A PROPOSED PROCESS MODEL FOR VISUAL PENETRATIVE ABILITY IN GEOLOGIC VISUALIZATION

This study was designed to better characterize the spatial abilities of introductory geology lab students, specifically the ability to visualize the 3D underground structure of folded sedimentary rocks from 2D surface clues. Visual Penetrative Ability (VPA), identified as a distinct spatial ability by Kali and Orion in 1996, is a basic skill for any geology undergraduate student and is also required in many introductory laboratory exercises designed for non-majors. Despite its importance to structural geology education, our understanding of VPA from a cognitive or instructional perspective remains incomplete. Students in two of our sample of four Physical Geology laboratory sections at SDSU were given Geo 3D, a Flash-based learning aid designed by Kali and Orion, and the other two sections were given exercises traditionally used in the course. We used the GeoSAT instrument developed by Kali and Orion for pre- and post-test assessment. Post-instruction problem-solving interviews were conducted with students representing the range of performance on the GeoSAT. The post-test performance of both groups was essentially the same and showed only minor gains for either instructional approach. Qualitative analysis of interviews yielded insight into the nature of the difficulties faced by students in solving this style of spatial problem, and explained the origin of many of the common incorrect responses seen by previous workers using the GeoSAT. Students with high VPA appear to rapidly construct a complete, three-dimensional internal visual model, and after some work can draw cross-sectional and face-completion diagrams of cubic slices of geologic structures based only on surface information. Students with poor VPA tend to view external information as merely a type of “gift wrapping” over the cubic volume and do not perceive the internal structure presented. Their attempts at completing cross sections or blank faces illustrate how many common non-penetrative errors are generated. We construct a process model for VPA which shows the origin of commonly observed errors as a function of a spectrum of varying VPA ability at crucial steps, and associated accommodation strategies used by students struggling with spatial visualization of this type.