As human-robot interaction (HRI) researchers, like all scientists, we must demonstrate the reproducibility of findings-especially across robots. We present a three-study replication effort that illustrates the challenges and opportunities for replication science in HRI.

We propose Action-Oriented Semantic Maps (AOSMs), a representation that enables a robot to acquire object manipulation behaviors and semantic information about the environment from a human teacher with a Mixed Reality Head-Mounted Display (MR-HMD). AOSMs are a representation that captures both: a) high-level object manipulation actions in an object class's local frame, and b) semantic representations of objects in the robot's global map that are grounded for navigation. Humans can use a MR-HMD to teach the agent the information necessary for planning object manipulation and navigation actions by interacting with virtual 3D meshes overlaid on the physical workspace. We demonstrate that our system enables users to quickly and accurately teach a robot the knowledge required to autonomously plan and execute three household tasks: picking up a bottle and throwing it in the trash, closing a sink faucet, and flipping a light switch off.

We present a decision-theoretic model and robot system that interprets multimodal human communication to disambiguate item references by asking questions via a mixed reality (MR) interface. Existing approaches have either chosen to use physical behaviors, like pointing and eye gaze, or virtual behaviors, like mixed reality. However, there is a gap of research on how MR compares to physical actions for reducing robot uncertainty. We test the hypothesis that virtual deictic gestures are better for human-robot interaction (HRI) than physical behaviors. To test this hypothesis, we propose the Physio-Virtual Deixis Partially Observable Markov Decision Process (PVD-POMDP), which interprets multimodal observations (speech, eye gaze, and pointing gestures) from the human and decides when and how to ask questions (either via physical or virtual deictic gestures) in order to recover from failure states and cope with sensor noise. We conducted a between-subjects user study with 80 participants distributed across three conditions of robot communication: no feedback control, physical feedback, and MR feedback. We tested performance of each condition with objective measures (accuracy, time), as well as evaluated user experience with subjective measures (usability, trust, workload). We found the MR feedback condition was 10% more accurate than the physical condition and a speedup of 160%. We also found that the feedback conditions significantly outperformed the no feedback condition in all subjective metrics.

Human-robot trust is crucial to successful human-robot interaction. We conducted a study with 798 participants distributed across 32 conditions using four dimensions of human-robot trust (reliable, capable, ethical, sincere) identified by the Multi-Dimensional-Measure of Trust (MDMT). We tested whether these dimensions can differentially capture gains and losses in human-robot trust across robot roles and contexts. Using a 4 scenario × 4 trust dimension × 2 change direction between-subjects design, we found the behavior change manipulation effective for each of the four subscales. However, the pattern of results best supported a two-dimensional conception of trust, with reliable-capable and ethical-sincere as the major constituents.

With increasing autonomy, robots like drones are increasingly accessible to untrained users. Most users control drones using a low-level interface, such as a radio-controlled (RC) controller. For a wider adoption of these technologies by the public, a much higher-level interface, such as natural language or mixed reality (MR), allows the automation of the control of the agent in a goal-oriented setting. We present an interface that uses natural language grounding within an MR environment to solve high-level task and navigational instructions given to an autonomous drone. To the best of our knowledge, this is the first work to perform fully autonomous language grounding in an MR setting for a robot. Given a map, our interface first grounds natural language commands to reward specifications within a Markov Decision Process (MDP) framework. Then, it passes the reward specification to an MDP solver. Finally, the drone performs the desired operations in the real world while planning and localizing itself. Our approach uses MR to provide a set of known virtual landmarks, enabling the drone to understand commands referring to objects without being equipped with object detectors for multiple novel objects or a predefined environment model. We conducted an exploratory user study to assess users' experience of our MR interface with and without natural language, as compared to a web interface. We found that users were able to command the drone more quickly via both MR interfaces as compared to the web interface, with roughly equal system usability scores across all three interfaces.

Anthropomorphic robots, or robots with human-like appearance features such as eyes, hands, or faces, have drawn considerable attention in recent years. To date, what makes a robot appear human-like has been driven by designers» and researchers» intuitions, because a systematic understanding of the range, variety, and relationships among constituent features of anthropomorphic robots is lacking. To fill this gap, we introduce the ABOT (Anthropomorphic roBOT) Database---a collection of 200 images of real-world robots with one or more human-like appearance features (http://www.abotdatabase.info). Harnessing this database, Study 1 uncovered four distinct appearance dimensions (i.e., bundles of features) that characterize a wide spectrum of anthropomorphic robots and Study 2 identified the dimensions and specific features that were most predictive of robots» perceived human-likeness. With data from both studies, we then created an online estimation tool to help researchers predict how human-like a new robot will be perceived given the presence of various appearance features. The present research sheds new light on what makes a robot look human, and makes publicly accessible a powerful new tool for future research on robots» human-likeness.

