Category: Science

The Bog

If you like wading through deposits of dead animal material, then you should go over and visit Richard Littauer’s new blog, The Bog. Having been exposed to his writings on both this blog, and through the Edinburgh language society website, I’m sure it will be worth a visit — for good writing, if not for your dire need to distinguish between forest swamps and shrub swamps. His first post is on Mung, the colloquial name for Pylaiella littoris, which is apparently a common seaweed. Here is his quick overview of the blog:

So, The Bog is going to be the resting place for various studies and explorations. Richard Littauer is the writer; he is working on his MA in Linguistics at Edinburgh University. He writes about evolutionary linguistics and culture at Replicated Typo, about general linguistic musings at a non-academic standard at Lang. Soc., about constructed languages on Llama, and about various philosophical things at Pitch Black Press. Since none of these blogs were a perfect fit for the scientific equivalent of a swamp-romp through subjects he doesn’t study, he set up this blog. Expect posts about ecology, biology, linguistics, anthropology, or anything in between.

The fact that it’s called the Bog has nothing to do with the British slang for ‘bathroom’. Rather, Richard (well, I) have an affinity with swamps for some unexplained reasons. Expect posts on swamps.

If that doesn’t appeal to you, then Richard is also well-known for being the world’s number one Na’vi fan.

From Natyural to Nacheruhl: Utterance Selection and Language Change

Most of us should know by now that language changes. It’s why the 14th Century prose of Geoffrey Chaucer is nearly impenetrable to modern day speakers of English. It is also why Benjamin Franklin’s phonetically transcribed pronunciation of the English word natural sounded like natyural (phonetically [nætjuɹəl]) rather than our modern variant with a ch sound (phonetically [nætʃəɹəl]). However, it is often taken for granted on this blog that language change can be understood as an evolutionary process. Many people might not see the utility of such thinking outside the realm of biology. That is, evolutionary theory is strictly the preserve of describing biological change, and is less useful as a generalisable concept. A relatively recent group of papers, however, have taken the conceptual machinery of evolutionary theory (see Hull, 2001) and applied it to language.

It's all natyural, yo!

Broadly speaking, these utterance selection models highlight that language change occurs across two steps, each corresponding to an evolutionary process: (1) the production of an utterance, and (2) the propagation of linguistic variants within a speech community. The first of these, the production of an utterance, takes place across an extremely short timescale: we will replicate particular sounds, words, and constructions millions of times across our production lifetime. It is as this step where variation is generated: phonetic variation, for instance, is not only generated through different speakers having different phonetic values for a single phoneme — the same speaker will produce different phonetic values for a single phoneme based on the context. Through variation comes the possibility of selection within a speech community. This leads us to our second timescale, which sees the selection and propagation of these variants — a process that may “take many generations of the replication of the word, which may–or may not–extend beyond the lifetime of an individual speaker.” (Croft, in press).

Recent mathematical work in this area has highlighted four selection mechanisms: replicator selection, neutral evolution, neutral interactor selection, and weighted interactor selection. I’ll now provide a brief overview of each of these mechanisms in relation to language change.

Continue reading “From Natyural to Nacheruhl: Utterance Selection and Language Change”

Williams Syndrome, Modularity and Language Evolution

Williams Syndrome (WS) is a rare genetic condition which manifests itself as a severe deficit in development and IQ, however it leaves language ability largely unaffected and is, as a result, often cited as evidence for a specific language module (Bellugi et al. 1988), as language can be unaffected despite other mental deficits. This argument has a strong bearing on the evolution of language as it contributes to the debate of whether language evolved for language’s sake or whether it is as the result (an exaptation or spandrel) of general cognitive capability in other areas.

Work by Brock (2007) has shown that the language abilities of people with WS could be predicted by non-linguistic abilities (You could probably argue this of the language abilities of anyone, but that’s another blog post). It has also been shown that language acquisition in WS children is behind that of normal children. Many studies have shown deficits in WS children’s language (reflexive pronouns, grammatical morphems, verb raising, negative wh-sentences) which are generally put down to normal-but-delayed language acquisition as people with the condition will usually pick these grammatical rules up by adolescence.

