Social networks and Cooperation

January 26, 2012 in Abstracts, Science News

A new paper in Nature, by Apicella, Marlowe, Fowler & Christakis, was published today. It hypothesises that social network structure may have been present in early human history, and this structure may account for the emergence of cooperation. The study used data from the Haza people of Tanzania, who presumably already have cooperation, so I’m not sure what data they’re using to back up claims of emergence. I can’t read the article because I don’t have institutional access any more, so I’d be keen to hear thoughts others have.

Here’s the abstract:

Social networks show striking structural regularities, and both theory and evidence suggest that networks may have facilitated the development of large-scale cooperation in humans. Here, we characterize the social networks of the Hadza, a population of hunter-gatherers in Tanzania. We show that Hadza networks have important properties also seen in modernized social networks, including a skewed degree distribution, degree assortativity, transitivity, reciprocity, geographic decay and homophily. We demonstrate that Hadza camps exhibit high between-group and low within-group variation in public goods game donations. Network ties are also more likely between people who give the same amount, and the similarity in cooperative behaviour extends up to two degrees of separation. Social distance appears to be as important as genetic relatedness and physical proximity in explaining assortativity in cooperation. Our results suggest that certain elements of social network structure may have been present at an early point in human history. Also, early humans may have formed ties with both kin and non-kin, based in part on their tendency to cooperate. Social networks may thus have contributed to the emergence of cooperation.

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The Great Mystery of the Vanishing Phonemes

January 26, 2012 in Linguistics, Science

It’s been well over a year since I first wrote about the relationship between phoneme inventory size and demography (see here and here). Since then, I have completed a thesis examining this relationship further, especially in the context of the relative roles of demography and tradeoffs between other linguistic subsystems (namely, a language’s lexicon and its morphological complexity). Outside my own bubble, the topic has exploded in popularity, culminating in the publication of Quentin Atkinson’s paper, Phonemic diversity supports a Serial Founder Effect Model of Language Expansion from Africa. It really hit home how big the topic was when I saw that the New York Times had picked up on the article. For me, this was a double-edged sword: obviously, I saw myself as the phoneme-guy over at Replicated Typo, so having someone else take this niche topic and make it popular dented my ego somewhat, but it was also a positive development in that the idea was now going to get the attention it deserved…

… Well, it sort of did and didn’t. Atkinson raised two major theoretical points in his paper. The first, and the one I’m interested in, made the link between phoneme inventory sizes, mechanisms of cultural transmission and the underlying demographic processes supporting these changes. Sadly, it was Atkinson’s second idea – that we could develop a serial founder effect model from Africa based on the phoneme inventory size – where most of the attention fell. In a methodological sense, I admired Atkinson’s approach to testing this second hypothesis, but I did feel he jumped the gun somewhat: I think more work was needed on the cultural transmission model before testing for serial founder effects. Indeed, that we haven’t developed an initial model linking the relationship between phoneme inventory size and demography, may yet prove to be Atkinson’s downfall: we should be testing multiple explanatory models (Bayesian MCMC comparison, perhaps?) rather than taking a one-size-fits-all approach.

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Beware the Raconteur, my son!

January 20, 2012 in Just so, Science

We all tell stories. Be it in the elegant prose of a finely-crafted novel or merely relaying the day’s events to someone else, this capacity for storytelling is something found across our various cultures and has its roots deep in our prehistory. Stories are powerful tools with which we understand the world and share social information. They can also be dangerous. In the art of weaving together a tale, details might be omitted, others highlighted and some manipulated. Simple stories, where we abstract away from our complex and messy lives, are especially prone to this narrative fallacy, where we take facts and force an explanation into them, which, in the words of Nassim Nicholas Taleb, is misleading when it “increases our impression of understanding”. A similar warning is made in this brilliant video by Professor Tyler Cowen (of Marginal Revolution):

N.B. The featured picture is of the painting The Boyhood of Raleigh by John Everett Millais. The story behind its use here is simple: it appears on the storytelling page of wikipedia. It also began me on a quest of hyperlink jumps, but that’s another story… Yawn.

