An android can show the facial expressions of complex emotions

Trust and rapport are essential abilities for human-robot interaction. Producing emotional expressions in the robots' faces is an effective way for that purpose. Androids can show human-like facial expressions of basic emotions. However, whether androids can show the facial expression of complex emotions remains unknown. In this experiment, we investigated the android Nikola's ability to produce 22 dynamic facial expressions of complex emotions. For each video, 240 international participants (120 Japanese, 120 German) rated the emotions expressed by Nikola. For 13 complex emotions (i.e., amusement, appal, awe, boredom, contentment, coyness, hatred, hesitation, moral disgust, not face, pain, sleepiness, suspicion), participants of both samples rated the target emotion above the mean of other non-target emotions. Four emotions (bitterness, confusion, pride, relief) were rated above mean by one sample. For twelve of these emotions, target emotions were among the highest ranked. The results suggest that androids can produce the facial expressions of a wide range of complex emotions, which can facilitate human-robot interactions.