Thanks! I'm glad it's out of the way tbh. The data collection took ages. Ideally, I'd get access to something like Global Mapping International, which would provide better area and inter-language contact data.

@ Razib: Yeah, I think it would be interesting to look at the allele differences in mormons vs. non mormons. Is there much data on mormon populations? @ Dr Howard: I too have tended to wonder about those who may be predisposed to what we would now consider anti-social behaviour. They actually briefly touched on this topic in the above paper. But I haven't really looked into the topic.

Cool post. It's good to have another blogger in the fold. Btw, I found this sentence particularly amusing: "As you can see in Figure 1, the Y chromosome (on the right) is puny and diminutive. It really is kind of pathetic once you look at it."

For those of you interested in a related, albeit fictional, look at linguistic diversity, then check out Desperanto -- a sci-fi story by one of my former lecturers, Prof Jim Hurford.

Interesting. I wish I'd read Shalizi & Thomas' paper before writing this post... Although, as far as I can tell from a cursory glance, they only use random copying in their model.

Yeah, evolution will inevitably lead to language, which is why we have talking cats... Oh, wait a minute. Seriously though, if language was inevitable, then how come we only see it in humans? And by language, I mean a strict definition that adheres to Hockett's design features. Now, vocalisation can be advantageous, which is why we see it in many species. For example, the vervet monkey. But this is nowhere near the level of sophistication found in humans. In certain developmental environments, Chimpanzees do manage to learn a relatively sophisticated form of gesturing, and this may also be a starting point for us to investigate language in animals. Your cat, on the other hand, is quite capable of communicating, but this is not language. Unless, of course, your cat is Garfield. In which case, I feel very sorry for you and your monthly food budget.

@ albatross: "That suggests that language is being selected partly for universality..." -- Good point. The way I look at it, the universal features of language are probably not arbitrary rules, with our brains and vocal anatomy being adapted to only the most stable features. Personally, I think the important questions are in regards to the observed differences. So, yeah, a language is unlikely to use constructions that human brains have trouble parsing. One way of looking at it is to view language as being a product of competing pressures e.g. expressivity versus learnability. "If it stays isolated in a small population, it’s likely to die out when that population dies out, or is assimilated into a larger population with a different language." -- I don't think it's an inevitable conclusion that a language in a small population will die out. There are plenty of communities who don't speak any other languages than their own, despite only having a small number of effective speakers. I do, however, think you are leaning in the right direction. Just substitute 'universality' for 'learnability'. Languages that are more learnable by adult learners (L2) will be advantageous in populations where there are many different languages operating. It also tends to be the case that languages in small, isolated populations will be better adapted to the learning biases of children (L1). Here are two recent papers expanding upon these points: The myth of language universals; Language structure is partly determined by social structure.

@ J. Goard: Haha, I actually replaced 'of' with 'have' before you commented, so I guess the post hasn't updated on RSS readers (assuming that's where you read it). @ Donald: I think Goard sufficiently answered your point. I would like to add that evolution is blind, and does not have foresight -- which is what you appear to be claiming when you say language is inevitable. Feel free to correct me if this is not what you meant to imply.

Awesome. Potentially a clash of the evolutionary linguistic titans with the Pinker and Deacon papers. Having quickly scanned Pinker's paper, I came across this gem: "The theory of the cognitive niche, I believe, has several advantages as an explanation of the evolution of the human mind. It incorporates facts about the cognitive, affective, and linguistic mechanisms discovered by modern scientific psychology rather than appealing to vague, prescientific black boxes like 'symbolic behavior' or 'culture'". ... Let the battle commence.

@ D J Wray: I think that's quite a negative outlook, given you're attempting to model God, Evolution and Reincarnation. Both reincarnation and God contain a large amount of unknowns, namely: Do these concepts exist outside of people's heads? I wish you all best.

@ Steve Sailer: Yeah, I agree. I could have probably condensed the opening about mathematical modelling, and included some examples. In truth, I think the whole article was probably too long, and might have benefited from more rigorous editing. Anyway, I'm glad you found it helpful.

Actually, the languages of these groups tend to be morphologically more complex. So it's not really an issue of tribes lacking language complexity. Languages in larger groups, such as users of English, are instead much more likely to use lexical strategies to encode evidentiality, negation, aspect, and possession. There are several good papers in explaining, and providing reasons for, the differences between small communities and large communities of language users: Wray & Grace (2007) and Lupyan & Dale (2010).

@ TGGP: The paper was basically looking at population-level variation in behaviour. So the cultural similarities and differences among populations are primarily the result of a combination of within-group information transmission and population fissioning. @ Michael Blume: Thanks Michael. Yeah, I'm quite interested in the role of cultural variance. I'm planning on writing a post in the near future. @ DavidB: Well, the data sets are a mixture of both types you mention. From my memory, the data sets included Neolithic pottery and projectile points, among many others. So I think they paid adequate attention to technology. Not so sure about food production, so I'll have a look. @ John Emerson: I'd be interested to read the paper (or article) you mentioned.

