Determining appropriate first contact distance : trade-offs in human-robot interaction experiment design

Robots are increasingly working in close proximity to and in collaboration with people. Yet much is still unknown about the best behaviors for robots to use in interactions with humans. For example, in approaching someone for help, is there an optimal distance from a candidate person at which the robot should attempt to initiate contact? What distance is neither so far away as to risk not getting the person’s attention nor so close that the person has already committed to passing the robot? Experiments that attempt to answer such questions must balance tensions. In this paper, we argue for relatively lowcost, rapid turnaround experiments achieved by carrying out experiments “in the wild” in partially controlled ways using Wizard of Oz robot control with on-board sensing. We present the trade-offs of such experiments and illustrate the approach with a set of experiments we are carrying out to determine an appropriate distance for initial contact.