Touch is a central aspect of social human-human interaction, yet when designing social human-robot interaction, the experience of touch is very often neglected. This work explores whether a robot should feel alive by investigating the effect of life-like haptic stimuli inspired by bio-physiological signals (heartbeat, purring, and thermal feedback) on user perception. The results of an interaction study (n=42) showed that haptic cues which simulate bio-physiological signals significantly increased perceived anthropomorphism, social warmth, and likeability of the PARO robot compared to no additional haptics or abstract vibration. We discuss how multimodal haptic cues, despite increasing perceived eeriness, also increased perceived likeability of the robot, providing novel insights into whether the uncanny valley effect may extend into non-visual modalities. These results provide the first empirical evidence that life-like tactile cues can enhance user perceptions of social robots, offering design guidance for deploying effective and engaging touch interactions between humans and zoomorphic robots.

Physical interactions with socially assistive robots (SARs) positively affect user wellbeing. However, haptic experiences when touching a SAR are typically limited to perceiving the robot’s movements or shell texture, while other modalities that could enhance the touch experience with the robot, such as vibrotactile stimulation, are under-explored. In this exploratory qualitative study, we investigate the potential of enhancing human interaction with the PARO robot through vibrotactile heartbeats, with the goal to regulate subjective wellbeing during stressful situations. We conducted in-depth one-on-one interviews with 30 participants, who watched three horror movie clips alone, with PARO, and with a PARO that displayed a vibrotactile heartbeat. Our findings show that PARO’s presence and its interactive capabilities can help users regulate emotions through attentional redeployment from a stressor toward the robot. The vibrotactile heartbeat further reinforced PARO’s physical and social presence, enhancing the socio-emotional support provided by the robot and its perceived life-likeness. We discuss the impact of individual differences in user experience and implications for the future design of life-like vibrotactile stimulation for SARs.

Haptics is an essential element of interaction between humans and socially assistive robots. However, it is often limited to movements or vibrations and misses key aspects such as temperature. This mixed-methods study explores the potential of enhancing human-robot interaction [HRI] through thermal stimulation to regulate affect during a stress-inducing task. Participants were exposed to thermal stimulation while completing the Mannheim-multicomponent-stress-task (MMST). Findings yielded that human-robot emotional touch may induce comfort and relaxation during the exposure to acute stressors. User affect may be further enhanced through thermal stimulation, which was experienced as comforting, de-stressing, and altered participants’ perception of the robot to be more life-like. Allowing participants to calibrate a temperature they perceived as calming provided novel insights into the temperature ranges suitable for interaction. While neutral temperatures were the most popular amongst participants, findings suggest that cool (4 – 29 ºC), neutral (30 – 32 ºC), and warm (33ºC -36 ºC) temperatures can all induce comforting effects during exposure to stress. The results highlight the potential of thermal HRI in general and, more specifically, the advantages of personalized temperature calibration.