This dissertation explores the effect of virtual humans’ facial emotional displays in the context of persuasion. In a collaborative problem-solving game, participants received persuasive information from a virtual teammate. The first study demonstrated that a subservient virtual teammate’s facial emotional displays reduced his or her persuasive capacity. The second study revealed that the effect of a virtual human’s facial emotional displays was jointly determined by whether the observer was in power, and/or whether the observer considered it appropriate to express emotions. Emotional expressions undermined persuasion when the observer overpowered the virtual human, and/or when the observer perceived emotional expressions to be inappropriate. When both conditions were satisfied, emotional expressions reduced persuasion the most. The third study suggested that the amount of anger expressions predicted the outcome of persuasion. Photorealism, while on one hand enhanced the perception of anger expressions, did not moderate the effect of emotional expressions. Findings from this study inform theories of emotional expressions in persuasion, and guide the design of persuasive virtual humans.

Publication Date


Document Type


Student Type


Degree Name

Computing and Information Sciences (Ph.D.)

Department, Program, or Center

PhD Program in Computing and Information Sciences


Joe Geigel

Advisor/Committee Member

Reynold Bailey

Advisor/Committee Member

Jonathan Gratch


RIT – Main Campus

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