Babel's Dawn

Just How Long Ago Did Adam Eat that Apple?

In thinking about how language might have begun, one of the tempting details of the human vocal system has been the “laryngeal descent.” The larynx (aka, the voice box or the “Adam’s apple”) moved a bit down the throat. This anatomical detail was long thought to be exclusive to humans and was also believed to be important in producing certain acoustic distinctions between vowels, so that English speakers can say poke or puke without causing confusion. As the descent appears to have been only 200,000 years old, it seemed that the descent might have had something to do with the introduction of speech, which many people believe to be at most 200,000 years old. Put crudely, the hypothesis said that the human cognitive features needed to support language developed first, but speech only appeared after the laryngeal descent.

This hypothesis supported the Chomsky school of linguistics which asserts that language first emerged as a tool for supporting thinking and only later interfaced with the ability  to vocalize and engage in speech.

It has been known for some  time now that the laryngeal descent is not found only in humans. A report in the latest Science magazine—"Which way to the dawn of speech?” by Jean-Louis Boë et al—reviews the work on laryngeal descent and determined that the previously accepted date for the descent was a bit late. In fact, the paper claims that the trait belongs to many apes, is not essential for making vowel distinctions, and has been part of the human ancestral lineage for at least 20 million years. The surviving great apes all share much of that lineage with us, thus falsifying the conjecture that the laryngeal descent was one of the last steps in evolving speech.

Boë et al go on to ask, “While speech had been thought of as an enabling communication of already developed linguistic cognition, should it now be thought of as an early driver of linguistic cognitive development?” This blog has never expressed the process in quite that way, but it has long supported the notion that vocalizations led to words which led to phrases and, ultimately, to modern language. This latest report does not prove the point, but at least it removes some theoretical obstacles to accepting this blog’s position.

 

Twixt Brain and Tongue

I have been pretty busy of late,  but  I have an urge to say something if only to prove I’m still alive so I thought I’d summarize what I know about the brain’s evolution and language. The main thing we know for an absolute certainty is that the brain suddenly got a lot bigger, about 3.3 times larger than the ape brains of Australopithecus of 2.5 million years ago.

Brains are expensive body parts. They put heavy metabolic demands on the system and they do not forgive malnutrition, especially in childhood. So the expansion of  the brain size was only possible if food was reliable throughout the year. There are some possible trade-offs. We can sacrifice other metabolic demands. Chimpanzees and gorillas are much stronger than humans, strong enough to be able to tear humans apart. So we might have sacrificed some serious muscle strength in order to support our brains, but that only works if the ancestors found some substitute for muscle power. Stone tools were part of the kit of the earliest Homo and perhaps there were other wooden and vegetable tools  that did not survive. Fire is another solution. Cooked food provides many more  calories than raw stuff, but when did cooked food come into style? A quarter million years ago? Half a million? A million? A million and a half? There are advocates for each of these answers. I lean toward old dates, but who can say? It seems fairly clear that the brain was already growing when fire came along, but cooked food probably made further growth possible.

Another source of reliable food is cooperation and moral duties. In many societies, especially poor ones, people with food have a duty to share it with people (especially kin) who don’t have it. How far back do those customs go? I’m willing to say that sharing food probably goes back 2 million years to the earliest Homo habilis. Presumably, their manner of sharing was simple and without moral complexity, but sharing is a way to get everybody through the rough patches. One of the peculiarities of humans of every society is the shared feast. Mealtime is a social time. People eat together and pass food between themselves. Thus, the sick, the weak, the young, and the unlucky do not starve with anything like the frequency that starvation plagues animal societies.

Shared food is my own candidate for the earliest source of sufficient calories to support a bigger brain. Tools are the other candidate. Fire seems to imply sharing already existed  (the idea of everybody making their own fire to cook their own hard won bit of meat is too nutso to tolerate). When fire came along, people were already first-class cooperators.

Meanwhile language may have been tagging along for the ride. I am a proponent of very old language, 2 million years old, but that first language was very simple, perhaps no more complex or rich than the speech of today’s eighteen month old. Language grew more complicated as the brain grew big enough to support more elaborate speech. That brings us to Deacon’s theory of the co-evolution of brain and language. It seems clear that the brain evolves more slowly than language does, so  there was probably no co-evolution that favored a particular set of syntactical rules (sorry, Noam) but a more general co-evolution is quite possible. Clearer enunciation, increased vocabulary size, the ability to understand complete sentences as a unitary image, the use of abstractions and metaphors… all these things are part of every language but were probably not part of the bah-bah speech of M. and Mme. Habilis.

