Softness, Warmth, and Responsiveness Improve Robot Hugs

Abstract

Hugs are one of the first forms of contact and affection humans experience. Due to their prevalence and health benefits, roboticists are naturally interested in having robots one day hug humans as seamlessly as humans hug other humans. This project's purpose is to evaluate human responses to different robot physical characteristics and hugging behaviors. Specifically, we aim to test the hypothesis that a soft, warm, touch-sensitive PR2 humanoid robot can provide humans with satisfying hugs by matching both their hugging pressure and their hugging duration. Thirty relatively young and rather technical participants experienced and evaluated twelve hugs with the robot, divided into three randomly ordered trials that focused on physical robot characteristics (single factor, three levels) and nine randomly ordered trials with low, medium, and high hug pressure and duration (two factors, three levels each). Analysis of the results showed that people significantly prefer soft, warm hugs over hard, cold hugs. Furthermore, users prefer hugs that physically squeeze them and release immediately when they are ready for the hug to end. Taking part in the experiment also significantly increased positive user opinions of robots and robot use.

Exercising with Baxter: preliminary support for assistive social-physical human-robot interaction

“…The Haptic Creature Project, for example, explores an expressively actuated furry robotic companion that people treat in pet-like ways [15]. The Paro [16], Huggable [17], and HuggieBot [18] robots leverage physical interaction with people to comfort and support them. Our work explores a new and highly dynamic application of social touch with the potential to benefit the lives of older adults.…”

The Social Robot in Rehabilitation and Assistance: What Is the Future?

“…The research in this direction [32][33][34][35][36][37][38] concerns using information about the user in order to adapt the SRs to the user's particular needs and performance intentions, thereby improving acceptance; therefore several studies focus, for example, on how movements of the robot's body parts imitate human emotions to express different emotions such as anger, disgust, fear, happiness, sadness and surprise.…”

The persuasive power of robot touch. Behavioral and evaluative consequences of non-functional touch from a robot

“…In summary, touch research in the realm of human-robot interaction has so far yielded mixed results regarding the question of whether tactile interaction with robots has behavioral and evaluative consequences that are to some extent similar to reactions to animal touch [63,73,74] and also to interpersonal touch [7,8]. However, the majority of studies concentrated on touch directed to robots [3,16,62,73,74] or reciprocal touches [66][67][68]60], while only a small number of studies have investigated robot-initiated touch [5,7,9,75]. Furthermore, no firm conclusions can be drawn from previous studies on robot-initiated touch, as the studies either relied on the mere observation of touch [68,76], which might be qualitatively different from actual touch, or the researchers implemented robot-initiated touch in a way that required the human to touch the robot first [6,7].…”

“…Holding hands with a robot thus appeared to change the image participants had of the robot: On the one hand, it increased trust and friendship, but on the other hand, the similarity to a warm human hand seemed to make them feel uneasy. Recently, work by Block and Kuchenbecker [ 67 ] supports that individuals favor soft and warm over hard and cold robot hugs.…”

“…However, the robot in the latter investigation was not an android robot but a collaborative robotic arm equipped with a facial display (Rethink Robotics’ Sawyer). Additionally, Block and Kuchenbecker [ 67 ] demonstrated that temperature (cold versus warm) and softness (hard plastic cover versus soft custom-made cover) affect how individuals evaluate hugs with a humanoid robot.…”