Social HRI Research Articles

Embodiment Matters in Social HRI Research: Effectiveness of Anthropomorphism on Subjective and Objective Outcomes

Anthropomorphism, as a design feature of robots, is widely applied to enhance human-robot interaction in the social domain. Current knowledge of how anthropomorphism influences perception, attitudes, and actual behavior is gained via research with depicted and embodied robots. However, it remains unclear how comparable gained insights of both approaches are. Results of a current meta-analysis suggest that anthropomorphism positively influences subjective and objective measures in case of embodied robots, whereas in case of depicted robots predominantly effects on subjective measures seem to emerge. This follow-up analysis aims to further investigate this difference by using a recoded dataset including data of 41 studies, involving over 3,000 participants. The results illustrate that anthropomorphism investigated via embodied robots indeed facilitates both subjective and objective outcomes. Remarkably, studies concerning effects of anthropomorphism using depicted robots showed positive effects on a subjective level but failed to show any effects on an objective level. In conclusion, the results show that the consequences of anthropomorphism in human-robot interaction depend on how robots are presented to participants. Moreover, they reveal that the transfer of results gained via depicted robots to embodied human-robot interaction might lead to both overestimation on a subjective level and underestimation on an objective level regarding the consequences of anthropomorphism.

Stress Game: The Role of Motivational Robotic Assistance in Reducing User’s Task Stress

In social HRI context, the robot’s usefulness and appropriate behavior plays an important role. A robot should be able to understand the human’s internal state (i.e., physiological and psychological states) so as to provide an adaptive and thus efficient assistance within daily life activities. Measuring stress and frustration of an individual while performing a certain task is a critical element that can help the robot adapt its behavior so as to improve user’s interest and task performance and to reduce his/her frustration. In this paper, we designed an experiment called “Stress Game”. In our work, stress is measured in terms of heart rate signal. The robot displays different behaviors as a function of user’s personality and game condition. We conducted our experiments with the NAO robot. The experimental results support our hypotheses that the robot has a positive effect on stress relief.

Social vs. Useful HRI: Experiencing the Familiar, Perceiving the Robot as a Sociable Partner and Responding to Its Actions

We explore the human affective state of the familiar during a new or unknown situation as it relates to interacting with a robot. In a real unannounced interaction, we measure the familiar experienced by two humans interacting with a robot and the intensity and adequacy of their response to its proactive social (greetings) and practical (task to fulfill) actions. We investigate the participants’ response to three non-verbal actions performed by the robot NAO: greeting hello (social), handing a questionnaire to the participant (practical), and greeting goodbye (social). We analyze the participants’ reactions to the robot’s actions, the motion of their arms, and their answers to some parts of a questionnaire designed to measure their experience of the familiar and the robot’s sociability. We show that (1) the higher the familiar is experienced while interacting with the robot, the more participants responded to its practical action; no similar interdependency was found regarding its social actions; (2) the change of behavior of the robot between participants had no significant effect on the familiar experienced nor on the readiness to respond to the robot; (3) the higher the appreciation of the robot’s sociability, the more intense was the human movement when responding to the social actions; no similar interdependency was found for the practical action; and (4) the more the participants responded adequately to the robot in a practical action, the more they responded to its social actions.

A two-dimensional facial-affect estimation system for human–robot interaction using facial expression parameters

A social robot should be able to autonomously interpret human affect and adapt its behavior accordingly in order for successful social human–robot interaction to take place. This paper presents a modular non-contact automated affect-estimation system that employs support vector regression over a set of novel facial expression parameters to estimate a person’s affective states using a valence-arousal two-dimensional model of affect. The proposed system captures complex and ambiguous emotions that are prevalent in real-world scenarios by utilizing a continuous two-dimensional model, rather than a traditional discrete categorical model for affect. As the goal is to incorporate this recognition system in robots, real-time estimation of spontaneous natural facial expressions in response to environmental and interactive stimuli is an objective. The proposed system can be combined with affect detection techniques using other modes, such as speech, body language and/or physiological signals, etc., in order to develop an accurate multi-modal affect estimation system for social HRI applications. Experiments presented herein demonstrate the system’s ability to successfully estimate the affect of a diverse group of unknown individuals exhibiting spontaneous natural facial expressions.