This raises another question. What did we do with all our new smarts? We did not just scale up the chimpanzee brain. The overwhelming growth was in the neocortical region with the cerebellum following not that far behind. One brain part that was unable to keep up with the increase was the corpus callosum, the wiring that links the two halves of the brain. Ours cannot allow for as much synchronization between right and left portions of the brain. Thus,  the mere fact of getting a much bigger brain meant that significant localization of functions, particularly with new functions, was likely. A function would evolve on one side of the brain and not the other.

That localization suggests a role for consciousness. If the left side of the brain organizes language syntactically and the right side organizes it rhythmically, perhaps it takes consciousness (or even talking out loud) to put it all together. Years ago, on this blog, I cited work on Nicaraguan sign language that found rhythm was essential to creating language. Perhaps here is a reason. It gets the two halves of the overstuffed brain working  together.

That may be fanciful, but even if not, the main key to organizing language has been the rise of many circuits in the brain linking the many parts together electrically. You can wonder how valuable all this brain imagery really is, but it has definitely established that there is no region of the  brain controlling language the way there is a visual region and an auditory one. Language construction connects all these different parts to create a whole. When we think in words, we think of ways to connect the previously unconnected. Listening to a great story gets the whole brain chugging along. (While listening to a great liar (as we do these days) puts different parts of the brain in conflict.) That connecting seems to account for much of what our brain has been up to for the past two million years. It has been running wires from a billion point As to another billion point Bs and we are still working out the consequences of the change.

In other animals, the neocortex is largely used to handle sensory input and perception. In humans, it might seem that we have not used our brains to improve our senses, but language lets us know what is going on in other heads. Talking as sharing sounds too much like a 12-step program’s concept to appeal to me but it seems to have much in its favor. There seems no question that the main ways people have gotten so much more powerful is that they learn from history and each other. Without our big brains we’d still be babbling, but without language our big brains would just be a few trillion more cells to feed.

Chimpanzees Warning Calls -- How Close to Language?

The New York Times has a story in today's Science section about chimpanzees changing their warning call if they think other chimps already know about the danger:

The significance of the finding, Dr. Crockford said, is that it challenges the view that only humans keep track of what others know and change their communication to match. “This experiment shows they are monitoring their audience,” she said of the chimps.

That part did not interest me much. Chimps are smart and know something of what their fellows think. This is the kind of finding that gets a reaction when the finder (and Times reporter) have no theory about what matters.

But I have a theory and something else in the story struck me as quite important:

...chimps that thought their fellows were unaware of the road hazard made more alert hoo calls. They also stayed longer to look back and forth from the snake to where they thought their companions were. That’s the way chimps try to show their friends where a danger is.

Why do I think that's a big deal? Because the chimpanzees are drawing attention to something.

It sounds like they are drawing attention to their own location rather than the snake itself. It is not quite joint-attention. The signaler focuses attention on another chimp and the listener looks at the signaler rather than trying to make out the snake. But they have a topic (a snake) and wouldn't have to change much to have a true speech triangle. Keep your eye on chimp behavior during warning signals.

 

News From Prairie Dog Town

This week’s New York Times Sunday Magazine has an article titled Can Prairie Dogs Talk? The answer is so obviously no, that one is forced to read it to see what kind of case the author can make. Turns out he makes an interesting one.

It is easy to come up with a definition of language that bars prairie-dogese. If you define a language as the set of sentences that can be generated by its syntactical rules, why then the answer is still no. Prairie dogs do not speak in sentences and appear to have no generative syntax. But I don’t define language that way.

A biologist with the unusual name of Constantine Slobodchikoff has been studying prairie dogs for decades. He has demonstrated that the varmints make a distinct sound when people appear and a different sound when a coyote appears. This kind of thing has long been known about vervet monkeys and suggests the minimum that one can try to pass off as a language.

