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Dynamical and behavioural
approaches in reaching development
Claudine Boyer , Jean-Claude
Darcheville, Samuel Delepoulle
Université de
Lille, Ch. de Gaulle, France
Currently, dynamical approach
disputes the relevance of classical theories to account for motor
development. Thelen (1994) postulates that motor development
results from intrinsic components' interaction (biomechanical,
energetic...-) with components extrinsic to the organism (environmental).
This leads to emergence of stable pattern by a process of self-organisation.
Reaching is a transition from a cyclic to a point attractor.
Our approach completes this point. Darcheville (1998) postulate
that emergence of an attractor results from the control of a
reinforcing stimulus. To test this assumption, we study new-borns'
reaching development and simulation with adaptive agents. We
developed a control architecture for a very simplified mobile
arm. This architecture can control a virtual arm composed of
two articulations. We used a parallel architecture made of autonomous
agents, each agent is responsible for the behaviour of a muscle.
Agents' behavioural evolution is based on the simulation of operant
behaviour (Q-Learning algorithm). The dynamics of behaviour is
very similar to the baby's one : from an irregular pattern of
movements evolves co-ordinated, stable movements. Moreover, the
architecture demonstrates some behavioural features like extinction,
generalisation or shaping. Experiences with new-borns are now
in progress.
Keywords: reaching, contingencies
of reinforcement, new-born, Q-learning, non-linear dynamic. |