Haha, I'm glad some have finally reached the realisation that we're human. I was particularly surprised by this: "...where juries–and even focus groups–have begun their deliberations with a group prayer." I think this highlights the different approaches to religion in America and the UK. Over here, my religious friends would laugh at the prospect at praying before deliberations (or at the very least, they'd be quite surprised if someone suggested such an option).

I was just highlighting the difference between the overt displays of belief in America when compared with the generally more reserved nature of us British. That's why my religious friends would probably find such a scenario amusing. I'll run it by them next time we're down the pub :-)

@ John Hawks: I'm not wholly convinced by the ecological reason. Primarily because East Asia is quite large and covers a variety of ecological niches; it's not a uniform area. I suppose, really, the argument here is whether or not the ecological conditions trumps the demographic underpinnings. Also, it may not be one factor over another that explains why the patterns of handaxes east of the Movius line tend to be geographically sparse; instead, it may very well be the combination of partly ecological factors and partly the demographic limitations surrounding cultural and technological development. I think there are three important factors to consider in this particular context: 1) Was there available access to significant quantities of high-quality, fine-grained stone for tool production in these areas east of the Movius Line? Obviously, blade technology is quite dependent on fine-grained stone such as flint, chert, obsidian etc. Furthermore, did hominin populations rely on locally-sourced materials, such as wood or bamboo, for tool manufacture. 2) What are the specific functions for this stone tool technology? For instance, if the initial colonisation followed a costal route, then these technologies may have needed to adapt for the exploitation of coastal resources. 3) Lastly, there are the issues of demography and the potential role of serial founder effects as relatively small population units migrated eastward. Do we see instances where serial founder effects not only operate on the genetic features of populations, but in addition leads to a loss in the complexity and diversity of cultural and technological patterns as the result of an increasing distance from the demographic point of origin? As for the point about those Flores hominids: I don't know enough about them to really make an informed comment. For the moment though, I'd say that having a small population is not the only factor. If they had a sufficient level of density, then this may have led to stronger and more regular instances of social interconnectedness. So, as the probability of encountering increases, so does the ability to maintain certain forms of technology.

@Razib: Human stupidity may very well prevail. But I think if (and it's a big if) the methods are presented correctly, then people should be able to grasp the data made available -- especially if they have new ways of visualising and managing the data. @p-ter: Well, perhaps it's a fatal flaw. I think the authors are hoping the data fairies will bestow them with gifts of larger sample sizes and more sensitive measurements.

Haha, brilliant. 'Death by tickle' sounds like something from a Monty Python sketch. Although having tickling cause a cerebral haemorrhage sounds like something South Park would use... Especially if it involved Massa.

Yeah, it's a nice thought. But as far as I know there's nothing to demonstrate that the Hittites, and other ancient peoples, had different vocal tract morphology to that of current human populations. Maybe the reason why all the laryngeal consonants coalesced with the vowels, and subsequently disappeared from present day Indo-European languages, is because the languages themselves underwent selection to become easier to produce and comprehend? Present day humans, for instance, have the ability to produce a wide repertoire of speech sounds, but the actual range of sounds utilised within that repertoire is dependent on which language you speak (assuming you remain monolingual). And even though Saussure's laryngeal theory is now generally accepted, we're still not sure as to the exact place of articulation for the laryngeal consonants. ... Having said that, I remember reading a fascinating language log post about the adaptive evolution of human hearing -- Ongoing human evolution for spoken language?. Apparently, there may be genes for hearing that have taken root as recently as 2,000 years ago.

I don't think those with Williams Syndrome really reveal much about the debate surrounding domain-specificity for language. In fact, we know language processing is distributed across both hemispheres. For instance, prosody is processed in the right hemisphere whilst syntax is processed on the left side. The point of contention surrounding domain-specificity is actually in regards to the processing of certain aspects that make up language and its sub-domains. So, a domain-specific argument would say: portion x of the brain is dedicated to processing feature a. Whereas a domain-general argument says: portion x of the brain processes features a,b,c. An actual example of this argument in practice is Broca's area. One set of arguments (which I wrote about here ) posits that Broca's area is crucial in the processing of hierarchical sequences. A domain-specific case says: only hierarchically organised phrases in language are processed by Broca's area. However, those coming from a domain-general perspective point towards other, non-linguistic behaviours -- such as music, action sequences, tool-use and tool production -- that all show instances of hierarchical organisation. The question then being asked is: Does Broca's Area subserve the processing of hierarchical sequences across many behaviours? Teasing out the answer to this question is extremely difficult. And there are those who would even argue that Broca's area is not involved in hierarchical structure building at all. But that's a completely different argument.

A slight addendum: I tend to think of the brain as being composed of domain-general (or independent) regions that are networked in a domain-specific manner. For example, the language network and the tool-use network will share many overlapping regions (e.g. LH Broca's area), but the way in which each of these individual behaviours are processed involve different activation patterns. I'm not a neuroscientist though, so I might be completely off on this point.