Human interaction with the physical world is increasingly mediated by autonomy, as planes assist pilots, robots assist surgeons, and cars assist drivers. Automation is introduced in such systems to aid humans and guarantee safety and performance. However, such guarantees are hard to provide, since humans may misunderstand the automation's intentions or behave in an unanticipated manner; tragic examples like the crash of Air France flight 447 illustrate that such confusion between pilots and autopilots can lead to catastrophic outcomes. Although some applications may someda