Limits to general expertise: A study of in- and out-of-field graph interpretation

Graphs are pervasive features in professional science journals, which makes graphing one of (if not the) most important practice (and therefore skill) of professional science. Scientists generally are expected to be experts in graphing. Contrary to this expectation, recent investigations showed that scientists asked to interpret graphs from introductory-level textbooks in their own field did not at all exhibit expert-like behavior. The present study was designed to understand better the nature of graphing practices among professional scientists. I investigated the similarities and differences in scientists’ interpretation of structurally identical in-field and out-of-field graphs. Seventeen physicists interpreted 3 graphs that were derived from entry-level university textbooks in ecology—for cross validation purposes, these were the same graphs used in an earlier expert-expert study—and 3 structurally identical graphs from the field of physics. My analyses reveal that the graphing expertise of physicists is limited even within their field. Their graph interpretations are highly idiosyncratic and contingent both within and across content domains. Common to the interpretive practices on in-field and out-of field graph was that scientists interpreted them according to the purposes of (a) graphing in science in general and (b) those of the graph interpretation interview session specifically. In using varying resources and in experiencing breakdowns, they exhibited considerable differences between in-field and out-of-field graph interpretations. Working on in-field graphs, they drew on general knowledge and prior experiences from their professional life, whereas in the context of out-of-field graph interpretations, scientists provided verbal equivalents for the visible, surface features of the line graphs and drew on mundane everyday life experiences to explicate them