Sunday, June 22, 2008

Thriller-Writer Lee Child and Linguist Dieter Wunderlich on the Evolution of Language


Lee Child is one of my favorite Thriller-authors. Normally I don’t find the time to read non-studying related fiction, but I especially enjoy his audio books because of the cool American accent of the narrator. However, when I stumbled on an essay by Lee Child called “The Origin of the Thriller”, I was a bit confused. Here’s his take on the evolution of language: According to Lee Child, a couple of hundred thousand years ago, Neanderthals and humans, the only homo “contenders” left were competing for resources, and Neanderthalers had the upper hand:

“They were heavier and stronger and faster. They were superb tool makers. They were much better equipped to survive the brutal conditions of prehistory.

But they didn't survive. We did. Why?

Because Homo Sapiens developed language. Many primitive species could communicate by making sounds — and many still do: prairie dogs make distinctive noises if a predator is spotted — one noise for a ground predator, and another for an airborne predator. But Homo Sapiens went beyond two words. After a random mutation our brains grew large and the new capacity was colonized by language, with a theoretically infinite number of available words, and more importantly with syntax, such that as well as reporting we could plan and speculate. Not just: a predator is coming, but also: a predator will come, or might come. Not just reaction, but also prediction: if we do this, we'll be OK, or if we do that, we'll be in trouble. “

But here’s the gem According to Child, humans are weak and fragile and in disorganized groups we would quickly be killed by predators:

“But a coordinated crowd of two hundred humans is the most powerful animal on earth. The heaviest, the strongest, the hardest to stop, the hardest to kill. Thus, grunting Neanderthals slowly died out, despite their muscle and bone and strength and speed, and talking humans marched on toward the present, despite our slender limbs and fragile skulls”
The last Sentence is faboulus isn’t it? We better don’t tell him anything about Neanderthal-DNA, Neanderthal Vocal Anatomy, FOXP2, Introgression, etc.

But I want to present a more plausible and worked out view on the topic. Yesterday I was searching for material on the evolution of syntax, because a friend of mine asked me to comment on a section of his MA-Thesis in which he shortly discusses the topic. (For a discussion of the speculation, that certain features of language are ‘living fossils’, or vestiges of an older proto-language, see this post).

On my search I found the slides of a talk given by German linguist Dieter Wunderlich on the evolution of language, that he held in Leipzig, Germany, in December 2007. The talk and the slides are in German, but because he offers a very comprehensive and nice review on some aspects of the current state of the art in language evolution research/evolutionary linguistics, I decided to write an English summary of it.


Key Questions

When looking at the evolution of language, there are three question that guide our inquiry:

1. How exactly did language get started? What is hotly debated is whether it evolved in a gradual manner (continuist/adaptationist position: see e.g. Pinker & Bloom 1990) or in a ‘sudden leap’ (discontinuist/ exaptationist: see e.g. Hauser et al. 2002)

2. When did language evolve? Depending on our answer to question 1., the question would be when each step toward language took place, or when the big leap happened.

3. Did language evolve only once or several times?


What is language?

Basically, language can be described as a system for expression, that relates Utterances and meaning to one another, in relation to certain contexts.

Morphosyntax governs the construction of complex utterances out of smallest units of language, namely lexical entries (=”words” in your mental lexicon) as well as morphemes (-s, -ed, un-, -er, etc.). Its system is compositional, that is every construction leads to complex expressions of meaning which are determined by the single lexical entries as well the rules that govern their combination. The rules governing the compositional construction of utterances are recursive.

There are two interfaces to non-linguistic abilities:

1. an interface with the system responsible for the production and perception of sounds and gestures (In generativist terminology this would be the Sensori-Motor System (SM) or the Articulatory-Perceptual (AP) System)

2. an interface with our mental representations and our discourse intentions (in generativist terminology: the Conceptual-Intentional (CI) system. cognitive linguists would probably call it our conceptual system)


Important events which shaped the current state of language

There are 5 important events that have shaped how languages and our mental structures that enable us to use it look:

In chronological Order:

1. There was an expansion of the cortex (frontal lobe) in early hominids such as homo erectus, who lived approx. 2 million years ago. In just 1 million years, brain size rose from 600 to 1400ccm. This may be related to the begin of an ice-age about 2.5 million years ago.

