Special issue of Evolutionary Psychology on language evolution

The Journal of Evolutionary
Psychology has published its special issue on language evolution, and access is currently free.

Here’s the table of contents:

Evolutionary psychology and the origins of language (editorial)
Thomas C. Scott-Phillips

Review of geographic variation in terrestrial mammalian acoustic signals: Human speech variation in a comparative perspective
Adriano R. Lameira, Roberto A. Delgado and Serge A. Wich

Environment, methodology, and the object choice task in apes: Evidence for declarative comprehension and implications for the evolution of language
H. Lyn

Modelling vocal anatomy’s significant effect on speech
Bart de Boer

What exactly evolved?
A review of The Evolution of Human Language: Biolinguistic Perspectives , edited by Richard K. Larson, Viviane Déprez, Hiroko
Yamakido
Robert Truswell

A minimal approach is insufficient
A review of Language Evolution and Syntactic Theory by Anna R. Kinsella
Martin Edwardes

How language came to be?
A review of The Evolution of Language , by Tecumseh Fitch
Robin Dunbar

Imitation and Social Cognition in Humans and Chimpanzees (I): Imitation, Overimitation, and Conformity

ResearchBlogging.org

Imitation is often seen as one of the crucial foundations of culture because it is the basis of  social learning and social transmission. Only by imitating others and learning from them did human culture become cumulative, allowing humans to build and improve on the knowledge of previous generations. Thus, it may be one of the key cognitive specializations that sparked the success of the human evolutionary story:

Much of the success of our species rests on our ability to learn from others’ actions. From the simplest preverbal communication to the most complex adult expertise, a remarkable proportion of our abilities are learned by imitating those around us. Imitation is a critical part of what makes us cognitively human and generally constitutes a significant advantage over our primate relatives (Lyons et al. 2007: 19751).

Indeed, there have been some interesting experiments suggesting that the human capacity -and, above all, motivation – for imitation is an important characteristic that separates us from the other great apes.

In a series of intriguing experiments by Victoria Horner and Andrew Whiten from the University of St. Andrews in Scotland, and Derek Lyons and his colleagues from Yale University,  young wild-born chimpanzees and Children aged 3 to 4 were shown how to get a little toy turtle/ a reward out of a puzzle box. In the first condition of the experiment the puzzle box was transparent, whereas in the second condition the puzzle box was opaque.

And here’s the catch: both chimpanzees and children were not shown the ‘right’ or ‘simple’  solution to how to get the reward but one that was actually more complicated and involved unnecessary steps.

Continue reading “Imitation and Social Cognition in Humans and Chimpanzees (I): Imitation, Overimitation, and Conformity”

The Danish Language Collapse

On a lighter note, some writers at the Norwegian show Uti Vår Hage wondered what would happen if a language collapsed. It’s quite funny – they do the standard thing along the way of mocking Danish. This video reminds me of another joke I heard recently, where the Dutch refer to Afrikaans as ‘loldutch.’ For instance, giraffe is kameelperd, meaning ‘camel leopard.’ Weird. For more examples, look at the Facebook page of people making fun of Afrikaans. It’s apparently amusing, but I don’t understand a word.

Note: There are a few swear words in the video.

Erro Replicado

Replicated Typo is, as the name suggests, interested in transmission and change of cultural phenomena.  I’m also particularly interested in bilingualism.  That’s why I have to point out my recent discovery at Cognição, Linguagem e Música: A post by me, in Portuguese.

Well, more accurately, Pedro Lourenço Gomes has translated one of my recent articles.  It’s fascinating that some of my thoughts may reach people with whom I could not communicate directly.  Here’s an extract:

Original: There is a battle about to commence.  A battle in the world of cognitive modelling.  Or at least a bit of a skirmish.  Two articles to be published in Trends in Cognitive Sciences debate the merits of approaching cognition from different ends of the microscope.

Translation: Há uma batalha prestes a começar. Uma batalha no mundo da modelagem cognitiva. Ou pelo menos uma escaramuça. Dois artigos a serem publicados na Trends in Cognitive Sciences debatem os méritos de abordar a cognição a partir de lados diferentes do microscópio.

