1. Self-organisation in vowel systems
Bart de Boer
June 1999
Now Assistant professor at the AI department of
Rijksuniversiteit Groningen
50 jaar AI symposium, Brussel 2006

2. 50 jaar AI symposium, Brussel 2006
The AI-lab context
PhD 1994–1999
Postdoc 1999–2000 en 2002–2003
Cooperators:
Paul Vogt, Tony Belpaeme, Edwin de Jong, Jelle Zuidema, Joris van Looveren, Joachim de Beule, Bart Jansen, Bart de Vylder
The transition from robotic work to evolution of language work
50 jaar AI symposium, Brussel 2006

3. 50 jaar AI symposium, Brussel 2006
The context
Explain universals of vowel systems
Why are do certain (combinations of) vowels occur more often than others (acoustic distinctiveness)
How does the optimisation take place?
Unsolved problem in phonetics
50 jaar AI symposium, Brussel 2006

4. 50 jaar AI symposium, Brussel 2006
The question
Hypothesis
Self-organisation in a population under constraints of production, perception, learning causes optimal systems to emerge
Model
Agent-based model
Imitation games
50 jaar AI symposium, Brussel 2006

5. 50 jaar AI symposium, Brussel 2006
The model
For vowels:
Realistic production articulatory synthesiser (Maeda, Valleé)
Realistic perception Formant weighting (Mantakas, Schwarz, Boë)
Learning model Prototype based associative memory
Sounds
Production
Perception
Associative
Memory
50 jaar AI symposium, Brussel 2006

6. 50 jaar AI symposium, Brussel 2006
The interactions
Imitation with categorical perception
Humans hear speech signals as the nearest phoneme in their language (?)
Correctness of imitation depends not only on the signals used, but also on the agents’ repertoires
Initiator
Imitator
50 jaar AI symposium, Brussel 2006

7. 50 jaar AI symposium, Brussel 2006
Imitation failure
Initiator
Imitator
50 jaar AI symposium, Brussel 2006

8. Interactions – the imitation game
Imitation with categorical perception
Humans hear speech signals not continuously, but as discrete categories
Correctness of imitation depends not only on the signals used, but also on the agents’ repertoires
Imitation game has later been used in robotic experiments as well
50 jaar AI symposium, Brussel 2006

9. 50 jaar AI symposium, Brussel 2006
Results
Imitative success
Energy of vowel systems (Liljencrants & Lindblom)
Size
Preservation
Success of imitation between agents from populations a number of generations apart
Only in systems with changing populations
Realism
50 jaar AI symposium, Brussel 2006

10. 50 jaar AI symposium, Brussel 2006
Impact
Result:
The Journal of Phonetics paper is highly cited in evolution of language research and phonetics.
Evolutionary approaches are now gaining currency in linguistics
Method:
Using agent-based computer simulations is nowadays an accepted way of investigating linguistic questions. This method has been pioneered in Brussels.
50 jaar AI symposium, Brussel 2006

11. 50 jaar AI symposium, Brussel 2006
The future
The application of AI-techniques to social sciences and humanities is wide open and full of opportunities
Agent-based models in economics
Agent-based models and GIS in social geography
Linguistics
The same relation between macro- and microbehavior (language level vs. individual level).
Agent-based modelling contributes
Application of speech recognition/synthesis techniques to linguistic questions
50 jaar AI symposium, Brussel 2006