Using graphs is a key social practice of professional science. As part of a research program that investigates the development of graphing practices from elementary school to professional science activities, this study was designed to investigate similarities and differences in graph-related interpretations between scientists and college students engaged in collective graph interpretation. Forty-five students in a second-year university ecology course and four scientists participated in the study. Guided by domainspecific concerns, scientists' graph-related activities were characterized by a large number of experiencebased, domain-specific interpretive resources and practices. Students' group based activities were characterized by the lack of linguistic distinctions (between scientific terms) which led to ambiguities in group negotiations; there was also a lack of knowledge about specific organism populations which helped field ecologists construct meaning. Many students learned to provide correct answers to specific graphing questions but did not come to make linguistic distinctions or increase their knowledge of specific populations. In the absence of concerns other than to do well in the course, students did not appear to develop any general interpretive skills for graphs, but learned instead to apply the professor's interpretation. This is problematic because, as we have demonstrated, there are widely differing viable interpretations of the graph. Suggestions for changes in learning environments for graphing that should alleviate this problem are made. John Wiley & Sons, Inc. J Res Sci Teach 36: 1020-1043 Laboratory studies point to the generation and interpretation of inscriptions (e.g., graphs, tables, diagrams) as the central activity of scientists (Latour & Woolgar, 1986; Lynch, 1985). Graphs are probably the most important of scientists' ways of presenting their data because they pictorially illustrate the relationships between different measured variables in, for instance, scatter plots (Bastide, 1990;Lemke, 1998). Schank (1994) listed graphing-which by definition included producing, reading, and critiquing graphs-as one of the seven most important skills of a professional biologist. Learning to produce, read, and critique graphs should therefore be an important ingredient of any university biology program. However, there is evidence that even college graduates with B.Sc. and M.Sc. degrees by and large have not developed much competence in using graphs in contexts where scientists employ them by default (Roth, McGinn, & Bowen, 1998). JOURNAL OF RESEARCH IN SCIENCE TEACHING VOL. 36, NO. 9, PP. 1020 -1043 © 1999 John Wiley & Sons, Inc. CCC 0022-4308/99/091020-24Correspondence to: G. M. BowenStudents' deficiencies in graphing have been researched largely from an information-processing paradigm (Leinhardt, Zaslavsky, & Stein, 1990). Research from this perspective shows that few students arrive at the normative interpretations of graphs that researchers hold as referents for student-generated sol...