2. Anatomically modern man (homo sapiens) probably evolved about 170.000 years ago in east Africa.

3. Starting from about 50.000 years ago, there is archaeological evidence of improved tool-making capacities, burials, ornaments, and figurative art in several parts of the world (the so-called Upper Palaeolithic Revolution). In Africa these features can be found even earlier, as is especially salient from about 85.000 years ago, which even led some researchers to call this period an “African Upper Palaeolithic” (see e.g. Dubreuil 2008).

4. From 12.000 years ago onwards, there was a spread in agriculture which seemed to have happened independently in several parts of the world (The Neolithic Transition)

5. Starting from 6000 years ago, writing systems were developed independently in several parts of the world.

Of these 5 events, the first three are biological of nature, whereas the last two are cultural events. A diversification of biological events brought about by mutations and selection led to one single event: genetically modern man. In principle, every human being can reproduce with every other opposite-sex human, which fulfils the criterion of biological species. Furthermore, every child, regardless of its parents, can learn every language of the world when it is put into the critical environment at the right age. Thus language is a common and uniting feature of humans, and we all share the genetic structure that enables us to learn language (but for evidence that there is still genetic variation on a small scale, see these two posts)


What are the differences between and non-human communication systems?

Influential linguist Charles F. Hockett has posed 13 ‘design features of language’, 7 of which are especially interesting regarding the evolution of language. These are:


1. For the majority of human languages, the vocal-auditory channel the basic mode of communication.


2. Parity/Interchangeability: hearer and speaker constantly switch roles during conversation, which also means that a communicator is able to both produce and receive the same signal, which isn’t the case with say, gender-specific calls in sticklefish.


3. Semanticity/Arbitrarines: specific signals can be equipped with specific meaning in a manner where there is no necessary or logical connection between form meaning (“table” has nothing to do with any actual properties of a table)


4. Displacement: humans can talk about things that are not present in their immediate environment, or even things that do not exist at all (say, for example, my comprehension of mathematics). Human reference thus extends “beyond the horizon” and the perceptual space, but extends to mental spaces and shared systemic spaces.


5. Honey bee communication about the location of nectar of course is also displaced, but it only built to convey very specific information, and is not unbounded and productive like human language.


6. Traditional Transmission/Learnability human children are able to learn the language of their environment. As W.v.O. Quine said “language is a social art”, which essentially depends on the ability to be part of and interact with a complex culture that transmits complex behavior and knowledge. This complexity and language-specificness is probably the dividing feature, because song-birds also have to learn their songs from other birds, vervet monkeys need to be reinforced in their innate tendencies to hiss at snakes and have to zoom in on the exact referent for eagle alarm callas through positive reinforcements by other group members, and chimpanzees have been shown to adhere to some forms of social transmission and conformity as well as for rational imitation (e.g. Whiten et al. 2005)


7.Discreteness/Duality of Patterning the smallest units of language combine with each other in a systematic and combinatorial manner (that is Phonemes/Sound units combine to form Morphemes) , which then also combine in a systematic fashion (Morphemes built whole words and then sentences). This method allows for “infinite expression by finite means” (Humboldt) and is responsible for the diverse displaced productivity of language.

Wunderlich argues that homo erectus already possessed most of these features, but maybe not 6. and 7.


So what could homo erectus do?

Although he certainly didn’t have full-fledged human language, he was able to perform complex and social tasks. From 1.5 million years ago onwards, he was able to keep a fire burning, and from 0.8 million years ago he could even make fire.

He was able to make hand-axes (1.4 million years ago) and was also able to throw them, which, according to William Calvin, is suggested by neuropaleontological evidence. He way able to hunt together with other group members. He was very mobile: signs of him can be found in Georgia (1.8 million), later on there are also signs in China, Indonesia, and Europe.

Homo erectus was divided in several species that probably lived alongside each other. The last ones co-existing with us were the Neanderthals.


