The way children learn language sets the adaptive landscape on which languages evolve. This is acknowledged by many, but there are few connections between models of language acquisition and models of language Evolution (some exceptions include Yang (2002), Yu & Smith (2007) and Chater & Christiansen (2009)).
However, the chasm between the two fields may be getting smaller, as theories are defined as models which are both more interpretable to the more technically-minded Language Evolutionists and extendible into populations and generations.
Also, strangely, models of word learning have been getting simpler over time. This may reflect a move from attributing language acquisition to specific mechanisms towards a more general cognitive explanation. I review some older models here, and a recent publication by Fazly et al.
The Boston Globe reported today that Marc Hauser is on leave due to scientific misconduct . The Great Beyond summarises the article as follows:
The trouble centers on a 2002 paper published in the journal Cognition (subscription required). Hauser was the first author on the paper, which found that cotton-top tamarins are able to learn patterns – previously thought to be an important step in language acquisition. The paper has been retracted, for reasons which are reportedly unclear even to the journal’s editor, Gerry Altmann.
Two other papers, a 2007 article in Proceedings of the Royal Society B and a 2007 Science paper, were also flagged for investigation. A correction has been published on the first, and Science is now looking into concerns about the second. And the Globe article highlights other controversies, including a 2001 paper in the American Journal of Primatology, which has not been retracted although Hauser himself later said he was unable to replicate the results. Findings in a 1995 PNAS paper were also questioned by an outside researcher, Gordon Gallup of the State University of New York at Albany, who reviewed the original data and said he found “not a thread of compelling evidence” to support the paper’s conclusions.
Hauser has taken a year-long leave from the university.
Speaking in Tones: Music and Language Partner in the brain. The first of two really good articles in Scientific American. As you can guess by the title, this article is looking at current research into the links between music and language, such as the overlap in brain circuitry, how prosodic qualities of speech are vital in language development, and the way in which a person hears a set of musical notes may be affected by their native language. Sadly, the article is behind a paywall, so unless you have a subscription you’ll only get to read the first few paragraphs, plus the one I’m about to quote:
In a 2007 investigation neuroscientists Patrick Wong and Nina Kraus, along with their colleagues at Northwestern University, exposed English speakers to Mandarin speech sounds and measured the electrical responses in the auditory brain stem using electrodes placed on the scalp. The responses to Mandarin were stronger among participants who had received musical training — and the earlier they had begun training and the longer they had continued training, the stronger the activity in these brain areas.
Our hypothesis involves the unintended consequences of aesthetic and perceptual laws that evolved to help creatures quickly identify what in their surroundings is useful (food and potential mates) and what constitutes a threat (environment dangers and predators). We believe that these laws indirectly drive many aspects of the evolution of animals’ shape, size and coloration.
It’s important to note that they are not arguing against natural selection; rather, they are simply offering an addition force that guides the evolution of a species. It’s quite interesting, even if I’m not completely convinced by their hypothesis — but my criticisms can wait until they publish an actual academic paper on the subject.
A robotic model of the human vocal tract?Talking Brains links to the Anthropomorphic Talking Robot developed at Waseda University. Apparently it can produce some vowels. Here is a picture of the device (which looks like some sort of battle drone):
Battle Drone or Model Vocal Tract?
Y Chromosome II: What is its structure?Be sure to check out the new contributor over at GNXP, Kele Cable, and her article on the structure of the Y Chromosome. 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.
Scientopia. A cool collection of bloggers have banded together to form Scientopia. With plenty of articles having already appeared it all looks very promising. In truth, it’s probably not going to be as successful as ScienceBlogs, largely because it doesn’t pay contributors and, well, nothing is ever going to be as big as ScienceBlogs was at its peak. This new ecology of the science blogosphere is well articulated in a long post by Bora over at A Blog Around the Clock.
New hypothesis of language evolution. Language Evolved due to an “animal connection” according to Pat Shipman:
Next, the need to communicate that knowledge about the behavior of prey animals and other predators drove the development of symbols and language around 200,000 years ago, Shipman suggests.
For evidence, Shipman pointed to the early symbolic representations of prehistoric cave paintings and other artwork that often feature animals in a good amount of detail. By contrast, she added that crucial survival information about making fires and shelters or finding edible plants and water sources was lacking.
“All these things that ought to be important daily information are not there or are there in a really cursory, minority role,” Shipman noted. “What that conversation is about are animals.”
Of course, much evidence is missing, because “words don’t fossilize,” Shipman said. She added that language may have arisen many times independently and died out before large enough groups of people could keep it alive.
