Interaction Substrates: Combining Power and Simplicity in Interactive Systems

Today's graphical user interfaces tend to be either simple but limited, or powerful but overly complex. In order to combine power and simplicity, we introduce Substrates, which act as "places for interaction" where users can manipulate objects of interest in a principled and predictable way. Substrates structure and contain data, enforce user-defned constraints among objects and manage dependencies with other substrates. Users can "tune" and "tweak" these relationships, "curry" specialized tools or abstract relationships into interactive templates. We frst defne substrates and provide in-depth descriptions with examples of their key characteristics. After explaining how Substrates extend the concept of Instrumental Interaction, we apply a Generative Theory of Interaction approach to analyze and critique existing interfaces and then show how using the concepts of Instruments and Substrates inspired novel design ideas in three graduate-level HCI courses. We conclude with a discussion and directions for future work.

• Human-centered computing → Human computer interaction (HCI).