Area I: Presence Measures

The experiments of Chapter 4 measured the relative effect of different visual conditions on the perception of self-motion. A visual-inertial nulling technique was used in which the strength of the visual stimuli was measured by its ability to overwhelm conflicting inertial motion cues. The technique is outlined in Figure 3.1.

**Figure 3.1:** Presence Measure Experimental Configuration
$\includegraphics{ills/rotator.eps}$ A. Participant is seated in a chair which oscillates in yaw (i.e., in the horizontal plane) while wearing an HMD. The HMD shows a scene which also oscillates in yaw. B. In the real world, when one turns to the right the visual field flows to the left. The sense of self-motion is towards the right. C. The visual motion in the HMD can be set to turn in the same direction as the inertial motion. In this case, the inertial cues make one think one is moving to the right, whereas the visual cues make one think one is moving to the left. The sense of self-motion depends on their relative strength. D. Any visual-inertial phase angle is possible.