Paper No. 11
Presentation Time: 10:50 AM
WHAT WOULD CHAMBERLIN THINK? EXPERTS MAP WITHOUT MULTIPLE WORKING HYPOTHESES
T.C. Chamberlin is well known for advocating the use of multiple working hypotheses in solving geologic problems. His classic argument warns of the danger to the reliability of a geologic investigation if “affection” for a ruling theory, rather than the actual data, drives the outcome. Little prior work has empirically tested the role of multiple working hypotheses in geologic practice. In this study, two highly-experienced professional geologists mapped a field area while wearing a head-mounted video camera with an attached microphone to record their visible actions and their spoken thoughts, creating “video logs”. This mapping task was part of a larger expert–novice study; the field area has a relatively simple geologic structure for which there exists a consensus understanding of the underlying geology (i.e., an “answer key”). The video logs reveal that both expert geologists proposed a single hypothesis of the structures early in the day (within approximately 30 minutes). However, the hypotheses were not the same. Nor were they both correct. In the end, one of the experts correctly mapped a large fold that dominates the field area; the other expert did not.
From analyses of the video logs, we find that despite reaching different conclusions, the two experts approached the mapping problem in demonstrably similar ways. Both experts developed early initial mental models of the geologic structure, which they tested and refined over the course of the day. A key difference, however, was that one expert encountered multiple locations at which his observations conflicted with his mental model. He repeatedly rejected the new evidence on the grounds of geologic uncertainty (e.g. outcrop out of place, change in orientation insignificant).
Because the task itself was a novice-level problem (appropriate for advanced undergraduate students), we cannot assume that the experts’ performance accurately reflects authentic expert practice. On the other hand, the answer was unknown to the experts, giving us insight into how experts solve student-level tasks. In either case, the fact that neither geologist articulated multiple working hypotheses is of interest. Does this imply that a hazard of expertise is forgetting Chamberlin’s warning about the danger of ruling theories?