Human Perception of Audio-Visual Synthetic Character Emotion Expression in the Presence of Ambiguous and Conflicting Information

Computer simulated avatars and humanoid robots have an increasingly prominent place in today´s world. Acceptance of these synthetic characters depends on their ability to properly and recognizably convey basic emotion states to a user population. This study presents an analysis of the interaction between emotional audio (human voice) and video (simple animation) cues. The emotional relevance of the channels is analyzed with respect to their effect on human perception and through the study of the extracted audio-visual features that contribute most prominently to human perception. As a result of the unequal level of expressivity across the two channels, the audio was shown to bias the perception of the evaluators. However, even in the presence of a strong audio bias, the video data were shown to affect human perception. The feature sets extracted from emotionally matched audio-visual displays contained both audio and video features while feature sets resulting from emotionally mismatched audio-visual displays contained only audio information. This result indicates that observers integrate natural audio cues and synthetic video cues only when the information expressed is in congruence. It is therefore important to properly design the presentation of audio-visual cues as incorrect design may cause observers to ignore the information conveyed in one of the channels.