Tool use

Chimpanzees and orangutans use tools (see here, for a cool post on spear fishing in orangutans)such as sticks for termite fishing, stones to crack open nuts, and leaves to soak up water, but these tools are contextually available, that is they do not have to be crafted in the same complex way as hand-axes, for example. Interestingly, there is population level handedness of 2:1 in chimpanzees. Termite fishers are mostly left-handed, whereas nut-crackers and wadge-dippers are mostly right-handed, this means that handedness seems to be heritable. In humans, the left-right ratio is 9:1. The distribution of handedness means that handedness is task-specific, and “

that the motor and cognitive demands of different tasks can have a significant influence on handedness in human and nonhuman primates” (Lanson & Hopkins 2005).
This means
“that antecedents of lateralization of function associated with hand use were present at least 5 million years ago, before the Pan-Homo split,”
and that due to tool-use the human-brain specialized, probably making possible further changes in human neurology and cognitive behaviour (for evidence that there is a neurological link between tool-making and speech, see this post). It is interesting to consider what the cognitive preconditions were that enabled tool-making. The Oldowan technique, which
can be found from 2.6 million years ago. This technique is used to make cutting tools by breaking off sharp-edged flakes from a larger stone. This is achieved by striking a core stone with a hammerstone, thereby knocking flakes from the core (see Ambrose 2001).


This technique definitely requires intentional planning that isn’t bound to the here-and-now, but directed at the future. Also, and more important for language, it requires the ability for complex propositional thought. Thus the following conscious key cognitive mechanisms found in language are also necessary for tool-making and thus already existed 2.6 million years ago:


1. Predication: the same referent (core stone), can be subject of different predications, a structure that can be called “Topic-Comment”-structure (see also this post):

George (Topic) is eating brains (Comment) / George (Topic) is a Zombie (Comment) / George (Topic) is (Comment).

2. Qualification of predications that have already been made and higher-order temporal hierarchical ordering.

To wit, what this basically means is that both in linguistics and tool-making you first have an initial structure which you change by commenting/acting on it. This new structure can then be the topic of new comments or actions, and the new structure arising from these computations/ actions can again be the topic of new predications and ad infinitum. Consider for example the sentence: The living homeless, who wanted money, had infested South Park, but then they went to California

A hierarchical behavioral sequence like toolmaking seems to have similar properties:


I don’t know about you, but for me this looks like recursion, the only difference being that for toolmaking the recursive operation are applied to a physical object, and for language they are applied to a mental object. However, if toolmaking requires intentional planning, there had to be at least some recursive mental operations that in mental action planning. This would mean that, pace Hauser et al. (2002), recursion is neither special to language nor recently evolved.

As Wunderlich writes in his (2006) paper “What forced syntax to emerge?”

"Both fast processing and mapping from hierarchical structure to temporal ordering, two other fundamental features of human language, can be attributed to progresses in the timing of actions necessary for producing and using hand axes, [as well as throwing] that is, to sensomotoric skills that could have been adapted for language.”

All this is made all the more exciting by converging evidence that combinatorial and hierarchical structure of any kind (be it linguistic, cognitive, or sensori-motor are constructed by the same part of the brain and via the same mechanisms:

“Similarities exist between the architecture for sentence structure and blackboard architectures for combinatorial structures in visual cognition, derived from the structure of the visual cortex” (van der Velde & de Kamps 2006: 1)

“Evidence is mounting that much temporally sequenced hierarchical structure is constructed by the same part of the brain – roughly Broca’s area and subcortical areas connected to it – whether the material being assembled is language, dance (Lieberman 2005: 297), hand movements (Lieberman 2005: 294; Wilkins 2005: 279), or music (Patel 2003). Nor, within language, is Broca’s area confined to syntax, as often asserted: it also appears to play a role in phonological and semantic combinatoriality, possibly in distinct though overlapping subareas (Hagoort 2005; Poeppel and Embick 2005)" (Jackendoff 2007: 388)

“On the basis of all these results, it can be hypothesized that [the recursive morphosyntax of modern language] is the computational output of a cortical premotor network originally evolved to control/represent the hierarchical structure of goalrelated action When in evolution, selective pressure led to the emergence of language, the same neural circuits doing computations to control the hierarchy of goal-related actions were ‘exploited’ to serve the newly acquired function of language syntax. A similar functional overlap between action and language acquisition is indeed evident during children’s development, i.e. children parallel their capacity to master hierarchical complexity both in the domain of language and goal-related action.“ (Gallese 2007: 666)”

That’s it for today. In my next post I will continue my summary of Wunderlich’s presentation.


