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.

Ant Navigation SNL-style

If you appreciated Saturday Night Live's Mother Lover, then this ode to ant navigation should be right up your alley, produced by student in Dave Barner's Developmental Psychology course at UCSD.

OK, the videos have nothing to do with each other, but both are worth watching.

More amazing birds

I've been hearing for some time that starlings are remarkable vocal learners. For a brief time, there was a starling lab in our building.

I came across this video on grrlscientist's blog. I'm not sure if "amazing" or "creepy" is the right response.

Text messages for elephants

It has been widely noted that even in areas too remote or poor to have regular telephone service, cell phones and text messaging are ubiquitous. Now, even elephants send text messages.

Modern conservation
As reported by the New York Times, a protected elephant has been fitted with a collar that sends a text message whenever the elephant nears local farms. This was done after several elephants on a local reservation had to be shot to protect the area farmers. Now, when the elephant wanders from its range, rangers arrive to scare it back.

The article is worth reading in its entirety. It's great that a smart method has been found to help wild animals and human civilization coexist.

What struck me, though, was the note that elephants learn from one another, and deterring one elephant from raiding farms can help stop other elephants as well. If anybody knows more about this, I'd be very interested in hearing what is known about elephant social learning.

Do you have the memory of a crow?

It appears that humans aren't the only ones with exceptionally good long-term memory. Crows not only remember individual faces over long periods of time and even seem to be able to communicate to other crows information about the people in question.

That animals, especially birds, have good memories is not all that surprising. That they remember human faces so well is striking.

There is an ongoing debate in the literature about whether the fact that humans are so good at processing faces is because we have specialized neural circuitry for human faces. Given that humans are an intensely social species, it would make sense for us to develop special face-recognition systems. It remains to be seen just how good crow memory for human faces is (the study in question is limited in some ways), but if their human face perception is very good, that would call for a very interesting explanation.

Cats, instincts, and evolution

Cats are very strange animals. One of their odder behaviors is scratching around their food bowl. They look like they are trying to kick dirt over the food in order to bury it. Presumably that is what they do in the wild. But the "dirt" house cats are kicking over the food is imaginary.

This suggests that wild cats do not know they are burying their food. That is, it is not goal-directed behavior. If it were goal-directed, house cats would either not bother with the scratching, or they would be very frustrated by their lack of success.

This is not to suggest at all that cats are all dumb instinct. On the one hand, much of their behavior seems very human-like. On the other hand, plenty of human behavior is instinct masquerading as goal-directed behavior. Sex, for instance, has a clear purpose but that's not usually why we do it. (Even if you believe sex has purposes other than procreation, such as pair bonding, it is hard to explain prostitution -- which, while not as common as cats "burying" their food, is still common enough to require explanation.

So why do cats scratch around their bowl? I suspect it just feels good. Evolution does not require that we know why we do what we do -- just that we do it.

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.

Sure faces are special, but why?

Faces are special. There appears to be a dedicated area of the brain for processing faces. Neonates just a day or two old prefer looking at pictures of faces to looking at non-faces.

This has led many researchers to claim humans are born with innate knowledge about faces. Others, however, have claimed that these data are not the result of nature so much as nurture. Pawan Sinha at MIT attached a video camera to his infant child and let the tape roll for a few hours. He found that faces were frequently the most salient objects in the baby's visual field, and (I'm working from memory of a talk here) also found that a computational algorithm could fairly easily learn to recognize faces. Similarly, a number of researchers have claimed that the brain area thought to be specialized for face detection is in fact simply involved in detecting any object for which one has expertise, and all humans are simply face experts.

