Modulating Perceived Authority and Warmth of Mobile Social Robots Through Bodily Openness and Vertical Movement in Gait

Social robots are increasingly utilized across domains like education, healthcare, and elderly care. Research has examined how the robot's postures impact social perceptions, but few studies have investigated the effects of robots' bodily movements with dynamics gait variations on attributed authority and warmth. Moreover, gait patterns play a crucial role in human emotional communication and in conveying important social qualities such as authority and warmth. To address the limitation, this work examines how systematic modifications of a robot's walking gait influence perceived authority and warmth. Specifically, we designed robot gaits manipulating three parameters: bodily openness (BO), vertical oscillation (VO), and speed. Openness encompasses the expansiveness versus constriction of the limbs and torso. Vertical oscillation imitates natural human gaits. We conducted a perceptual study with 114 participants using an authority assessment scale and a warmth assessment scale to evaluate videos of a robot walking with different combinations of bodily openness (BO), vertical oscillation (VO), and speed. Results revealed that postures with high BO significantly increased perceived authority, and low BO significantly increased perceived warmth. VO significantly heightened warmth. Faster speeds augmented authority while slower speeds increased warmth. There were also significant interactions between VO and speed for presenting authority and warmth. To conclude, our findings provide new insights into how tuning walking dynamics can shape critical social perceptions, and inform designing robot gaits that convey desired attributes through systematic locomotion variations.