The Role of Assertiveness in a Storytelling Game with Persuasive Robotic Non-Player Characters

Can social agents be assertive and persuade users? To what extent do the persuasion abilities of robots depend on the users' own traits? In this paper, we describe the results of a study in which participants interacted with robotic Non-Player Characters (NPC) displaying different levels of assertiveness (high and low), in a storytelling scenario. We sought to understand how the level of assertiveness displayed by the robots impacted the participants' decision-making process and game experience. Our results suggest that NPCs displaying lower levels of assertiveness evoke more positive emotional responses but are not more effective at influencing players' decisions when compared to NPCs displaying higher levels of this trait. However, NPCs displaying a personality trait are more effective persuaders than NPCs not displaying this feature. Overall, this paper highlights the importance of considering the player's personality and its relation to task-specific attributes during the process of game design.