Effects of Body Type and Voice Pitch on Perceived Audio-Visual Correspondence and Believability of Virtual Characters

We examined the effects of virtual characters' body type and voice pitch on perceived audio-visual correspondence and believability. For our within-group study (N = 72), we developed nine experimental conditions using a 3 (body type: ectomorph vs. mesomorph vs. endomorph body types) x 3 (voice pitch: low vs. medium vs. high fundamental frequency [F(sic)]) design. We found statistically significant main effects from voice pitch and statistically significant interaction effects between a virtual character's body type and voice pitch on both the level of perceived audio-visual correspondence and believability of female and male virtual characters. For female virtual characters, we also observed an additional statistically significant main effect from body type and a statistically significant interaction effect between the participant's biological sex and the virtual character's voice pitch on both perceived audio-visual correspondence and believability. Moreover, the results show that perceived believability is highly correlated to perceived audio-visual correspondence. Our findings have important practical implications in applications where the virtual character is meant to be an emotional or informational guide that requires some level of perceived believability, as the findings suggest that it is possible to enhance the perceived believability of the virtual characters by generating appropriate voices through pitch manipulation of existing voices.