Replicated Typo

Cultural differences in lateral transmission: Phylogenetic trees are OK for Linguistics but not biology

An article in PLos ONE debunks the myth that hunter-gatherer societies borrow more words than agriculturalist societies. In doing so, it suggests that horizontal transmission is low enough for phylogenetic analyses to be a valid linguistic tool.

Lexicons from around 20% of the extant languages spoken by hunter-gatherer societies were coded for etymology (available in the supplementary material). The levels of borrowed words were compared with the languages of agriculturalist and urban societies taken from the World Loanword Database. The study focussed on three locations: Northern Australia, northwest Amazonia, and California and the Great Basin.

In opposition to some previous hypotheses, hunter-gatherer societies did not borrow significantly more words than agricultural societies in any of the regions studied.

The rates of borrowing were universally low, with most languages not borrowing more than 10% of their basic vocabulary. The mean rate for hunter-gatherer societies was 6.38% while the mean for 5.15%. This difference is actually significant overall, but not within particular regions. Therefore, the authors claim, “individual area variation is more important than any general tendencies of HG or AG languages”.

Interestingly, in some regions, mobility, population size and population density were significant factors. Mobile populations and low-density populations had significantly lower borrowing rates, while smaller populations borrowed proportionately more words. This may be in line with the theory of linguistic carrying capacity as discussed by Wintz (see here and here). The level of exogamy was a significant factor in Australia.

The study concludes that phylogenetic analyses are a valid form of linguistic analysis because the level of horizontal transmission is low. That is, languages are tree-like enough for phylogenetic assumptions to be valid:

“While it is important to identify the occasional aberrant cases of high borrowing, our results support the idea that lexical evolution is largely tree-like, and justify the continued application of quantitative phylogenetic methods to examine linguistic evolution at the level of the lexicon. As is the case with biological evolution, it will be important to test the fit of trees produced by these methods to the data used to reconstruct them. However, one advantage linguists have over biologists is that they can use the methods we have described to identify borrowed lexical items and remove them from the dataset. For this reason, it has been proposed that, in cases of short to medium time depth (e.g., hundreds to several thousand years), linguistic data are superior to genetic data for reconstructing human prehistory “

Excellent – linguistics beats biology for a change!

However, while the level of horizontal transmission might not be a problem in this analysis, there may be a problem in the paths of borrowing. If a language borrows relatively few words, but those words come from many different languages, and may have many paths through previous generations, there may be a subtle effect of horizontal transition that is being masked. The authors acknowledge that they did not address the direction of transmission in a quantitative way.

A while ago, I did study of English etymology trying to quantify the level of horizontal transmission through time (description here). The graph for English doesn’t look tree-like to me, perhaps the dynamics of borrowing works differently for languages with a high level of contact:

Claire Bowern, Patience Epps, Russell Gray, Jane Hill, Keith Hunley, Patrick McConvell, Jason Zentz (2011). Does Lateral Transmission Obscure Inheritance in Hunter-Gatherer Languages? PLoS ONE, 6 (9) : doi:10.1371/journal.pone.0025195

Scientifically Pedantic Movie Reviews…

Hello!

I’ve written a review of the new Planet of the Apes film (“Rise of the Planet of the Apes”, ARGH! OH GOD THE PLANET IS RISING etc.). It concentrates on the linguistic abilities of apes a bit, but I hope I haven’t made it too dull for the purposes of a movie review. There should be more scientifically/linguistically pedantic reviewing going on out there… get on it guys. It’s up on lablit.com now. Here’s a excerpt and link:

As someone who has dedicated quite a lot of time to reading about the linguistic abilities of apes, I didn’t enter the cinema to see “Rise of the Planet of the Apes” hoping for viable or realistic linguistic science. After all, we’ve all seen the original films and the apes talk just as humans do. It shouldn’t come as a surprise to anyone that this would never happen in the real world, and this is not just because of the cognitive abilities of apes, but also because of the vocal tract of apes. That is to say that no matter how intelligent an ape is, it will not be possible for that ape to create the sounds of English as the physical ability simply isn’t there…

Read more at: lablit.com

Free Online Machine Learning Course

Hello!

This is a quick post about a free online course on Machine Learning. The course is run by Andrew Ng at Stanford and I thought it would be of interest to those who read this blog as it covers learning algorithms which help us to understand how humans learn things as well as machines.

The course comes in structured chunks which are released a week at a time. It hasn’t started yet as it is in the pre-launch period but you can go on the site, sign up and watch the first week of videos and answer the review questions to get a head start.

It seems that this course is running as a beta version of what online courses could be in the future. If you’re even slightly interested in how machines, and indeed humans, learn I suggest you sign up and take part. You can set the difficulty as basic or advanced and it’s FREE!