References:


Ambr Ambrose, Stanley H. 2001. Paleolithic Technology and Human Evolution. Science 291, no. 5509 (March 2): 1748-1753. doi:10.1126/science.1059487.


Dubreuil, Benoît (2008): “What do modern behaviours in Homo sapiens imply for the evolution of language?”, in A. D. M. Smith, K. Smith, and R. Ferrer i Cancho (eds.), The Evolution of Language. Proceedings of the 7th International Conference (Evolang 7), World Scientific, 99-106.


Gallese, Vittorio (2007). Before and below 'theory of mind': Embodied simulation and the neural correlates of social cognition. Philosophical Transactions of the Royal Society B-Biological Sciences 362 (1480):659-669



Hagoort, Peter (2005). On Broca, brain, and binding: a new framework. Trends in Cognitive Sciences 9: 416–423



Hauser, Marc D., Noam Chomsky and W. Tecumseh Fitch (2002). “The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?” In: Science 298, 1569-1579.


Jackendoff, Ray (2007): Linguistics in Cognitive Science: The State of the Art, The Linguistic Review 24, 347-401.


Lieberman, Phillip (2005): The pied piper of Cambridge. The Linguistic Review 22: 289–302.


Lonsdorf, Elizabeth V., and William D. Hopkins. 2005. Wild chimpanzees show population-level handedness for

tool use. Proceedings of the National Academy of Sciences 102, no. 35 (August 30): 12634-12638. doi:10.1073/pnas.0505806102.


Patel, Aniruddh D. (2003). Language, music, syntax, and the brain. Nature Neuroscience 6: 674– 681.


Pinker, Steven & Paul Bloom (1990). “Natural Language and Natural Selection.” In: Behavioral and Brain Sciences 13.4: 707-726.


Poeppel, David, and David Embick (2005). Defining the relation between linguistics and neuroscience. In Twenty-first century psycholinguistics: Four cornerstones, A. Cutler (ed.), Hillsdale, NJ: Erlbaum.


Van der Velde, F. & de Kamps, M. (2006). Neural blackboard architectures of combinatorial structures in cognition. In: Behavioral and Brain Sciences, 29, 1-72.


Whiten, Andrew, Victoria Horner & Frans B. M. de Waal. 2005. “Conformity to Cultural Norms of Tool Use in Chimpanzees.” Nature 437: 737-740.


Wilkins, Wendy K. (2005). Anatomy matters. The Linguistic Review 22: 271–288.


Wunderlich, Dieter (2006): “What forced syntax to emerge?” In H.-M. Gärtner et al. (eds.) Between 40 and 60 puzzles for Krifka. ZAS Berlin

1 comment:

Marc Verhaegen said...

Speech origins in the light of the littoral theory:

POSSIBLE PREADAPTATIONS TO SPEECH -
A PRELIMINARY COMPARATIVE APPROACH

Marc Verhaegen & Stephen Munro
Human Evolution 19: 53-70, 2004

Human language is a unique phenomenon and its evolutionary origins are uncertain. In this paper we attempt to explore some of the preadaptations that might have contributed to the origin of human speech.
The comparative approach we use is based on the assumption that all features of a species are functional, and that all features can be compared with those of other animals and correlated with certain lifestyles. Using this method we attempt to reconstruct the different evolutionary pathways of humans and chimpanzees after they split from a common ancestor.

Previous results from comparative studies suggest human ancestors may not have evolved on the open African savannas as was once believed, but more probably were coastal omnivores feeding on plant matter and easy to catch invertebrates such as shellfish from beaches and shallow waters. Fossil and archaeological data suggest this coastal phase occurred at the beginning of the Pleistocene, when Homo ergaster-erectus dispersed between East-Africa, North-Africa, South-Asia and Indonesia.

This paper presents comparative data suggesting the various human speech skills may have had their origins at different times and may originally have had different functions. Possible preadaptations to speech include, for instance,
- musical skills present in a variety of primate species (sound production);
- airway closure and breath-hold diving for collecting seafood (voluntary breath control); and
- suction feeding adaptations for the consumption of fruit juice or certain seafoods (fine control of oropharyngeal movements).

The different evolutionary pathways of chimpanzees and humans might explain why chimpanzees lack language skills and why human language is a relatively recent phenomenon.