DO MAPS TELL THE WHOLE STORY? GEOLOGIC MENTAL MODELS AS EXPRESSED VERBALLY AND BY MAPS

Geologic mapping is a complex and cognitively demanding task, the end product of which is the actual map. This map is a 2-dimensional representation of the geologist’s 3-dimenstional mental model of the rock units and their structural relationship to one another. Nearly all undergraduate geology students in the United States are taught geologic mapping, often as a multi-week summer course. The maps that students produce are the dominant means by which their understanding of the geology is assessed. As part of a larger study of expertise in geologic mapping, we investigated how well geologic maps created by study participants correlated with their mental models of the underlying geology as expressed verbally. Seventy volunteers, representing a range of none to over 30 years prior mapping experience, completed several cognitive tasks plus a 1-day bedrock mapping project in the Rocky Mountains, Montana, USA. During a post-mapping interview, each volunteer was asked to explain his or her map. For the majority of participants, the rock units and structures identified on the map correlated well with their verbal explanations. In some cases, participants were unable to clearly explain their mental models, even when their maps were of apparent high quality. However, many participants, particularly novice mappers, could verbalize a better model of the geology than their map indicated. Results of this study suggest that in addition to assessing student maps, field course instructors might consider using written or verbal questions to ensure that students hold accurate mental models of the underlying geology.