Things have seemed to be at an impass, but today, Yoichi Sugita from AIST spoke at both Harvard and MIT. The abstract itself was enough to catch everybody's attention:

Infant monkeys were reared with no exposure to any faces for 12 months. Before being allowed to see a face, the monkeys showed preference for human- and monkey faces in photographs. They still preferred faces even when presented in reversed contrast. But, they did not show preference for faces presented in upside-down. After the deprivation period, the monkeys were exposed first to human faces for a week. Soon after, their preference changed drastically. They preferred upright human faces but lost preference for monkey faces. Furthermore, they lost preference for human faces presented in reversed contrast. These results indicate that the interrelated features of the face can be detected without experience, and that a face prototype develops abruptly when flesh faces are shown.

Just to parse this: the monkeys were raised individually without contact with other monkeys. They did have contact with a human caregiver who wore a mask that obstructed view of the face. The point about not preferring upside down faces is important, as this is a basic feature of face processing.

This seems pretty decisive evidence for an innate face module in the brain, though one that requires some tuning (the monkeys' face preferences evolved with experience). However, Sugita apparently noted during the talk -- I heard this second-hand -- that perhaps the monkeys in question did in fact have some experience with faces prior to the face preference test; they could have learned by touching their own faces. This strikes me as a stretch, since that doesn't explain why they would become face experts.

The algebraic mind

The brain is a computational device. There may be some cognitive scientists out there who disagree with that statement, but I don't think there are many. There is much less agreement on what type of computational device it is.

One possibility is that the brain is a symbol-processing device very much like a computer. A computer can add essentially any two numbers using the same circuitry. It does not have one microchip for adding 1 + 1 and a different one for adding 2 + 2. It has a single algorithm that can be applied to any arbitrary number (assuming the computer can represent that number -- obviously there are numbers too large for any modern machine to handle).

One of the big mysteries of the brain is that it is unclear how to make a symbol-processing/algebraic device out of neurons. This has led many schools of thought, such as Connectionists, to deny that the brain can do symbol-processing or works anything like a digital computer (see Marcus's The Algebraic Mind for some blow-back). On the flip side, folks like Randy Gallistel have argued that if we don't know how to implement read/write memory into neurons (a related question), then there is a gaping hole in our knowledge about neurons.

This all comes to mind in relation to some work done in the last decade on barn owls. Barn owls locate their prey via both sight and sound, and neuroscientists have located the area of the brain where these two signals are combined. If you put prism goggles on a barn owl so that it's vision is offset (e.g., everything looks like it's 10 degrees left of where it actually is), the two signals get distorted at first, but eventually the neural map that represents location according to the ears shifts so that it's in sync with the the visual map.

As a computer programmer, the obvious thing to do would be to just add 10 degrees to the auditory signals across the map. However, that's not what the brain does. This can be shown by putting barn owls into goggles that shift only part of the field of vision. Only the auditory signals for that region of space shift. That strikes me as very non-algebraic in nature (not that a computer programmer couldn't achieve this effect, but why would she write that ability into the code. Keep in mind that barn owls didn't evolve to wear prism goggles).

That said, there's no reason that all the brain must compute things algebraically. Perceptual systems may be unusual in that respect. Still, as very little is known about how the brain computes anything, this example is very interesting.

For those interested in the barn owl details, check out:

Knudsen, E.I. (2002). Instructed learning in the auditory localization pathway of the barn owl. Nature, 417, 322-328.

Angry cats

What is it like to be an angry cat? According to a new study, not much different than being an angry human.

I'm curious, though, how much evidence there is that other animals don't share many/most of their emotions with humans. It was definitely common to think once that animals didn't have emotions, but as far as I can tell, it's widely accepted now that they do.

For previous posts about cat behavior, click here or here.

Having solved the question of monkeys & humans, I move on to children and adults

Newborns are incredibly smart. They appear to either be born into the world knowing many different things (the difference between Dutch and Japanese, for instance), or they learn them in a blink of an eye. On the other hand, toddlers are blindingly stupid. Unlike infants, toddlers don't know that a ball can't roll through a solid wall. What is going on?

