Brittany A. Duncan, a doctoral candidate at the university, and her faculty adviser, a professor of computer science and engineering named Robin R. Murphy, were on the team providing technical support for the micro-helicopters and the AirRobot quadcopter-style drone that were used to represent Shakespeare’s fairies. In rehearsals, the actors tended to behave as if the AirRobot—roughly the diameter of a large pizza, with four exposed rotors—were as safe as the fist-size micro-helicopters. So Murphy urged them to think of the AirRobot as “the flying weedwacker of death.” But when audiences also displayed a high level of comfort, she began to wonder whether small drones “are just not scary to people.”
In a new study, Duncan and Murphy found that people don’t perceive some drones as invasive at all—which might be a problem, the researchers argue. The subjects’ heart rates failed to register anxiety even when an AirRobot approached just two feet away at roughly head height. That was surprising, because most previous experiments by other researchers showed that people tended to react to earthbound robots by maintaining a personal space of three feet or more, much as with another human. Also contrary to expectation, the test subjects were inclined not to treat the airspace under the drone as if it were occupied. Instead, they reacted as if the drone were roughly as threatening as Tinker Bell.
Why would people steer clear of a robot on the ground but let a flying contraption buzz their heads? Duncan speculates that most of the predators in our evolutionary past would have approached at ground level, not head height. Perhaps small drones bypass our usual defensive response because of a certain birdlike disconnect from terra firma.