Unprompted Touch with Touch Surface Characteristics: A Survey

This survey article investigates human-initiated touch interaction with a touch surface on a robot, reviewing 37 papers, with seven papers involving unprompted touch interaction and 30 papers involving prompted touch interaction. The 37 papers are examined in depth as to whether the touch interaction was unprompted, which of the nine touch surface characteristics (appearance, haptic feedback, light, material, movement, shape, size, texture, and temperature) were examined, and the methods used to measure the effects of the touch surface characteristics. This survey makes three findings. One is that no unprompted touch interaction provides an understanding of what factors influence its initiation. Two, four studies involving prompted touch suggest two methods for inferring influence on causation from attentiveness or engagement. Three, the touch surface characteristics involved in human-initiated touch interaction consist of nine characteristics, and the limited set of four touch surface characteristics presented within the unprompted touch literature should be expanded to the nine characteristics. The survey sets the foundation for future research into unprompted touch, especially for use in disasters and medical intervention, by (a) expanding the demographics, groups, and scenarios by investigating unprompted touch, (b) investigating the triggers and affordances associated with unprompted touch, and (c) investigating the interaction and affect touch surface characteristics have on one another and the touch interaction when combined.