Science – Page 22 – Replicated Typo

Words as alleles: A null-model for language evolution?

For me, recent computational accounts of language evolution provide a compelling rationale that cultural, as opposed to biological, evolution is fundamental in understanding the design features of language. The basis for this rests on the simple notion of language being not only a conveyor of cultural information, but also a socially learned and culturally transmitted system: that is, an individual’s linguistic knowledge is the result of observing the linguistic behaviour of others. Here, this well-attested process of language acquisition, often termed Iterated Learning, emphasises the effects of differential learnability on competing linguistic variants. Sounds, words and grammatical structures are therefore seen to be the products of selection and directed mutation. As you can see from the use of terms such as selection and mutation it’s clear we can draw many parallels between the literature on language evolution and analogous processes in biology. Indeed, Darwin himself noted such similarities in the Descent of Man. However, one aspect evolutionary linguists don’t seem to borrow is that of a null model. Is it possible that the changes we see in languages over time are just the products of processes analogous to genetic drift?

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Can linguistic features reveal time depths as deep as 50,000 years ago?

Throughout much of our history language was transitory, existing only briefly within its speech community. The invention of writing systems heralded a way of recording some of its recent history, but for the most part linguists lack the stone tools archaeologists use to explore the early history of ancient technological industries. The question of how far back we can trace the history of languages is therefore an immensely important, and highly difficult, one to answer. However, it’s not impossible. Like biologists, who use highly conserved genes to probe the deepest branches on the tree of life, some linguists argue that highly stable linguistic features hold the promise of tracing ancestral relations between the world’s languages.

Previous attempts using cognates to infer the relatedness between languages are generally limited to predictions within the last 6000-10,000 years. In the present study, Greenhill et al (2010) decided to examine more stable linguistic features than the lexicon, arguing:

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What we're not talking about

Without trying to sound too sensationalist: ScienceBlogs is seeing a mass exodus of writers. The main reason revolves around Seed Media, the parent company of ScienceBlogs, selling blog space to advertisers. As MarkCC, of Good Math, Bad Math, notes:

Seed has, in its corporate wisdom, decided to let Pepsico buy its way into a blog on ScienceBlogs. Pepsi writes SMG a nice check, and suddenly their content gets mixed in to the ScienceBlog RSS feeds, the ScienceBlog feed to Google News, etc., exactly the way that my blog posts do.

This is not acceptable.

For now, I’m suspending my blog for a few days. If Seed decides to back out of this spectacular stupidity, then I’ll start posting here again. If not, then I’ll go looking for a new home for GM/BM. The money that I’ve made from the ads that Seed has sold has been nice – but it’s not worth my integrity.

If Blogs here are for sale, then I’m gone.

The blog in question is Food Frontiers. What’s it all about? Well, as the opening article itself states:

On behalf of the team here at ScienceBlogs, I’d like to welcome you to Food Frontiers, a new project presented by PepsiCo.

As part of this partnership, we’ll hear from a wide range of experts on how the company is developing products rooted in rigorous, science-based nutrition standards to offer consumers more wholesome and enjoyable foods and beverages. The focus will be on innovations in science, nutrition and health policy. In addition to learning more about the transformation of PepsiCo’s product portfolio, we’ll be seeing some of the innovative ways it is planning to reduce its use of energy, water and packaging.

Is it just me, or does that paragraph leave a sickly taste in your mouth? Maybe I’m just a synaesthete for blatantly corporate PR gimmicks. There are, of course, many arguments to be had about the role of advertising on blogs — it needs to generate money, after all. Still, whether you care or not about the ethics of the situation, I think ScienceBlogs made a very bad move not to consult their writers before going ahead with this.

N.B. If you’re worried about who has left and, more importantly, where they’ve gone, then Skulls in the Stars is keeping track of the situation: The Sciencebloggosphere is a changing. Of the blogs I regularly read, only one of them has made the move: Neuron Culture. The other blog I read, Laelaps, is still undecided as to where he’s going to take up permanent residence. You can, however, follow his twitter feed: http://twitter.com/laelaps.