However, the vervet sounds appear to be innate rather than learned and prompt different reactions: tree climbing in case of the leopard warning, ducking under bushes for the hawk or eagle warning, and bolting upright while checking the ground for a snake warning. Maybe these shouts are words, although there is no reason to insist on it. The vervets have a small set of distinctive warnings that produce different responses in the listeners. Perhaps prairie dogs have something similar, except for the fact that their response to pretty much any danger is to run down into their underground world.

Let’s remind ourselves that in human language, words are cultural inventions that can be understood in a context. Some words like into and doesn’t require other words if they are to mean anything at all, and some words like table have a default meaning, but if said alone are likely to provoke a response along the lines of What about a table? Or perhaps the speaker is eighteen-months old, in which case the response may be yes, it’s a ping-pong table. It is going to take more than this to argue that vervets or prairie dogs have words.

Then Slobodchikoff took his work a step further, sending students wearing different colored tee shirts to wander amongst the prairie dog grounds. The animals made their usual human warning but combined it with another sound that varied according to tee-shirt color. It seems the prairie dogs might be speaking phrases. Some scholars object to the proposal because there is no visible reaction to the different bits of color information, but that point misses one of the unusual features of language. Language needn’t produce any reaction at all in the audience. I can sit in a chair for two hours reading a book, showing no response beyond the occasional turning of a page. Yet I can then arise from my chair a changed man. The only way you might discover the change is three months later I say something based on that book.

Suppose that some humans belong to an environmental group and when they go hiking they wear their organization’s green tee shirt. They pride themselves on the way they don’t mess with nature, and they pose no threat to the prairie dog community. But perhaps there is another group, this one a gang of trouble makers who wear red shirts and like to indulge in sadistic torment of the prairie dog, pouring gasoline down the holes and setting it on fire. Suddenly the human/green and human/red cries carry important, distinctive bits of information. I do not know, and the article does not say, but it suggests an area for further research: do the prairie dogs ever make use of the information in their distinctive warning cries?

In my last post I discussed “The Ultimate Test” of a theory about language: could such a system evolve? Is it possible for prairie dogs to have evolved the ability to speak in phrases about events on the earth’s surface? Unfortunately, these animals lead the most important part of their lives underground where observation is difficult to conduct. Just how communal are these animals? They do not seem to be like mole rats, another burrowing mammal, that live like eusocial insects. Mole rats have a reproductive queen while the other females do the labor of the colonies. I know nothing about their communication system, but eusocial insects use elaborate chemical systems to pass the news. Prairie dogs are not this cooperative, but maybe they are at least humanly communitarian, in the sense of sharing a great deal of the burden, joys, food, and information of life with their fellows. If they are heavily into sharing, I can easily imagine an evolutionary process that leads to sharing information through some kind of phrase-based system. But prairie dogs do not seem to live that way. A quick check of Wikipedia shows they are family-based, with rivalries between families and breeding groups. “A prairie dog town may contain 15-26 family groups.” A mix of families that do not share much between them does not sound like fertile soil for evolving a communication system much beyond warning alarms.

Warning sounds are a valuable group benefit that have evolved many times in many non-communal species, and if prairie dogs can make complex, phrase-like warnings, that is an interesting discovery. But warning sounds, even complex ones, are not going to satisfy this blog’s understanding of language.

The definition of language that is used on this blog proposes a triad of (1) a speaker (or signer or writer) and (2) a listener (or observer or reader) paying joint attention to (3) a topic. The prairie dog does not have this triad. First, there seem to be innumerable speakers, who—at best—pass along a message, but more likely act on a reflex that sets many of them to issuing the same signal.

Second, it is not clear that any of the listeners pay joint attention to the intruder. They hear the warning and zip back underground. Like vervets they respond appropriately, but do not seem to attend to it in the same way the speaker does. Why would they? The alarm is a cry for action, not a bit of social bonding.

Finally, they have only one topic: intruders. It may be unfair to demand that animals with a grape-sized brain take much interest in the nature of the world around them, but without it they are not going to discuss many topics.

The triad requires a special kind of community, one in which members are willing to inform one another of secret information, and one in which members are willing to listen and trust what other members report. It also requires that community members be capable of addressing any topic that seems worthy of study. A language restricted to various forms of shouting, “Look out,” would be no language at all.

