“…Interactions in natural settings (e.g., public spaces) are too complex to be simulated in controlled laboratory settings, so to understand natural HRI it is important to conduct field studies. Many HRI systems have been tested in public spaces such as hospitals [55], train stations [31], service points [36,38], airports [35], shopping malls [65], hotels [19], and museums [66], among others. Although robots investigated in these works are sometimes surrounded by a group of people in a public place, these robots typically interact with only one person at a specific time (i.e., one-to-one interaction).…”