouse "chimera" with the human variant of the FOXP2 gene. This time, the only differences they could find between the transgenic mice and typical mice was in their vocalizations.

Read more about FOXP2.

(Disclosure: This research does not appear to have been published yet. I heard about it from Marc Hauser of Harvard University, who heard about it this summer from a conference talk by Svante Paabo of Max Plank, one of the researchers involved in the project.)

Monkeys know their plurals

Anybody who reads this blog knows that I am deeply skeptical of claims about animal language. Some of the best work on animal language has come from Marc Hauser's lab at Harvard. Recently they reported that rhesus monkeys have the cognitive machinery to understand the singular/plural distinction.

First, a little background. Many if not most scientists who study language are essentially reverse-engineers. They/we are in the business of figuring out what all the parts are and how they work. This turns out to be difficult, because there are many parts and we don't really have the option of taking apart the brains of random people since they usually object. So the task is something like reverse-engineering a Boeing 747 while it's in flight.

There are many different ways you could approach the task. Hauser tries to get at language by looking at evolution. Obviously, rhesus monkeys can't speak English. Just as obviously, they can do some of the tasks that are necessary to speak English (like recognizing objects -- you have to recognize something before you can learn its name). Any necessary components of language that non-human animals can successfully perform must not be abilities that evolved for the purpose of language. If you can figure out what they did evolve for, you can better understand their structure and function. So the next step is perhaps to figure out why those particular abilities evolved and what non-human animals use them for. This ultimately leads to a better understanding of these components of language.

That is one reason to study language evolution in this manner, but there are many others (including the fact that it's just damn cool). If you are interested, I suggest you read one this manifesto on the subject.

Back to the result. Nouns in many languages such as English can either be singular or plural. You couldn't learn to use "apple" and "apples" correctly correctly if you couldn't distinguish between "one apple" and "more than one apple". This may seem trivial to you, but no non-human animals can distinguish between 7 apples and 8 apples -- seriously, they can't. In fact, some human groups seemingly cannot distinguish between 7 apples and 8 apples, either (more on that in a future post).

So can rhesus monkeys? Hauser and his colleagues tested wild rhesus monkeys on the beautiful monkey haven of Cayo Santiago in Puerto Rico. The monkeys were shown two boxes. The experimenters then put some number of apples into each box. The monkeys were then allowed to approach one box to eat the contents. Rhesus monkeys like apples, so presumably they would go to the box that they think has more apples.

If one box had 1 apple and the other had 2 apples, the monkeys went with the two apples. If one box had 1 apple and the other had 5, the monkeys picked the 5 apple box. But they chose at random between 2 and 4 apples or 2 and 5 apples. (For those who are familiar with this type of literature, there are some nuances. The 2, 4 or 5 apples had to be presented to the monkeys in a way that encouraged the monkeys to view them as a set of 2, 4 or 5 apples. Presenting them in a way that encourages the monkeys to think of each apple as an individual leads to different results.)

This suggests that when the monkeys saw one box with "apple" and one with "apples," they knew which box to choose. But when both boxes had "apples," they were at a loss. Unlike humans, they couldn't count the apples and use that as a basis to make their decision.



Full disclosure: I considered applying to his lab as a graduate student. I am currently a student in a different lab at the same school.

Caveat: These results have not been formally published. The paper I link to above is a theory paper that mentions these results, saying that the paper is under review.

Can a parrot really talk? (So long, Alex)

Alex the Parrot, research subject and beloved friend of Irene Pepperberg of Brandeis and Harvard Universities, died last week. This may be the first parrot to merit an obituary in the New York Times. The parrot was famous for being able to not just name objects, but count them -- something not all human cultures do. Alex could also name the colors of objects.

A colleague of mine has actually seen this in action and confirms that it is really true. Alex was no doubt a very remarkable birrd, but that doesn't mean tha the parrot could really talk. Clever Hans, an early 20th century phenomenon, was a horse that was able to stomp out the answers to simple math problem with his hooves. It turned out that Hans didn't actsually know the answer to 3 + 3, but he did know to watch the behavior of his human observers. Whenever he noticed his owner getting excited, he knew that if he stopped stomping right then, he'd get a horsey treat.

The question, then, is whether Alex really used words as symbolic labels for colors, or if he was just very good at getting crackers. Dr. Pepperberg has been met with a lot of skepticism, partly because she is actually trained as a chemist, not as a linguist, psychologist or even biologist. Even my colleague, who admires Dr. Pepperberg greatly, isn't convinced that the professor uses the proper controls in her experiments to rule out simpler explanations for Alex's behavior.

Another reason to be skeptical is that there is a long history of animal language hoaxes. By "hoax," I don't mean that the researcher is pulling a fast one. Clever Hans's owner really believed his horse could complete math problems. The most famous example, though, is Koko the gorilla.

Koko, trained by Dr. Francine Patterson, is said to be able to use more than 1,000 words from American Sign Language and to understand approximately 2,000 words of spoken English. She was the inspiration for the talking gorilla in Michael Crichton's novel Congo. The problem with Koko, is that her conversations are always interpreted by her trainers, who can be rather fanciful in ascribing meaning to the ape's gestures.

The best way to see this is to read Koko's Internet chat from 1998. Here are some excerpts:

HaloMyBaby: Is Koko aware that she's chatting with thousands of people now?
LiveKOKO: Good here.
DrPPatrsn: Koko is aware.

Patterson's translation seems reasonable, if a stretch, but look at the next question:

HaloMyBaby: Koko are you going to have a baby in the future?
LiveKOKO: Pink

Huh?

It continues:

DrPPatrsn: What about a baby? She's thinking...
LiveKOKO: Unattention
DrPPatrsn: She covered her face with her hands...which means it's not happening, bascially, or it hasn't happened yet.

Or maybe she's playing peekaboo.

HaloMyBaby: What are the names of your kittens? (and dogs?)
LiveKOKO: foot
DrPPatrsn: Foot isn't th e name of your kitty
HaloMyBaby: Koko, what's the name of your cat?
LiveKOKO: no
....
Question: Do you like to chat with other people?
LiveKOKO: fine nipple
DrPPatrsn: Nipple rhymes with people. She doesn't sign people per se, she was trying to do a "sounds like..."

I don't know of anybody who has accused Patterson of a hoax. It seems like she really believes that Koko talks. But the evidence isn't very compelling.

Koko is by all accounts a remarkable ape. Alex may be one of the brightest animals alive. But are they really talking, or just "aping," as it were, language?

The NYT piece ended by saying that as Dr. Pepperberg left the lab the last evening that Alex was alive, "Alex looked at her and said: 'You be good, see you tomorrow. I love you.'" Here's a quote from the Language Log:

"It's certainly not unimpressive that Alex had apparently learned to associate the quoted string of words above with being put back in his cage for the night. Call me callous, but I can't help thinking that Alex's last words would have been very different if Dr. Pepperberg and her associates had taken to saying 'see you later, bird-brain' to Alex every night."