It is always good to be reminded that we build our nature on powers scattered throughout the biological world, but it is also good to keep in mind that there is a reason for having and not having a power. We live in cultural niches and need language to survive in them. Prairie dogs can do many things that I cannot do, and apparently they can spread the word about my tee-shirt color, but they are not on the royal road to Shakespeare.

The Ultimate Test

I got a letter the other day that presented a theory of language my correspondent wanted me to consider. Regrettably, I doubted his idea could be accomplished by plain old evolution and I told him that I cannot take seriously any account of language that requires a miraculous beginning.

Years ago I read Stephen Pinker’s famous book The Language Instinct. Pinker is a gifted writer and his book is filled with interesting and entertaining facts, but I could never persuade myself to even consider his account of how language works. His system requires a set of modules in the brain for generating sentences. If language had been evolving for 15 or 20 million years I might have said OK, but we have had nowhere near enough time to evolve and perfect the linguistic modules Pinker talks about.

Back in 1970 it struck me that evolution had played an important part in language origins and ever since that time I have required ideas about language origins to make evolutionary sense. So naturally I was delighted when reading Daniel Dor’s chapter, “The Evolution of Language and Its Speakers,” in The Instruction of Imagination, I came across this passage:

The question of the evolution of language… [is] the most crucial bottleneck that any theory of language should be able to squeeze through…. For every theory of language we should thus ask: how is this evolvable? [p. 184]

What makes a language evolvable?

First, language should be adaptive; it should solve some problem. This may seem like an easy one, as language is so generally useful, but we always run into the fact that only humans have language. Why don’t many other species converse, if language is so darned useful? The most obvious answer is that it solves a problem faced only by humans. In writing this blog, I have found the problem of adaptation peculiarly vexing. The work of Michael Tomasello has been particularly helpful. His thesis is that humans alone live in dependent communities where we share things or die.

Many thinkers try to finesse the issue by saying some primary support for language (e.g., recursive capacity, control of the lips, the ability to breathe irregularly while talking, etc.) evolved for some reason other than language and was co-opted by language. But this only pushes the question back a step. Why did that first step evolve? Many scholars seem willing to say the reason is unknown. Dor closely examines the adaptive issue in the notorious Hauser, Chomsky, Fitch paper of 2002 in which the authors propose that language depends on a recursive capacity that may have evolved originally for some task other than generating syntax. Dor groans:

There is nothing here but a weary and desperate attempt to keep the essence of language … away from … evolutionary expression. Of course, capacities may evolve for one function and then be adapted for others, … but in such processes the capacities evolve and change to fit their new functional contexts: they do not stay the same. [187]

Many attempts at evolutionary accounts begin with a genetic mutation that produces some novel benefit. But Dor is strong on the point that mutation need not be the trigger. The environment to which an organism is well adapted may change, tossing the creature into a sink or swim setting. New patterns of behavior will arise and, if they prove helpful, the genes will bring up the rear and evolve to support the new behavior, turning something burdensome into something easy.

This explanation may seem scandalously Lamarckian, urging evolution based on traits developed behaviorally rather than genetically. I wondered if Dor was going to say the giraffe got its neck by stretching. But there is a sound, Darwinian process in which behavior can precede genetic change. Known as the Baldwin Effect, it allows for selection based on behavior. Suppose a species is confined to a single mountain valley and the valley suddenly becomes uninhabitable. Some of the species members die, and some are able to find a mountain pass that lets them escape to a new environment where they (with difficulty) survive. The members that died are out of the story. The descendants come from those who for whatever reason escaped and over time we would expect a series of genetic changes that allow them to do well enough in the new setting.

There have been many attempts to explain language origins in Baldwinian terms, but the work of Morten Christiansen and Nick Chater has established an important limitation. The genetic support for the new behavior comes slowly, but cannot come so slowly that the behavior often changes before the new genetic structure can be fixed. I do not think Dor’s account is clear enough on the limits of flexible (or plastic) behavior.

The qualities that made Latin Latin, for example, could not be genetic because well before the Latin genes could be fixed the language moved on to become French, Spanish, Romanian, etc. This limitation puts the rules of vocabulary, syntax, and phonetics outside the range of the Baldwin effect, and since those rules are the main elements of any language, we have to wonder what is left to evolve.

