CfP: New Directions in Language Evolution Research

Panorama of Tallinn from the sea (Source: https://commons.wikimedia.org/wiki/File%3ATallinnPan.jpg, by Terker, CC-BY-SA 3.0)

Jonas Nölle, Peeter Tinits and I are going to submit a workshop proposal to next year’s Annual Meeting of the Societas Linguistica Europaea (SLE), which will be held in Tallinn from August 29th to September 1st, 2018. We thought this would be a nice opportunity to bring evolutionary linguistics to SLE – and a also a good opportunity to discuss novel and innovative approaches to language evolution in a condensed workshop setting.

Please note that there will be – as usual at SLE – a three-step selection process:

Step 1: You submit a 300-word abstract to us (the organizers: newdir.langev@gmail.com) by November 10th. We then select up to 12 papers that we include in our workshop proposal. As we want the “New directions” in our title to be more than a shallow phrase, we will base our selection as much as possible on the innovativeness of the abstracts we receive. If we’re unable to consider your paper for the workshop, there’s still the option to submit to the general session.

Step 2: Our workshop proposal is then reviewed by the scientific committee, and we’ll receive a notification of acceptance or rejection by December 15th. Good news: If you’ve submitted an abstract, there’s nothing for you to do at this point except for keeping your fingers crossed.

Step 3: If the workshop is accepted, we will ask you to submit a 500-word abstract via the conference submission system, which will be peer-reviewed like any general session paper. Notifications of acceptance or rejection can be expected in March 2018.

We’re looking forward to your contributions, and regardless of the outcome of our proposal, we hope to see many of you in Tallinn!

Here’s our CfP, which will also appear on Linguist List and on the official SLE2018 website soon:

Research on language evolution is undoubtedly among the fastest-growing topics in linguistics. This is not a coincidence: While scholars have always been interested in the origins and evolution of language, it is only now that many questions can be addressed empirically drawing on a wealth of data and a multitude of methodological approaches developed in the different disciplines that try to find answers to what has been called “the hardest problem in science” (Christiansen & Kirby 2003). Importantly, any theory of how language may have emerged requires a solid understanding of how language and other communication systems work. As such, the questions in language evolution research are manifold and interface in multiple ways with key open questions in historical and theoretical linguistics: What exactly makes human language unique compared to animal communication systems?  How do cognition, communication and transmission shape grammar? Which factors can explain linguistic diversity? How and why do languages change? To what extent is the structure of language(s) shaped by extra-linguistic, environmental factors?

Over the last 20 years or so, evolutionary linguistics has set out to find answers to these and many more questions. As, e.g., Dediu & De Boer (2016) have noted, the field of language evolution research is currently coming of age, and it has developed a rich toolkit of widely-adopted methods both for comparative research, which investigates the commonalities and differences between human language and animal communication systems, and for studying the cumulative cultural evolution of sign systems in experimental settings, including both computational and behavioral approaches (see e.g. Tallerman & Gibson 2012; Fitch 2017). In addition, large-scale typological studies have gained importance in recent research on language evolution (e.g. Evans 2010).

The goal of this workshop is to discuss innovative theoretical and methodological approaches that go beyond the current state of the art by proposing and empirically testing new hypotheses, by developing new or refining existing methods for the study of language evolution, and/or by reinterpreting the available evidence in the light of innovative theoretical frameworks. In this vein, we aim at bringing together researchers from multiple disciplines and theoretical backgrounds to discuss the latest developments in language evolution research. Topics include, but are not limited to,

  • experimental approaches investigating the emergence and/or development of sign systems in frameworks such as experimental semiotics (e.g. Galantucci & Garrod 2010) or artificial language learning (e.g. Kirby et al. 2014);
  • empirical research on non-human communication systems as well as comparative research on animal cognition with respect to its relevance for the evolution of cognitive prerequisites for fully-fledged human language (Kirby 2017);
  • approaches using computational modelling and robotics (Steels 2011) in order to investigate problems like the grounding of symbol systems in non-symbolic representations (Harnad 1990), the emergence of the particular features that make human language unique (Kirby 2017, Smith 2014), or the question to what extent these features are domain-specific, i.e. evolved by natural selection for a specifically linguistic function (Culbertson & Kirby 2016);
  • research that explicitly combines expertise from multiple different disciplines, e.g. typology and neurolinguistics (Bickel et al. 2015); genomics, archaeology, and linguistics (Pakendorf 2014, Theofanopoulou et al. 2017); comparative biology and philosophy of language (Moore 2016); and many more.