Cultural Evolution: A Vehicle for Cooperative Interaction Between the Sciences and the Humanities

Bill Benzon of New Savanna has a long article over at On the Human about cultural evolution. It touches on some very important topics, which includes an example of coordinating behaviour:

Consider the bi-modal clapping that routinely rewards a successful performances—music, drama, circus, etc.—in eastern European communities, but which is less common in western Europe and North America. Z. Néda and colleagues (2000) have investigated this phenomenon, recording applause for a number of performances in Romania and Hungary. The applause would start out randomly and then quickly become strongly synchronized. Synchronized clapping would continue for a short while (one mode) and then disintegrate into random clapping (the other mode), from which synchronized clapping would reemerge, and so forth.

He also emphasises the importance of, and the need for, description in cultural evolution, drawing on Darwin’s own situation in the 19th Century:

Consider the situation of Darwin faced in the 19th century. When he began formulating his ideas on the origin of species he had three bodies of knowledge to work from: prior thought on the topic, his own observations over three decades, and the cumulative results of four centuries of descriptive work in natural history (cf. Ogilvie 2006) to which he had access through books and collections. That descriptive work provided models for his own observation and description. Plants and animals, and their lifeways, are very complex. Which traits and features are the most important to observe and describe? That is not an obvious matter, and it took naturalists decades to arrive the useful descriptive methods (cf. Foucault 1973, pp. 128 ff.). Secondly, it gave him the means to abstract and generalize from his own observations, to explore their implications throughout the natural world, most of which, of course, was beyond his immediate experience.

I’m planning on posting a comment tomorrow, but only if I’ve got something worth adding to the discussion. I think there are definitely areas worth looking at, such as the use of phylogenetic techniques in investigating culture, though I’m still juggling in my head whether they are entirely relevant to the conversation at hand. Also, be sure to check out John Wilkins’ comment about memes.

The story of Jeremy and his magic magnets

Note: Before reading this post, you should pop over to the Independent and read this shocking piece of journalism by Jeremy Laurance: Magnet’s can improve Alzheimer’s symptoms. Then, read the scientific report in question: Improved language performance in Alzheimer disease following brain stimulation. I found myself asking how Mr Laurance could have come up with this, and reached the following conclusion…

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Some Links #4

Back to the future on syntax and Broca’s area. Talking Brains provide a concise and humorous post about why Broca’s area is not the seat of syntax, be it domain-specific or domain-general. I tend to think that areas important for syntactic processing are probably distributed throughout the left perisylvian region. Hence why Broca’s aphasiacs are quite capable of making grammatical judgements. Then again, another reason why damage to Broca’s area doesn’t, to quote Hickok, “obliterate the ability to make such judgements”, is because the processing shifts to another region (sort of an ancillary system). This is very possible in the advent of neuroplasticity.

Neuroplasticity is a dirty word. Having mentioned neuroplasticity, I now feel obligated to mention this brilliant post over at Mind Hacks. It provides a sort of 101 approach to neuroplasticity, which, after all, simply means something in the brain has changed. Still, as one poster from Ethnographer.com pointed out: “However, at its most abstract, the concept of neuroplasticity is often arrayed against that other commonplace abstract notion, that the brain is genetically ‘hard-wired’ in some way”.

Dialect Geography and Social Networks. Mark Lieberman over at Language Log discusses geographical patterns of linguistic variation and recent analyses of facebook networks in the US. Put succinctly: they don’t line up very well. He also asks some interesting questions about the role facebook might play as a proxy for communication patterns.

How best to learn R. R is an invaluable statistical package. If, like me, you find yourself being dropped in at the deep end, then things can seem slightly confusing in an environment that is far less user friendly than, say, SPSS. All the important stuff is in the comments section of the post, but you should take some time out to have a general poke around Statistical Modelling, Causal Inference and Social Science.

Are Scottish People Living Dangerously? The short answer: Yes. Barking Up The Wrong Tree links to a study claiming that “Almost the entire adult population of Scotland (97.5%) are likely to be either cigarette smokers, heavy drinkers, physically inactive, overweight or have a poor diet.”

The Sun Gone Crazy? Apparently, for the past two years there’s been a prolonged absence in sunspots. But as Adam Frank mentions, “The magnetic activity of stars like sun, which is the root cause of the sunspot cycle, is still poorly understood even after decades of intense study. It’s more than an academic concern”.

Three Questions for Michael Tomasello. A cool little interview with the chimpanzee, linguistic and cooperation guru, Michael Tomasello, over at cognition and culture.