The answer is surprisingly rich. The psychological supports for language are universal and they include our compulsion to learn to speak (when young) and our compulsion to speak when we witness something amazing, our ability to remember what we are talking about so that we can understand pronouns, our ability to organize the directing of another’s attention, and so on. All of these features could trace to Baldwinian plasticity rather than a mutation.

One complaint I do have about this critically important chapter is that it does not devote enough attention to the issue of selection. Can it really be true that a way with words is important to an individual’s survival capacity or ability to leave descendants?

My mother once told me that she fell in love with my father partly because of his unusual way with words, yet I still have a hard time believing that glibness is a trait that increases descendants. Many inarticulate adults have large families.

On the other hand, I can readily imagine a group of people out-surviving their neighbors because their linguistic skills make them better able to act cooperatively. Ergo, I lean toward group explanations of linguistic selection.

Dor does not have to do the same, but I wish he had more fully addressed the problem of how and why language-supporting traits were selected. He brought such diligence to the rest of this chapter.

How Language Got to Be This Way

The first [question lying behind my work] is, why is language as it is? Mankind could have evolved an enormous number of different semiotic systems; why did they evolve a system which has these particular properties that language has? – M.A.K. Halliday

I have been reading a series of interviews with the Australian linguist Halliday and I ran across the above passage. Derek Bickerton asks this question as well. So it crossed my mind to see how far along I have come on this blog to answering it.

New functions, of course, do not evolve out of nothing. They take what they have and build on it. In language’s case it is plain that one of the things we took is the vocalization system that already existed in mammals generally and primates particularly. Apes do a lot of screeching. We kept up that part, but at the same time we tightened our controls over the sounds we make. We got rid of the ape air sacs that make sounds louder but less distinctive. We gained a finer control over our tongues. We developed the ability to prolong our exhaling without becoming giddy for lack of oxygen. These sorts of things are all routine evolutionary adjustments and carry few theoretical surprises. If they comprised the whole story, there would be precious little reason for language’s exclusivity. All apes would be talkers, having long ago adapted their vocalizing apparatus. Yet that did not happen, so there needs to have been some sort of trigger, a reason to adapt vocalizing beyond the limits reached by apes.

The benefits of language seem clear enough. Speech helps organize group efforts. A further benefit is the rise of traditions that pass hard won knowledge to new generations. Yet there must be more, or else apes too should be talking. Wouldn’t chimps benefit by being told, “I saw leopards off to the left and ripe mangos to the right”?

The problem with any group benefit is the greedy individual. That’s the guy who takes what the group provides and keeps his own discoveries to himself. If he is warned of leopards to the left, he goes right. But if he knows of mangos to the right, he keeps the secret to himself and lets the others wander as they will. The greedy guy has a slight survival advantage over those who share, and in evolution a slight advantage is all it takes. Over the long run, the greedy guy’s genes will out, so silence prevails.

There is, however, a case where silence does not benefit the greedy. That’s when individuals are so interdependent that they hurt themselves when they by hurting others. They cannot afford to let others stroll toward leopards even if stopping them means getting fewer mangos. This kind of development is very rare in the biological world, and tends to come late along an evolutionary trail. The most familiar example are eusocial insects like termites, ants and bees. From a mammalian perspective, they are very old, but by insect standards they are new boys on the block. They are also extremely successful, accounting for much of the world’s insect life and having found niches around the globe. They too share a great deal of information that makes cooperation much easier. Humans too are recent mammals who depend on one another for mutual survival. In such a situation, communication is not just tolerable; it is a necessity.

At the same time, the ability to tell strangers apart becomes important. Grasshoppers needn’t worry about friend or foe distinctions. No other grasshopper is a friend. Ants, however, need to spot their enemies. Ants from other colonies do not smell right and are put to death. Humans live more subtle lives and may not put strangers to death, but they still need to distinguish the trustworthy tribal members from the outsiders. A big clue comes from language, like the famous biblical tale (Judges 12) in which enemies were spotted by their inability to pronounce the Hebrew word shibboleth. This being a bible story, those who could only say sibboleth were killed. Another biblical example is in the Gospels (Matthew) when a serving girl in an inn says surely Peter is a follower of Jesus as even his accent gives him away. The advantage of telling friend from foe is probably one reason most all of language is not hard wired in the brain. People can hear the strangers among them and (at the tribal level) know who is trustworthy enough to be told a secret.

