Article: Computer architecture and mental models
COMPUTER ARCHITECTURE AND MENTAL MODELS
Yehezkel, C., Ben-Ari, M., Dreyfus, T. (2005) – Inroads of SIGCSE, 37(1)
Article Summary:
The EasyCPU visualization environment was developed for teaching computer architecture to novice students of computer science. During the development, the process of choosing the appropriate conceptual model of the computer for the visualization motivated research on the mental models that arise in the students as they learn. These mental models come from attempts by the students to make sense of the conceptual models presented to them by the software tool and their learning materials (textbook and exercises). The research findings support the view that the visualization was critical in enabling the construction of a viable mental model, a process that did not occur from textbook learning alone, because for the majority of students, their mental models were based upon their experience as end-users of computers rather than on the theoretical learning about computers.
We evaluated the contribution of the EasyCPU visualization environment to the understanding of a conceptual model of a computer. When studying computer architecture, a student interacts with a learning model of the target system that is presented by the visualization environment and therefore the resultant mental model may be different from what it would have been, had the student worked directly with target system. The mental models of the students were investigated at two points of time: first, after studying the material theoretically from the textbook but before they were exposed to the EasyCPU system, and second, after activities with the EasyCPU environment. The research tools were a pretest, two activities, and a posttest, in which the students were asked to describe both, the topology of the interconnections between the units and their dynamic interactions. The research was carried out on a class of eleven tenth-grade high school students. We found that the students developed mental models that can be categorized into three different topologies: The CC (CPU centered) model, the correct one for this target system in which all memory accesses and I/O operations are performed via the CPU; the CM (Central Memory) model, which incorrectly assumes that I/O is done directly to memory; and the while the ICO (Input>CPU>Ouptut) model, which focuses of the relation between the I/O units, downplaying the role of the main memory. On the pretest, five of the eleven students chose to draw systems consistent with the ICO model, two others drew CM models, and only four drew the CC model. On the posttest, after the students had interacted with the conceptual model presented by the visualization, all students drew models consistent with the CC model.
This supports the view that the EasyCPU visualization environment was critical in enabling the construction of a viable mental model. After studying the material theoretically, the majority of the students still held mental models that have been influenced by their earlier experience as end-users. The visualization feature of the EasyCPU environment enabled the students to develop a viable model of the computer architecture by visualizing dynamic interaction between the units during scenarios of instruction execution.
Author 1: Cecile Yehezkel [email protected]
Author 2: Mordechai Ben-Ari [email protected]
Author 3: Tommy Dreyfus [email protected]
Article Link: http://portal.acm.org/citation.cfm?id=1047390&coll=portal&dl=ACM&CFID=9122936&CFTOKEN=32438184