Restricted focus viewer: a tool for tracking visual attention

Eye-tracking equipment has proven useful in examining the cognitive processes people use when understanding and reasoning with diagrams. However, eye-tracking has several drawbacks: accurate eye-tracking equipment is expensive, often awkward for participants, requires frequent re-calibration and the data can be difficult to interpret. We introduce an alternative tool for diagram research: the Restricted Focus Viewer (RFV). This is a computer program which takes an image, blurs it and displays it on a computer monitor, allowing the participant to see only a small region of the image in focus at any time. The region in focus can be moved using the computer mouse. The RFV records what the participant is focusing on at any point in time. It is cheap, non-intrusive, does not require calibration and provides accurate data about which region is being focused upon. We describe this tool, and also provide an experimental comparison with eye-tracking. We show that the RFV gives similar results to those obtained by Hegarty (1992) when using eye-tracking equipment to investigate reasoning about mechanical diagrams.