Perovic and Wexler (2010) suggest that if some grammatical knowledge is shown not to be present in WS children by adolescence, (as is apparently the case with verb raising) then this is evidence to suggest not just ‘normal-but-delayed’ language, but in fact, ‘atypical’ language.

Perovic and Wexler (2010) did a study on 26 children with Williams Syndrome between the ages of 6 – 16. They were tested using picture matching comprehension tasks on passives featuring ‘actional’ verbs and ‘psychological verbs’. The results confirmed what has been seen in previous studies, that WS children can process actional passives with ease, but also showed a previously unreported deficiency in their ability to process psychological verbs.

They also found this deficiency in 5 adult sufferers of WS.

So it seems that the linguistic ability of people with WS is not so exceptional after all.

In the discussion of this paper it is explored as to whether these differences could just be down to the general cognitive impairments which people with developmental problems face. The fact that this question even needs to be discussed is evidence to contradict a ‘language module’ theory. That is that if the deficit in WS children’s passive is a specifically linguistic one then WS can no longer be used as evidence for affected intellectuality but unaffected language, and on the other hand, if it is as a result of general cognitive deficiency, then this is evidence to suggest that it is general cognitive ability that results in much, if not all, linguistic ability in the first place.

References

Bellugi, U. Marks, S. Bihrle, A. and Sbo, H. (1988) Dissociation between language and cognitive functions in Williams Syndrome. In D. Bishop and K. Mogford (Eds.) Language developement in excpetional circumstances (pp. 177 – 189). Hillsdale, NJ: Erlbraum

Brock, J. (2007) Language abilities in Williams syndrome: A critical review. Development and Psychopathology, 19, 97-127.

Perovic A, & Wexler K (2010). Development of verbal passive in Williams syndrome. Journal of speech, language, and hearing research : JSLHR, 53 (5), 1294-306 PMID: 20631227

Tool making and Language Evolution

There’s an often cited gap in tool making history in which humans did not advance from simple Oldowan tools (which date back to about 2.5 million years ago) until about 500,000 years ago when progress became much faster. There is much debate as to whether this gap in progress is the result of the cognitive abilities to make more innovative tools or if it was an issue of dexterity.

A recent article by Faisal et al. (2010) “The Manipulative Complexity of Lower Paleolithic Stone Toolmaking” has tried to address these problems by assessing the manipulative complexity of tool making tasks from the Oldowan tools to the more advanced hand axes from much later.

A stone ‘core’ (A) is struck with a hammerstone (B) in order to detach sharp stone ‘flakes’. In Oldowan toolmaking (C, top) the detached flakes (left in photo) are used as simple cutting tools and the core (right in photo) is waste. In Acheulean toolmaking (C, bottom), strategic flake detachments are used to shape the core into a desired form, such as a handaxe. Both forms of toolmaking are associated with activation of left ventral premotor cortex (PMv), Acheulean toolmaking activates additional regions in the right hemisphere, including the supramarginal gyrus (SMG) of the inferior parietal lobule, right PMv, and the right hemisphere homolog of anterior Broca's area: Brodmann area 45 (BA 45).

The following is taken from a press release from Eureka.org:

Researchers used computer modelling and tiny sensors embedded in gloves to assess the complex hand skills that early humans needed in order to make two types of tools during the Lower Palaeolithic period, which began around 2.5 million years ago. The cross-disciplinary team, involving researchers from Imperial College London, employed a craftsperson called a flintnapper to faithfully replicate ancient tool-making techniques.

The team say that comparing the manufacturing techniques used for both Stone Age tools provides evidence of how the human brain and human behaviour evolved during the Lower Palaeolithic period.

The flintnapper who participated in today’s study created two types tools including the razor-sharp flakes and hand-held axes. He wore a data glove with sensors enmeshed into its fabric to record hand and arm movements during the production of these tools.

After analysing this data, the researchers discovered that both flake and hand-held axe manufacturing techniques were equally complex, requiring the same kind of hand and arm dexterity. This enabled the scientists to rule out motor skills as the principal factor for holding up stone tool development.

The team deduced from their results that the axe-tool required a high level of brain processing.

