Share and Share Alike?: Social Information and Interaction Style in Coordination of Shared Use

Interfaces are commonly designed from the perspective of individual users, even though most of the systems we use in everyday life are in fact shared. We argue that more attention is needed for system sharing, especially because interfaces are known to influence coordination of shared use. In this work, we aim to deepen the understanding of this relation. To do so, we design three interfaces for a shared lighting system that vary in the type of social information they allow people to share with others and in their overall interaction style. We systematically compare longitudinal and real-life use of the interfaces, evaluating (1) people's appraisal of three types of social information and (2) the influence of an interaction style on coordination of shared use. The results disclose relations between the interface and the amount of verbal communication, consideration, and accountability. With this work, we urge the need for interaction designers to consider shared use.