And what secrets shall we share? When language was new and taking its basic shape, the richest form of knowledge enjoyed by these suddenly talkative apes was perceptual. They recognize shapes, sounds, and scents. They can see threats and opportunities, and they can navigate their way through space, so the most powerful way to structure language among a group of trusting apes is to share perceptions. If I saw mangos off to the right, I can share that knowledge by saying mangos and pointing. In this way I am directing another’s attention in a particular direction and introducing a topic. The role of attention in language is more controversial, but on this blog meaning comes from directing attention and syntax provides a way of shifting attention while holding several focal points of attention together. Once language got rolling, abstract ideas could be expressed as well, but they are expressed as perceptions. Your infidelity has shattered my trust in you. Infidelity and trust are both abstractions, yet they are expressed as objects in space that can act and be acted upon.

So why did we evolve a system with the properties of natural languages? Given the fact of vocalization and interdependence, we overlaid the sound system with a way of sharing attention and the perceptual knowledge it brings. This communication system never hardened into a hereditary system, as it did among eusocial insects.  Over the long generations, language became more elaborate and powerful than it was for the first talkers, but the foundations of culture, community and a perceptual way of knowing are still built into our primary means of communication.

Can Languages Evolve?

Note: This post continues a discussion of the book Creating Language by Morten Christiansen and Nick Chater. For previous posts see here and here.

The authors turn generative grammar on its head by asserting that language evolves to fit the brain rather than vice-versa. It is an appealing idea, but how literally are we to take this word evolution? How many features of biological evolution are visible in linguistic change?

Have Linguists Been Barking Up the Wrong Tree?

Inquiring into language’s origins can seem like a quixotic adventure, but it does bump you into the heart of the classical humanist question of what makes a human human. Two issues in particular stand out:

1. How much of language is cultural and how much inborn? This is a variant on the widespread dispute about nature or nurture, but it provides a specific focus. It does not seem unreasonable to think the question might have an answer.
2. Why is language so different from other animal communications? Animal signals are nothing like sentences, either in semantics, syntax, or vocabulary. Other animals do not discuss topics together. They do not construct a body of lore that can be useful at some later date. They cannot call the dead to mind by the simple expedient of speaking a name. Yet, how can we square the differences being so great with the Darwinian premise that species do not evolve powers they do not need to survive? A prey animal needs to evolve the ability to outrun its predators by only a little bit. No need to run at 100 miles per hour when the fastest predator can only go 50.

Scribbles on a Blank Slate

I received an unexpected e-mail from the Dutch zoologist/cognitivist/linguist Johan Bolhuis that, among other things, asked rhetorically, “How do you evolve a blank slate?” He was referring to John Locke’s famous metaphor for the human mind of the newborn baby. We are born, said Locke, with a blank paper on which experience writes what we learn. The image gained a powerful place in western philosophy and afforded one more separation between humans and animals. Humans learn what their world teaches them and what they figure out; animals, meanwhile, live by instincts.

Although I have thought about the issues behind Bolhuis’s question for many years, I don’t think I have ever heard the matter put so bluntly and neatly. If animals have instincts and humans have blank slates, and if humans evolved from animals with instincts, how did we come to replace those instincts with a blank slate?

Ideas v. Perceptions

Whale anatomy shows flippers evolved from hands. Likewise modern abstract sentences have the anatomy of perceptual statements.

My last post discussed the main thesis of my paper, “The Evolution of a Hierarchy of Attention,” included in the book Attention and Meaning. A secondary theme in the paper concerns the problem of whether language was based originally on perception or mentalese, Steven Pinker’s term for innate concepts built into the brain. Presumably, these concepts take the form of brain circuits. Defenders of the mentalese-origin like to point out that we can speak in purely non-perceptual terms, e.g., “Justice is justice only when it is merciful.” There are no concrete nouns in that sentence and no metaphorical verbs or prepositions, yet it seems perfectly intelligible. I can imagine a teacher throwing that sentence out to a class to discuss in an essay. So it appears undeniable that modern language does not have to say things that are visualizable or expressible by the evocation of any of the other senses. Some smart people insist that since we do not need to speak in perceptible terms, language cannot be based on paying attention to perceptible things. Indeed, that attitude dominates linguistics and cognitive psychology in general (with some important exceptions).