If you are interested in participating in the workshop, please send an abstract (c. 300 words) to the organizers (newdir.langev@gmail.com) by November 10th. We will let you know by November 15th if your paper is eligible for the proposed workshop. If our workshop proposal is accepted, you will be required to submit an anonymous abstract of ca. 500 words via the SLE submission system by January 15th. If our proposal is not accepted or if we cannot accommodate your paper in the workshop, you can still submit your abstract as a general session paper.

References

Bickel, Balthasar, Alena Witzlack-Makarevich, Kamal K. Choudhary, Matthias Schlesewsky & Ina Bornkessel-Schlesewsky. 2015. The Neurophysiology of Language Processing Shapes the Evolution of Grammar: Evidence from Case Marking. PLOS ONE 10(8). e0132819.

Christiansen, Morten H. & Simon Kirby. 2003. Language Evolution: The Hardest Problem in Science. In Morten H. Christiansen & Simon Kirby (eds.), Language Evolution, 1–15. (Oxford Studies in the Evolution of Language 3). Oxford: Oxford University Press.

Culbertson, Jennifer & Simon Kirby. 2016. Simplicity and Specificity in Language: Domain-General Biases Have Domain-Specific Effects. Frontiers in Psychology 6. doi:10.3389/fpsyg.2015.01964.

Dediu, Dan & Bart de Boer. 2016. Language evolution needs its own journal. Journal of Language Evolution 1(1). 1–6.

Evans, Nicholas. 2010. Language diversity as a tool for understanding cultural evolution. In Peter J. Richerson & Morten H. Christiansen (eds.), Cultural Evolution : Society, Technology, Language, and Religion, 233–268. Cambridge: MIT Press.

Fitch, W. Tecumseh. 2017. Empirical approaches to the study of language evolution. Psychonomic Bulletin & Review 24(1). 3–33.

Galantucci, Bruno & Simon Garrod. 2010. Experimental Semiotics: A new approach for studying the emergence and the evolution of human communication. Interaction Studies 11(1). 1–13.

Harnad, Stevan. 1990. The symbol grounding problem. Physica D 42. 335–346.

Kirby, Simon, Tom Griffiths & Kenny Smith. 2014. Iterated Learning and the Evolution of Language. Current Opinion in Neurobiology 28. 108–114.

Kirby, Simon. 2017. Culture and biology in the origins of linguistic structure. Psychonomic Bulletin & Review 24(1). 118–137.

Moore, Richard. 2016. Meaning and ostension in great ape gestural communication. Animal Cognition 19(1). 223–231.

Pakendorf, Brigitte. 2014. Coevolution of languages and genes. Current Opinion in Genetics & Development 29. 39–44.

Smith, Andrew D.M. 2014. Models of language evolution and change: Language evolution and change. Wiley Interdisciplinary Reviews: Cognitive Science 5(3). 281–293.

Steels, Luc. 2011. Modeling the Cultural Evolution of Language. Physics of Life Reviews 8. 339–356.

Tallerman, Maggie & Kathleen R. Gibson (eds.). 2012. The Oxford Handbook of Language Evolution. Oxford: Oxford University Press.

Theofanopoulou, Constantina, Simone Gastaldon, Thomas O’Rourke, Bridget D. Samuels, Angela Messner, Pedro Tiago Martins, Francesco Delogu, Saleh Alamri & Cedric Boeckx. 2017. Self-domestication in Homo sapiens: Insights from comparative genomics. PLOS ONE 12(10). e0185306.

Call for participation: IACS3 in Toronto

Call for papers of IACS3 in Toronto is below, including research topics of experimental semiotics, speech and gesture and the evolution of language. And lots more, of course. Full call can be seen here: http://www.perceptualartifacts.org/iacs-2018/cfp.html

The International Association for Cognitive Semiotics in cooperation with OCAD University and Ryerson University is pleased to announce The Third Conference of the International Association for Cognitive Semiotics (IACS3 – 2018) TorontoOntarioCanada: iacs-2018.org

Plenary speakers confirmed (as of )

  • John M. Kennedy • University of Toronto
  • Kalevi Kull • University of Tartu
  • Maxine Sheets-Johnstone • University of Oregon

Conference Theme: MULTIMODALITIES

This non-restrictive theme is intended to encourage the exploration of pre-linguistic and extra-linguistic modes of semiotic systems and meaning construal, as well as their intersection with linguistic processes.

