Bug or Feature? Covert Impairments to Human Computer Interaction

Computer users commonly experience interaction anomalies, such as the text cursor jumping to another location in a document, perturbed mouse pointer motion, or a disagreement between tactile input and touch screen location. These anomalies impair interaction and require the user to take corrective measures, such as resetting the text cursor or correcting the trajectory of the pointer to reach a desired target. Impairments can result from software bugs, physical hardware defects, and extraneous input. However, some designs alter the course of interaction through covert impairments, anomalies introduced intentionally and without the user's knowledge. There are various motivations for doing so rooted in disparate fields including biometrics, electronic voting, and entertainment. We examine this kind of deception by systematizing four different ways computer interaction may become impaired and three different goals of the designer, providing insight to the design of systems that implement covert impairments.