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a) Wheatstone-style haploscope used for the virtual environment. (b) Dikablis/Vicon system used for the physical environment.Figure 1: Virtual and physical environments used in the study to compare vergence estimates. AbstractWe show that the error in 3D gaze depth (vergence) estimated from binocularly-tracked gaze disparity is related to the viewing distance of the screen calibration plane at which 2D gaze is recorded. In a stereoscopic (virtual) environment, this relationship is evident in gaze to target depth error: vergence error behind the screen is greater than in front of the screen and is lowest at the screen depth. In a physical environment, with no accommodation-vergence conflict, the magnitude of vergence error in front of the 2D calibration plane appears reversed, increasing with distance from the viewer.

This tutorial describes DynaSearch, a Web-based system that supports process-tracing experiments on coupled-system dynamic decision-making tasks. A major need in these tasks is to examine the process by which decision makers search over a succession of situation reports for the information they need in order to make response decisions. DynaSearch provides researchers with the ability to construct and administer Web-based experiments containing both between- and within-subjects factors. Information search pages record participants' acquisition of verbal, numeric, and graphic information. Questionnaire pages query participants' recall of information, inferences from that information, and decisions about appropriate response actions. Experimenters can access this information in an online viewer to verify satisfactory task completion and can download the data in comma-separated text files that can be imported into statistical analysis packages.