This has implications for language evolution as brain scans from tool makers have shown significant overlap with areas involved in discourse-level language processing as well as complex hand gestures. The study finishes with the following:

…the anatomical overlap of Late Acheulean toolmaking and right hemisphere linguistic processing may reflect the flexible “mapping” of diverse overt behaviors onto shared functional substrates in the brain. This implies that: 1) selection acting on either language or toolmaking abilities could have indirectly favored elaboration of neural substrates important for the other, and 2) archaeological evidence of Paleolithic toolmaking can provide evidence for the presence of cognitive capacities also important to the modern human faculty for language.

Read the original article at PLoS ONE:

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013718

Cultural and linguistic diversity: evolutionary approaches

Via HENRY:

There’s a special issue of Philosophical Transactions of the Royal Society out on the theme of Cultural and linguistic diversity: evolutionary approaches.

From the introduction:

Evolutionary approaches to cultural change are increasingly influential, and many scientists believe that a ‘grand synthesis’ is now in sight. The papers in this Theme Issue, which derives from a sym- posium held by the AHRC Centre for the Evolution of Cultural Diversity (University College London) in December 2008, focus on how the phylogenetic tree-building and network-based tech- niques used to estimate descent relationships in biology can be adapted to reconstruct cultural histories, where some degree of inter-societal diffusion will almost inevitably be superimposed on any deeper signal of a historical branching process.

Papers:

  • On the shape and fabric of human history – Russell D. Gray, David Bryant, and Simon J. Greenhill

    • Twitter Evolution: Converging Mechanisms in birdsong and human speech

    In my last post, I made reference to the similarities between birdsong and human speech, and how the development of these two might inform us on the evolution of language. So, it comes as a pleasant surprise that there is a new review in Nature Neuroscience on the very topic: Twitter Evolution: converging mechanisms in birdsong and human speech (click here for paper). I haven’t yet had chance to fully read the paper, but I think the following figure is quite instructive of the connective complexity we’re dealing with:

    On Phylogenic Analogues

    A recent post by Miko on Kirschner and Gerhart’s work on developmental constraints and the implications for evolutionary biology caught my eye due to the possible analogues which could be drawn with language in mind. It starts by saying that developmental constraints are the most intuitive out of all of the known constraints on phenotypic variation.  Essentially, whatever evolves must evolve from the starting point, and it cannot ignore the features of the original. Thus, a winged horse would not occur, as six limbs would violate the basic bauplan of tetrapods. In the same way, a daughter language cannot evolve without taking into account the language it derives from and language universals. But instead of viewing this as a constraint which limits the massive variation we see biologically or linguistically between different phenotypes, developmental constraints can be seen as a catalyst for regular variation.

    ResearchBlogging.orgA recent post by Miko on Kirschner and Gerhart’s work on developmental constraints and the implications for evolutionary biology caught my eye due to the possible analogues which could be drawn with language in mind. It starts by saying that developmental constraints are the most intuitive out of all of the known constraints on phenotypic variation.  Essentially, whatever evolves must evolve from the starting point, and it cannot ignore the features of the original. Thus, a winged horse would not occur, as six limbs would violate the basic bauplan of tetrapods. In the same way, a daughter language cannot evolve without taking into account the language it derives from and language universals. But instead of viewing this as a constraint which limits the massive variation we see biologically or linguistically between different phenotypes, developmental constraints can be seen as a catalyst for regular variation.

    A pretty and random tree showing variation among IE languages.

    Looking back over my courses, I’m surprised by how little I’ve noticed (different from how much was actually said) about reasons for linguistic variation. The modes of change are often noted: <th> is fronted in Fife, for instance, leading to the ‘Firsty Ferret’ instead of the ‘Thirsty Ferret’ as a brew, for instance. However, why the <th> is fronted at all isn’t explained beyond cursory hypothesis. But that’s a bit besides the point: what is the point is that phenotypic variation is not necessarily random, as there are constraints – due to the “buffering and canalizing of development” – which limit variation to a defined range of possibilities. There clearly aren’t any homologues between biological embryonic processes and linguistic constraints, but there are developmental analogues: the input bottleneck (paucity of data) given to children, learnability constraints, the necessity for communication, certain biological constraints to do with production and perception, etc. These all act on language to make variation occur only within certain channels, many of which would be predictable.