Cognitive Semiotics investigates the nature of meaning, the role of consciousness, the unique cognitive features of human beings, the interaction of nature and nurture in development, and the interplay of biological and cultural evolution in phylogeny. To better answer such questions, cognitive semiotics integrates methods and theories developed in the human, social, and cognitive sciences.

The International Association for Cognitive Semiotics (IACS, founded 2013) aims at establishing cognitive semiotics as a trans-disciplinary study of meaning. More information on the International Association for Cognitive Semiotics can be found at http://iacs.dk

The IACS conference series seeks to gather together scholars and scientists in semiotics, linguistics, philosophy, cognitive science, psychology and related fields, who wish to share their research on meaning and contribute the interdisciplinary dialogue.

Topics of the conference include (but are not limited to):

  • Biological and cultural evolution of human cognitive specificity
  • Cognitive linguistics and phenomenology
  • Communication across cultural barriers
  • Cross-species comparative semiotics
  • Evolutionary perspectives on altruism
  • Experimental semiotics
  • Iconicity in language and other semiotic resources
  • Intersubjectivity and mimesis in evolution and development
  • Multimodality
  • Narrativity across different media
  • Semantic typology and linguistic relativity
  • Semiosis (sense-making) in social interaction
  • Semiotic and cognitive development in children
  • Sign use and cognition
  • Signs, affordances, and other meanings
  • Speech and gesture
  • The comparative semiotics of iconicity and indexicality
  • The evolution of language

We invite abstract submissions for theme sessions, oral presentations and posters. Please select your chosen format along with your submission. Format types and guidelines are here:  http://www.perceptualartifacts.org/iacs-2018/cfp.html

Important Dates

Deadline for submission of theme sessions:
Deadline for abstract submission (oral presentations, posters):
Notification of acceptance (oral presentations, posters):
Last date for early registration:

Usage context and overspecification

A new issue of the Journal of Language Evolution has just appeared, including a paper by Peeter Tinits, Jonas Nölle, and myself on the influence of usage context on the emergence of overspecification. (It has actually been published online already a couple of weeks ago, and an earlier version of it was included in last year’s Evolang proceedings.) Some of the volunteers who participated in our experiment have actually been recruited via Replicated Typo – thanks to everyone who helped us out! Without you, this study wouldn’t have been possible.

I hope that I’ll find time to write a bit more about this paper in the near future, especially about its development, which might itself qualify as an interesting example of cultural evolution. Even though the paper just reports on a tiny experimental case study, adressing a fairly specific phenomenon, we discovered, in the process of writing, that each of the three authors had quite different ideas of how language works, which made the write-up process much more challenging than expected (but arguably also more interesting).

For now, however, I’ll just link to the paper and quote our abstract:

This article investigates the influence of contextual pressures on the evolution of overspecification, i.e. the degree to which communicatively irrelevant meaning dimensions are specified, in an iterated learning setup. To this end, we combine two lines of research: In artificial language learning studies, it has been shown that (miniature) languages adapt to their contexts of use. In experimental pragmatics, it has been shown that referential overspecification in natural language is more likely to occur in contexts in which the communicatively relevant feature dimensions are harder to discern. We test whether similar functional pressures can promote the cumulative growth of referential overspecification in iterated artificial language learning. Participants were trained on an artificial language which they then used to refer to objects. The output of each participant was used as input for the next participant. The initial language was designed such that it did not show any overspecification, but it allowed for overspecification to emerge in 16 out of 32 usage contexts. Between conditions, we manipulated the referential context in which the target items appear, so that the relative visuospatial complexity of the scene would make the communicatively relevant feature dimensions more difficult to discern in one of them. The artificial languages became overspecified more quickly and to a significantly higher degree in this condition, indicating that the trend toward overspecification was stronger in these contexts, as suggested by experimental pragmatics research. These results add further support to the hypothesis that linguistic conventions can be partly determined by usage context and shows that experimental pragmatics can be fruitfully combined with artificial language learning to offer valuable insights into the mechanisms involved in the evolution of linguistic phenomena.

In addition to our article, there’s also a number of other papers in the new JoLE issue that are well worth a read, including another Iterated Learning paper by Clay Beckner, Janet Pierrehumbert, and Jennifer Hay, who have conducted a follow-up on the seminal Kirby, Cornish & Smith (2008) study. Apart from presenting highly relevant findings, they also make some very interesting methodological points.