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Clever Corvid

January 16, 2012 in Irreverant and Irrelevant

Continuing with the theme of ravens, I’d thought I’d quickly point out this pretty cool video of a crow snowboarding down a roof using a small disc it found. When it gets to the bottom, the crow goes back up and does it again. This reminds me of the New Zealand orcas which have learned to surf the waves there. Hopefully, the crow teaches this to its young.

On an only tangentially related note, I’m still trying to decide if this is the use of a tool or not. If so, it’s a major win for dogs.

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The Stoned Ape Theory of Speech Origins

January 13, 2012 in Irreverant and Irrelevant, Just so

Outside the world of evolutionary linguistics I used to spend some of my time working in a charity shop. Of the many dull moments, much of which spent bickering with overzealous bargain hunters about the arbitrary nature of our pricing, there were a few gems of conversation. On one of these days, I found myself conversing with several people about language change, when one of the customers chimed in with something I hadn’t heard before. He said, quite confidently, that the origin of speech and language lay in our ancestor’s proclivity for getting stoned. I humoured him on the magic mushroom hypothesis of speech origins, until he decided to share his wisdom about the foretold destruction of our society in 2012 (at which point I directed him to our copy of Emerich’s latest disasterpiece). Still, it appears he wasn’t completely barmy, at least on the speech origins front, as there is a Stoned Ape theory of human evolution by one Terence McKenna (from Wikipedia):

The mushroom, according to McKenna, had also given humans their first truly religious experiences (which, as he believed, were the basis for the foundation of all subsequent religions to date). Another factor that McKenna talked about was the mushroom’s potency to promote linguistic thinking. This would have promoted vocalisation, which in turn would have acted in cleansing the brain (based on a scientific theory that vibrations from speaking cause the precipitation of impurities from the brain to the cerebrospinal fluid), which would further mutate the brain. All these factors according to McKenna were the most important factors that promoted evolution towards the Homo sapiens species. After this transformation took place, the species would have begun moving out of Africa to populate the rest of the planet. Later on, this theory by McKenna was given the name “The ‘Stoned Ape’ Theory of Human Evolution”.

I’m fairly sure this just offloads part of the craziness onto McKenna, but I might name drop the theory next time I’m looking for a more lively reaction when discussing language origins.

N.B. This is one of my many posts that was written some time ago. I decided to publish in 2012 just in case the customer was right about our impending doom. With that out of the way, we can now focus on the critical issues surrounding the size of a language’s phoneme inventory and the distribution of Psilocybe cubensis.

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Animal Cognition & Consciousness (II): Metacognition & Mentalizing

January 12, 2012 in Evolution, Science

As I wrote in my last post, three kinds of behaviours are most often discussed in debates about animal consciousness and cognition:

“1. Mirror self-recognition

2. Tests of metacognition;

3. Metacognition of others’ mental states” (Gómez 2009: 45)

After having discussed the first capacitiy in my previous post, I will discuss the latter two in this post, starting with metacognition, that is being aware of one’s own knowledge states, and then turn to being aware of other’s mental states.

Metacognition.

Being aware of one’s own mental states, i.e., reflective consciousness, surely seems to be one of the most crucial components of self-awareness. In one paradigm used to test for metacognitive awareness, monkeys were trained to select, out of a number of two or more images, the one that is identical to an image they have been shown earlier. As is to expected, the monkeys’ performance progressively deteriorated the longer the delay was between the sample image and the selection task.

 

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Free online Natural Language Processing course

January 11, 2012 in Uncategorized

Chris Manning and Dan Jurafsky are running a free online 8-week course on Natural Language Processing to students worldwide, January 23rd – March 18th 2012:

For those of you who know students or colleagues who might be looking for an introduction to NLP next quarter, encourage them to join us and the 40,000 students who have already registered in the course!

