This study addresses how anthropomorphic features shape users' social perception and trust towards service robots and whether anthropomorphic characteristics influence the way people jointly navigate with them facing several obstacles in a course. Therefore, an experimental study was conducted where two communication and appearance designs (humanlike vs. machinelike) were examined for a service robot that provides transportation of goods by semi-automated following. The results of the study indicate that the humanlike robot design is rated more competent, warmer, less discomforting, and is generally preferred. Furthermore, participants jointly navigating with the humanlike designed robot walked around obstacles significantly more often indicating a more considerate navigation behavior and better remembering of system limits; both probably evoked by the humanlike design characteristics. In sum, the results of this study provide intriguing implications on how to target HRI for the service robot examined to enhance pleasant and error-free interaction.

In this work, we provide an argument and first empirical insights that existing technology acceptance models fall short when it comes to explaining spontaneous, unplanned and unsolicited encounters between humans and delivery robots on the street. Since technology acceptance models have been defined by the technology's perceived ease of use, perceived usefulness and behavioural intention to use, they are not well suited to explain acceptance in situations in which humans meet robots without any prior intention to use. Nevertheless, acceptance of delivery robots might be a driving force for safe navigation. Thus, the concept of acceptance should not be limited to its current focus on (planned) usage. In consequence, we i) expand the understanding of technology acceptance, ii) propose the concept of Existence Acceptance for autonomous systems, and iii) explore a new model for acceptance in an online study (n = 185). Theoretical considerations hint towards the relevance of existence acceptance models for autonomous systems.

This paper addresses how robots should communicate with humans so that the interaction is successful and satisfying for the user. Specifically, within the present study, nine different communication strategies were examined for a service robot that provides transportation of goods by semi-automated following. The communication style (humanlike friendly, humanlike professional, machinelike) and modality (auditive male, auditive female, visual) of communication was varied and their influence on system evaluation regarding competence, warmth, discomfort, embodiment and preferences were investigated in an online study. The results of the study indicate that a humanlike communication is rated more competent, warmer, less discomforting, and is generally preferred. With regard to gender, no clear preferences or differences in evaluation were found. In terms of modality, a combination of auditive and visual interaction was favored. It should be noted that the data were collected online and verification of the results in situ is essential. Nevertheless, the results of this study provide intriguing implications on how to target HRI for the service robot examined.