Virtual reality (VR)systems let users intuitively interact with 3D environments and have been used extensively for robotic teleoperation tasks. While more immersive than their 2D counterparts, early VR systems were expensive and required specialized hardware. Fortunately, there has been a recent proliferation of consumer-grade VR systems at affordable price points. These systems are inexpensive, relatively portable, and can be integrated into existing robotic frameworks. Our group has designed a VR teleoperation package for the Robot Operating System (ROS), ROS Reality, that can be easily integrated into such frameworks. ROS Reality is an open-source, over-the-Internet teleoperation interface between any ROS-enabled robot and any Unity-compatible VR headset. We completed a pilot study to test the efficacy of our system, with expert human users controlling a Baxter robot via ROS Reality to complete 24 dexterous manipulation tasks, compared to the same users controlling the robot via direct kinesthetic handling. This study provides insight into the feasibility of robotic teleoperation tasks in VR with current consumer-grade resources and exposes issues that need to be addressed in these VR systems. In addition, this paper presents a description of ROS Reality, its components, and architecture. We hope this system will be adopted by other research groups to allow for easy integration of VR teleoperated robots into future experiments.

Gone are the days of robots solely operating in isolation, without direct interaction with people. Rather, robots are increasingly being deployed in environments and roles that require complex social interaction with humans. The implementation of human-robot teams continues to increase as technology develops in tandem with the state of human-robot interaction (HRI) research. Trust, a major component of human interaction, is an important facet of HRI. However, the ideas of trust repair and trust violations are understudied in the HRI literature. Trust repair is the activity of rebuilding trust after one party breaks the trust of another. These trust breaks are referred to as trust violations . Just as with humans, trust violations with robots are inevitable; as a result, a clear understanding of the process of HRI trust repair must be developed in order to ensure that a human-robot team can continue to perform well after a trust violation. Previous research on human-automation trust and human-human trust can serve as starting places for exploring trust repair in HRI. Although existing models of human-automation and human-human trust are helpful, they do not account for some of the complexities of building and maintaining trust in unique relationships between humans and robots. The purpose of this article is to provide a foundation for exploring human-robot trust repair by drawing upon prior work in the human-robot, human-automation, and human-human trust literature, concluding with recommendations for advancing this body of work.

Trust serves as a powerful social capacity that can influence the course of a relationship, either spurring a willingness or refusal of one agent to interact with another. As we attempt to build increasingly complex and useful social robots, we must consider what factors will engender such trust and thus benefit human-robot interaction. In this paper we describe a line of inquiry that is investigating how a person's perceived involvement in helping a robot recover from failure affects the person's trust in the robot and in its future actions. We posit that a person's active involvement with a robot, compared with passive observation, will lead to greater trust in the robot.

Robot assistive technology is becoming increasingly prevalent. Despite the growing body of research in this area, the role of type of interaction (i.e., small groups versus individual interactions) on effectiveness of interventions is still unclear. In this paper, we explore a new direction for socially assistive robotics, where multiple robotic characters interact with children in an interactive storytelling scenario. We conducted a between-subjects repeated interaction study where a single child or a group of three children interacted with the robots in an interactive narrative scenario. Results show that although the individual condition increased participant's story recall abilities compared to the group condition, the emotional interpretation of the story content seemed more dependent on the difficulty level rather than the study condition. Our findings suggest that, despite the type of interaction, interactive narratives with multiple robots are a promising approach to foster children's development of social-related skills.

Changes in type of interaction (e.g., individual vs. group interactions) can potentially impact data-driven models developed for social robots. In this paper, we provide a first investigation in the effects of changing group size in data-driven models for HRI, by analyzing how a model trained on data collected from participants interacting individually performs in test data collected from group interactions, and vice-versa. Another model combining data from both individual and group interactions is also investigated. We perform these experiments in the context of predicting disengagement behaviors in children interacting with two social robots. Our results show that a model trained with group data generalizes better to individual participants than the other way around. The mixed model seems a good compromise, but it does not achieve the performance levels of the models trained for a specific type of interaction.

Short et al. found that in a game between a human participant and a humanoid robot, the participant will perceive the robot as being more agentic and as having more intentionality if it cheats than if it plays without cheating. However, in that design, the robot that actively cheated also generated more motion than the other conditions. In this paper, we investigate whether the additional movement of the cheating gesture is responsible for the increased agency and intentionality or whether the act of cheating itself triggers this response. In a between-participant design with 83 participants, we disambiguate between these causes by testing (1) the cases of the robot cheating to win, (2) cheating to lose, (3) cheating to tie from a winning position, and (4) cheating to tie from a losing position. Despite the fact that the robot changes its gesture to cheat in all four conditions, we find that participants are more likely to report the gesture change when the robot cheated to win from a losing position, compared with the other conditions. Participants in that same condition are also far more likely to protest in the form of an utterance following the cheat and report that the robot is less fair and honest. It is therefore the adversarial cheat itself that causes the effect and not the change in gesture, providing evidence for a cheating detector that can be triggered by robots.

Robots that engage in social behaviors benefit greatly from possessing tools that allow them to manipulate the course of an interaction. Using a non-anthropomorphic social robot and a simple counting game, we examine the effects that empathy-generating robot dialogue has on participant performance across three conditions. In the self-directed condition, the robot petitions the participant to reduce his or her performance so that the robot can avoid punishment. In the externally-directed condition, the robot petitions on behalf of its programmer so that its programmer can avoid punishment. The control condition does not involve any petitions for empathy. We find that externally-directed petitions from the robot show a higher likelihood of motivating the participant to sacrifice his or her own performance to help, at the expense of incurring negative social effects. We also find that experiencing these emotional dialogue events can have complex and difficult to predict effects, driving some participants to antipathy, leaving some unaffected, and manipulating others into feeling empathy towards the robot.