Measurements of Presence and Multisensory Stimulation in Virtual Reality

Author/Creator

Author/Creator ORCID

Date

2023-05

Department

University of Baltimore. Division of Science, Information Arts and Technologies

Program

University of Baltimore. Doctor of Science in Information and Interaction Design

Citation of Original Publication

Rights

This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by The University of Baltimore for non-commercial research and educational purposes.

Abstract

Presence in virtual reality measures the extent to which users respond to a virtual experience as if they were present in it. Users experiencing presence will respond to the virtual environment as if it were real and ignore real-world stimuli to varying degrees. Studies show that incorporating additional multisensory stimuli along with the standard audio-visual stimuli may increase feelings of presence. Presence is typically measured via post hoc questionnaires or neurophysiological measurements. Although subjects who are immersed in virtual reality may exhibit neurophysiological reactions to virtual stimuli similar to those they would exhibit in the real world, subjects in some studies do not report feelings of presence in post-test questionnaires. This discrepancy may occur because the questionnaires are administered post-test when users have been removed from the experience that elicited feelings of presence. This study examined whether users experience higher levels of presence when additional sensory stimulation is integrated into a task-based virtual reality system and presence is measured during the experience. A modified repeated-measures experimental pre-test/post-test was conducted using task-based scenarios to measure presence and neurophysiological responses. This study manipulated timing and method of survey delivery as well as haptic and olfactory integration. The iGroup Presence Questionnaire (IPQ) and electroencephalography (EEG) activity were used to measure presence. Subjects also received a short qualitative survey post-test. No statistically significant differences were found in EEG measurements or IPQ scores among subjects (N=15) who received different sensory treatments. This may be partially attributed to COVID campus requirements that subjects wear masks during the study. There was a significant difference in the F8 EEG band (placed over the frontal lobe) measurements for in-test survey with additional sensory stimulation compared to post-test survey with no additional sensory stimulation. Combining additional sensory stimulation and administering a survey in-test showed increased EEG activity in the frontal lobe, which may indicate higher levels of presence. Subjects answering a short qualitative questionnaire reported higher levels of presence when olfactory stimuli and olfactory stimuli in conjunction with haptic stimuli were introduced during treatment. IPQ scores and EEG measurements do not support self-reports. A larger sample of subjects (N=35) who did not receive any additional sensory stimulation showed a statistically significant difference in the O2 EEG band (placed over the occipital lobe) measurements between groups that were administered a questionnaire in-test by a non-player character compared to groups where the questionnaire was administered in-test by a researcher or post-test on a computer (traditional method). Integrating a presence survey into a virtual reality experience (via NPC) may cause increased EEG activity in the occipital lobe, which may suggest higher levels of presence in users.