Category: Uncategorized

Cross-species signaling

One of the conundrums of language is why an individual would give away information.  Humans appear desperate to tell people about things.  Animals, on the other hand, aren’t that interested in communicating beyond basic signalling for survival.  However, the wildlife video below points out another problem:  Even if an animal has a desire to communicate, others might not want to listen.

This video captures the difficulty of trying to make yourself understood through arbitrary signalling systems, and the relative ease of gesture.

Something I didn’t know was that Hedgehog spines, as well as being protective,  evolved so that they can be vibrated as a form of signalling.

Mutual Exclusivity in the Naming Game

The Categorisation Game or Naming Game looks at how agents in a population converge on a shared system for referring to continuous stimuli (Steels, 2005; Nowak & Krakauer, 1999). Agents play games with each other, one referring to an object with a word and the other trying to guess what object the first agent was referring to. Through experience with the world and feedback from other agents, agents update their words. Eventually, agents are able to communicate effectively.  The model is usually couched in terms of agents trying to agree on labels for colours (a continuous meaning space).  In this post I’ll show that the algorithms used have implicit mutual exclusivity biases, which favour monolingual viewpoints.  I’ll also show that this bias is not necessary and obscures some interesting insights into evolutionary dynamics of langauge.

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Basic word order and Uniform Information Density

This week we had a talk by visiting PhD student Luke Maurits about basic word order.  The distributions of basic word orders around the world (Subject-Verb-Object, Subject-Object-Verb etc. ) has been the focus of much attention.  The overwhelming majority of languages have SOV and SVO orders, with fewer having VSO and very small numbers having OVS and OSV.  In order of frequency, this is:

(SOV, SVO) > VSO > (VOS, OVS) > OSV

A standard approach has been to assume that this ordering reflects an ordering of functionality:  Somehow, SOV order is more functional or efficient or intuitive than OSV.  However, Maurits points out that the literature on diachronic change opposes this view.  Languages often change from SOV to VSO or SVO over time, but rarely the other way around (see diagram below).

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Animal Signalling Theory 101 – The Handicap Principle

One of the most important concepts in animal signalling theory, proposed by Amotz Zahavi in a seminal 1975 paper and in later works (Zahavi 1977; Zahavi & Zahavi 1997), is the handicap principle. A general definition is that females have evolved mating preferences for males who display exaggerated ornaments or behaviours that are costly to maintain and develop, and that this cost ensures an ‘honest’ signal of male genetic quality.

As a student I found it quite difficult to identify a working definition for this important type of signal mainly due to the apparent ‘coining fest’ that has taken place over the years since Zahavi outlined his original idea in 1975. For this reason, I have decided to provide a brief outline of the terminological and conceptual differences that exist in relation to the handicap principle in an attempt to help anyone who might be struggling to navigate the literature.

As Zahavi did not define the handicap principle mathematically, a number of interpretations can be found in the key literature due to scholars disagreeing as to the true nature of his original idea. Until John Maynard Smith and Harper simplified and clarified things wonderfully in their 2003 publication Animal Signals, to my knowledge at least four different interpretations of the handicap were being used and explored empirically and through mathematical modelling, each with distinct differences that aren’t all that obvious to grasp without delving into the maths.

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Sexual Selection in the age of Mass Media

This month a red deer was crowned as Emperor of Exmoor and Britain’s largest wild animal in a series of newspaper articles.  Today, it’s emerged that the deer has been shot by a hunter willing to pay the presumably high price on the hunting rights.

When Richard Austin, the photographer that took the pictures for the articles, was asked if he felt responsible, he said that he always believed the size of the deer’s antlers would get him killed in the end.  The Emperor’s antlers may have kept other deer away, but it attracted far deadlier predators.  Humans have been breeding animals – and killing them – for sport for a long time, but it’s only recently that prize targets can be advertised so widely.  The size of the antlers may be a product of sexual selection, but now cultural processes are counteracting this.  The Emperor was even killed during the mating season, unable to pass on its genes.  If you’re a deer, it’s maybe best to stay mid-size rather than risk the growing threat of trophy-hunting.

