Using Behavioral Realism to Estimate Presence: A Study of the Utility of Postural Responses to Motion Stimuli

Abstract

We recently reported that direct subjective ratings of the sense of presence are potentially unstable and can be biased by previous judgments of the same stimuli (Freeman et al., 1999). Objective measures of the behavioral realism elicited by a display offer an alternative to subjective ratings. Behavioral measures and presence are linked by the premise that, when observers experience a mediated environment (VE or broadcast) that makes them feel present, they will respond to stimuli within the environment as they would to stimuli in the real world. The experiment presented here measured postural responses to a video sequence filmed from the hood of a car traversing a rally track, using stereoscopic and monoscopic presentation. Results demonstrated a positive effect of stereoscopic presentation on the magnitude of postural responses elicited. Posttest subjective ratings of presence, vection, and involvement were also higher for stereoscopically presented stimuli. The postural and subjective measures were not significantly correlated, indicating that nonproprioceptive postural responses are unlikely to provide accurate estimates of presence. Such postural responses may prove useful for the evaluation of displays for specific applications and in the corroboration of group subjective ratings of presence, but cannot be taken in place of subjective ratings.

FIJI: A Framework for the Immersion-Journalism Intersection

“…For example, Barfield et al (1999) found that the introduction of stereoscopy-"the display of different images to each eye to provide an additional depth cue" (Bowman and McMahan, 2007)-resulted in increased levels of reported presence, despite not improving user performance for a 3D wire tracing task. Similarly, Freeman et al (2000) and IJsselsteijn et al (2001) found that stereoscopy caused increases in reported presence when viewing virtual scenes. Lin et al (2002) used a three-screen driving simulator to control FOR and found that users reported greater presence with increasing degrees of FOR.…”

“…However, some qualities of immersion have been found to affect engagement. Freeman et al (2000) found that stereoscopy increased users' subjective ratings of involvement when viewing a virtual scene. Lugrin et al (2013) compared a CAVE-based implementation of a first-person shooter, which used a six-degree-of-freedom (6-DOF) tracked device for 3D shooting and hand-directed steering, to a traditional desktop version that used keyboard and mouse.…”

Influence of 3D Stereoscopic Video Running Time on Audience Perceptions

“…헨드릭스와 바필드(Hendrix & Barfield) [38] 는 2D와 비교하여 3D 이미지가 15% 이상 높은 프레즌스 수준을 경험하며, 3D 이미지의 부정적 요인인 중 첩(double image)이나 고스트(ghost) 현상이 발생하지 않았 을 때 더 높게 나타난다고 말하였다. 프리맨과 아본(Freeman & Avons) [6] 도 3D 영상을 시청하는 동안 더 많은 프레 즌스를 경험하는 것으로 밝혀졌는데, 3D 영상의 현실감, 자 연스러움, 흥미, 관심 등이 프레즌스를 더욱 느끼게 하는 요인이며, 3D 영상에서 본 장면이 현실에서 본 장면보다 더 사실적으로 느껴진다고 했다. 양호철과 정동훈 [17] 그리 고 정동훈과 양호철 [16] [17] 은 이러한 프레즌스의 효과를 측 정하기 위해 측정도구를 개발하였고, 이를 통해 프레즌스 가 시각피로도와 부적(negative) 관계를 갖고 있음을 밝힌 바 있다.…”

“…이러한 피로의 측정은 뇌파검사, 플리커 테스트 (flicker test), 안구운동측정 등의 객관적 측정 방법이 사용되 기도 하나, 개인의 평가를 중요시하는 주관적인 측정방법 또 한 여러 학자에 의해 강조되어지고 있다 [49] [50] . 3D 영상의 가장 큰 특징인 입체감이 과장되면 양안 시차 때문에 피로감을 느낄 수 있고, 이로 인하여 수용자가 입체 감의 부자연스러움을 인식하게 되면 이로 인하여 프레즌스 경험에 부정적인 영향을 미치는 것이 일반적이다 [6] . 이는 개인에 따라 다르게 나타나는데, 3D를 인지하지 못하는 사 람이 있는가하면 3D를 잘 볼 수 있는 사람들도 불편함을 느끼는 정도가 다르기 때문이다.…”

Contributions to the Development of Objective Techniques for Presence Measurement in Virtual Environments by means of Brain Activity Analysis

“…In a more recent study [27], participants in a within-subject design were exposed to four conditions based on two variables: stereoscopy and moving or still images. Results showed that stereoscopy had a positive effect on the magnitude of the participant's automatic postural responses (which were measured via a magnetic tracking device).…”