Author: Sean

I recently posted about a thematic session entitled ‘Theory and evidence in language evolution research’ at the Poznan Linguistics Meeting.  The call for paper is still open!  Here’s the call:

PLM2012 – Session CfP – Theory and evidence in language evolution

Monica Tamariz presented a poster at Evolang (runner up for the best poster award) about linguistic replicators.  This is an alternative view to Andrew Smith’s talk and Bill Benzon’s post on the same subject.

Below I’ve copied out sections of Tamariz’s poster:

Continue reading “Evolang coverage: More on linguistic replicators”

Yashuiro Suzuki (from Nagoya University, co-authoring with Megumi Sakai and Kazuhiro Adachi) presents a model of the evolution of an honest signalling system between plants and insects.  While honest signalling systems have been studied before, this was the first I harve heard of one between species, and certainly between kingdoms.

The vast majority of animals communicate to some extent.  Many signalling systems used by animals use costly signals, the paradigm case bign the peacock’s tail (Zahavi & Zahavi, 1997).  Growing a long tail imposes a developmental and predatory cost and so only fit individuals can afford to grow long tails.  This makes it difficult to trick others into thinking that you are fitter than you actually are.

However, there are systems which use ‘cheap’ signals, the most often used example being badges of status in sparrows.  Sparrows have a patch of bright feathers on their chest.  A bigger patch signals a better fighter.  This is advantageous since they can avoid fights they would not win.  Yet, there appears to be no cost to growing the patch (although this is contested by some).  Zahavi & Zahavi suggest that ‘cheaters’ who do sport badges larger than their abilities are eventually punished when they get into fights with bigger birds.  Thus, the system remains honest.

Suzuki describes a system of communication between plants and insects.  Plants are in constant danger of bugs such as caterpillars.  However, some plants can emit a chemical that attracts small insects that will come and attack and eat the bugs.  The chemical is emitted when there are many bugs attacking.  However, there are plant mutants named ‘cry-wolf’ plants who emit the chemical even when there are very few bugs attacking it.  In this way, the cry-wolf plants have a small advantage over the normal plants.  However, the cry-wolf plants damage the stability of the signalling system.  The insects are attracted to the cry-wolf plants only to find a smaller meal than expected.  If this situation presists, the insect’s association between the chemical and food diminishes and they eventually stop coming.

Continue reading “Evolang Coverage: Honest signalling between plants and insects”

Evolang is over, but I have a backlog of posts to get out!

The idea that language change can be biased by the cognitive profiles of its learners has attracted a lot of interest (see Hanna’s post), and was a frequent topic of discussion at Evolang.  In the talk by James Winters and I, we urge a pluralistic approach involving statistical tests, models and experiments.  Here I describe some of the new studies relating to this presented at the conference.

Roland Mühlenbernd and Michael Franke discuss the network properties that characterise language contact.  They constructed an agent-based model where agents had to converge on a system of mapping two meanings onto two signals.  There were two evolutionary stable mappings:  Meaning 1 maps to word 1 and Meaning 2 maps to word 2, or meaning 1 maps to word 2 and meaning 2 maps to word 1.

Agents played communication games with others to settle on the mapping they use.  Mühlenbernd & Franke used two types of agent:  The rational agent which chooses the rationally best response and reinforcement learners based around a Polya-Urn model.  However, this factor didn’t make a significant difference in the results presented in this talk.

The main focus was the structure of the social network that determined which agents interacted.  Small world networks were generated using the Watts-Strogatz method which creates a variety of networks with certain degree and centrality features.  The social structure was held constant within each run, then the results over several runs were analysed.  Homogeneity always emerged, although the reinforcement learning maintained a higher number of ‘language regions’ (where connected agents used the same mappings) for longer.  These langauge regions tended to form in tightly connected regions of the network, not surprisingly.  Mühlenbernd & Franke looked at the properties of the langauge regions, including how early agents settled on a mapping (early vs late learners) and the strategies of agents on the border between dense communities (border agents).

Interestingly, there was a big overlap in late learners and border agents.  That is, people on the border between two communities tend to be late learners.  This offers an interesting take on the hypotheses linking second language learners and linguistic change.  Lupyan & Dale (2010) find a correlation between group size and morphological complexity.  They suggest that the cognitive profiles of L2 learners biases language change towards morphologically simpler languages.

