Brenda K. Wiederhold,

The effects of varying levels of immersion in virtual reality environments on participantÕs heart rate, respiration rate, peripheral skin temperature, and skin resistance levels were examined. Subjective reports of presence were also noted. Participants were presented with a virtual environment of an airplane flight both as seen from a twodimensional computer screen and as seen from within a head-mounted display. Subjects were randomly assigned to different order of conditions presented, but all subjects received both conditions. Differences between the non-phobicsÕ physiological responses and the phobicÕs response when placed in a virtual environment related to the phobia were noted. Also noted were changes in physiology based on degree of immersion.