Tag Archives: language evolution

Talk Like a Neanderthal Day

Like “Talk Like a Pirate Day,” but more scientific!

Human language is probably more than One Weird Trick. It’s multiple weird tricks. We’ve already posted about phonemes, and how they can be strung together to make words. That’s (at least) one trick. And then words are strung together to make phrases and sentences: but there are a multiple weird tricks here as well. Consider this quotation from some language researchers:

Every human language sentence is composed of two layers of meaning: a lexical structure that contains the lexical meaning, and an expression structure that is composed of function elements that give shape to the expression. In the question, Did John eat pizza?, the lexical layer is composed of the words Johneatpizza … The sentence also contains did, which has two functions: it marks tense, and by occurring at the head of the sentence, it also signifies a question. (Miyagawa et. al.)

The lexical level of language includes content words: nouns, most verbs, adjectives. The expressive level contains functional words (auxiliary verbs, conjunctions, articles, and so on), as well as tenses and other inflections, and even functional operations like moving around the parts of a phrase. We can think of a sentence like a piece of carpentry, a bookshelf, say. A typical bookshelf will consist of the parts that hold things up (shelves, sides, etc., analogous to lexical structure), and parts that fasten these parts together (dowels, screws, bolts, nuts, nails, glue, etc., analogous to expressive structure).
bookshelf1
So language gets its open-ended expressive power by fastening together expressive and functional constructions in (more-or-less) alternating levels.

But there are other ways to build furniture. For example, here’s a desk with no fasteners. Instead, the load bearing parts have slots and tabs that fit together. This is simpler but less flexible than having boards and fasteners that you can put together however you see fit.
bookshelf2

The analogy with language would be a protolanguage with nothing but content words – nouns, verbs, and adjectives, say – and lexical structure. The analogy works because verbs come with built in slots that nouns can fit into, even without any extra “fasteners” to hold them together. Linguists call this the “argument structure” of a verb. (Think about functions and their arguments if you’re into math or computer science.) For example fear and frighten are both transitive verbs, but they have different argument structures

  • Carg fear thunder.
  • Thunder frighten Carg.

In one case the experiencer goes in the subject slot, and the agent goes in the direct object slot. In the other case it’s the reverse. Some verbs, like burn, have more than one argument structure.

  • Carg burn meat.
  • Meat burn.

English verbs have some tens of different argument structures. (Note that I haven’t put any tense on the verbs. That would be part of expressive structure, which we’re leaving off here.)

So a protolanguage, one step along the way to a full blown language, could consist of a bunch of verbs and their argument structures, together with nouns slotted in the appropriate spaces as needed, and adjectives added to convey additional information. Is this what Neanderthal language was like? There is evidence that Neanderthal ancestors as far back as 430,000 years had hearing specialized for the frequencies of speech. (This is not the case with chimpanzees, or earlier hominins.*) But we don’t know yet how complex Neanderthal speech was. Eventually, as we figure out the genetics of language, we’ll find out. For now though, let’s make today – just about the last day on Logarithmic History that Neanderthals are around – “Talk Like a Neanderthal Day.”

Carg build shed. Carg nail trim today. Carg publish blogpost now. Tonight Carg dance. Goodbye!

*My spellchecker keeps changing “hominins” to “hominids.” Get with the 21st century, spellchecker!

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Learn This One Weird Trick (Part Two)

… that humans use, and now you can too! (Continued from the previous post.)

recursion 3) Recursion. What if you have one mirror facing a second mirror, so the first mirror shows what’s in the second mirror, which shows what’s in the first mirror …? What if you take a chameleon, which tries to take on the color of its surroundings, and put it on a mirror? What if you point a video camera at the very screen that’s showing what the video camera is pointing at? What if (getting mathematical) you use a function in defining that same function? What if you use the cleaning attachment from your vacuum cleaner to suck dust off the vacuum cleaner itself? (Okay, the last one is a bit lame.) The basic idea in each of these cases is called recursion, which is a major concept in mathematics and computer science. Douglas Hofstadter’s Gödel, Escher, Bach is all about recursion. Some people think recursion – nesting ideas about ideas inside one another in a potentially infinite hierarchy, or (for syntax) phrases inside phrases — is central to human uniqueness. Noam Chomsky has lately been pushing a hard-core version of this argument. Here he is with Robert Berwick defending his view.

