Design Rationale as Theory

usage scenario: A group works together in a virtual world Members of a real world group meet online to discuss a shared concern. In the space they browse andinteract with virtual objects that are surrogates for objects in the real world; as part of their discussion theypoint at and annotate the virtual objects. The surrogates evoke their experiences with the real worldcounterparts, which enriches the online experience, helping them to remember and better articulate a range of shared and personal concerns. As the discussion progresses, supporting information is needed. One participant remembers having usedthe information at another place, and navigates to this other place to retrieve it. As s/he enters this otheronline place, the images and other objects in that virtual space evoke prior history with it—the people s/heknows who also use it, their activities, and their various roles. S/he automatically adjusts behavior to meetthe expectations and standards of this group. When s/he leaves this place and returns to the starting place, s/he again adjusts role and social behavior accordingly. Claim: situating online interaction in a familiar place-based environment + evokes and applies the interaction partners’ history and common ground + supports social context-switching as place-based boundaries are crossed —but important aspects of the classroom may be missing, making interaction inappropriate or awkward Claim: online objects that refer directly to real world objects + expands mental experience of the virtual object with existing personal knowledge —but may limit creativity with respect to virtual attributes and operations Claim: a virtual structure that mimics real world physical containment relations + creates a simple and extensible decomposition for storing and retrieving objects + leverages people’s real world skills of spatial browsing and navigation —but highly nested structures may make search and navigation difficult