This hypothesis is further supported by the work of Christian Bentz and Bodo Winter (not to be confused with James Winters, founder of this blog) also presented at this conference which shows that the ratio of L1 to L2 speakers of a language correlates with morphological features (number of cases, cast syncretism and case symmetry), while controlling for language family and geographic region.  However, as I suggested in my talk with James Winters, backing up a statistical correlation with another statistical correlation is not as powerful as running an experiment or a model.

Mühlenbernd & Franke’s model might provide some insight into this problem.  It shows that people who are the most likely to be in contact situations (on the borders of communities) are also more likely to be late learners.  If late learners in the model can equate to L2 learners, then this suggests a closer link than previously hypothesised between L2 learners and langauge change.  It would be interesting to think more about this dynamic.  However, Franke urged caution in interpreting the model in this way, since the concept of a ‘late learner’ is fairly abstract.

As a side note, Bart de Boer raised the intriguing idea you could use statistical analyses like Bentz and Winter’s to find exceptions to the rule.  Rather than them being problematic, perhaps by studying the causes of change in these exceptions, a clearer idea of the role of L2 speakers could emerge.

What’s clear is that there is an emerging body of work surrounding the linguistic niche hypothesis using statistical and modelling techniques.  Combined with Hannah Little’s experiment on this phenomenon, I’m wondering how long before we get a special issue on this subject.

Cedric Boeckx gave a remarkable plenary which tried to pull together the fields of cultural language evolution and biolinguistics, with surprising concessions on either side.  Boeckx started from a relatively uncontroversial part of Chomsky’s claim:  That aspects of language can be studied scientifically as part of biology.  However, Boeckx noted that Luria in 1976 was confident that ‘within a few years’ linguists would be interfacing with and contributing to findings from biology.  However, formal syntax has failed to carry out the biological commitment, and Boeckx wonders why linguists don’t have more to say about, for instance, the recent developments in the study of FOXP2.

Boeckx outlined his own position as minimalist, in the sense that a fully specified UG is not plausible.  We need to realise that biology is complex, and move beyond the classical model of Broca and Wernicke’s area as dedicated centers of language.  Also, Boeckx urged the audience to forget about the FLN/FLB distinction, since from a biological viewpoint this view is misleading:  Genes build neural structures, not behaviour (although linguists should note the richness of the range of aspects now thought to be part of FLB).

Instead, Boeckx suggests that the subject of study should be a set of formal properties.  Boeckx suggested the following, while emphasising that the particular terms were not important and it is just the concepts that he would focus on:

• An edge property:  This removes selectional restrictions on concepts in different domains and makes it possible to combine them.  For example, humans can pull together concepts from very different domains.  Also, lexical items have the property of being able to combine with other lexical items.
• Set formation or Merge:  The ability to combine lexical items.
• Cyclic transfer:  Elements are combined at different levels before being passed to other operations.  This allows recursion.

These specify a minimal specification of universal grammar for which might realistically find biological explanations.  Boeckx sees no problem with the idea that we share some of these abilities with animals.  An even bigger concession is that he believes that the particular structures of language (e.g. word order or pro-drop) can be explained by cultural evolution i.e. grammaticalism.  The minimal specifications are weak biases, but we need a cultural explanation.

Boeckx went on to suggest how the biological underpinnings of the minimal specification might be approached.  He promoted the concept of the ‘Global workspace’ as used by Dehanene and colleagues.  This approach suggests that cross-modular computation is the key to human cognition.  It focuses on distributed networks of neurons with long-distance connections which allow different modules of the brain to interact.  Humans are particularly good at integrating concepts across perceptual modalities or time.  Boeckx suggests that this ability is the biological basis for the edge property.  It allows different perceptions to be treated in such a way that they can be combined.  I was put in mind of synaesthesia and the work of Chrissy Cuskley on synaesthesia and language evolution.

Boeckx went on to suggest that the thalmus could act as a regulator of information exchange in this global workspace and cited some studies showing that it is sensitive to syntax and semantics, but not phonology.  The thalmus is ideally placed – right at the center of the brain.  Boeckx also suggested that humans have evolved to have a more regularly spherical brain, facilitating this workspace by placing the thalmus equidistantly from all brain areas (suggesting that earlier ancestors of modern humans had a more elongated brain).  However, he was skeptical that we could ever know if this was an adaptation for language.