Related to the idea of recursion is the idea of “meta-representation”: not just having ideas about the world but having ideas about ideas, being able to put a box around a proposition, and then attaching a tag to it that says the equivalent of “This is true” or “This is false” or “This will be true later” or “Suppose this were true,” and then manipulating it accordingly. A nice little essay in “imagination,” elaborating this idea, is here from Simon Baron-Cohen, best known as an authority on autism.

4) Shared intentionality. Suppose you and I are friends with a couple, Fred and Wendy Smith. I tell you “I saw Wendy Smith kissing a man in the park yesterday.” Logically speaking, there’s nothing to say the man wasn’t Fred. But you’ll probably assume that I meant she was kissing someone other than Fred. Why? Well if the man had been Fred I could just as easily have said “I saw Wendy Smith kissing Fred in the park yesterday.” Since I didn’t say that, you assume I mean to convey the man wasn’t Fred. Note this only works if both of us try to pack as much relevant information into our sentences as possible and know the other person is doing the same. (If you think this sounds like recursion, you’re right.) Back in the 1950s, Paul Grice, a philosopher, worked out a lot of how we pack non-literal meanings into sentences. But the same principles are at work even when people are communicating non-linguistically. This leads to another theory of human uniqueness: human beings are uniquely good at developing shared intentions with one another: each party knows the other party is trying to communicate something, so they converge on the correct answer. People may have been doing this even before language evolved. Following up on this can quickly get you into game theory, where a central concept is “common knowledge”: not just “I know X” and “You know X,” but “I know X,” and “I know X is common knowledge,” and similarly for you. Here’s a philosophical treatment.

scleraBut you can skip the philosophy if you want and move on to a telling little piece of anatomy that’s relevant here. In most mammals, including chimpanzees, the sclera (white of the eyes) is not visible. It’s hard to tell where a chimpanzee is looking, easy for a human. Human eyes make it easy to cooperate in sharing attention, a first step in developing shared intentions. If you know your card games, chimpanzees are playing poker, humans are playing bridge.

Our discussion of human uniqueness on Logarithmic History has been frustratingly short on specific dates. But human sclera are probably a fairly simple trait genetically, and we may soon enough discover the genes involved and even tell how long ago they mutated.

Learn This One Weird Trick … (Part One)

… that humans use, and now you can too!

There are people who think that human beings are nothing special. Sure (the argument goes) people have uniquely large brains. But all sorts of creatures have unique features. Elephants are the only animals with trunks. Tamarins and marmosets are the only primates that give birth to twins. Platypuses are the only venomous mammals. Spotted hyenas are the only mammals whose females sport pseudo-penises (through which they give birth!). And so on. If we could ask members of these species they’d claim that they’re the special ones.

But of course we can’t ask them, and in any case, this isn’t a very convincing argument. Human beings have an absolutely outsize impact on the Earth, and the advent of human beings looks like one of the major evolutionary transitions, comparable in importance to the origin of the eukaryotic cell or multicellular life. But even if we buy this, it still leaves open the question of whether there’s a key adaptation – a One Weird Trick – that accounts for the exceptional course of human evolution. Here are some candidates that being are being batted around these days:

1) The cognitive niche. The basic idea is at least as old as Aristotle, that human brings are defined by their capacity for Reason. A modern version of this is advocated by evolutionary psychologist John Tooby and cognitive scientist Steven Pinker. Pinker in particular has elaborated the argument that humans are uniquely adapted to acquire and share knowledge, by virtue of a suite of cognitive, social, and linguistic adaptations. We’ve already touched on several aspects of this: Human beings seem to have taken the capacity for thinking about physical space and retooled it for thinking about the abstract cognitive space of possession – a social relationship. (Other abstract cognitive spaces include kinship, time, and change-of-state.) And humans seem to harness the machinery for processing the sounds of interacting solid objects in creating major categories of phonemes. For a more complete exposition, here’s an academic article by Pinker, and a talk on youtube.