Nothing but wild conjecture as usual but still interesting.
The limitations of geological periods, imposed by physical science, cannot, of course, disprove the hypothesis of transmutation of species; but it does seem sufficient to disprove the doctrine that transmutation has taken place through ‘descent with modification by natural selection’. — Lord Kelvin (Of Geological Dynamics, 1869).
It might seem odd that I start a post about evolution with a quote claiming natural selection is inadequate to account for the transmutation of species. It is, though, highly relevant to what I’m going to discuss in the post, and strikes at the heart of why it’s fundamental for us to understand the theory of evolution by natural selection. See, in 1869, Lord Kelvin’s position was fairly reasonable, and, as you’d expect for a man of such high scientific standing, the available evidence in physics did seem to conflict with Darwin’s theory. The Sun was one particularly salient point of contention: to get the diversity of species we see on Earth, evolution needs a long time to work (on the order of hundreds of millions, if not billions of years), yet according to 19th-century physics the Sun could only have been burning for 40-million years.
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.
It is well documented that Thomas Robert Malthus’ An Essay on the Principle of Population greatly influenced both Charles Darwin and Alfred Russell Wallace’s independent conception of their theory of natural selection. In it, Malthus puts forward his observation that the finite nature of resources is in conflict with the potentially exponential rate of reproduction, leading to an inevitable struggle between individuals. Darwin took this basic premise and applied it to nature, as he notes in his autobiography:
In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work.
The interaction of demographic and evolutionary processes is thus central in understanding Darwin’s big idea: that exponential growth will eventually lead to a large population, and in turn will generate competition for natural selection to act on any heritable variation which conferred a greater fitness advantage. Under these assumptions we are able to interpret the evolutionary record of most species by appealing to two basic causal elements: genes and the environment. As we all know, in most cases the environment generates selection pressures to which genes operate and respond. For humans, however, the situation becomes more complicated when we consider another basic causal element: culture. The current paper by Richerson, Boyd & Bettinger (2009) offers one way to view this muddied situation by delineating the demographic and evolutionary processes through the notion of time scales:
The idea of time scales is used in the physical environmental sciences to simplify problems with complex interactions between processes. If one process happens on a short time scale and the other one on a long time scale, then one can often assume that the short time scale process is at an equilibrium (or in some more complex state that can be described statistically) with respect to factors governed by the long scale process. If the short time scale and long time scale interact, we can often imagine that at each time step in the evolution of the long time scale process, the short time scale process is at “equilibrium.” A separation of time scales, if justified, makes thinking about many problems of coupled dynamics much easier.
In the deliberations over humanity and its perceived uniqueness, a link is frequently made between our ability to support a rich, diverse culture and the origin of complex human behaviour. Yet what is often overlooked in our view of these two, clearly connected phenomena is the thread that weaves them together: the ability to coordinate behaviour. We need only look at the products of our culture, from language to religion, to see that any variant we may deem successful is contingent on coordinating the behaviour of two or more individuals. Still, what is truly illuminating about this ability is that, far from being a uniquely human feature, the ability to coordinate behaviour is ubiquitous throughout the many organismal kingdoms.
From the regulation and reproduction in bacteria colonies (Bassler, 2002) to complex smell and taste systems of humans (Van Toller & Dodd, 1988), the ability of sensing chemical stimuli, known as chemosensation, is believed to be the most basic and ubiquitous of senses (Bhutta, 2007). One strain of thought places chemosensation as merely an evolved ability to detect dangerous and volatile substances – such as putrefied food (see Bhutta, 2007). Still, the notion that this ability to detect chemical stimuli, particularly in the domain of smell, serves a purpose in communication is not necessarily a contemporary concept (Wyatt, 2009).
The debate concerning the origin of our minds stems back to the diverging opinions of Darwin (1871) and Wallace (1870). When Charles Darwin first discussed the evolution of our seemingly unique cognitive faculties, he proposed that there is “no fundamental difference between man and the higher mammals in their mental faculties.” (Darwin, 1871, pg. 66). Conversely, Wallace was suspicious of whether natural selection alone could have shaped the human mind, writing: “[…] that the same law which appears to have sufficed for the development of animals, has been alone the cause of man’s superior mental nature, […] will, I have no doubt, be overruled and explained away. But I venture to think they will nevertheless maintain their ground, and that they can only be met by the discovery of new facts or new laws, of a nature very different from any yet known to us.” In the intervening years, the debate surrounding the degree of continuity between animal and human minds still rages on in contemporary discussions (Bolhuis & Wynne, 2009; Penn, Holyoak & Povinelli, 2009).
