Gestural coupling between humans and virtual characters in an artistic context of imitation

International audienceWe present a human-agent interaction based on a theatrical mirroring game. The user and the agent imitate each other's body movements and introduce, from time to time, changes by proposing a new movement. The agent responses are linked to the game scenario but also to the user's behavior, which makes each game session unique. This demonstration has been realized within the collaborative French project called Ingredible. The fundamental goal of this project is to reproduce the mutual influence that is intrinsic to human-human interaction for a human-virtual agent interaction. The Ingredible project focuses, especially, on the gestural behavior and gestural expressive quality shown by both the virtual agent and the user while interacting. This type of interactions contains some spontaneous and emergent behaviors which are hard to tackle for virtual characters because the evolution of the interaction is shared between the protagonists. A first attempt was proposed by [5] but this work does not show the evolution of the decision relative to the quality of the interaction. Previous works on human-human interaction have studied the dynamical evolution of communication. In " Alive Communication " [3], Fogel and Garvey showed that, while interacting, people coordinate their behaviors and mutually influence their actions and intentions. Ordinary variability, that is slight modifications in the behavior due, for example , to personal style, emerges naturally without braking the bounds of the interaction. From time to time, extraordinary variability (called innovation) can appear, obliging interactants to make an effort to integrate the novelty in order to keep the communication going. This theory highlights the dynamical evolution of human-human interactions, the mutual influence and the capability to resist and to adapt to changes. Regular and unexpected behaviors appear naturally and previous works showed that reproducing the equilibrium between them in human-agent interactions is fundamental to improve agent believability and user's engagement [1]. Within the Ingredible project we aim to reproduce this evolving equilibrium between regularity and surprise, that we call coupling [2]. This demonstration shows our last progress in this direction