Just for comparison, here’s the original run through Google translate : Há uma batalha prestes a começar. Uma batalha no mundo da modelagem cognitiva. Ou pelo menos um pouco de uma escaramuça. Dois artigos que serão publicados no Trends in Cognitive Sciences debate o mérito de abordar a cognição de lados diferentes do microscópio.

Actually, it looks like Google translate has done an OK job, although I don’t know anything about Portuguese.  I had a look for more translations of Replicated Typo posts by searching for “Replicated Typo” with various language filters.  Alas, I could find nothing.

Cognição, Linguagem e Música looks like a great blog with reviews of books and articles and lots of posts about music.

Dog exhibits mutual exclusivity bias

Pilley & Reid (2010) describe an experiment where a border collie was trained to learn proper nouns for objects.  After 3 years of training, the dog had learned over 1,000 proper names and showed no sign of slowing.  Experiments were run to test whether the dog understood the difference between nouns and commands and whether the dog could learn words that represented categories of things.  Hot on the tail of Rico, another wonderdog, this provides striking evidence for word learning in non-primate species.

This dog has more toys than I did, including a weird levitating moose.

I liked some of the descriptions in the methodology section: “Upon successful retrieval of the item, Chaser was told ‘Good dog’.”.  There’s not nearly enough of this kind of encouragement in human experiments.  I also liked the fact that the authors posted videos with the article so you can see the experiments in action.

I’m especially interested in the mutual exclusivity experiment (although they call it ‘reasoning by exclusion’).  The dog was presented with a range of objects that the dog knew plus one unfamiliar object (how you find a toy that’s strikingly different to the other 1,000, I don’t know).  He was then asked to retrieve an object with an unfamiliar label.  Here’s the key paragraph:

Early in Chaser’s training, we corrected her immediately if she retrieved an incorrect object. As the result of this training, if she did not remember the name of an object, she would simply stand among all the objects without selecting one. Thus, on the first exclusion learning trial when she did not return with an object, a quick look revealed that she was simply standing among the objects. Only with repeated encouragements to fetch the newly named novel object, did she finally retrieve the novel object. Special encouragement was also necessary on the second replication. On the remaining six replications, she continued to retrieve novel objects successfully without further encouragement or error. Thus, Chaser was successful in eight successive replications, conducted over 8 days, in retrieving the novel objects.

Not the most clear-cut result, but the dog clearly got the idea that he was being asked for an object he had no label for.  However, it’s less clear whether the dog learned a new label in this way.  When asked to retrieve the new object with the new label immediately after the trial, the dog was successful.  However, success declined over time to well below chance after 24 hours.  Pilley & Reid suggest that positive feedback (e.g. a period of play with the toy whilst using the new label) is needed to form new word-object mappings.

Children exhibit mutual exclusivity, and can use it to learn new words.  However, this may be a learned process rather than an innate bias, because bilingual children do not reliably exhibit mutual exclusivity.  Chaser appeared to have a weak Mutual Exclusivity bias – he needed encouragement to fetch the novel object.  Learning did not occur as a process of the deduction, either.  It would be interesting to see this experiment done with a bilingual dog.  Maybe Chaser was bilingual already, with his own doggy-words for his gigantic mountain of toys.

Pilley JW, & Reid AK (2010). Border collie comprehends object names as verbal referents. Behavioural processes PMID: 21145379

Dialects in Tweets

A recent study published in the proceedings of the Empirical Methods in Natural Language Processing Conference (EMNLP) in October and presented in the LSA conference last week found evidence of geographical lexical variation in Twitter posts. (For news stories on it, see here and here.) Eisenstein, O’Connor, Smith and Xing took a batch of Twitter posts from a corpus released of 15% of all posts during a week in March. In total, they kept 4.7 million tokens from 380,000 messages by 9,500 users, all geotagged from within the continental US. They cut out messages from over-active users, taking only messages from users with less than a thousand followers and followees (However, the average author published around 40~ posts per day, which might be seen by some as excessive. They also only took messages from iPhones and BlackBerries, which have the geotagging function. Eventually, they ended up with just over 5,000 words, of which a quarter did not appear in the spell-checking lexicon aspell.

