Peripheral anatomy and cognitive traits in crows, with a word on humans

An new paper in Nature Communications (Troscianko et al, 2012; see also the discussion at Not Exactly Rocket Science) suggests that the extraordinory extent of tool use by the New Caledonian crow (NCC) is accompanied by a morphology that differentiates them from other corvids. Specifically, a straight bill and a ever so slightly different position of their eyes enlarging their binocular sector, i.e. the part of the visual field where they have increase depth perception, allows them to follow what they’re doing with their tools much better than other crows, even when operating in narrow openings.
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Mice as vocal learners?

Short notice: There’s a new paper out in PLoS ONE (Arriaga et al., 2012) about signatures of vocal learning in mice. The main evidence is from neurological data – activation of the motor cortex during vocalisations, among others – and from behavioural experiments demonstrating sensitivity to feedback, both from others – mice modify their vocalisations when put into novel groups – and auditory feedback about their own vocalisations: the song of deafened mice deteriorates over time.

(Found through Brian Owens blogging at Nature.)

Arriaga, G., E. P. Zhou, and E. D. Jarvis (2012): Of Mice, Birds, and Men: The Mouse Ultrasonic Song System Has Some Features Similar to Humans and Song-Learning Birds. PLoS ONE 7:10: e46610. doi:10.1371/journal.pone.0046610

Adjective Order Restrictions and Perceptual Biases

A phenomenon that has been discussed much in the linguistic literature is the relative orders of stacked adjectives. In multiple unrelated languages, adjectives of different “semantic classes” display a tendency to show up in similar relative orders when jointly modifying a noun. For English, one formulation of the sequence, in abbreviated form, looks something like (1), modified after Scott (2002), but similar hierarchies can be found in other sources with sometimes very different analyses (e.g. Dixon, 1982), though some would describe them as trends rather than categorical (Bouchard, 2002; Truswell, 2009; among others).

(1) size > shape > texture > color > provenance > material > N

In other words, a stone that is both green and round would more naturally be described as

(2) a round green stone


(3) a green round stone

and similar effects are observed in many other languages (in languages with postnominal adjectives, the order is typically reversed, but what remains constant is that COLOR is closer to the noun than SHAPE in the unmarked case).

What I’m interested in is the cognitive basis for such ordering restrictions. Continue reading

pan faber – tool use and action, and the roots of language*

Language and labour

Along with language, extensive tool use is one of the defining characteristics of our species. Unlike compositional language, human tool use has clear homologues in our closest relatives. Nonetheless, there are qualitative differences between human and chimpanzee tool traditions. Only humans show cumulative evolution of (tool) culture, i.e. the innovations of one generation not only being transmitted to subsequent generations, but being built upon and refined over time in a way that allows a technological explosion.

Perhaps not surprisingly, philosophers and students of human evolution have long attempted to draw parallels and functional/causal links between the two faculties. Continue reading

Pragmatic prerequisites for human language

(This post is more a more or less verbatim replica of a post from April this year in a discussion board which I was intermittently spending way too much time on; if I were to write it now, I’d at least include a reference to Whiten (2011) (Whiten, A., Hinde, R. A., Stringer, C. B. & Laland, K. N. (2011). Culture Evolves. Phil. Trans. R. Soc. B 366, 938-948.), and maybe somewhat qualify that the dichotomy between cumulative human and non-cumulative chimpanzee culture may be based on relatively minor and gradual differences in underlying transmission mechanisms. This post was in response to another participant asking whether signing apes would “talk to researchers on their own” and what we could learn about their ways of thinking from them doing so.)

If by “talk to researchers on their own” you mean initiate a conversation untriggered by an immediate need, or by an object present in the immediate environment, the answer is no. This is in and of itself a very interesting result, though. It means that we have to be cautious when attributing differences in outcome between chimpanzees and humans to limitations on chimpanzees’ cognitive abilities – it may be that the most decisive difference underlying the presence of cumulative cultural evolution in humans (senso Tennie et al. 2009) and its absence in chimps isn’t in what chimps can’t do, but in what they won’t do. Continue reading

Accent on accentless words

Before I came to concern myself with negative concord, I was at one point thinking a lot about accent shift to proclitics in Serbo-Croatian. I was reading a lot about the Neo-Štokavian(1) accent system in general (including a Serbian translation of Lehiste and Ivić, 1986, which was, unlike the original, available through my university’s Slavic Studies department), but I didn’t find a whole lot about the accent shift specifically back then, and least of all works. Two relevant works have appeared since: Werle (2009), a dissertation analysing the phenomenon from a mostly phonological perspective, and a short paper by Aljović and Riđanović (2009). I’m writing this post because last week, I finally got my hands on the latter.

I’ll try to make this as accessible as possible to people who haven’t previously concerned themselves with proclitics and/or Serbo-Croatian intonation, so bear with me while I attempt to explain a few terms.

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Altruistic Punishment, Cultural Evolution – and Group Selection?

There’s a couple of new papers out of Tomasello’s Leipzig lab (Kaiser et al., 2012, Riedl et al.,2012) about chimpanzees’ (and bonobos’) failure to punish defectors in different experimental settings. Kaiser et al. discuss a new experiment confirming the group’s earlier finding (Jensen et al., 2007) that apes act as “rational maximisers” in an Ultimatum Game, i.e. that they accept unfair offers where humans frequently reject them despite a cost to themselves from doing so. Riedl et al. discuss the absence of third-party punishment (while showing that chimpanzees are able to discriminate, and selectively punish accordingly, unfair acts towards themselves). In both cases, the human behaviours that fail to be replicated in chimpanzees contribute to creating an environment where cooperation is more rewarding than defection.
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