MMIEL Summer School in experimental and statistical methods

September Tutorial in Empiricism: Practical Help for Experimental Novices

In September, the Language Evolution and Interaction Scholars of Nijmegen (LEvInSoN group), based in the Language and Cognition Department at the Max Planck Institute for Psycholinguistics will be hosting a workshop about research in Language Evolution and Interaction (September 21-22) – call for posters here: http://www.mpi.nl/events/MMIEL

As an addition to this workshop, we will be hosting a short tutorial series bookending the workshop (Sept 20 & 23) covering experimental and statistical methods that should be of broad interest to a general audience. In this tutorial series, we will cover all aspects of creating, hosting, and analysing the data from a set of experiments that will be run live (online) during the workshop.

Details of the summer school can be found here: http://www.mpi.nl/events/MMIEL/summer-school

 

Registration is free, but required. Spots are limited and come on a first come first served basis, and a waitlist will be established if necessary.

Register here

EVOLANG XII (2018): Call for Papers

The 12th International Conference on the Evolution of Language invites substantive contributions relating to the evolution of human language.

IMPORTANT DATES
Abstract submission: 1 September 2017 Add deadline to calendar
Notification of acceptance: 1 December 2017
Early-bird fee: 31 December 2017
Conference: 16-19 April 2018

Submission Information
Submissions may be in any relevant discipline, including, but not limited to: anthropology, archeology, artificial life, biology, cognitive science, genetics, linguistics, modeling, paleontology, physiology, primatology, philosophy, semiotics, and psychology. Normal standards of academic excellence apply. Submitted papers should aim to make clear their own substantive claim, relating this to the relevant, up to date scientific literature in the field of language evolution. Submissions should set out the method by which the claim is substantiated, the nature of the relevant data, and/or the core of the theoretical argument concerned. Novel and original theory-based submissions are welcome. Submissions centred around empirical studies should not rest on preliminary results.

Please see http://evolang.org/submissions for submission templates and further guidance on submission preparation. Submissions can be made via EasyChair (https://easychair.org/conferences/?conf=evolang12) by SEPTEMBER 1, 2017 for both podium presentations (20 minute presentation with additional time for discussion) and poster presentations. All submissions will be refereed by at least three relevant referees, and acceptance is based on a scoring scheme pooling the reports of the referees. In recent conferences, the acceptance rate has been about 50%. Notification of acceptance will be given by December 1, 2017.

For any questions regarding submissions to the main conference please contact scientific-committee@evolang.org.

Workshops: in addition to the general session, EVOLANG XII will host up to five thematically focused, half-day workshops. See here for the Call for Workshops.

Deadline extended for Triggers of Change in the Language Sciences

The deadline for the 2nd XLanS conference on Triggers of Change in the Language Sciences has extended its submission deadline to June 14th.

This year’s topic is ‘triggers of change’:  What causes a sound system or lexicon or grammatical system to change?  How can we explain rapid changes followed by periods of stability?  Can we predict the direction and rate of change according to external influences?

We have also added two new researchers to our keynote speaker list, which now stands as:

 

Wh-words sound similar to aid rapid turn taking

A new paper by Anita Slonimska and myself attempts to link global tendencies in the lexicon to constraints from turn taking in conversation.

Question words in English sound similar (who, why, where, what …), so much so that this class of words are often referred to as wh-words. This regularity exists in many languages, though the phonetic similarity differs, for example:

English Latvian Yaqui Telugu
haw ka: jachinia elaa
haw mɛni tsik jaikim enni
haw mətʃ tsik jaiki enta
wət kas jita eem;eemi[Ti]
wɛn kad jakko eppuDu
wɛr kuɾ jaksa eTa; eedi; ekkaDa
wɪtʃ kuɾʃ jita eevi
hu kas jabesa ewaru
waj ˈkaːpeːts jaisakai en[du]ceeta; enduku

In her Master’s thesis, Anita suggested that these similarities help conversation flow smoothly.  Turn taking in conversation is surprisingly swift, with the usual gap between turns being only 200ms.  This is even more surprising when one considers that the amount of time it takes to retrieve, plan and begin pronouncing one word is 600ms.  Therefore, speakers must begin planning what they will say before current speaker has finished speaking (as demonstrated by many recent studies, e.g. Barthel et al., 2017). Starting your turn late can be interpreted as uncooperative, or lead to missing out on a chance to speak.