You can also see a lecture series by Andrew Ng on youtube here: http://www.youtube.com/watch?index=1&v=UzxYlbK2c7E&list=PLA89DCFA6ADACE599

Neural Language Networks at Birth

I haven’t had chance to read this paper, but it throws up some interesting discussion points relating to this blog. In particular, it relates to a hypothesis I put forward last year on Domain-General Regions and Domain-Specific Networks. Here is the abstract:

The ability to learn language is a human trait. In adults and children, brain imaging studies have shown that auditory language activates a bilateral frontotemporal network with a left hemispheric dominance. It is an open question whether these activations represent the complete neural basis for language present at birth. Here we demonstrate that in 2-d-old infants, the language-related neural substrate is fully active in both hemispheres with a preponderance in the right auditory cortex. Functional and structural connectivities within this neural network, however, are immature, with strong connectivities only between the two hemispheres, contrasting with the adult pattern of prevalent intrahemispheric connectivities. Thus, although the brain responds to spoken language already at birth, thereby providing a strong biological basis to acquire language, progressive maturation of intrahemispheric functional connectivity is yet to be established with language exposure as the brain develops.

Paper Link: http://www.pnas.org/content/108/38/16056.short?rss=1

Does a Smart Phone make Smart Science?

A new paper in plos one, published today, has shown that experiments on human cognition needn’t be confined to the lab.

Experiments on human cognitive abilities, such as language, often rely on testing small and homogeneous groups of volunteers (mostly undergraduate students) coming to research facilities where they are asked to participate in behavioral experiments. This arrangement is not ideal as your sample will not be representative of the population as a whole and will also be restricted as there is only so many participants that money and time will allow you to get into the lab to be tested.

This new research by Dufau et al. shows that the sampling limitations which laboratory experiments produce can be overcome by using smartphones. Using smart phone technology, data can be collected for cognitive science experiments from thousands of subjects from all over the world.

To illustrate how this can be done the authors carried out a large-scale study using iPhone and iPads. This was a linguistic study looking at people’s ability to distinguish words from similar non-words.

The project, which began in December 2010 has managed to collect data from 4,157 subjects in just 4 months! This can be compared with the English Lexicon Project which acquired a similar volume of data using traditional methods which took more than 3 years.

The data was collected using applications which were produced in seven languages (English, Basque, Catalan, Dutch, French, Malay, Spanish). Smartphones can also support studies in alphabets other than Roman including Chinese, Greek, and Japanese. This creates the opportunity to create large-scale cross linguistic studies without even having to move from behind your desk.

Whilst the example here is linguistic there is every reason that smart phones can be implemented in looking at how universal other areas of cognitive behaviour are. Or even neurosceince and experimental philosophy. I wonder if it would be possible to carry out experiments using transmission chains using smart phones.

However, I do worry that using things like iPhones will have the same problems as using things like mechanical turk, as it means that experimenters will not be able to make sure that participants are carrying out the tasks properly and removes quite a lot of control. Smartphones are also still a luxury and therefore only people within a certain socio-economic class will have smartphones, so maybe these methods may not reach such a wide audience, which seems to be why they’re being proposed in the first place.

The authors of the paper are hailing smartphones “a potential revolution in cognitive science” but only time will tell if this really kicks off!

Reference

Stephane Dufau, Jon Andoni Dun abeitia, Carmen Moret-Tatay, Aileen McGonigal, David Peeters, F.-Xavier Alario, David A. Balota, Marc Brysbaert, Manuel Carreiras, Ludovic Ferrand, Maria Ktori, Manuel Perea, Kathy Rastle, Olivier Sasburg, Melvin J. Yap, J (2011). Smart Phone, Smart Science: How the Use of Smartphones Can Revolutionize Research in Cognitive Science PlosOne, 6 (9) : 10.1371/journal.pone.0024974

Stephen Fry’s Planet Word

Stephen Fry has embarked on a series of documentaries about language, beginning with the evolution of language which he calls ‘the final frontier’ of human understanding. The typical documentary hype is all here: Stephen Pinker sits in a gigantic fish tank with bits of taxidermied brain lying around like sandwiches; Michael Tomasello appears to live in a tropical primate enclose; Fry conducts his studies from a medieval study complete with quills, a CGI tree of languages and a talking parrot.

Despite this, it was actually a coherent and comprehensive review of topics in the field: Language versus communication in animals, phisological constraints of language, creativity and the desire to share information, the pragmatic origins of language, FoxP2 and the poverty of the stimulus. Bilingualism is even added to this cannon of interesting ways to approach the origins of language, somewhat tempered by Fry’s question “wouldn’t it be better if everybody spoke Esperanto?”.

Mercifully, Fry seems to be actually interested rather than trying to build up the conspiracy plot format endemic in other science documentaries. There are some odd diversions to a Klingon version of Hamlet, a trip to a German Christmas market and a slightly awkward re-enactment of a feral child case, but all in all the message is not objectionable: There is a graded difference between non-human and human communication, it’s partly genetic and partly cultural and languages continually change under pressures to be learned and to express new ideas. There are also welcome additions of the original Wug test and, of course, Fry & Laurie’s seminal sketch about language.

