“We hypothesized that to the degree that a VE seems real, it would evoke physiological responses similar to those evoked by the corresponding real environment, and that greater presence would evoke a greater response.” - Abstract, pg. 645
They use a metric called “Change in Heart Rate” as a physiological measure as a surrogate to presence. In total, they used these metrics:
To measure heart rate, they went with a cumbersome chest-attached 3-electrode ECG device. Users soon forgot they were wearing the ECG.
They had a setup with a 20ft virtual hole with a small plank where the user was situated. The users were given an initial task in a different virtual room to practice walking around and placing objects in the Training room; they were then instructed to move an object to the next room (the pit room, though unknown to the participants at the time) and place it at a designated location. The hazard is unexpected to users, as the door to the pit room is closed until this step.