2) Culture. Rob Boyd and Pete Richerson, who’ve done a lot of mathematical modeling of cultural evolution, are skeptical about the “cognitive niche” argument. Too much culture, they argue, is things that have been learned by trial-and-error, and are passed on from one generation to the next without people understanding why they work. Boyd and Richerson appeal, as anthropologists have for generations, to the importance of culture. We mentioned earlier their argument that the frequency of climate change in the Ice Age was nicely calibrated to favor social learning rather than individual learning or instinct. Joseph Henrich provides a recent defense of the importance of culture. Contra Pinker, he thinks humans often don’t have a good cause-and-effect understanding of the things they do, but depend heavily on imitation and the accumulated wisdom of the elders.

Coming up: Part Two. Recursion and Shared Intentionality

Hits, slides, and rings

Part of the challenge of language is coming up with some way to distinguish thousands or tens of thousands of words from one another. It would be hard to come up with that many unique sounds. What human languages do instead is to come up with phonemes and rules for stringing phonemes together into syllables, and then create words by arbitrarily pairing up one syllable, or a few, with a meaning. Phonemes are the individual sounds of a language, roughly comparable to individual letters. There are about forty phonemes in most dialects of English. (English spelling does a pretty sloppy job of matching up phonemes and letters. Finnish comes close to one phoneme per letter.)

Often in evolution organisms don’t solve new problems from scratch, but instead harness preexisting adaptations. I argued earlier that the abstract “space” of possession (“The Crampden estate went to Reginald.”) may have developed by harnessing preexisting concepts of physical space. And our abilities to recognize speech sounds may harness our preexisting capacities for recognizing the sounds of solid objects interacting. At least that’s the argument of a recent book by Mark Changizi, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.

Changizi notes that even though we’re mostly not aware of it, we’re very good at using our hearing to keep track of what’s going on in our physical surroundings. For example, people easily recognize the difference between someone going upstairs and someone going downstairs, and we’re pretty good at recognizing individuals by their treads. The sounds that solid objects make can be broadly categorized as hits, slides, and rings. Hits: one object collides with another and sends out a sharp burst of sound. Slides: an object scrapes against another and sends out a more extended sound. Rings: an object reverberates after a collision. Changizi argues that these correspond to the major categories of phonemes.

  • Hits = plosives, like p b t g k
  • Slides = fricatives, like s sh th f v z
  • Rings = sonorants, including sonorant consonants, like l r y w m n, and vowels

These are not the only sounds we can make with our mouths. We can do barks and pops and farts and so on. But our auditory systems are especially cued into solid object physics, so when we try to come up with easy-to-distinguish phonemes, that’s what we focus on. And a lot of rules about how phonemes hook up also follow from this principle – for example hits followed by rings are more common than the reverse.

There’s surely more going on with speech sounds than Changizi allows for. But if imitating nature is not the whole story of phonemes, it may at least be where they got started.

Later on when we talk about writing systems, we’ll see there’s a similar argument about how these are tuned to tickle our primate visual systems.

Speech sounds

562-532 thousand years ago

Below are some reflections on language. There will be plenty more in days to come. For a science-fictional take on language, try Octavia Butler’s account of a world where language has disappeared, Speech Sounds. It’s one of her best. It won science fiction’s Hugo Award for best short story in 1984.

