Dominant and submissive nonverbal behavior of virtual agents and its effects on evaluation and negotiation outcome in different age groups.

In this work, we explore the effects of dominant nonverbal behavior of a virtual agent on users in different age groups regarding their evaluations of the system as well as persuasion. We report a bipartite experimental laboratory study with young adults (N = 87) and seniors (N = 38). In the first part of the study, young adults interacted with the virtual agent in a desert-survival-scenario-task in a 2 (dominant vs. submissive nonverbal behavior) x 2 (no attention guiding behavior vs. attention guiding behavior) experimental between-subjects design. Besides scrutinizing the effects of dominant nonverbal behavior, we wanted to know how adding nonverbal behavior to guide the users' attention influences the perception of dominant nonverbal behavior. While the dominant agent was indeed perceived as being more dominant, evaluations of the agent regarding likability and intelligence was not influenced by its nonverbal behavior. There were some effects for the perception of the game, however, the dominant behavior was not more successful regarding persuasion (following the agents suggestions during the game). Adding attention guiding nonverbal behavior did only result in lower perceived competence of the agent. In the second part of the study, we replicated the submissive/dominance manipulation with senior participants in order to explore age differences. We found a number of effects: seniors evaluated the agent generally more positively (e.g., more likable, autonomous, intelligent, submissive, verbally and nonverbally capable). Moreover, we found an interaction effect for persuasion, showing that seniors strongly follow the suggestions of the dominant agent. We discuss these findings especially against the background of agent applications in a medical context.