SOCRATES: from SOCial Relation to ATtitude ExpressionS Florian Pecune LTCI, CNRS, Telecom ParisTech, Universite Paris-Saclay pecune@enst.fr Magalie Ochs LSIS, Universite Aix-Marseille 13005, Marseille, France magalie.ochs@lsis.org Stacy Marsella Northeastern University Boston, MA 02115, USA s.marsella@neu.edu Catherine Pelachaud LTCI, CNRS, Telecom ParisTech, Universite Paris-Saclay pelachaud@enst.fr ABSTRACT To be perceived as believable partners in human-machine interactions, virtual agents have to express adequate social attitudes. The social attitude expressed by an agent should reflect the social situation of the interaction. The agent ought to take into account its role and its social relation toward its interactants when deciding how to react in the interaction. To build such an agent able to reason about its role and relation and to adapt its social attitude, we build a model of social decision making. First, we formalize the dynamics of the social relation through a combination of goals and beliefs. Then, we design a decision making model based on the social goals and the situational goals of the agent. Keywords Virtual agents, social relations, social attitudes, decision making 1. INTRODUCTION Nowadays machines own a prominent place in our life. Studies show that we are becoming more comfortable with the idea of interacting with them [34] in particular when the interaction involves virtual humans as partners. Our purpose is to improve the naturalness and the believability of these human-machine interactions by integrating socio- emotional components into virtual agents. These compo- nents should allow agents to manage the inherently social and emotional dimension of the interaction by expressing an emotional behavior and a social attitude relevant to the context of the interaction. In [32], Scherer defines social attitudes (also called inter- personal stance) as an ”affective style that spontaneously de- velops or is strategically employed in the interaction with a person or a group of persons, coloring the interpersonal exchange in that situation” . Strategical processes can be understood under the light of social roles. Indeed, in partic- Appears in: Proceedings of the 15th International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2016), J. Thangarajah, K. Tuyls, C. Jonker, S. Marsella (eds.), May 9–13, 2016, Singapore. Copyright c  2016, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved. ular social contexts or situations, people endow particular roles [9] and intend to express particular behavior and so- cial attitude. Thus, in a restaurant (social context), waiters (social role) are supposed to be nice and polite (social atti- tude). The same goes for a teacher giving a lesson to a class: they want to be perceived as dominant and controlling the situation. Spontaneous development of the social attitude can be understood under the light of social relations. Indeed, the social relation between two people influences their behaviour and their social attitudes. For instance, two people who like each other spontaneously tend to comply with the other’s requests thus showing a friendly attitude [7]. Moreover, de- pending on their actions during the interactions, their social relation might change. Hence, their social attitudes have to follow this evolution: if the same people end up hating each other, they will probably express more hostility than they did before. In order to give the capability to a virtual agent to rea- son about its role and its own social relation toward the user, and express an adequate social attitude according to the situation, we designed a model of social decision mak- ing. First, we propose a formal model of social relations dynamics based on the agent’s goals and beliefs. This repre- sentation allows the agent to reason about the situation in order to take a decision and build a strategy influenced by the agent’s socio-emotional state. We also propose a model of decision making influenced by the agent’s social relations toward its interaction partners and the agent’s role in the interaction. The paper is organized as follows. In Section 2, we present the existing models of social relations while our general approach is described in section 3. In Section 4, our formalization of social relation dynamics is introduced. Our model of decision making is explained in Section 5 and illus- trated by variations of a teacher/student scenario in Section 6. We conclude and discuss future work in Section 7. 2. RELATED WORKS OF SOCIAL RELA- TIONS MODELS In the first section of this related work, we present works modeling the influence of actions and events on an agent’s social relations. In the second section, we present works modeling the influence of social roles on the agent’s attitude and behaviour.