The Generative Model

In order to figure out lexical variation accurately, both topic and geographical regions had to be ascertained. To do this, they used a generative model (seen above) that jointly figured these in. Generative models work on the assumption that text is the output of a stochastic process that can be analysed statistically. By looking at mass amounts of texts, they were able to infer the topics that are being talked about. Basically, I could be thinking of a few topics – dinner, food, eating out. If I am in SF, it is likely that I may end up using the word taco in my tweet, based on those topics. What the model does is take those topics and figure from them which words are chosen, while at the same time figuring in the spatial region of the author. This way, lexical variation is easier to place accurately, whereas before discourse topic would have significantly skewed the results (the median error drops from 650 to 500 km, which isn’t that bad, all in all.)

ResearchBlogging.orgThe way it works (in summary and quoting the slide show presented at the LSA annual meeting, since I’m not entirely sure on the details) is that, in order to add a topic, several things must be done. For each author, the model a) picks a region from P( r | ∂ ) b) picks a location from P( y | lambda, v ) and c) picks a distribution over P( Theta | alpha ). For each token, it must a) pick a topic from P( z | Theta ), and then b) pick a word from P( w | nu ). Or something like that (sorry). For more, feel free to download the paper on Eisenstien’s website.

This post was chosen as an Editor's Selection for ResearchBlogging.orgWell, what did they find? Basically, Twitter posts do show massive variation based on region. There are geographically-specific proper names, of course, and topics of local prominence, like taco in LA and cab in NY. There’s also variation in foreign language words, with pues in LA but papi in SF. More interestingly, however, there is a major difference in regional slang. ‘uu’, for instance, is pretty much exclusively on the Eastern seaboard, while ‘you’ is stretched across the nation (with ‘yu’ being only slightly smaller.) ‘suttin’ for something is used only in NY, as is ‘deadass’ (meaning very) and, on and even smaller scale, ‘odee’, while ‘af’ is used for very in the Southwest, and ‘hella’ is used in most of the Western states.

Dialectical variation for 'very'

More importantly, though, the study shows that we can separate geographical and topical variation, as well as discover geographical variation from text instead of relying solely on geotagging, using this model. Future work from the authors is hoped to cover differences between spoken variation and variation in digital media. And I, for one, think that’s #deadass cool.

Jacob Eisenstein, Brendan O’Connor, Noah A. Smith, & Eric P. Xing (2010). A Latent Variable Model for Geographic Lexical Variation. Proceedings of EMNLP

Python: Your one stop shop for social science research.

Python is easy to use and pretty solid across platforms.  Drew Conway has written an essential list of python tools for social science researchers.  From running experiments to analysis and modelling, Python can do practically anything you’d ever want, mostly in two or three lines.  Hooray!

http://www.drewconway.com/zia/?p=204

Recursion: what is it, who has it, and how did it evolve?

Hello Hello and Happy New Year,

So a new article appeared on the internet late last year by Coolidge, Overmann and Wynn (2010) (hereafter referred to as COW because it makes me smile). It’s a really short sweet little paper and you should read it as recursion is perhaps one of the hottest topics around language evolution. This generally stems from Hauser, Chomsky and Fitch’s (HCF, 2002) claim that it is the only feature of language unique to humans. I thought it would be useful to outline some of the issues surrounding it as put forward by the COW paper due to its high-profile, controversial and important position within current issues in language evolution.

History

Recursion was first talked about within the field of linguistics by Bar-Hillel in 1953. This was before Chomsky included the concept in his Generative Grammar in 1956.

It wasn’t until 2002 that HCF made the claim that recursion was the only feature of language which was included in the faculty of language in the narrow sense (FLN) and was therefore unique to humans.

Definition

The article outlines two definitions of recursion (within linguistics):

(1) embeddedness of phrases within other phrases, which entails keeping track of long-distance dependencies among phrases

(2) the specification of the computed output string itself, including meta-recursion, where recursion is both the recipe for an utterance and the overarching process that creates and executes the recipe

I always worry when there is more than one definition for a thing because this often results in people talking past eachother or getting confused within their own arguments. These definition are also important to define before one starts making claims about whether recursion is present in species outside of humans or what people are talking about when referring to the evolution of recursion.

Evolutionary Scenarios

The paper also outlines two evolutionary scenarios for the adaptive value of recursion in human language.

