Vection strength increases with simulated eye-separation

Abstract

Research has previously shown that adding consistent stereoscopic information to self-motion displays can improve the vection in depth induced in physically stationary observers. In some past studies, the simulated eye-separation was always close to the observer's actual eye-separation, as the aim was to examine vection under ecological viewing conditions that provided consistent binocular and monocular self-motion information. The present study investigated whether large discrepancies between the observer's simulated and physical eye-separations would alter the vection-inducing potential of stereoscopic optic flow (either helping, hindering, or preventing the induction of vection). Our self-motion displays simulated eye-separations of 0 cm (the nonstereoscopic control), 3.25 cm (reduced from normal), 6.5 cm (approximately normal), and 13 cm (exaggerated relative to normal). The rated strength of vection in depth was found to increase systematically with the simulated eye-separation. While vection was the strongest in the 13-cm condition (stronger than even the 6.5-cm condition), the 3.25-cm condition still produced superior vection to the 0-cm control (i.e., it had significantly stronger vection ratings and shorter onset latencies). Perceptions of scene depth and object motion-in-depth speed were also found to increase with the simulated eye-separation. As expected based on the findings of previous studies, correlational analyses suggested that the stereoscopic advantage for vection (found for all of our non-zero eye-separation conditions) was due to the increase in perceived motion-in-depth.

Influence of the Size of the Field of View on Visual Perception While Running in a Treadmill-Mediated Virtual Environment

“…Specifically, some studies have shown that stereopsis can provide information about relative distance not only in the peripersonal space but also at greater observation distances (Palmisano et al, 2010), and that perceived depth tends to be more “compressed” under monocular viewing conditions (Allison et al, 2009). Moreover, stereoscopic cues seem to enhance the precision of perceived speed, thereby helping to estimate the rate of self-motion (Brooks and Rafat, 2015) and the perceived speed of vection (Palmisano et al, 2019).…”

The stereoscopic advantage for vection persists despite reversed disparity

“…If this stereoscopic optic flow is filmed and then later presented to stationary observers (e.g., through a head-mounted display), they will typically experience compelling illusions of self-motion, known as vection. 1 While such illusions can be induced by presenting optic flow to only a single eye, research has shown that there is a stereoscopic advantage for vection (Allison, Ash, & Palmisano, 2014;Lowther & Ware, 1996;Palmisano, 1996Palmisano, , 2002Palmisano, Summersby, Davies, & Kim, 2016b;Palmisano, Davies, & Brooks, 2019;Seya & Shinoda, 2018). These studies have reported that stereoscopic optic flow induces vection that is not only stronger and perceived to be faster, but also starts sooner and lasts longer, than the vection induced by comparable monocular or synoptic self-motion displays.…”

“…Based on the above, Palmisano (2002) proposed that stereoscopic information might need to be consistent with monocular motion signals in order to improve vection-in-depth. Palmisano, Davies and Brooks (2019) recently tested this proposal by examining whether large discrepancies between the 2 Conceivably these dynamic stereoscopic and changing-size cues could have improved vection by simply replacing the information in non-stereoscopic patterns of same-size optic flow that indicated no motion-in-depth. observer's simulated and physical eye-separations affected the vection induced by stereoscopic optic flow.…”

Visual-Vestibular Sensory Integration During Congruent and Incongruent Self-Motion Percepts

“…Previous studies also found that the simulated normal IOD of 6.5 cm increased vection, but this was assumed to be the case because it was close to true eye separation causing more natural and compelling vection. However, Palmisano et al's (2018) findings show that increasing the IOD incrementally beyond 0 cm and up to 13 cm increased vection strength ratings. Therefore, the use of stereoscopic viewing devices in studying vection has shown that depth perception caused by eye separation enhances vection.…”

“…Vection has also been investigated using stereoscopic viewing devices (Allison, Ash, & Palmisano, 2014;Lowther & Ware, 1996;Palmisano, Davies, & Brooks, 2018;Seya & Shinoda, 2018;Wolfe & Held, 1980). Palmisano et al (2018) investigated the impact of different depth perspectives on vection. The inter-ocular difference of two LED screens was manipulated.…”