Research

 
 

In January 2009, I started as a PhD candidate at the Amsterdam Center for Language and Communication (ACLC) of the University of Amsterdam. My project is part of Bart de Boer's NWO Vidi project "Modelling the evolution of speech".


During my PhD project I developed a great interest in the workings of cultural evolution. It fascinates me how social behaviours (such as language, music and dance) and the systems for those behaviours emerge, develop and are preserved through cultural transmission. How did these behaviours all get to consist of (essentially pretty similar) hierarchical combinatorial structures and why do people acquire them so naturally? Very much inspired by the work of Simon Kirby, I am intrigued by the idea that the process of cultural transmission and the cognitive biases of the people learning and reproducing the behaviours play an important role in the shaping of such structures.


The focus of my project is on the evolution of complex (combinatorial) systems of sounds for speech. The methods I use are a combination of agent-based computer modelling and experiments with human participants to simulate cultural transmission. Computer simulations provide an excellent tool for investigating evolutionary processes and they help shed light on the relations between micro level interactions of speaking individuals and macro level behaviour of the sound system as a whole. However, assumptions and simplifications need to be made when creating computer models which means that computer agent speakers do not necessarily resemble real speakers in every aspect, especially in terms of their cognitive power. Therefore, it is important to incorporate real human speakers in the research about speech evolution as well. The method of experimental iterated learning (Kirby, Cornish and Smith, 2008) has proven to be very suitable for this and forms the main inspiration for my experimental work. Computer models and experiments together provide a good basis for testing existing theories and generating new ones.



Most of the laboratory experiments I do are about the cultural evolution of a system of sounds produced with a slide whistle (never played with a slide whistle? Try my virtual one here!). In these experiments the language a participant is trained on is the recalled output that the previous participant produced. We found that transmission from participant to participant causes the system of whistles to change: it becomes cumulatively more learnable and gains combinatorial structure.



As part of the analysis of the whistle languages that evolve in the experiments, I am running an online experiment, disguised as a UFO game in which good aliens need to be saved and bad aliens need to be killed. It is fun and takes about 15 minutes. I invite you to participate! The game can be found here. This game is adapted from the game that was originally created by Jelle Zuidema and Vanessa Ferdinand.



Publications:


  1. Verhoef, T., de Boer, B., & Kirby, S. (2012) Holistic or synthetic protolanguage: Evidence from iterated learning of whistled signals. In The evolution of language: Proceedings of the 8th international conference (evolang8). (pp. 386-375). Hackensack NJ: World Scientific.

  2. de Boer, B. & Verhoef, T. (2012) Language Dynamics in Structured Form and Meaning Spaces, Advances in Complex Systems 15(3),1150021-1–1150021-20

  3. Verhoef, T., Kirby, S. & Padden, C. (2011) Cultural emergence of combinatorial structure in an artificial whistled language. In L. Carlson, C. Hölscher & T. Shipley (Eds.), Proceedings of the 33rd Annual Conference of the Cognitive Science Society (pp. 483-488). Austin, TX: Cognitive Science Society.

  4. Verhoef, T. & de Boer, B.G. (2011) Cultural emergence of feature economy in an artificial whistled language. In E. Zee & W. Lee (Eds.), Proceedings of the 17th International Congress of Phonetic Sciences (pp. 2066-2069). Hong Kong: City University of Hong Kong.

  5. Verhoef, T., Boer, B.G. de, Giudice, A. del, Padden, C. & Kirby, S. (2011). Cultural evolution of combinatorial structure in ongoing artificial speech learning experiments. CRL Technical Report, 23(1), 3-11.

  6. Verhoef, T. & Boer, B.G. de (2011). Language acquisition age effects and their role in the preservation and change of communication systems. Linguistics in Amsterdam, 4(1), 1-23.

