UC San Diego

Dynapad is a prototype software application designed to support users in organizing and exploring personal collections of digital information. It provides a continuously zoomable workspace, essentially an infinite desktop, on which users can arrange digital photos and document "portraits", visual summaries of collected PDF documents. To support users in engaging with their collections, Dynapad offers a unique combination of affordances. These include: 1) "brushing" media objects to reveal and highlight others related by various metadata; 2) interactively revisiting any episode in the history of one's workspace; and 3) employing portable "region-tools" which are computationally enriched with various forms of localized automation. An important special case of these region-tools is a digital "pile" which emulates -- and augments -- the affordances of paper which make "piling" a ubiquitous complement to "filing" as an organizational strategy. The resulting environment is flexible enough that users are left considerable freedom and responsibility to invent organizational strategies and to structure their own activity. The tactics they adopt are emergent and exaptive behaviors shaped by small details of Dynapad's design, the affordances and cues which together constitute the environment's "cost structure" for interaction. My research explores that cognitive ecology through detailed exploratory observation of two Dynapad users working with collections of their own digital documents. To analyze those observations, I trace a network of influences from design details to the behaviors they shape. My representation of that network identifies and dissociates affordances that participate differently in the cost structure, particularly in their contributions to piling. It is not meant to provide a predictive model of users' behavior; instead, it offers a theoretical framework for interpreting and synthesizing my and others' observations. Such a description is a necessary component of the understanding required for effective redesign of Dynapad and the design and development of other interactive systems