First, the evidence. Construct a ramp. Let a ball roll down the ramp until it hits a barrier (like a small wall). The ball will probably bounce a little and rest in front of the wall. Now let an infant watch this demonstration, but with a screen blocking the infant's view of the area around the barrier. That is, the infant sees the ball roll down a ramp and go behind a screen but not come out the other side. The infant can also see that there is barrier behind the screen. If you then lift the screen and show the ball resting beyond the barrier -- implying that the ball went through the solid barrier, the infant acts startled (specifically, the infant will look longer than if the ball was resting in front of the barrier as it should be).

Now, do a similar experiment with a toddler. The main difference is there are doors in the screen, one before the barrier and one after. The toddler watches the ball roll down the ramp, and their task is to open the correct door to pull out the ball. Toddlers cannot do this. They seem to guess randomly.

Here is another odd example. It's been known for many decades that three-year-olds do not understand false beliefs. One version of the task looks something like this. There are two boxes, one red and one green. They watch Elmo hide some candy in the red box and then leave. Cookie Monster comes by and takes the candy and moves it from the red box to the green box. Then Elmo returns. "Where," you ask the child, "is Elmo going to look for his candy?"

"In the green box," the child will reply. This has been taken as evidence that young children don't yet understand that other people have beliefs that can contradict reality. (Here's a related, more recent finding.)

However, Kristine Onishi and Renee Baillargeon showed in 2005 that 15-month-old infants can predict where Elmo will look, but instead of a verbal or pointing task, they just measured infant surprise (again, in terms of looking time). (Strictly speaking, they did not use "Elmo," but this isn't a major point.)

So why do infants succeed at these tasks -- and many others -- when you measure where they look, while toddlers are unable to perform verbal and pointing tasks that rely on the very same information?

One possibility is that toddlers lose an ability that they had as infants, though this seems bizarre and unlikely.

Another possibility I've heard is that the verbal and pointing tasks put greater demands on memory, executive functioning and other "difficult" processes that aren't required in the infant tasks. One piece of evidence is that the toddlers fail on the ball task described above even if you let them watch the ball go down the ramp, hit the wall and stop and then lower the curtain with two doors and make them "guess" which door the ball is behind.

A third possibility is something very similar to Marc Hauser's proposal for non-human primate thought. Children are born with many different cognitive systems, but only during development do they begin to link up, allowing the child to use information from one system in another system. This makes some intuitive sense, since we all know that even as adults, we can't always use all the information we have available. For instance, you may know perfectly well that if you don't put your keys in the same place every day, you won't be able to find them, put you still lose your keys anyway. Or you may know how to act at that fancy reception, but still goof up and make a fool of yourself.

Of course, as you can see from my examples, this last hypothesis may be hard to distinguish from the memory hypothesis. Thoughts?

How are monkeys and humans different (I mean, besides the tail)

Marc Hauser, one of a handful of professors to be tenured by Harvard University (most senior faculty come from other universities), has spent much of his career showing that non-human primates are smart. It is very dangerous to say "Only humans can do X," because Hauser will come along and prove that the cotton-top tamarin can do X as well. Newborn babies can tell Dutch from Japanese? Well, so can the tamarins.

For this reason, I have wondered what Hauser thinks really separates human cognition from that of other animals. He is well-known for a hypothesis that recursion is the crucial adaptation for language, but I'm never sure how wedded he is to that hypothesis, and certainly he can't think the ability to think recursively is all that separates human thought from tamarin thought.

Luckily for me, he gave a speech on just that topic at one of the weekly departmental lunches. Hopefully, he'll write a theory paper on this subject in the near future, if he hasn't already. In the meantime, I'll try to sketch the main point as best I understood it.

Hauser is interested in a paradox. In many ways, non-human primates look quite smart -- even the lowly tamarin. Cotton-top tamarins have been able to recognize fairly complex grammatical structures, yet they do not seem to use those abilities in the same ways we do -- for instance, they certainly don't use grammar.

