Effects of alternate representations of evidential relations on collaborative learning discourse

Over the past decade or so, a number of software environments have been created to support students engaged in collaborative investigations in science (e.g., Belvedere, CoVis, CSILE, SenseMaker, and WebCamile). These environments have used a variety of representations for recording information such as alternate hypotheses, empirical observations, and evidential relations (e.g., node-link graphs, structured lists, and containers). There are both empirical and theoretical reasons to believe that the expressive constraints imposed by a representation and the information (or lack of information) that a representation makes salient may have important effects on students' discourse during collaborative learning. However, to date no systematic study has been undertaken to explore possible effects. This paper outlines a research agenda to address this need; provides theoretically motivated predictions; and reports initial results from a pilot study. Students worked together in groups of two on hypertext-based "science challenge" problems. Two groups used each of free text (MS Word), matrix (Excel) or graph (Belvedere) representations of evidence, for a total of six groups. Analysis of discourse transcripts suggests that these representations have quite different effects on the extent to which students discuss evidential relations.