Abstract

Drawing on Experience: Use of Sketching to Evaluate Knowledge of Spatial Scientific Concepts Benjamin D. Jee ([email protected]) 1 Dedre Gentner ([email protected]) 1 Kenneth Forbus ([email protected]) 2 Bradley Sageman ([email protected]) 3 David H. Uttal ([email protected]) 1 Department of Psychology Department of Electrical Engineering and Computer Science Department of Earth and Planetary Sciences Northwestern University Evanston, IL 60607 USA causal knowledge about the formation of the structure. For the fault depicted in Figure 1, the geoscientist would notice that the block of rock above the fault plane has moved downward relative to the block of rock below the plane. This indicates that extensional forces deformed the rock until it fractured along the fault plane. Abstract How does learning affect the structure of domain knowledge? This question is difficult to address in domains such as geoscience, where spatial knowledge is paramount. We explore a new platform, called CogSketch, for collecting and analyzing participants’ sketches as a means of discerning their spatial knowledge. Participants with differing levels of experience in the geosciences produced sketches of geologic structures and processes on a tablet computer running CogSketch software. This allowed for the analysis of not only the spatial-relational structure of the sketches, but also the process through which the sketches were constructed. Introduction The development of expertise is a central issue in cognitive science and education. Understanding the paths by which people acquire mastery in a domain is important both in guiding the design of training in the domain and in shaping theories of learning high-level knowledge (Bransford, Brown, & Cocking, 2000; Chi, Glaser, & Farr, 1988). To support student learning, cognitive scientists and educators need to assess the mental models that students develop at different points along the continuum of knowledge acquisition. This is a challenge in domains that are intensely spatial, such as geoscience, architecture and engineering, because evaluating students’ spatial mental models requires that students produce a spatial depiction; assessing such sketches and designs is extremely laborious. In this paper we describe a new method for eliciting students’ spatial knowledge through sketching. Spatial knowledge in Geoscience Geoscience requires learning about complex, large-scale processes that occur over large ranges of space and time. These include the structure of the Earth’s interior, the deformation processes that occur within its crust (e.g., folds, faults, and fissures) and unifying both, the model of plate tectonics. All these topics are deeply spatial. Consider the simple concept of a fault (see Figure 1). Faults are defined by the spatial relationship between the blocks of rock along a fracture. For the experienced geoscientist, this perceptual information is connected to Figure 1. Example of a fault Thus, simply to identify a basic geoscience concept, students must understand relevant spatial structures, which are intimately connected to causal knowledge. To take a more complex example, consider subduction, depicted in Figure 2. Understanding this process involves identifying spatial structures – e.g., that one plate is moving underneath another. Yet, noticing that structure is just the beginning. The student must also understand the driving forces: that the subduction process is causally related to both the process of seafloor spreading, which creates new ocean crust at divergent spreading zones, and differences in crustal density between converging plates, which determines which plate sinks below the other. In addition, subduction drives other relevant geologic processes, such as volcanic activity. Figure 2. Diagram of Subduction