Perhaps the harshest environment for turn-taking is answering a content question.  Responders must understand the question, retrieve the answer, plan their utterance and begin speaking.  It makes sense to expect that cues would evolve to help responders recognise that a question is coming.  Indeed there are many paralinguistic cues, such as rising intonation (even at the beginning of sentences) and eye gaze.  Another obvious cue is question words, especially when they appear at the beginning of question sentences. Slonimska hypothesised that wh-words sound similar in order to provide an extra cue that a question is about to be asked, so that the speaker can begin preparing their turn early.

We tried to test this hypothesis, firstly by simply asking whether wh-words really do have a tendency to sound similar within languages.  We combined several lexical databases to produce a word list for 1000 concepts in 226 languages, including question words.  We found that question words are:

  • More similar within languages than between languages
  • More similar than other sets of words (e.g. pronouns)
  • Often composed of salient phonemes

Of course, there are several possible confounds, such as languages being historically related, and many wh-words being derived from other wh-words within a language. We attempted to control for this using stratified permutation, excluding analysable forms, and comparing wh words to many other sets of words such as pronouns which are subject to the same processes.  Not all languages have similar-sounding wh-words, but across the whole database the tendancy was robust.

Another prediction is that the wh-word cues should be more useful if they appear at the beginning of question sentences.  We tested this using typological data on whether wh-words appear in initial position.  While the trend was in the right direction, the result was not significant when controlling for historical and areal relationships.

Despite this, we hope that our study shows that it is possible to connect constraints from turn taking to macro-level patterns across languages, and then test the link using large corpora and custom methods.

Anita will be presenting an experimental approach to this question at this year’s CogSci conference.  We show that /w,h/ is a good predictor of questions in real English conversations, and that people actually use /w,h/ to help predict that a question is coming up.

Slonimska, A., & Roberts, S. G. (2017). A case for systematic sound symbolism in pragmatics: Universals in wh-words. Journal of Pragmatics, 116, 1-20. ArticlePDF.

All data and scripts are available in this github repository.

Call for Posters – Minds, Mechanisms and Interaction in the Evolution of Language

The workshop “Minds, Mechanisms and Interaction in the Evolution of Language” will be hosted at the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands on 21st-22nd September 2017. The workshop will include a poster session on topics related to the themes of the meeting. We are interested in contributions investigating the emergence and evolution of language, specifically in relation to interaction.

We are looking for work in the following areas:

  • biases and pre-adaptations for language and interaction
  • cognitive and cultural mechanisms for linguistic emergence
  • interaction as a driver for language evolution

We invite submissions of abstracts for posters, particularly from PhD students and junior researchers.

Please submit an abstract of no more than 300 words (word count not including references) by email to hannah.little@mpi.nl.  Please include a title, authors, affiliations and contact email addresses.  

Deadline: July 9th 2017

Outcome of decision process by: 24th July

Abstracts will be reviewed by the workshop committee.

The poster session will take place on the evening of Thursday September 21st 2017.

Registration is free (details to follow).

Plenary speakers:

  • David Leavens, University of Sussex
  • Jennie Pyers, Wellesley College
  • Monica Tamariz, Heriot Watt University

The workshop also includes presentations from the Levinson group (Language Evolution and Interaction Scholars of Nijmegen)  and an introduction by Stephen Levinson himself!

Summer school:

The workshop will also be bookended with a summer school on 20th and 23rd September specifically aimed at PhD students. The school will consist of a short tutorial series covering experimental and statistical methods that should be of broad interest to a general audience, though focussed around the theme of the workshop. In this tutorial series, we will cover all aspects of creating, hosting, and analysing the data from a set of experiments that will be run live (online) during the workshop! More details for the summer school and registration will follow.

2 PhD positions available with Bart de Boer in Brussels!

Two PhD positions are available in the AI lab at the Vrije Universiteit Brussel with Bart de Boer.

