Does a Robot's Subtle Pause in Reaction Time to People's Touch Contribute to Positive Influences?

This paper addresses the effects of a subtle pause in reactions during human-robot touch interactions. Based on the human scientific literature, people's reaction times to touch stimuli range from 150 to 400 msec. Therefore, we decided to use a subtle pause with a similar length for reactions for more natural human-robot touch interactions. On the other hand, in the human-robot interaction research field, a past study reports that people prefer reactions from a robot in touch interaction that are as quick as possible, i.e., a 0- second reaction time is slightly preferred to 1- or 2- second reaction times. We note that since the resolution of the study's time slices was every second, it remains unknown whether a robot should take a pause of hundreds of milliseconds for a more natural reaction time. To investigate the effects of subtle pauses in touch interaction, we experimentally investigated the effects of reaction time to people's touch with a 200-msec resolution of time slices between 0 second and 1 second: 0 second, 200, 400, 600, and 800 msec. The number of people who preferred the reactions with subtle pauses exceeded the number who preferred the 0- second reactions. However, the questionnaire scores did not show any significant differences because of individual differences, even though the 400-msec pause was slightly preferred to the others from the preference perspective.