(1) The gradualist position posits precursors, such as animal communication and protolanguages, and holds that the selective purpose of recursion was for communication.

(2) The saltationist position assumes no gradual development of recursion and posits that it evolved for reasons other than communication

The latter of these is the stand point taken by the HCF paper. Reasons for recursion evolving if one discounts communication could include the increase of working memory for other reasons or spacial navigation.

Pinker and Jackendoff (2005) argue that since recursion only exists in language to express recursive thoughts it must have pre-existed language.

COW (2010) points out that this is all very well but the question remains of what are recursive thoughts and why are they adaptive? These recursive acts may exist for the purposes of diplomatic speech, perlocutionary acts or for prospective memory and cognition (these are discussed at greater length in COW). These assume that the adaptive force was a social one which before Pinker and Jackendoff was not considered because recursion is often understood away from the social context of speech acts in the realm of mathematics.

Unique to Humans?

An often cited example debunking recursion’s importance to human language is the Piraha tribe who apparently do not have it (Everett 2005). The data from Everett is anecdotal, from one source and sketchy. Even if one was to accept the claims of lack of recursion they can be attributed to other factors such as cultural constraints or (although I think this is going a bit far, but then Bickerton always does go a bit too far) claiming the Piraha tribe have an underlying neurophysiological deficiency such as a limited working memory capacity or an extreme case of acquisitional delay.

COW then covers several animal studies which claim that recursion is present in animals including starlings and various monkeys. These are subject to the claim that the ability to acquire a phrase structure grammar means the presence of recursive ability (which is bollocks). These studies also fall short when one considers that starling’s songs are used to communicate emotional states, not recursive thoughts.

References

Bar-Hillel Y. (1953) On recursive definitions in empirical science. Proceedings of the 11th International Congress of Philosophy, Brussels. 1953, 5:160–165.

Coolidge, F., Overmann, K., & Wynn, T. (2010). Recursion: what is it, who has it, and how did it evolve? Wiley Interdisciplinary Reviews: Cognitive Science DOI: 10.1002/wcs.131

Hauser MD, Chomsky, N, Fitch (2002) The faculty of language: what is it, who has it and how did it evolve? Science, 298:1569-1579

http://www.st-andrews.ac.uk/~wtsf/downloads/HCF2002.pdf

Bored birds, busy brains: Habituation to song initiates significant molecular changes in auditory forebrain of zebra finch

When we think of habituation, we tend to think of a process in which there is a decrease in psychological and behavioural response(s) over time following an organism’s exposure to a stimulus. Conceptualising habituation in this manner seems to imply the loss of something once an initial learning event has taken place. Although this may accurately describe what occurs at the psychological and behavioural levels, a study by a group of scientists from the University of Illinois (Dong et al. 2010), which examines habituation at the neurobiological level, shows that contrary to this conceptualisation, both initial exposure and habituation to song playbacks initiates a vast array of genetic activity in the zebra finch brain.

The systematic regulation of FoxP2 expression in singing zebra finches has been the subject of previous posts, but there is also a growing literature, of which Dong et al’s study is a part, documenting increases in ZENK gene (which encodes a transcription factor protein that in turn regulates the expression of other target genes) expression in zebra finch auditory forebrain areas in response to playbacks of song or the song of a conspecific. Studies showed that ZENK expression seems to mirror the typical decline in response associated with habituation in that after a certain amount of repetition, presentation of the song that originally elicited upregulation of ZENK no longer did so, and that ZENK returned to baseline levels – although upregulation of ZENK would occur if a different song or an aspect of novelty was introduced (i.e. the original song was presented in a different visual or spatial context).

What Dong et al. have demonstrated by conducting a large scale analysis of gene expression at initial exposure, habituation, and post-habituation stages however, is that unexpectedly profound genetic changes occur as a result of habituation in the absence of any additional novel stimuli following the surge of activity observed during initial exposure to novel song. Thus, the resounding merits of the Dong et al. (2010) study lie in the broadness of their approach, providing a true sense of magnitude with respect to genomic involvement in vocal communication and illuminating important influences that have gone unnoticed by studies with a narrower focus. I summarise the experimental design and findings of the paper below.

Continue reading “Bored birds, busy brains: Habituation to song initiates significant molecular changes in auditory forebrain of zebra finch”