    Another interesting point raised by the article is the robustness of living systems to mutation. The buffering effect of embryonic development results in the accumulation of ‘silent’ variation.  This has been termed evolutionary capacitance. Silent variation can lay quiet, accumulating, not changing the phenotype noticeably until environmental or genetic conditions unmask them. I’ve seen little research (not that I don’t expect there to be plenty) on the theoretical implications of the influence of evolutionary capacitance on language change – in other words, how likely a language is to make small variations which don’t affect language understanding before a new language emerges (not that the term language isn’t arbitrary based on the speaking community, anyway). Are some languages more robust than others? Is robustness a quality which makes a language more likely to be used in multilingual settings – for instance, in New Guinea, if seven languages are mutually indistinguishable, is it likely the that local lingua franca is forced by its environment to be more robust in order to maximise comprehension?

    The article goes on about the cost of robustness: stasis. This can be seen clearly in Late Latin, which was more robust than the daughter languages as it was needed to communicate in different environments where the language had branched off into the Romance languages, and an older form was necessary in order for communication to ensue. Thus, Latin retained usage well after the rest of it had evolved into other languages. Another example would be Homeric Greek, which retained many features lost in Attic, Doric, Koine, and other dialects, as it was used in only a certain environment and was therefore resistant to change. This has all been studied before better than I can sum it up here. But the point I am making is that analogues can be clearly drawn here, and some interesting theories regarding language become apparent only when seen in this light.

    A good example, also covered, would be exploratory processes, as Kirschner and Gerhart call them. These are processes which allow for variation to occur in environments where other variables are forced to change. The example given is the growth of bone length, which requires corresponding muscular, circulatory, and other dependant systems to also change. The exploratory processes allow for future change to occur in the other systems. That is, they expedite plasticity. So, for instance, an ad hoc linguistic example would be the loss of a fixed word order, which would require that morphology step in to fill the gap. In such a case, particles or affixes or the like would have to have already paved the way for case markers to evolve, and would have had to have been present to some extent in the original word order system. (This may not be the best example, but I hope my point comes across.)

    Naturally, much of this will have seemed intuitive. But, as Miko stated, these are useful concepts for thinking about evolution; and, in my own case especially, the basics ought to be brought back into scrutiny fairly frequently. Which is justification enough for this post. As always, comments appreciated and accepted. And a possible future post: clade selection as a nonsensical way to approach phylogenic variation.

    References:

    Caldwell, M. (2002). From fins to limbs to fins: Limb evolution in fossil marine reptiles American Journal of Medical Genetics, 112 (3), 236-249 DOI: 10.1002/ajmg.10773

    Gerhart, J., & Kirschner, M. (2007). Colloquium Papers: The theory of facilitated variation Proceedings of the National Academy of Sciences, 104 (suppl_1), 8582-8589 DOI: 10.1073/pnas.0701035104

    Gerhart, J., & Kirschner, M. (2007). Colloquium Papers: The theory of facilitated variation Proceedings of the National Academy of Sciences, 104 (suppl_1), 8582-8589 DOI: 10.1073/pnas.0701035104

    Domain-General Regions and Domain-Specific Networks

    The notion of a domain-specific, language acquisition device is something that still divides linguists. Yet, in an ongoing debate spanning at least several decades, there is still no evidence, at least to my knowledge, for the existence of a Universal Grammar. Although, you’d be forgiven for thinking that the problem was solved many years ago, especially if you were to believe the now  sixteen-year old words of Massimo Piattelli-Palmarini (1994):

    The extreme specificity of the language system, indeed, is a fact, not just a working hypothesis, even less a heuristically convenient postulation. Doubting that there are language-specific, innate computational capacities today is a bit like being still dubious about the very existence of molecules, in spite of the awesome progress of molecular biology.

