Affective Touch in Human–Robot Interaction: Conveying Emotion to the Nao Robot

Abstract

Affective touch has a fundamental role in human development, social bonding, and for providing emotional support in interpersonal relationships. We present, what is to our knowledge, the first HRI study of tactile conveyance of both positive and negative emotions (affective touch) on the Nao robot, and based on an experimental set-up from a study of human-human tactile communication. In the present work, participants conveyed eight emotions to a small humanoid robot via touch. We found that female participants conveyed emotions for a longer time, using more varied interaction and touching more regions on the robot's body, compared to male participants. Several differences between emotions were found such that emotions could be classified by the valence of the emotion conveyed, by combining touch amount and duration. Overall, these results show high agreement with those reported for human-human affective tactile communication and could also have impact on the design and placement of tactile sensors on humanoid robots.

Designing for a Wearable Affective Interface for the NAO Robot: A Study of Emotion Conveyance by Touch

“…This was done in order to assess the potential for NAO to decode emotions based on smart textiles, i.e., WAffI imbued with smart sensors. The dataset was previously utilized in [42] but in the current investigation the analysis, both for encoding and decoding of emotions, focuses on whether the NAO was clothed or not (WAffi-On vs. WAffI-Off).…”

“…Gender was balanced across the two conditions (16 males and 16 females for each condition). Potential gender differences identified in the study were investigated elsewhere [42] and are not the focus of the current paper; however, we include gender as an independent variable within our analysis of touch duration so as to discount interaction effects between gender and clothing type variables. Different subjects are used for WAffI-On and WAffI-Off interaction.…”

“…It can be observed from Figure 5 that subjects in the WAffI-On condition interact with the NAO robot for longer durations on average than those in the WAffI-Off condition over 7 of the 8 emotions, the exception being Anger. While gender effects were not a critical part of this investigation and were studied elsewhere [42]-with the finding that duration of touch was significantly influenced by gender-we were interested to see whether gender and clothing would foster interactive effects. Using a three-way (mixed design) ANOVA with independent variables of clothing, i.e., WAffI-On/Off (between subjects), gender (between subjects) and emotion type (within subjects), we found a significant main effect of clothing: F(1,64) = 12.08, p < 0.01; we also found a significant main effect of gender: F(1,64) = 12.63, p < 0.01; and a significant main effect of emotion: F(7,64) = 2.63, p < 0.01.…”

Skin-On Interfaces

“…The artificial skin sensors generally have a high spatial resolution (1mm − 4mm) but cover only small surfaces ( 2cm). The second type of application is to use artificial skin to cover the surface of a robot to improve motion guidance and environment sensing [5] as a means to increase human likeness, as well as to encourage contact with end-users [3] or to replicate the camouflaging capabilities of natural cephalopods [66,76].…”

Tactile Interaction and Social Touch

“…Based on previous results from a human-robot interaction study [4], we selected seven types of touches (stroke, scratch, poke, press, push, squeeze and grab) and used a soft array sensor to classify them. The results from this previous study showed that squeezing, stroking and pressing constituted more than half (59%) of all tactile interaction in the study.…”