We’re now six months through the year 2016 at Logarithmic History. We raced through time at the rate of 754 million years a day on January 1. December 31 we’ll cover just one year per day. Today, June 30, covers 30,714 years, from 562,439 to 5531,726 years ago.

By today’s date, the universe is a lot more complicated than when we started. As we mentioned before, one of the major sources of complexity is the origin of new discrete combinatorial systems, made of small units that can be combined into larger units that have different properties than their constituents. Elementary particles are the first discrete combinatorial system to appear, already present in the early moments of the Big Bang. The different chemical elements are another major discrete combinatorial system. It took billions of years for enough heavy atoms, beyond hydrogen and helium, to accumulate from stellar explosions, allowing the complex chemistry and geology that we know on Earth. It may be that the paucity of heavy elements in the early Universe is what prevented earlier planetary systems from developing complex life.

With the origin of life comes another discrete combinatorial systems, or rather two connected systems: nucleotides strung together to make genes, which code for amino acids strung together to make proteins.

For the second half of the Logarithmic History year, we’ll be spending a lot of time looking at the consequences of another discrete combinatorial system: language. Or maybe, as with genes-and-proteins there are really two systems here: words strung into phrases and sentences, and concepts strung together into complex propositions in a Language of Thought.

The origin of modern human is one of the major transitions in evolution, comparable to the origin of eukaryotic cells, or of social insects. Language is crucial here: ants organize high levels of cooperation by secreting pheromones. Humans organize by secreting cosmologies.

It’s a small world after all!

592-560 thousand years ago

The story of human origins is partly a story of Big Things like the Taming of Fire and the Dawn of Speech. But it’s also the story of some odd byways and quiddities. A nice introduction to some of these is Chip Walter’s book Thumbs, Toes, and Tears: And Other Traits That Make Us Human. (His more recent Last Ape Standing is good too.) Walters considers funny bits of anatomy like our unique big toes and thumbs, and funny bits of behavior like our habits of laughing, weeping, and kissing. Toes and thumbs fossilize, but behaviors can be hard to date, evolutionarily. Presumably these behaviors appeared sometime before modern humans evolved and spread, so let’s pick today’s date. It’s also hard to figure out the exact evolutionary rationale for some of these behaviors. Humor, for example, is not a simple phenomenon: intellectually appreciating a joke, actually finding it funny and enjoying it, and finally laughing, each involve separate areas of the brain.

Laughter, specifically, is a minor human oddity that sheds an interesting light on some big events in human evolution. Robert Provine, a leading laughter researcher, spells out the argument in “Curious Behavior: Yawning, Laughing, Hiccuping, and Beyond.” Chimpanzees have a kind of laugh, a modified vocalized panting synchronized with inhalation and exhalation. Presumably laughter first resulted when panting-during-play evolved into a play signal. But the short bursts of human laughter go further, having freed themselves from synchrony with the inhalation/exhalation cycle. Laughter, in other words, is just one instance of the more general phenomenon of humans having separate controls for vocalization and for respiration. Interestingly, the most prominent examples of complex vocalization – songbirds and some other birds, whales, bats, and humans – are all found in non-quadrupeds. In quadrupeds, breathing is tightly coupled with locomotion: lungs need to be full to stiffen the thorax when the forelimbs hit the ground. Giving up quadrupedalism seems to have allowed for an “adaptive release” in the evolution of vocal abilities in a number of unrelated lineages. So the study of laughter (and other vocalizations) suggests that two key human adaptations – bipedalism and spoken language – are more closely linked than one might have expected.

Another and overlapping set of human particularities involves facial expressions of the emotions. Darwin got a whole book out of this. He concluded (admittedly based on somewhat anecdotal methods) that different emotional expressions are largely innate. It’s an interesting illustration of his ability to reason from small facts to large conclusions that he also drew a big conclusion about human evolution from this. In Darwin’s day, there were scientists who believed that different human races had evolved from very different prehuman progenitors: one prehuman species giving rise to Europeans, another to Africans, and so on. But Darwin reasoned that the very close similarity in facial expressions (and he had traveled a lot, and witnessed a lot of expressions in a lot of places) and the very similar emotional makeup of humans around the world was evidence that human populations shared a fairly recent common ancestry. Here as in several other cases, a mixture of close reasoning and sheer luck led Darwin to the correct conclusion about evolution long before there was much solid evidence.