Overall, I’d say it was the second best documentary the BBC have made about the origins of language.

Here’s a clip:

Also a clip of Fry talking about the series:

Language is not necessary for analogy

Analogy is a trait thought to be uniquely human and the origin is largely unknown. Recent studies have suggested that some language trained apes can find relations between relations, which is thought to be what is at the root of analogy. However, a new study in the journal Psychological Science has tested baboons using shapes with matching features. These baboons were able to match pairs which had matching features and pairs which had no matching features.

The study was run by Joël Fagot of the Laboratoire de Psychologie Cognitive (CNRS/Université de Provence) and Roger Thompson of the Franklin & Marshall College (United States).

It has been hypothesised in the past that finding relations between relations is an ability only accessible by language, but these new findings with baboons cast doubt on this assertion.

The experiments were carried out on 29 baboons. The baboons were first shown two shapes on a screen. The baboons then touched one of these shapes and two other pairs of shapes appeared on the screen. To be successful at the task the baboons had to touch the pair representing the same relation as the initial pair. So if the first pair matched in a feature the baboon had to choose the pair which also had a matching feature, and avoid the pair where there was no matching feature, in order to gain a reward. This shows the inherent abilities behind analogy.

6 baboons correctly performed the task after thousands of trials of training showing that it is definitely within the abilities of old world monkeys to resolve analogy problems.

The researchers also revisited the same baboons with the same task a year later and the monkeys were much quicker at acquiring the task showing that they remembered what to do.

These results show that language is not necessary for analogy and leaves questions as to what might make this ability adaptive.

Reference

Fagot J, & Thompson RK (2011). Generalized Relational Matching by Guinea Baboons (Papio papio) in Two-by-Two-Item Analogy Problems. Psychological science PMID: 21934135

The evolution of computer science: Connecting top-down and bottom-up

David Krakauer from the Santa Fe Institute asks “what is intelligence?” and discusses the rift in the field of computer science between the top down, symbolic approach to cognition (how can we make a machine play chess?) and the bottom-up, inferential approach (how can we evolve a general-intelligence machine?). He suggests that the singularity – when machines will outpace human beings – will occur only when machines master both aspects. But is it a good idea to trust them?

This is a typical SFI talk, sweeping over evolving brain size, poetry, the Turing test, Evolution, the Matrix, Blade Runner and Doctor Strangelove. Fantastically, Krakauer mentions my work on a cultural singularity that I blogged about here!

Ultimately, his point is very similar to Adam Curtis’ documentary All Watched Over by Machines of Loving Grace, which is also brilliant.

See Krakauer’s talk here.

Degeneracy, Evolution and Language

Having had several months off, I thought I’d kick things off by looking at a topic that’s garnered considerable interest in evolutionary theory, known as degeneracy. As a concept, degeneracy is a well known characteristic of biological systems, and is found in the genetic code (many different nucleotide sequences encode a polypeptide) and immune responses (populations of antibodies and other antigen-recognition molecules can take on multiple functions) among many others (cf. Edelman & Gally, 2001). More recently, degeneracy is appreciated as having applications in a wider range of phenomena, with Paul Mason (2010) offering the following value-free, scientific definition:

Degeneracy is observed in a system if there are components that are structurally different (nonisomorphic) and functionally similar (isofunctional) with respect to context.

A pressing concern in evolutionary research is how increasingly complex forms “are able to evolve without sacrificing robustness or the propensity for future beneficial adaptations” (Whitcare & Bender, 2010). One common solution is to refer to redundancy: duplicate elements that have a structure-to-function ratio of one-to-one (Mason, 2010). Nature does redundancy well, and is exemplified by the human body: we have two eyes, two lungs, two kidneys, and so on. Still, even with redundant components, selection in biological systems would result in a situation where competitive elimination leads to the eventual extinction of redundant variants (ibid).

Continue reading “Degeneracy, Evolution and Language”

Confrontational scavenging as a possible source for language and cooperation

New language/cooperation paper by Bickerton and Szathmáry today. What a dream team. The best news is that it’s open access. WOO! GO OPEN ACCESS!

Here’s the abstract:

The emergence of language and the high degree of cooperation found among humans seems to require more than a straightforward enhancement of primate traits. Some triggering episode unique to human ancestors was likely necessary. Here it is argued that confrontational scavenging was such an episode. Arguments for and against an established confrontational scavenging niche are discussed, as well as the probable effects of such a niche on language and co-operation. Finally, several possible directions for future research are suggested.

Here’s a link:

http://www.biomedcentral.com/content/pdf/1471-2148-11-261.pdf