One position is on modelling an emerging sign language:

We are looking for a PhD student to work on modeling the emergence of sign languages, with a focus on modeling the social dynamics underlying existing signing communities.  The project relies on specialist expertise of the Kata Kolok signing community that has emerged in a Balinese village over the course of several generations. The emergence of Kata Kolok, and the demographics of the village have been closely studied by geneticists, anthropologists, and linguists. A preliminary model has been built in Python, simulating this emergence. The aim of the project is to investigate, using a combination of linguistic field research and computational modeling which factors – cultural, genetic, linguistic and others –  determine the way language emerges. There will be one PhD student in Nijmegen conducting primary field research on Kata Kolok and one based in Brussels (as advertised here) to be involved in the computational aspect of the project. Both positions are part of a FWO-NWO funded collaboration of the Artificial Intelligence lab of the Vrije Universiteit Brussel and the Center for Language Studies at Radboud University Nijmegen and the advertised position is supervised by profs. Bart de Boer and Connie de Vos.

Advertisement here: https://ai.vub.ac.be/PhDKataKolok

The other is on modelling acquisition of speech:

We are looking for someone who has (or who is about to complete) a master’s degree in artificial intelligence, speech technology, computer science or equivalent. You will work on a project that investigates advanced techniques for learning the building blocks of speech, with a focus on spectro-temporal features and dynamic Bayesian networks. It is part of the Artificial Intelligence lab of the Vrije Universiteit Brussel and is supervised by prof. Bart de Boer.

Advertisement here: https://ai.vub.ac.be/PhD_Spectrotemporal_DBN

The deadline for application is 1st July 2017. Other details available at the links above.

Questions about details of the positions themselves should be directed to Bart de Boer (bart@arti.vub.ac.be). However, I myself did my PhD with Bart at the VUB, so I’d also be happy to answer more informal questions about working in the lab/living in Belgium/other things (hannah@ai.vub.ac.be).

Iconicity evolves by random mutation and biased selection

A new paper by Monica Tamariz, myself, Isidro Martínez and Julio Santiago uses an iterated learning paradigm to investigate the emergence of iconicity in the lexicon.  The languages were mappings between written forms and a set of shapes that varied in colour, outline and, importantly, how spiky or round they were.

We found that languages which begin with no iconic mapping develop a bouba-kiki relationship when the languages are used for communication between two participants, but not when they are just learned and reproduced.  The measure of the iconicity of the words came from naive raters.

Here’s one of the languages at the end of a communication chain, and you can see that the labels for spiky shapes ‘sound’ more spiky:

An example language from the final generation of our experiment: meanings, labels and spikiness ratings.

These experiments were actually run way back in 2013, but as is often the case, the project lost momentum.  Monica and I met last year to look at it again, and we did some new analyses.  We worked out whether each new innovation that participants created increased or decreased iconicity.  We found that new innovations are equally likely to result in higher or lower iconicity: mutation is random.  However, in the communication condition, participants re-used more iconic forms: selection is biased.  That fits with a number of other studies on iconicity, including Verhoef et al., 2015 (CogSci proceedings) and Blasi et al. (2017).

Matthew Jones, Gabriella Vigliocco and colleagues have been working on similar experiments, though their results are slightly different.  Jones presented this work at the recent symposium on iconicity in language and literature (you can read the abstract here), and will also present at this year’s CogSci conference, which I’m looking forward to reading:

Jones, M., Vinson, D., Clostre, N., Zhu, A. L., Santiago, J., Vigliocco, G. (forthcoming). The bouba effect: sound-shape iconicity in iterated and implicit learning. Proceedings of the 36th Annual Meeting of the Cognitive Science Society.

Our paper is quite short, so I won’t spend any more time on it here, apart from one other cool thing:  For the final set of labels in each generation we measured iconicity using scores from nieve raters, but for the analysis of innovations we had hundreds of extra forms.  We used a random forest to predict iconicity ratings for the extra labels from unigrams and bigrams of the rated labels.  It accounted for 89% of the variance in participant ratings on unseen data.  This is a good improvement over some old techniques such as using the average iconicity of the individual letters in the label, since random forests allows the weighting of particular letters to be estimated from the data, and also allows for non-linear effects when two letters are combined.

However, it turns out that most of the prediction is done by this simple decision tree with just 3 unigram variables. Shapes were rated as more spiky if they contained a ‘k’, ‘j’ and ‘z’ (our experiment was run in Spanish):

So the method was a bit overkill in this case, but might be useful for future studies.

All data and code for doing the analyses and random forest prediction is available in the supporting information of the paper, or in this github repository.

Tamariz, M., Roberts, S. G., Martínez, J. I. and Santiago, J. (2017), The Interactive Origin of Iconicity. Cogn Sci. doi:10.1111/cogs.12497[pdf from MPI]