Students have access to screencast lecture videos, are given quiz questions, review exams and programming assignments in Java or Python, receive regular feedback on progress, and can participate in a discussion forum.

The course covers a broad range of topics in natural language processing at the advanced undergraduate or introductory graduate level, including word and sentence tokenization, text classification and sentiment analysis, spelling correction, information extraction, parsing, meaning extraction, and question answering, We will also introduce the underlying theory from probability, statistics, and machine learning that are crucial for the field, and cover fundamental algorithms like n-gram language modeling, naive bayes and maxent classifiers, sequence models, probabilistic dependency and constituent parsing, and vector-space models of meaning.

You can find more information about joining at http://www.nlp-class.org/

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Animal Cognition & Consciousness (I): Mirror Self-Recognition

January 8, 2012 in Evolution, Science

Darwin made a mistake. At least that is what Derek Penn and his colleagues (2008) claim in a recent and controversial paper in Behavioral and Brain Sciences. Darwin (1871) famously argued that the difference between humans and animals was “one of degree, not of kind.”

This, according to Penn et al. is of course true from an evolutionary perspective, but in their view,

“the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds” (Penn et al. 2008: 109).

They hold that humans are not simply smarter, but human cognition differs fundamentally and qualitatively from that of other animals.

One pervasive proposal is that we do not simply possess a unique set of cognitive capacities, but that it might be consciousness itself that is uniquely human as well, a view that goes back at least to Descartes (Burkhardt & Bekoff 2009: 41). However, there are also many scholars and researchers who agree that there is evidence for higher-order cognition in nonhuman animals ( ‘animals’ after this) and that they might possess at least some degree of consciousness (Burkhard & Bekoff 2009: 40f.).

In this and my next post, I will write about three kinds of phenomena that are most often discussed in debates on whether animals have some form of higher-order cognition and consciousness or not: self-awareness, awareness of one’s own cognitive states, and awareness of others’ cognitive states and intentions.

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Social structure and language evolution: resolving the synthetic/analytic debate

January 3, 2012 in Evolution

A cultural evolution approach to language suggests that genes encode weak prior biases that can be amplified through cultural transmission to produce strong language universals.  Below is a diagram from Kirby, Dowman & Griffiths (2007).

The link between biological predispositions and language structure, from Kirby, Dowman & Griffiths, 2007.

Note the long-term feedback between language universals and genes.  However, recent research is pointing towards a more complicated picture.  Read the rest of this entry →

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The power of diversity: New Scientist recognises the growing work on social structure and linguistic structure

December 14, 2011 in Uncategorized

A feature article in last week’s New Scientist asks why there is so much linguistic diversity present in the world, and what are the forces that drive it.  The article reads like a who’s who of the growing field of language structure and social structure:  Mark Pagel, Gary Lupyan, Quentin Atkinson, Robert Munroe, Carol and Melvin Ember, Dan Dediu and Robert Ladd, Stephen Levinson (click on the names to see some Replicated Typo articles about their work).  This is practically as close as my subject will come to having a pull-out section in Vanity Fair.  Furthermore, it recognises the weakening grip of Chomskyan linguistics.

Commentators have already gotten hung-up on whether English became simplified before or after spreading, but this misses the impact of the article:  There is an alternative approach to linguistics which looks at the differences between languages and recognises social factors as the primary source of linguistic change.  Furthermore, these ideas are testable using statistics and genetic methods.  It’s a pity the article didn’t mention the possibility of experimental approaches, including Gareth Robert’s work on emerging linguistic diversity and work on cultural transmission using the Pictionary paradigm (Simon Garrod, Nick Fay, Bruno Gallantucci, see here and here).

David Robson (2011). Power of Babel: Why one language isn’t enough New Scientist, 2842 Online

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