Human interaction is central to many computing systems that require a high level of assurance. We term such systems as high-confidence interactive systems. Examples of such systems include aircraft control systems (interacting with a pilot), automobiles with self-driving features (interacting with a driver), medical devices (interacting with a doctor), and electronic voting machines (interacting with a voter). A major challenge to verifying the correct operation of such systems is that it is difficult to formally specify the human user's view of correct operation and perception of the input/output interface. In this paper, we describe a promising approach towards addressing this challenge that combines formal verification with systematic testing by humans. We describe an illustrative application of this approach to electronic voting in the U.S., and outline directions for future work. © Springer-Verlag 2013.