There are two fascinating new papers about language evolution in Nature Neuroscience (institutional access required). The first, by Rilling et al is a comparative MRI scan of human and primates, looking at the circuit level activation of the arcuate fasciculus, the neural pathway that links two major language areas of the brain, Wernicke’s Area and Broca’s area. It is this pathway that is lesioned in Aphasiacs. They found a significant difference in the levels of connectivity and the location of the terminations of the pathway across the species. In two other control pathways where no difference was predicted, they found reasonable uniformity across the species.
Archive for the 'Animal Communication' Category
A new PLoS paper by Okanoya et al claims to show rats engaging in significant tool use. As you might expect, the paper is pretty extensive and convincing, clearly demonstrating that rats can not only use tools, but differentiate between different categories of tools in different contexts. This is another piece of evidence against the idea that only humans can use tools and that tool use is the product of some sort of higher cognitive function. Already tool use has been observed in a wide range of species, from chimpanzees to birds.
I had the pleasure of sitting next to Okanoya at dinner during Evolang. He was a lovely guy and he whipped out his laptop and showed us some of the videos in this paper. He said the paper had only really been done to prove that even rats could use tools. His team certainly wasn’t making a comment about rats in particular. As he says in the paper, this is just more evidence that “tool use is not a specific faculty resulting from higher intelligence, but is a specific combination of more general cognitive faculties”. It is important to bear in mind though that these rats were trained to use tools and we don’t have any evidence yet of natural tool use.
Well I’m back in the UK after a very pleasing Evolang 08 in Barcelona. It was an busy and fulfilling week of evolutionary linguistics, biology, primatology and cultural evolution. Our hosts were the University of Barcelona and CosmoCaixa, the fantastic local science museum. The beer and tapas certainly helped to make the week pass smoothly, although the conference threw up its usual raft of controversies.
There’s no way I can cover everything that was said in every talk, not least because lots of the sessions ran simultaneously. But I’m going to try to give you a brief outline of the plenary speakers and some of the more significant presentations I saw:
The workshop session kicked off with Duane Rumbaugh, legendary primatologist, who gave his standard talk about his primate research programme. He emphasised the importance of finding emergent behaviours in great apes, by which he meant behaviours that are insightful and synthesise learning experience without any apparent stimulus control or reinforcement. He pointed to lots of examples from Kanzi to reinforce this point. Ultimately this talk was interesting but familar.
Rumbaugh was followed by Dave Leavens, who I really couldn’t make my mind up on. He presented an argument that joint attention was essential for language competence, which seemed to fit neatly within the . However, his significant extrapolation was to present a range of evidence for pointing behaviour in primates. From this he concluded that the precursors of triadic pointing are present in other primates and therefore must (parsimonially) be in our common ancestor. I liked the argument but felt that the evidence he presented was a little bit rough around the edges, particularly his argument that environmental factors account for why we don’t see these behaviours as readily in captive chimpanzees. He drew an unnecessary and unpleasant comparison between caged primates and Romanian orphanage children, which failed to account for the differences in cognition found in these species under natural circumstances. research programme
This was followed by William Hopkins, another Yerkes researcher, who produced some excellent evidence that Chimpanzees are indeed lateralised, despite the scientific consensus. He showed some excellent studies of the differences in size of relevant brain areas, that reinforced extensive practical research performed on apes in captivity.
Many more to come as I get round to writing them up…
Understanding and sharing intentions: The origins of cultural cognition – Tomasello et al (2005)
Who’s it by? It’s by Michael Tomasello and some illustrious associates. Tomasello is a cognitive psychologist with an interest in cognitive development.
What’s it about? It presents a unifying hypothesis for a lot of the recent discoveries in human evolution, primatology and childhood development. Tomasello argues that the ability to read and share intentions is the basis for human cognition, and that we are adapted to this purpose in a way that close relatives like chimpanzees aren’t.
Why should an evolutionary linguist care? Because buried deep in that hypothesis is the assumption that language is part of this cognitive aparatus. Tomasello’s argument therefore offers the biggest contemporary challenge to the Chomskian consensus on language evolution, placing it behind the cognition of shared intentionality in terms of both emergence and importance.
So, thanks to the generosity of Chrissy Cuskley, here is a PDF of her presentation about this paper.
There is a great philosophy paper about animal cognition here. It covers a lot of familiar ground for evolutionary linguists but there is some great discussion of metacognition experiments and a pretty comprehensive list of all of the most important animal behavior papers of the last thirty years. Well worth reading for newcomers and experts alike.
Recent research demonstrates that the speed with which humans acquire and ditch new genes is the fastest yet studied in mammals. Primates are noticeably quick at genetic variation, but humans are the fastest of all, meaning that the eternally quoted “Chimps share 97 % (or 98%, take your pick) of our DNA” does not tell the whole story about genetic difference. Whilst they may share 97% of our nucleotide sequences, the differences in quantities of this gene may indicate a more notable genetic difference. According to this Science article “6.4% of the 22,000-odd human genes aren’t present in chimps” making the difference between them seem considerably larger.
Here is a high quality copy of the second part of Armand Leroi‘s acclaimed What Makes Us Human? documentary. It’s a little shallow in its representation of the issues and occasionally might have you screaming at the screen in frustration. (Pinker’s misrepresentation of the Chimpanzee language research programme had the veins popping in my neck). Overall however, it is a very good overview of all the most popular ideas in the field and is packed with great footage of Alex the Parrot, children with FOXP2 abnormalities, studies into autism and an exploration of mirror neurons. Requires the DIVX codec