Evolution – Page 12 – Replicated Typo

Why a lowered larynx is good for human speech production

Ok, there’s loads of theories as to why humans have a lowered larynx. I went to a talk about this in York probably about a year ago now and when I started reading about all this again it all came back and I thought I’d share Mark Jones‘ hypothesis with you all.

First, here’s a brief history of lowered larynx theories:

Whilst other primates have the ability to lower their larynx to make vocalisations it is only humans who have it permanently lowered. This means that humans when swallowing have to raise the larynx. This is thought to have not evolved in other species as it creates a significant risk of choking on food if the larynx is not raised on time. So if it’s so maladaptive how come it evolved in Humans?

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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

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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:

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.

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The 20th Anniversary of Steven Pinker & Paul Bloom: Natural Language and Natural Selection (1990)

The day before yesterday Wintz mentioned two important birthdays in the field of language evolution (see here): First, Babel’s Dawn turned four, and second, as both Edmund Blair Bolles and Wintz pointed out, Steven Pinker‘s and Paul Bloom‘s seminal paper “Natural Language and Natural Selection” (preprint can be found here) has its 20th anniversary.

Wintz wrote that he planned on writing

“a post on Pinker and Bloom’s original paper, and how the field has developed over these last twenty years, at some point in the next couple of weeks,”

and I thought I’d also offer a short perspective on the paper, by reposting an slightly edited post I wrote on the paper in 2008 (yes I know, I do a lot of reposting of old material, but I’m planning on writing more new stuff as well, I promise 😉 ).

So here we go:

Bleg: Why CULTURAL Evolution?

That is to ask: Why has there been so much interest in cultural evolution in the last two decades or so? It seems to me that a lot of this thinking is just messing around, seeing if evolutionary ideas can somehow be attached to cultural phenomena in a coherent way. It seems more motivated by a desire to extend evolutionary thinking than by a desire to understand culture. And it’s not obvious to me that anyone has actually explained anything in this process, not so far.

In particular, has anyone used some theory of cultural evolution to explain some phenomenon of culture as well as, and ideally, better than competing non-evolutionary accounts? It’s not at all obvious to me that the answer to that question is “Yes.”

Note that I don’t exempt my own efforts from this criticism, which is why, on the whole, I’ve devoted more time to examining and analyzing cultural phenomenon than I have conceptualizing cultural evolution. In particular, I’ve spent a lot of time thinking about popular music in America, and the interaction of African-derived and European-derived styles (see, e.g. this longish paper) and, more recently, I’ve been looking at graffiti, which I’ll address later on.

Evolution?

One caveat: A lot depends on just what one means by cultural evolution. If one is just using ‘evolution’ as a substitute for ‘change,’ then the question has little meaning. It seems to me that much of memetics is like this, with the added innovation of attributing agency to the memes, rather than to people.

And then there’s gene-cultural coevolution (GCCE). Those folks may well have succeeded in coming up with useful explanations, e.g. lactose tolerance. But it’s not at all clear to me that GCCE can work with the kinds of phenomena that most interest me and that do constitute a great deal of cultural activity. As I’ve explained here, it’s not clear to me that GCCE has anything to say, for example, about something like the growth of graffiti in the last 40 years.

Graffiti 1

By ‘graffiti’ I don’t mean any writing on walls, but the specific practice that originated on the East Coast of the USA in Philadelphia and New York City in the late 1960s and early 1970s. The practice seems to have been pretty much confined to those cities by the early 1980s. But it had gone world-wide by the start of the current millennium. How did that happen? And why?

I don’t see that GCCE has any tools to answer that question. The spread is too fast for any biological changes to have been involved. Whatever’s going on has been going on purely within the cultural sphere. There are obvious things to point to concerning how it happened: 1) Press coverage of early graffiti made the activity more visible. 2) When graffiti became associated with hip-hop, it followed hip-hop in its spread through world pop culture. 3) Photography, books, and films (Style Wars, Wild Style) spread the word. 4) The emergence of the world-wide-web created a new means by which photos of graffiti could made instantly available around the world.

