I just finished watching the latest episode of Horizon, Is seeing believing? It had lots of cool material on recent research into our perceptual systems and how some unique individuals (see bat man and synaesthesia) are providing clues into the degree of plasticity our brain is capable of. I think this developmental flexibility has important implications for how we view the evolution of language, which certainly chimes with Deacon’s latest explanations. Another segment of the episode focused on a famous linguistic perceptual trick, known as the McGurk effect, demonstrating the interaction between hearing and vision in speech perception. Here is the first video I found on the subject (although I thought the Horizon episode provided a better visual explanation of it):
Tag: research
Regularities in Cultural Evolution
I recently came across a post over at GNXP on the rise and crash of civilizations. It’s a really interesting discussion on a new paper by Currie et al. (2010), Rise and fall of political complexity in island South-East Asia and the Pacific. Here is the abstract:
There is disagreement about whether human political evolution has proceeded through a sequence of incremental increases in complexity, or whether larger, non-sequential increases have occurred. The extent to which societies have decreased in complexity is also unclear. These debates have continued largely in the absence of rigorous, quantitative tests. We evaluated six competing models of political evolution in Austronesian-speaking societies using phylogenetic methods. Here we show that in the best-fitting model political complexity rises and falls in a sequence of small steps. This is closely followed by another model in which increases are sequential but decreases can be either sequential or in bigger drops. The results indicate that large, non-sequential jumps in political complexity have not occurred during the evolutionary history of these societies. This suggests that, despite the numerous contingent pathways of human history, there are regularities in cultural evolution that can be detected using computational phylogenetic methods. [My emphasis].
I don’t have much to add on the subject as I think Razib covered most of the relevant points, plus I haven’t even finished reading the paper yet (I’m hoping to get back into research blogging later this week). I will, however, post one of their figures that shows the dynamic between the rise and fall of political complexity, and how it shows regularity (btw, RJMCMC means Bayesian reversible-jump Markov chain Monte Carlo… if that helps you in any way):
Under the Influence: An overview of recent insights into the CNTNAP2 gene
In my last post I outlined a number of experimental studies using the Zebra Finch that have highlighted an additional dimension to the FoxP2 gene – not only is it upregulated in the avian brain throughout song development, but it is also downregulated in important song nuclei of adult birds in singing contexts that seem to involve ‘listening to one’s own song’ and subsequent error correction. Given that the pattern of expression of this gene is very similar in the developing brain of both humans and birds, one conclusion that has been drawn from this research is that FOXP2 downregulation may equivocally serve to facilitate online language processing function in the adult human brain.
General background on an intriguing new celebrity
Naturally, the next step has been to try and identify the downstream genes regulated by FOXP2 in order to build up a more detailed picture of how interactions between complex genetic networks influence key language-related disorders in humans. It is as a result of such efforts that another gene, although discovered almost a decade ago, has found its way into the spotlight: CNTNAP2.
In the developing human brain, CNTNAP2 is enriched in functionally specialised regions such as the frontal cortex, the stratium, and the dorsal thalamus (circuits within these regions are referred to as cortico-striato-thalmic circuits) central to executive function, planning and executing complex sequential movements, and thus potentially, language. This presents a striking contrast to the more uniform expression of Cntnap2 observed in the developing rodent brain where there is no evidence for enrichment in specific regions, suggesting a functional difference in the human version that could be related to vocal learning and modification.
Continue reading “Under the Influence: An overview of recent insights into the CNTNAP2 gene”
Some quick announcements
Just thought I’d make three quick announcements:
First, I decided to drag myself into the age of 140-characters and (albeit begrudgingly) joined Twitter. I say begrudgingly because my day is already packed with plenty of distractions besides adding Twitter into the mix… But I noticed it’s the place where all the cool science bloggers are gathering, and gradually coagulating into an amorphous cloud of science networking, so I thought I might as well sign up (ever the follower, never the trendsetter).
Second, if you happen to find yourself in Edinburgh on Friday October 1st, then you can come and see me and Sean presenting our respective posters (click here and here for the abstracts) at the 24th Language at Edinburgh Lunch. I’m sure, for me at least, it’ll be quite a sobering experience in highlighting how little I know about phonology, phonetics, sociolinguistics and demography. On the plus side I’ll get some free food 🙂 .
Lastly, if you happened to click on my poster abstract, then the more observant of you will have noticed I’m now affiliated with Cardiff University. Yes, that’s right, I’m doing yet another masters course. This time it’s at the Centre for Language and Communication Research, with the idea being that I’ll get a more solid foundation in research methodology etc before pursuing a PhD or research assistant position.
That is all.
New Language and Genetics department
Next week, on the 1st October, there will be a new language and genetics department opening at the Max Planck Institute, the first research department in the world entirely devoted to understanding the relationship between language and genes!!!
This excites me so I wanted to share the news.
This statement is from Simon Fisher, who will head the new department about what they will be trying to achieve:
‘We aim to uncover the DNA variations which ultimately affect different facets of our communicative abilities, not only in children with language-related disorders but also in the general population, and even through to people with exceptional linguistic skills’, says L&G director Simon Fisher. ‘Our work attempts to bridge the gaps between genes, brains, speech and language, by integrating molecular findings with data from other levels of analysis, particularly cell biology and neuro-imaging. In addition, we hope to trace the evolutionary history and worldwide diversity of the key genes, which may shed new light on language origins.’