    Suffice to say, the analogy between applying scepticism of molecules and scepticism of Universal Grammar is a dud, even if it does turn out that the latter does exist. Why? Well, as stated above: we still don’t know if humans have, or for that matter, even require, an innate ability to process certain grammatical principles. The rationale for thinking that we have some innate capacity for acquiring language can be delineated into a twofold argument: first, children seem adept at rapidly learning a language, even though they aren’t exposed to all of the data; and second, cognitive science told us that our brains are massively modular, or at the very least, should entail some aspect that is domain specific to language (see FLB/FLN distinction in Hauser, Chomsky & Fitch, 2002). I think the first point has been done to death on this blog: cultural evolution can provide an alternative explanation as to how children successfully learn language (see here and here and Smith & Kirby, 2008). What I haven’t really spoken about is the mechanism behind our ability to process language, or to put it differently: how are our brains organised to process language?

    Continue reading “Domain-General Regions and Domain-Specific Networks”

    Mapping Linguistic Phylogeny to Politics

    In a recent article covered in NatureNews in Societes Evolve in Steps, Tom Currie of UCL, and others, like Russell Gray of Auckland, use quantitative analysis of the Polynesian language group to plot socioanthropological movement and power hierarchies in Polynesia. This is based off of previous work, available here, which I saw presented at the Language as an Evolutionary Systemconference last July. The article claims that the means of change for political complexity can be determined using linguistic evidence in Polynesia, along with various migration theories and archaeological evidence.

    I have my doubts.

    Note: Most of the content in this post is refuted wonderfully in the comment section by one of the original authors of the paper. I highly recommend reading the comments, if you’re going to read this at all – that’s where the real meat lies. I’m keeping this post up, finally, because it’s good to make mistakes and learn from them. -Richard

    §§

    I had posted this already on the Edinburgh Language Society blog. I’ve edited it a bit for this blog. I should also state that this is my inaugural post on Replicated Typo; thanks to Wintz’ invitation, I’ll be posting here every now and again. It’s good to be here. Thanks for reading – and thanks for pointing out errors, problems, corrections, and commenting, if you do. Research blogging is relatively new to me, and I relish this unexpected chance to hone my skills and learn from my mistakes. (Who am I, anyway?) But without further ado:

    §

    In a recent article covered in NatureNews in Societes Evolve in Steps, Tom Currie of UCL, and others, like Russell Gray of Auckland, use quantitative analysis of the Polynesian language group to plot socioanthropological movement and power hierarchies in Polynesia. This is based off of previous work, available here, which I saw presented at the Language as an Evolutionary Systemconference last July. The article claims that the means of change for political complexity can be determined using linguistic evidence in Polynesia, along with various migration theories and archaeological evidence.

    I have my doubts. The talk that was given by Russell Gray suggested that there were still various theories about the migratory patterns of the Polynesians – in particular, where they started from. What his work did was to use massive supercomputers to narrow down all of the possibilities, by using lexicons and charting their similarities. The most probable were then recorded, and their statistical probability indicated what was probably the course of action. This, however, is where the ability for guessing ends. Remember, this is massive quantificational statistics. If one has a 70% probability chance of one language being the root of another, that isn’t to say that that language is the root, much less that the organisation of one determines the organisation of another. But statistics are normally unassailable – I only bring up this disclaimer because there isn’t always clear mapping between language usage and migration.

    Continue reading “Mapping Linguistic Phylogeny to Politics”

    Referential labelling in Diana Monkeys

    ResearchBlogging.org Ok, so I was going to write an essay for my Origins of Language module on this but then got distracted by syntax (again) so I thought I’d put my thoughts in a blog post just so they don’t go to waste.

    Diana monkeys, like vervet monkeys, use alarm calls to communicate the presence of a predator to other monkeys.

    They produce (and respond to) different alarm calls corresponding to how close the predator is, whether the predator is above or below them and whether the predator is a leopard or an eagle.  They respond instantly regardless of how imminent an attack is.

    In this post I will explore some of the evidence relating to how sophisticated the Diana monkey’s understanding of the call’s meaning is and also the mental mechanisms relating to the call’s production.

    Zuberbühler (2000a) discusses some types of species which have alarm calls but instead of each alarm call representing a different predator, each alarm call represents a different level (or types) of danger. The aim of the Zuberbühler paper then, was to set out if this was the case for Diana monkeys or if they really did have referential ‘labels’ for different predators.

    Continue reading “Referential labelling in Diana Monkeys”