But none of that explains why the practice spread. What made graffiti so attractive to so many people in so many different places around the world? And why has it been, on the whole, so conservative, so that the themes and motifs that originated in the East Coast of the USA in the late 1970s and early 1980s are showing up in Japan in then 2000s? On one level that question answers itself. If the designs changed rapidly, so that putting any old design up on the walls counted as graffiti, then the activity would loose its identity, its genealogical connection with those first writers in New York City and Philadelphia. It would just be painting on walls, illegally. Big deal.

The genealogical connection IS important. Why? Note that, while stylistic conservatism maintains that identity, we also have to allow for the identity of individual writers within the tradtion. The tradition has to have enough internal variety to allow for that.

There are ways of talking about those questions, and you’ll find some of them in the literature, but the question I’m asking is this: Can a strong theory of cultural evolution do a better job of accounting for this spread than any other theory? If so, what would that theory look like?

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Specific Language Impairment, Autism and Language Evolution

My last post speculated about what some conditions which manifest impaired theory of mind could tell us about the evolution of ToM. Of these conditions autism was one which could be the most informative when it comes to looking at the genetics of how ToM evolved, in this post I will look at what autism could tell us, not only about theory of mind, but also about other aspects of the language faculty.

Dorothy Bishop has recently written a paper exploring the above average co-occurrence of Specific Language Impariment (SLI) and Autistic Spectrum Disorders (ASD).

SLI is a condition where a child fails to develop spoken language on the normal schedule, for no observable or obvious reason (Bishop and Norbury 2008). Whilst ASD and SLI are regarded as distinct conditions, these disorders co-occur at above chance levels.

Bishop (2010) explores why this might be. Bishop begins her paper by painting a textbook example of a child with SLI. This example is of a child with normal social interaction and nonverbal communication, but with specific difficulties in mastering structural aspects of language, especially syntax and phonological skills. So this typical picture is not one of an autistic child in that one of the defining features of autism is a limited capacity for normal social interaction and a child is much more likely to be deficient in pragmatic skills than syntactic or phonological skills.

Bishop states that despite the fact that according to conventional diagnostic frameworks, SLI andASD are mutually exclusive diagnoses, similarities exist between the two conditions and these include:

They are both highly heritable
Identical, monozygotic twins are significantly more concordant than fraternal, dizygotic twins for autism and SLI
In both conditions rates of impairment in first degree relatives are higher than in the general population
First degree relatives of affected individuals of both conditions often manifest sub-threshold symptoms
These conditions correspond to points on a continuum of impairment, rather than all-or-none diseases

So any model of causation for either condition must take into account the following considerations:

Above chance levels of comorbidity between SLI and ASD
Rates of language impairment in relatives of probands with SLI and ASD
Molecular genetic findings of shared genetic risk factors for ASD and SLI

Now the article goes on to explore etiological models which explain these considerations with varying degrees of success. I’m not going to pretend to understand these models as I have only ever been formally taught in linguistics and so I’m a bit stumped by genetic psychology. If you’re much smarter than me you can read the article yourself here:

http://www.springerlink.com/content/gg087q4h51j5127g/fulltext.pdf

So what I got from this article was that the genetic factors involved in autism can not only cause the characteristics typical of a person with autism (pragmatic impairments) but also other language impairments which are typical of a person with a Specific Language Impairment. Specifically the CNTNAP2 gene has been found in independent samples to be associated with both ASD and SLI. This is interesting because it could show that gene mutations which cause improved social abilities could have also caused changes in our linguistic ability on a syntactic or phonological level.

Disclaimer: Sorry if I’ve made too many assumptions in the conclusion I’ve just drawn. As I said above I know next to nothing about genetic psychology but I just felt this research would have interesting consequences in the field of language evolution. I’d love to hear the thoughts of people who know better than I do.

References

Bishop, DVM. (2010) Overlaps Between Autism and Language Impairment:
Phenomimicry or Shared Etiology? Behavior Genetics 40:5, 618-629

Bishop DVM, Norbury CF (2008) Speech and language disorders. In: Rutter M, Bishop DVM, Pine D, Scott S, Stevenson J, Taylor E, Thapar A (eds) Rutter’s child

Theory of Mind and Language Evolution; What can psychopathology tell us?

Theory of Mind is the ability to infer other persons’ mental states and emotions. It is thought to have evolved as part of the human’s social brain and probably emerged as an adaptive response to increasingly complex primate social interaction.