In Praise of the Garrulous

Today we had a talk by the author and translator Allan Cameron on his new book ‘In Praise of the Garrulous‘.  In it, he sings the praise of ‘Garrulousness’ or talkativeness, and rejects the idea that human languages were initially homogeneous.  Indeed, he claimed that monolingualism is not our natural state, but we are designed to handle multiple languages, dialects and registers.

He also talked about the idea that there is a trade-off between linguistic diversity and the ability of a society to accumulate knowledge through technologies such as writing.  Although he did acknowledge that some systems (e.g. Chinese) protect linguistic diversity by transcending exact phonetic representation.

The talk was illustrated by a wide range of sources – literary and historical – including the role of the printing industry in Venice on the standardisation and spread of modern day Italian.  The book promises to be an  interesting approach to language evolution that takes into account many aspects that current scientific researchers leave out such as how power and war influence how languages change.

Under the Influence: An overview of recent insights into the CNTNAP2 gene

In my last post I outlined a number of experimental studies using the Zebra Finch that have highlighted an additional dimension to the FoxP2 gene – not only is it upregulated in the avian brain throughout song development, but it is also downregulated in important song nuclei of adult birds in singing contexts that seem to involve ‘listening to one’s own song’ and subsequent error correction.  Given that the pattern of expression of this gene is very similar in the developing brain of both humans and birds, one conclusion that has been drawn from this research is that FOXP2 downregulation may equivocally serve to facilitate online language processing function in the adult human brain.

General background on an intriguing new celebrity

Naturally, the next step has been to try and identify the downstream genes regulated by FOXP2 in order to build up a more detailed picture of how interactions between complex genetic networks influence key language-related disorders in humans.   It is as a result of such efforts that another gene, although discovered almost a decade ago, has found its way into the spotlight: CNTNAP2.

In the developing human brain, CNTNAP2 is enriched in functionally specialised regions such as the frontal cortex, the stratium, and the dorsal thalamus (circuits within these regions are referred to as cortico-striato-thalmic circuits) central to executive function, planning and executing complex sequential movements, and thus potentially, language.  This presents a striking contrast to the more uniform expression of Cntnap2 observed in the developing rodent brain where there is no evidence for enrichment in specific regions, suggesting a functional difference in the human version that could be related to vocal learning and modification.

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Futurama Supports Cultural Evolution

A recent episode of Futurama – ‘A clockwork Origin‘ – sees the Professor go head to head with Creationists, and makes a good point about the difference between Creationism and Evolution.

After his work on the origin of man is mocked, the Professor decides to leave Earth for a desolate planet. However, the nano-bots which he designs to purify the water evolve overnight into a full-scale ecosystem, complete with robo-dinosaurs that are eventually wiped out by a solar flare.

At first, the Professor is unwilling to see the change in the robots as Evolution, saying ‘Those robots didn’t evolve by themselves, I put them there – I’m a genius, get over it’. However, after the crew is captured by robo-anthropologists (anthrobopologists?), he’s forced to admit that they really have Evolved. Further, he’s forced to admit that he has no problem with the idea of a creator playing a small part in the origins of Humans, just as he started the race of robots.

This is all good news for those studying Cultural Evolution – people are coming round to the idea that Evolution is an abstract process rather than the theory of how humans evolved from apes.  Perhaps us researchers will be spared in the robot uprising, which is sure to come:  As Bender says “Robots do everything faster, including evolving”.

Language, Thought, and Space (V): Comparing Different Species

ResearchBlogging.org As I’ve talked about in my last posts (see I, II, III, and IV) different cultures employ different coordinate systems or Frames of References (FoR) when talking about space.  FoRs

“serve to specify the directional relationships between objects in space, in reference to a shared referential anchor” (Haun et al. 2006: 17568)

As shown in my last post these linguistic differences seem to reflect certain cognitive differences:

Whether speakers mainly use a relative, ego-based FoR, a cardinal-direction/or landmark-based absolute FoR, or an object-based, intrinsic based FoR, also influences how they solve and conceptualise spatial tasks.

In my last post I also posed the question whether there is a cognitive “default setting” that we and the other great apes inherited from our last common ancestor that is only later overridden by cultural factors. The  crucial question then is which Frame of Reference might be the default one.

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