Recent Abstracts #1

In an effort to update this blog regularly, I’ve decided to take the lazy route and post up a list of abstracts. This will only happen once a week, but it’s a useful resource (for me at least), and will usually be an indicator of what articles I’m going to write about in the near future.

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Population size predicts technological complexity in Oceania

Here is a far-reaching and crucially relevant question for those of us seeking to understand the evolution of culture: Is there any relationship between population size and tool kit diversity or complexity? This question is important because, if met with an affirmative answer, then the emergence of modern human culture may be explained by changes in population size, rather than a species-wide cognitive explosion. Some attempts at an answer have led to models which make certain predictions about what we expect to see when populations vary. For instance, Shennan (2001) argues that in smaller populations, the number of people adopting a particular cultural variant is more likely to be affected by sampling variation. So in larger populations, learners potentially have access to a greater number of experts, which means adaptive variants are less likely to be lost by chance (Henrich, 2004).

Models aside, and existing empirical evidence is limited with the results being mixed. I previously mentioned the gradual loss of complexity in Tasmanian tool kits after the population was isolated from mainland Australia. Elsewhere, Golden (2006) highlighted the case of isolated Polar Inuit, who lost kayaks, the bow and arrow and other technologies when their knowledgeable experts were wiped out during a plague.Yet two systematic studies (Collard et al., 2005; Read, 2008) of the Inuit case found no evidence for population size being a predictor of technological complexity.

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Answering Wallace's challenge: Relaxed Selection and Language Evolution

How does natural selection account for language? Darwin wrestled with it, Chomsky sidestepped it, and Pinker claimed to solve it. Discerning the evolution of language is therefore a much sought endeavour, with a vast number of explanations emerging that offer a plethora of choice, but little in the way of consensus. This is hardly new, and at times has seemed completely frivolous and trivial. So much so that in the 19th Century, the Royal Linguistic Society in London actually went as far as to ban any discussion and debate on the origins of language. Put simply: we don’t really know that much. Often quoted in these debates is Alfred Russell Wallace, who, in a letter to Darwin, argued that: “natural selection could only have endowed the savage with a brain a little superior to that of an ape whereas he possesses one very little inferior to that of an average member of our learned society”.

This is obviously relevant for those of us studying language evolution. If, as Wallace challenged, natural selection (and more broadly, evolution) is unable to account for our mental capacities and behavioural capabilities, then what is the source behind our propensity for language? Well, I think we’ve come far enough to rule out the spiritual explanations of Wallace (although it still persists on some corners of the web), and whilst I agree that biological natural selection alone is not sufficient to explain language, we can certainly place it in an evolutionary framework.

Such is the position of Prof Terrence Deacon, who, in his current paper for PNAS, eloquently argues for a role for relaxed selection in the evolution of the language capacity. He’s been making these noises for a while now, as I previously mentioned here, with him also recognising evolutionary-similar processes in development. However, with the publication of this paper I think it’s about time I disseminated his current ideas in more detail, which, in my humble opinion, offers a more nuanced position than the strict modular adaptationism previously championed by Pinker et al (I say previously, because Pinker also has a paper in this issue, and I’m going to read it before making any claims about his current position on the matter).

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Experiments in cultural transmission and human cultural evolution

For those of you familiar with the formal mathematical models of cultural evolution (Cavalli-Sforza & Feldman, 1981; Boyd & Richerson, 1985), you’ll know there is a substantive body of literature behind the process of cultural transmission. It comes as a surprise, then, that experiments in this area are generally lacking.

For instance, if we look at evolutionary biology, then there are many experiments into small-scale microevolutionary processes, such as natural selection, sexual selection, mutation and drift, which are then applied in showing how these processes generate population-level, macroevolutionary patterns. It follows then, that this sort of population-level thinking can be applied to cultural evolution: the forces and biases of cultural transmission can be studied experimentally to see if they fit with population-level patterns of cultural change documented by scientists. As the current paper by Mesoudi & Whiten (2008) notes, this potentially gives cultural transmission experiments added significance: “cultural transmission should not only be studied for its own sake (i.e. in order to better understand cultural transmission itself), but also in order to explain broader cultural patterns and trends, all as part of a unified science of cultural evolution”.

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