Brüne and Brüne-Cohrs (2006) explore the ‘evolutionary cost’ of language evolution:

This sophisticated ‘metacognitive’ ability comes at an evolutionary cost, reflected in a broad spectrum of psychopathological conditions. Extensive research into autistic spectrum disorders has revealed that theory of mind may be selectively impaired, leaving other cognitive faculties intact. Recent studies have shown that observed deficits in theory of mind task performance are part of a broad range of symptoms in schizophrenia, bipolar affective disorder, some forms of dementia, ‘psychopathy’ and in other psychiatric disorders.

Now it’s fairly uncontroversial to assert that without the ability of theory of mind humans would have never evolved language (Sperber and Wilson, 2002). This is due to the fact that if one can’t attribute another to have a ‘mind’ like ones own, or assume that other minds hold different information to ones own then one would see little point in trying to share information. (I’m sorry for the amount of ‘ones’ in that sentence).

Sooo, it does not seem presumptuous to assume that people interested in the evolution of language should be interested in theory of mind, in fact for many years evolutionary linguists, psychologists and biologists have been looking into this, but mostly through observing the behaviour of animals, and especially primates to see if they display theory of mind capabilities. A good summary of this work can be found here, and a lot of relevant studies can be found on this blog in the What makes humans unique? posts by Michael. I’m not going to look at the animal data in this post, but instead what the deficiencies in some human conditions can tell us about the evolution of theory of mind. That is, what can autism, schizophrenia, bipolar affective disorder, dementia, ‘psychopathy’ and other psychiatric disorders tell us?

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Language About Language

How is it, then, that we can talk about talking? If you are willing to assume the existence of basic perceptual and cognitive capacities, a relatively simple answer follows immediately. The sounds of talk are, after all, sounds like any other sounds. We can perceive them in the same way we perceive the sound of a waterfall or a bird’s song, a thunderclap or the rustling of leaves in the wind, a cricket’s chirp or the breaking of waves on a beach. All are things we can hear, easily and naturally, and so it is with the sound of the human voice.

Roman Jakobson famously theorized that language has six functions: referential, emotive, poetic, conative, phatic, and the metalingual function. That’s the function we’re interested in, our capacity to speak about speech. Jakobson talked of the metalingual function as an orientation toward the language code, which seems just a bit grand. For I’m led to believe that many languages lack terms for explicitly talking about the ‘code.’ Thus, in The Singer of Tales (Atheneum 1973, orig. Harvard 1960), Albert Lord attests (p. 25):

Man without writing thinks in terms of sound groups and not in words, and the two do not necessarily coincide. When asked what a word is, he will reply that he does not know, or he will give a sound group which may vary in length from what we call a word to an entire line of poetry, or even an entire song. [Remember, Lord is writing about oral narrative.] The word for “word” means an “utterance.” When the singer is pressed then to way what a line is, he, whose chief claim to fame is that he traffics in lines of poetry, will be entirely baffled by the question; or he will say that since he has been dictating and has seen his utterances being written down, he has discovered what a line is, although he did not know it as such before, because he had never gone to school.

While I’m willing to entertain doubts about the full generality of this statement – “man without writing” – I assume the it is an accurate report about the Yugoslavian peasants among whom Milman Parry and Albert Lord conducted their fieldwork and that it also applies to other preliterate peoples, though not necessarily to all.

Given those caveats, the paragraph is worth re-reading. Before doing so, recall how casually we have come to see language as a window on the workings of the mind in the Chomskyian and post-Chomskyian eras. If that is the case, then what can one see through a window that lacks even a word for words, that fails to distinguish between words and utterances? And what of the poets who don’t know what a line is? The lack of such knowledge does not stand in the way of the poeticizing, no more than the lack of knowledge of generative grammar precludes the ability to talk intelligently on a vast range of subjects.

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What Makes Humans Unique ?(IV): Shared Intentionality – The Foundation of Human Uniqueness?

What Makes Humans Unique (IV): Shared Intentionality – The Foundation of Human Uniqueness?

Shared or collective intentionality is the ability and motivation to engage with others in collaborative, co-operative activities with joint goals and intentions. (Tomasello et al. 2005). The term also implies that the collaborators’ psychological processes are jointly directed at something and take place within a joint attentional frame (Hurford 2007: 320, Tomasello et al. 2005).