In some situations, non-human primates seem to have a theory of mind (an understanding of the contents of another's mind). For instance, if a low-ranking primate (I forget the species, but I think this was with Chimpanzeees) sees two pieces of good food hidden and also sees that a high-ranking member of the troop can see where one piece was hidden but not the other, the low-ranking primate will high-tail it to the piece of food only he can see. That might seem reasonable. But contrast it with this situation: these primates also know how to beg for food from the researchers. What if primate is confronted with two researchers, one who has a cloth over her eyes and one who has a cloth over her ears. Does the primate know to beg only from the one who can see? No.

Similarly, certain birds can use deception to lure a predator away from their nest, but they never use that deceptive behavior in other contexts where it might seem very useful.

These are just three examples where various primates seem to be able to perform certain tasks, but only in certain contexts or modalities. Hauser proposes that part of what makes humans so smart are the interfaces between different parts of our brains. We can not only recognize statistical and rule-based regularities in our environment -- just like tamarins -- but we can also use that information to produce behavior with these same statistical and rule-based regularities. That is, we can learn and produce grammatical language. We can take something we learn in one context and use it in another. To use an analogy he didn't, our brains are an office full of computers after they have been efficiently networked. Monkey computer networks barely even have modems.

This same theory may also explain great deal of strange human infant behavior. More about that in the future.

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.

Another non-human first

First ever Economist obituary for a non-human:

http://www.economist.com/obituary/displaystory.cfm?story_id=9828615

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."

Update on cat cognition

For those who were interested in how cats see the world, check out this new study. I'm not sure it isn't just saying that cats have motor memory (as do humans), but it's interesting nonetheless.

Cat Cognition

How do cats remember where they are?

Last Friday my wife and adopted two kittens. Their litter box was originally kept in the pantry. This was done in a sanitary manner, but it still wasn't ideal. Yesterday, we were able to clear a space in the mud room for the litter box and moved it there. The next step was to explain to Moshe and Noah where to find their litter.

When we brought them home, we taught them the location by picking them up every hour or two and carrying them to the litter box. It took most of the day, but they eventually caught on.

We tried the same method for teaching them the new location. Noam caught on reasonably well. Over the next day, I would see him march purposefully into the pantry, get to the wall, then stop and look puzzled. Finally, he'd begin to mew. I would pick him up and carry him to the mud room, where he found the litter box and proceeded to do his business. Through the day, he seemed more and more confident, but we still found him searching through the pantry.

Moshe had even more difficulty adjusting. I would find him in the pantry looking for the litter box. I would carry him from the pantry to the mud room and place him in the litter box. Sometimes he left immediately. Sometimes he'd scratch at the litter, or even lie down in it for a few minutes. He'd do anything but his business. Then he would go straight back to the pantry.

After a full day of him refusing to use the litter box, or go anywhere else, we moved it back. The new plan is to move it little by little each day from the pantry to the mud room (they are next to each other).

This says something interesting about the cat's conception of where to go to the bathroom. As humans, we see it as the litter box, but the cat may not see it that way at all. When given conflicting signals between the learned physical object (the box with litter) and the learned location (the pantry), Moshe chose the pantry. Even Noah, the more flexible of the two, perserverated on the pantry.

Humans, I admit, perservate on locations as well. You may get up in the middle of the night and expect to find your glasses on the shelf, only to remember you just through out that shelf yesterday and the glasses are on the new nightstand. Where we differ is you would not refuse to use your glasses just because they are on the nightstand, not on the shelf.

I'll keep an eye out for research on cat cognition, and if I find anything interesting, I'll post it here. I'm still on vacation, but when I get back to the lab in a couple weeks, I'll be posting more actual research rather than observations. Feel free to comment with links to cat cognition research.

This whole matter might have been simplified if cats could talk. Please help us study human language by participating in the Find the Dax experiment, which takes about 5 minutes. If you have already participated, thank you!