This integrative approach is in close alignment with proponents of cultural evolution such as Simon Kirby, who sees the structure of langauge as emerging from cultural transmission, but biology as proving the platform for cultural transmission.  Boeckx’s approach differs a great deal to that of Massimo Piattelli-Palmarini, whose talk essentially told cultural evolutionists that they were wrong and should stop researching explanations that could not be true.  However, one commenter wondered if Boeckx’s concessions were a dangerous form of moderate liberalism – these arguments might leave both the cultural camp and the formalist camp believing that there is no conflict and actually lead to further isolation.  However, I welcome this impressive synthesis and hope that it’ll raise the profile of cultural transmission in the evolution of language.

Luke McCrohon suggests that tools from evolutionary biology can be applied to linguistic borrowing between languages.  McCrohon correctly points out that the descent of lexicons are far from tree-like, and there is a great deal of horizontal transfer (see also my post on analysing an etymology dictionary). Although it’s mainly nouns that are borrowed into a language, any feature can potentially be borrowed, according to Thmason & Kaufman (1988).  However, we tend to observe hierarchies of borrowing such that some types of words are borrowed more frequently than others.  For instance, Haugen notes that nouns are more likely to be borrowed than verbs, which are in turn more likely to be borrowed than prepositions.  McCrohon links this with a similar observation in biological evolution that certain types of genes are more likely to be borrowed.  Informational genes (that provide the basis for functions) are less likely to be borrowed than operational genes (that modify other functions).  Jain et al.’s (1999) complexity hypothesis suggests that, while all genes have the same probability of being copied, simpler genes are more likely to be copied faithfully since they have fewer constraints on the precise form they must take to be effective.

McCrohon argues that In a similar way, the explanation of the linguistic borrowing hierarchy might also reflect the increasing constraints on how a word can be used.  For instance, most nouns can be substituted by other nouns, while prepositions are highly restricted by context or domain.  Also, language-interal change might be affected by these restrictions.  Even if there is a more effective form than in the existing system, removing one form might have knock-on consequences for the whole system.  This inter-connectedness could have implications for how languages are likely to change.

Furthermore, this model might predict that words are equally likely to be selected for borrowing, but only certain types have a good likelihood of being successfully borrowed.  However, a commenter wondered about words that are borrowed to fill conceptual gaps such as new technologies.  Still, an interesting analogy between problems in biology and problems in linguistics.  And McCrohon is confident that his studies will also have something to give back to the biology community by studying how this problem applies to linguistics.

Andrew Smith asks what are Darwinian linguistic replicators.  He starts with Croft’s conception of the lingueme.  Croft says that linguemes are external manifestations: utterances including their full context.  However, this might mean that they are not observable, since we can’t observe the full context of an utterance nor the speaker’s intention.  Furthermore, this ignores the fact that meanings are different for each hearer.  So linguemes cannot be observed on the hearer’s side either.  Nikolas Ritt’s conceptualisation of the lingueme suggests that it is an entirely internal entity.  However, this means that we can’t observe the lingueme at all.  Furthermore, it ignores the fact that langauge is ostensive and inferential.  Smith advocates a view stronger than Mufwene’s position that meanings are re-constructed in the minds of hearers:  Hearers build their own knowledge and infer the meaning of speakers – this is a far remove from replicating anything in the speaker’s mind.   So the lingueme does not replicate faithfully.  In fact, we should not expect the lingueme to replicate faithfully, but be on the opposite side of the continuum to replicators.

Smith concluded with the paradox that linguemes must contain some aspect of meaning, but meaning is individual and not observable.

Monica Tamariz asked whether linguistic replicators needed to have an aspect of meaning.  Alternatively, Tamariz argued you could have replication of forms without replication of meaning.  Smith disagreed, seeing a pairing of form and meaning as an essential part of a linguistic replicator.

Smith pointed out that some priming effects demonstrated that people can re-create speaker’s individual voices in their minds, so would this count as faithful replication.  Smith replied that we shouldn’t expect linguistic replicators to be faithfully transmitted.

Luke McCrohan later suggested that perhaps you could have replication of a communicative event- that is, the lingueme is both the speaker’s intention and the hearer’s inference and the external form.

This was a refreshing and no-nonsense take on the linguistic replicator question.  But whatever the right answer, it demonstrates that evolutionary linguists are still struggling to reconcile language in the individual and language in the environment.  Nowhere is this clearer than in models, where typically addressing one aspect compromises the other.