Michael Tomasello and his colleagues at the Max-Planck-Institute for Evolutionary Anthropology in Leipzig, Germany have proposed that shared intentionality and the cognitive infrastructure supporting it may be the crucial feature that makes humans unique.

(You can hear Michael Tomasello talk about shared intentionality in his brief 2009 acceptance speech for the prestigeous “Hegel-Price” here. Transcript here)

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What Makes Humans Unique ?(III): Self-Domestication, Social Cognition, and Physical Cognition

In my last post I summed up some proposals for what (among other things) makes human cognition unique. But one thing that we should bear in mind, I think, is that our cognitive style may more be something of an idiosyncrasy due to a highly specific cognitive specialization instead of a definitive quantitative and qualitative advance over other styles of animal cognition. In this post I will look at studies which further point in that direction.

Chimpanzees, for example, beat humans at certain memory tasks (Inoue & Matsuzawa 2007) and behave more rational in reward situations (Jensen et al. 2007).

In addition, it has been shown that in tasks in the social domain, which are generally assumed to be cognitively complex, domesticated animals such as dogs and goats (Kaminski et al. 2005) fare similarly well or even outperform chimpanzees.

Social Cognition and Self-Domestication

It is entirely possible that the first signs of human uniqueness where at first simply side-effects our self-domesticating lifestyle – the same way the evolution of social intelligence in dogs and goats is hypothesised to have come about –, acting on a complex primate brain (Hare & Tomasello 2005).

This line of reasoning is also supported by domesticated silver foxes which have been bred for tameness over a time period of 50 years but developed other interesting characteristics as a by-product: To quote from an excellent post on the topic over at a Blog Around the Clock (see also here):

“They started having splotched and piebald coloration of their coats, floppy ears, white tips of their tails and paws. Their body proportions changed. They started barking. They improved on their performance in cognitive experiments. They started breeding earlier in spring, and many of them started breeding twice a year.”

What seems most interesting to me, however, is another by-product of their experimental domestication: they also improved in the domain of social cognition. For example, like dogs, they are able to understand human communicative gestures like pointing. This is all the more striking because, as mentioned above, chimpanzees do not understand human communicative gestures like helpful pointing. Neither do wolves or non-domesticated silver foxes (Hare et al. 2005).

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Time Travel, Dreams and The Origin of Knowledge

I’ve been attending a weekly seminar on the Metaphysics of Time Travel, given by Alasdair Richmond. Yesterday, he was talking about the way knowledge arises in causal chains. Popper (1972 and various others) argues that “Knowledge comes into existence only by evolutionary, rational processes” (quoted from Paul Nahin, ‘Time Machines: Time Travel in Physics, Metaphysics and Science Fiction, New York, American Institute of Physics, 1999: 312). Good news for us scholars of Cultural Evolution. However, Richmond also talked about the work of David Lewis on the nature of causality. There are three ways that causal chains can be set up:

The first is an infinite sequence of events each caused by the previous one. For example, I’m typing this blog because my PhD work is boring, I’m doing a PhD because I was priced in by funding, I applied for funding because everyone else did … all the way back past my parents meeting and humans evolving etc.

The second option is for a finite sequence of events – like the first option, but with an initial event that caused all the others, like the big-bang.

The third option is a circular sequence of events. In this, A is caused by B which is caused by A. For instance, I’m writing doing a PhD because I got funding and I got funding because I’m doing a PhD, because I got funding. There is no initial cause, the states just are. This third option seems really odd, not least because it involves time-travel. Where do the states come from? However, argues Lewis, they are no more odd than any of the other two options. Option one has a state with no cause and option two has a cause for every event but no original cause. So, how on earth can we get at the origin of knowledge if there is no logical possibility of determining the origin of any sequence of events?

One answer is just to stop caring after a certain point. Us linguists are unlikely to get to the point where we’re studying vowel shifts in the first few seconds of the big bang.

The other answer is noise. Richmond suggested that ‘Eureka’ moments triggered by random occurrences, for instance (Nicholas J. J. Smith, ‘Bananas Enough for Time Travel?’, British Journal for the Philosophy of Science, Vol. 48, 1997: 363-89). mishearing someone or a strange dream, could create information without prior cause.

Spookily, the idea I submitted for my PhD application came to me in a dream.