This paper proposes a neural network architecture designed to exhibit learning and communication capabilities via imitation. Our architecture allows a "proto imitation" behavior using the "perception ambiguity" inherent to real environments. In the perspective of turn-taking and gestural communication between two agents, new experiments on movement synchronization in an interaction game are presented. Synchronization is obtained as a global attractor depending on the coupling between agents' dynamic. We also discuss the non-supervised context of the imitation process and we present new experiments in which the same architecture is able to learn perception-action associations without any explicit reinforcement. The learning is based on the ability to detect novelty or irregularities in the communication rhythm.

This paper examines the interest of a developmental approach applied to the design of autonomous robots and the understanding of adaptive behaviors, such as imitation. The proposed model is a neural network architecture that learns and uses associations between vision and arm movements, even if the problem is ill posed (in the case of mapping problems between the visual space and the joints space of the arm). The central part of the model is a visuo-motor map able to represent the arm end point's position in an ego-centered space (constrained by the vision) according to motor information (the proprioception). Sensorimotor behaviors such as tracking, pointing, spontaneous imitating, and sequences learning can then be obtained as the consequence of different internal dynamics computed on neural fields triggered by the visuo-motor map. The readout mechanism also explains how an apparently complex behavior can be generated and controlled from one simple internal dynamics and how at the same time the learning problems can be simplified. While highlighting the generic aspect of our model, we show that our robot can autonomously imitate and learn more complex sequences of gestures after the online learning of the visual and proprioceptive control of its hand extremity. Finally, we defend the idea of a co-development of imitative and sensorimotor capabilities, allowing the acquisition and the building of increasingly complex behavioral capabilities.

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