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Electronic Mail for Asynchronous Collaboration: Comprehension Effects of Context Representation
Author: Susan Harness Regli
Degree: Ph.D. in Rhetoric, Carnegie Mellon University, 2000

This dissertation presents a study of electronic mail used to support asynchronous groupwork, in which messages take the form of an informal conversation but are often used as a record of the group's progress and coordination on tasks. While print conventions exist for representing dialogs, current interfaces for electronic mail do not provide support for organizing a conversation for later review. Both rhetorical theory and cognitive science, however, indicate that a well-organized text, ordered according to meaningful issues or topics, is generally more effective for readers trying to comprehend and remember written material. Comprehension is likely to be degraded by reading messages in an interface that 1) places related statements or replies at a considerable distance from one another; 2) randomly intersperses messages from different situations or contexts with one another; and 3) makes it difficult to remedy either these problems without interrupting the reading process.

Preliminary studies indicated that individuals need better tools for creating external representations of how messages relate to one another. Design of such representations, however, must accommodate trade-offs for how much information can be visible at one time; this dissertation explores these trade-offs. A 2 x 3 x 3 within-subjects factorial experiment examined the performance of 24 subjects to explore what aspects of a representation will improve comprehension and recall of material exchanged in electronic mail. The experiment examined three hypotheses: 1) a persistently visible context, represented in the form of a dialog, will improve reading and recall processes; 2) individuals will recall details and referents of previous messages more accurately if the distance between related messages is lessened, and 3) the effects of persistent context and distance will differ for varying types of recall tasks associated with using electronic mail for groupwork.

Results for the effect of a persistently visible context were significant and surprising: while readers spent more time reading the dialogs, they did not improve their accuracy in recall and thus their overall performance was degraded. The study did not find effects of distance between messages or types of recall tasks. Proposed explanations of the unexpected effects of persistent context draw on the concepts of visual momentum and compensatory processing. Further research in these areas as they relate to electronic mail is warranted.