Sound effects have only minor contribution to perceptions of anthropomorphism and animacy of simple animated shapes.

While studies of anthropomorphism have spanned many decades, there is little evidence of the role that sound effects may play. We present two studies into sound's influence on perceptions of anthropomorphism and animacy using simple geometric animated shapes. For the first study, conducted on 149 participants, we simplified the animation to just two "bumping" squares. Study Two recreated the Heider-Simmel study of 1944, and was conducted on 250 participants under five conditions: without sound, and with one of two different sound types (interface sounds and "anthropomorphic" robot sounds) with two stereo modes (fixed in stereo position, or binaurally panned with the movement). We had participants answer both the Individual Differences in Anthropomorphism Questionnaire and the Godspeed Questionnaire, with three additional questions added. Results showed that the sound had a minor impact on anthropomorphism and potency in Study One, but did not impact animacy. Study Two showed no significant effect on anthropomorphism or animacy, but did show an impact on perceived intelligence and perceptions of activity.