Darwin’s work on emotions was neglected for most of the twentieth century by anthropologists favoring a blank slate view of human behavior, but was eventually largely vindicated by a number of researchers, notably Paul Ekman. There is now good evidence for six basic facially expressed emotions: Fear, Disgust, Joy, Anger, Sadness, and Surprise.

If you’re a movie watcher, this list may seem familiar. These emotions (all except for Surprise) are all depicted as little homunculi living inside the head of an 11 year old girl in the animated feature “Inside Out.” (The movie gets a strong thumbs up from Logarithmic History). Somebody at Pixar Studios knows their Ekman.

insideout

So the sappy song is right: There is just one moon and one golden sun, and a smile means friendship to everyone.

Talk Like a Neanderthal Day

Like “Talk Like a Pirate Day,” but more scientific!

Human language is probably more than One Weird Trick. It’s multiple weird tricks. We’ve already posted about phonemes, and how they can be strung together to make words. And then words are strung together to make phrases and sentences: but there are a multiple weird tricks here as well. Consider this quotation from some language researchers:

Every human language sentence is composed of two layers of meaning: a lexical structure that contains the lexical meaning, and an expression structure that is composed of function elements that give shape to the expression. In the question, Did John eat pizza?, the lexical layer is composed of the words John, eat, pizza … The sentence also contains did, which has two functions: it marks tense, and by occurring at the head of the sentence, it also signifies a question. (Miyagawa et. al.)

The lexical level of language includes content words: nouns, most verbs, adjectives. The expressive level contains functional words (auxiliary verbs, conjunctions, articles, and so on), as well as tenses and other inflections, and even functional operations like moving around the parts of a phrase. We can think of a sentence like a piece of carpentry, a bookshelf, say. A typical bookshelf will consist of the parts that hold things up (shelves, sides, etc., analogous to lexical structure), and parts that fasten these parts together (dowels, screws, bolts, nuts, nails, glue, etc., analogous to expressive structure).
bookshelf1
But there are other ways to build furniture. For example, here’s a desk with no fasteners. Instead, the load bearing parts have slots and tabs that fit together. This is simpler but less flexible than having boards and fasteners that you can put together however you see fit.
bookshelf2

The analogy with language would be a protolanguage with nothing but content words – nouns, verbs, and adjectives, say – and lexical structure. The analogy works because verbs come with built in slots that nouns can fit into, even without any extra “fasteners” to hold them together. Linguists call this the “argument structure” of a verb. (Think about functions and their arguments if you’re into math or computer science.) For example fear and frighten are both transitive verbs, but they have different argument structures

  • Carg fear thunder.
  • Thunder frighten Carg.

In one case the experiencer goes in the subject slot, and the agent goes in the direct object slot. In the other case it’s the reverse. Some verbs, like burn, have more than one argument structure.

  • Carg burn meat.
  • Meat burn.

English verbs have some tens of different argument structures. (Note that I haven’t put any tense on the verbs. That would be part of expressive structure, which we’re leaving off here.)

So a protolanguage, one step along the way to a full blown language, could consist of a bunch of verbs and their argument structures, with nouns slotted in the appropriate spaces as needed, and adjectives added to convey additional information. Is this what Neanderthal language was like? We don’t know yet, but as we figure out the genetics of language, we’ll find out. For now though, let’s make today – just about the last day on Logarithmic History that Neanderthals are around – “Talk Like a Neanderthal Day.”

Carg publish blogpost now. Next Carg get Mother brunch. Carg and Mother eat brunch. Goodbye!