  7. Verhoef, T. & de Boer, B. (2010) The critical period and preservation of emerged vowel systems, In: Smith, A. D. M., Schouwstra, M., de Boer, B. & Smith, K. (Eds.) The Evolution of Language, Proceedings of the 8th International Conference (evolang8) (pp. 509–510 ) New Jersey: World Scientific

  8. Verhoef, T., Lisetti, C., Ortega, F., van der Zant, T. & Cnossen, F. (2009) Bio-sensing for emotional characterization without word labels, In: J.A. Jacko (Ed.): Human-Computer Interaction, Part III, HCII 2009, LNCS 5612, pp. 693–702


Popular press:


Verhoef, T. (2011). Evoluerende fluittalen: het ontstaan van taal experimenteel onderzocht. Kennislink Vakpagina Taal & Spraak


Presentations:


  1. EvoLang 9: 9th International Conference on the Evolution of Language, “Holistic or synthetic protolanguage: Evidence from iterated learning of whistled signals”, Kyoto, 16 Mar 2012

  2. ACLC-LiA seminar (Amsterdam Center for Language and Communication), “Language acquisition age effects and their role in the preservation and change of communication systems”, University of Amsterdam, 3 Feb 2012

  3. Center for Research in Language (CRL) talk, “Cultural emergence of combinatorial structure through iterated learning of whistled signals”, University of California San Diego, 29 Nov 2011

  4. NAP-dag presentatie, “Language evolution studied in the laboratory: emergence of structure through iterated learning of whistled signals”, University of Amsterdam, 7 Oct 2011

  5. ICPhS 2011: 17th International Congress of Phonetic Sciences, “Cultural emergence of feature economy in an artificial whistled language”, Hong Kong, 18 Aug 2011

  6. CogSci 2011: 33rd Annual Conference of the Cognitive Science Society, “Cultural emergence of combinatorial structure in an artificial whistled language”, Boston, 21 Jul 2011

  7. SLC talk (Speech, Language, Music & Cognition meeting, ILLC), “Studying cultural emergence of structure in an artificial whistled language”, University of Amsterdam, 17Jun 2011

  8. ELiTU talk, “Cultural emergence of duality of patterning in an artificial whistled language”, University of Utrecht, 28 Mar 2011

  9. Language Evolution and Computation Research Unit (LEC) talk, “Cultural emergence of combinatorial structure in artificial sound systems”, University of Edinburgh, 18 Jan 2011

  10. ExAPP2010 poster presentation, “Micro-macro modeling of language change: cultural transmission of sound systems and consequences for their structure”, University of Groningen, 12 Nov 2010

  11. Computational Linguistics Seminar (CLS) talk, "Cultural emergence of phonemic structure: agent-based modeling and artificial language learning experiments", University of Amsterdam, 27 Oct 2010

  12. UC Berkeley Lunchtime seminar, "Cultural evolution and the emergence of combinatorial structure in artificial sound systems.", University of California, Berkeley, CA, 1 Oct 2010

  13. UC San Diego Linguistics - Evolang meeting talk, "Cultural evolution and the emergence of combinatorial structure in artificial sound systems.", University of California, San Diego, CA, 27 Sep 2010

  14. UQAM Summer Institute on the Origins of Language, poster presentation, “Cultural transmission of artificial sound systems and the emergence of structure”, UQAM, Montreal, 23 Jun 2010

  15. EVOLANG8 conference talk, “The critical period and preservation of emerged vowel systems”, Utrecht, 16 Apr 2010

  16. NAP-dag talk, “Age effects in language acquisition and their preserving powers: an agent-based computer modelling approach”, Universiteit van Amsterdam, 23 Oct, 2009

  17. Summer School on Embodied Language Games and Construction Grammar :10 minutes 10 slides presentation, “The critical period and its preserving powers in vowel systems”, Cortona, Italy, 2 Sept 2009

  18. Summer School on Embodied Language Games and Construction Grammar: poster presentation, “Preservation of emerged vowel systems in a population of agents with an age structure”, Cortona, Italy, 31 Aug 2009

  19. General Interest Special Interest Group talk, "Modelling the evolution of language acquisition", Florida International University, Miami, FL, 15 Apr 2009

  20. Master’s thesis defence, “Multimodal affective human-machine interaction: Towards the design and implementation of an affect-sensitive empathetic agent”, University of Groningen, 15 Jan 2009