More signs of the growing and diversifying field of language evolution!
Here’s a link to the news on the MPI website: http://www.mpi.nl/news/new-mpi-department-language-genetics
Alcohol Consumption affects Morphological Complexity
I previously talked about how changes in the demography of learners can affect the cultural evolution of a language. The hypothesis is that language adapts to the balance between declarative and procedural memory users. Since alcohol consumption affects procedural but not declarative memory (Smith & Smith, 2003), we might expect to see communities that have a high alcohol consumption using less complex morphology.
I find that communities that have a morphologically marked future tense have significantly higher alcohol consumption than communities that have a lexically marked future tense (Alcohol consumption data from WHO, language structure data from World atlas of language structures, 198 languages, t = 14.8, p<0.0001). This statistic does not take into account many factors, but is meant as a motivation for further research into language structure and social structure.
Smith C, & Smith D (2003). Ingestion of ethanol just prior to sleep onset impairs memory for procedural but not declarative tasks. Sleep, 26 (2), 185-91 PMID: 12683478
Genetic Anchoring, Tone and Stable Characteristics of Language
In 2007, Dan Dediu and Bob Ladd published a paper claiming there was a non-spurious link between the non-derived alleles of ASPM and Microcephalin and tonal languages. The key idea emerging from this research is one where certain alleles may bias language acquisition or processing, subsequently shaping the development of a language within a population of learners. Therefore, investigating potential correlations between genetic markers and typological features may open up new avenues of thinking in linguistics, particularly in our understanding of the complex levels at which genetic and cognitive biases operate. Specifically, Dediu & Ladd refer to three necessary components underlying the proposed genetic influence on linguistic tone:
[…] from interindividual genetic differences to differences in brain structure and function, from these differences in brain structure and function to interindividual differences in language-related capacities, and, finally, to typological differences between languages.”
That the genetic makeup of a population can indirectly influence the trajectory of language change differs from previous hypotheses into genetics and linguistics. First, it is distinct from attempts to correlate genetic features of populations with language families (e.g. Cavalli-Sforza et al., 1994). And second, it differs from Pinker and Bloom’s (1990) assertions of genetic underpinnings leading to a language-specific cognitive module. Furthermore, the authors do not argue that languages act as a selective pressure on ASPM and Microcephalin, rather this bias is a selectively neutral byproduct. Since then, there have been numerous studies covering these alleles, with the initial claims (Evans et al., 2004) for positive selection being under dispute (Fuli Yu et al., 2007), as well as any claims for a direct relationship between dyslexia, specific language impairment, working memory, IQ, and head-size (Bates et al., 2008).
A new paper by Dediu (2010) delves further into this potential relationship between ASPM/MCPH1 and linguistic tone, by suggesting this typological feature is genetically anchored to the aforementioned alleles. Generally speaking, cultural and linguistic processes will proceed on shorter timescales when compared to genetic change; however, in tandem with other recent studies (see my post on Greenhill et al., 2010), some typological features might be more consistently stable than others. Reasons for this stability are broad and varied. For instance, word-use within a population is a good indicator of predicting rates of lexical evolution (Pagel et al., 2007). Genetic aspects, then, may also be a stabilising factor, with Dediu claiming linguistic tone is one such instance:
From a purely linguistic point of view, tone is just another aspect of language, and there is no a priori linguistic reason to expect that it would be very stable. However, if linguistic tone is indeed under genetic biasing, then it is expected that its dynamics would tend to correlate with that of the biasing genes. This, in turn, would result in tone being more resistant to ‘regular’ language change and more stable than other linguistic features.
Continue reading “Genetic Anchoring, Tone and Stable Characteristics of Language”
Language and Complexity: Evolution Inside Out
Here is a video of Terrence Deacon, someone who needs no introduction on this website, giving a talk at Irving K. Barber Learning Centre about his latest research into language evolution:
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Language, Thought and Space (I): Lumpers and Splitters
There have been some very interesting discussions of the relationship between language and thought recently, including for example, Sean’s absolutely fascinating series of posts about the evolution of colour terms, a great post on descriptions of motion in different languages over at the lousy linguist (here), Guy Deutscher’s article “Does Your Language Shape How You Think?” (for discussions, see e.h. here and here), a slightly less recent piece by Lera Boroditsky in the Wall Street Journal, and an excellent recent discussion of her article by Mark Liberman (here). (see also James’ post, including a great/terrible joke about Whorf).
One of the things that Deutscher wrote in his article was that:
“The area where the most striking evidence for the influence of language on thought has come to light is the language of space — how we describe the orientation of the world around us.”
As I’ve written a bit about this topic on my other blog, Shared Symbolic Storage, I’ll repost a short series of posts over the next couple of days.
As Deutscher said, this is a very fascinating avenue of linguistic research that gives much insight into the nature of language and cognition as well as their relationship. In addition, it also presents us with new facts and considerations we have to take into account when we think about how language and cognition evolved.
Continue reading “Language, Thought and Space (I): Lumpers and Splitters”
Two new Greenhill Papers
Simon Greenhill has just announced two new papers on applying phylogenetic techniques to the study of culture. No doubt I’ll be blogging about these at some point in the future. Below are the abstracts: