ORCID Profile
0000-0002-4485-2665
Current Organisation
York University
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Psychology | Sensory Processes, Perception And Performance | Virtual Reality and Related Simulation | Sensory Processes, Perception and Performance |
Behavioural and cognitive sciences | Expanding Knowledge in Psychology and Cognitive Sciences | Air transport | Expanding Knowledge in Technology | Computer Gaming Software
Publisher: Springer Science and Business Media LLC
Date: 19-12-2022
Publisher: Springer Science and Business Media LLC
Date: 02-10-2012
DOI: 10.1007/S00221-012-3275-5
Abstract: Successful adaptation to the microgravity environment of space and readaptation to gravity on earth requires recalibration of visual and vestibular signals. Recently, we have shown that adding simulated viewpoint oscillation to visual self-motion displays produces more compelling vection (despite the expected increase in visual-vestibular conflict experienced by stationary observers). Currently, it is unclear what role adaptation to gravity might play in this oscillation-based vection advantage. The vection elicited by optic flow displays simulating either smooth forward motion or forward motion perturbed by viewpoint oscillation was assessed before, during and after microgravity exposure in parabolic flight. During normal 1-g conditions subjects experienced significantly stronger vection for oscillating compared to smooth radial optic flow. The magnitude of this oscillation enhancement was reduced during short-term microgravity exposure, more so for simulated interaural (as opposed to spinal) axis viewpoint oscillation. We also noted a small overall reduction in vection sensitivity post-flight. A supplementary experiment found that 1-g vection responses did not vary significantly across multiple testing sessions. These findings: (i) demonstrate that the oscillation advantage for vection is very stable and repeatable during 1-g conditions and (ii) imply that adaptation or conditioned responses played a role in the post-flight vection reductions. The effects observed in microgravity are discussed in terms of the ecology of terrestrial locomotion and the nature of movement in microgravity.
Publisher: Elsevier BV
Date: 2006
DOI: 10.1016/J.VISRES.2005.10.005
Abstract: Three experiments examined the effects of image decorrelation on the stereoscopic detection of sinusoidal depth gratings in static and dynamic random-dot stereograms (RDS). Detection was found to tolerate greater levels of image decorrelation as: (i) density increased from 23 to 676 dots/deg2 (ii) spatial frequency decreased from 0.88 to 0.22 cpd (iii) litude increased above 0.5 arcmin and (iv) dot lifetime decreased from 1.6s (static RDS) to 80 ms (dynamic RDS). In each case, the specific pattern of tolerance to decorrelation could be explained by its consequences for image s ling, filtering, and the influence of depth noise.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 11-2009
DOI: 10.1167/9.12.1
Publisher: Elsevier BV
Date: 04-2005
DOI: 10.1016/J.VISRES.2004.10.015
Abstract: The sign of an accommodative response is provided by differences in chromatic aberration between under- and over-accommodated images. We asked whether these differences enable people to judge the depth order of two stimuli in the absence of other depth cues. Two vertical edges separated by an illuminated gap were presented at random relative distances. Exposure was brief, or prolonged with fixed or changing accommodation. The gap was illuminated with tungsten light or monochromatic light. Subjects could detect image blur with brief exposure for both types of light. But they could detect depth order only in tungsten light with long exposure, with or without changes in accommodation.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 09-10-2014
DOI: 10.1167/14.12.5
Abstract: Compelling illusions of self-motion, known as vection, can be produced in a stationary observer by visual stimulation alone. The role of binocular vision and stereopsis in these illusions was explored in a series of three experiments. Previous research had provided evidence of stereoscopic enhancements for linear vection in depth (e.g., Palmisano, 1996, 2002). Here we examined for the first time the effects of binocular vision and stereopsis on linear vertical vection. Vertical vection was induced by the upward or downward translation of large stereoscopic surfaces. These surfaces were horizontally oriented depth corrugations produced by disparity modulation of patterns of persistent or short lifetime dot elements. We found that binocular viewing of such surfaces significantly increased the magnitudes and decreased the onset delays of vertical vection. Experiments utilizing short lifetime dot stereograms demonstrated that these particular binocular enhancements of vection were due to the motion of stereoscopically defined features.
Publisher: Springer Science and Business Media LLC
Date: 03-01-2020
DOI: 10.3758/S13414-019-01886-2
Abstract: Research has shown that consistent stereoscopic information improves the vection (i.e. illusions of self-motion) induced in stationary observers. This study investigates the effects of placing stereoscopic information into direct conflict with monocular motion signals by swapping the observer's left and right eye views to reverse disparity. Experiments compared the vection induced by stereo-consistent, stereo-reversed and flat-stereo patterns of: (1) same-size optic flow, which contained monocular motion perspective information about self-motion, and (2) changing-size optic flow, which provided additional monocular information about motion-in-depth based on local changes in object image sizes. As expected, consistent stereoscopic information improved the vection-in-depth induced by both changing-size and same-size patterns of optic flow. Unexpectedly, stereo-reversed patterns of same-size optic flow also induced stronger vection-in-depth than flat-stereo patterns of same-size optic flow. The effects of stereo-consistent and stereo-reversed information on vection strength were found to correlate reliably with their effects on perceived motion-in-depth and motion after-effect durations, but not with their effects on perceived scene depth. This suggests that stereo-consistent and stereo-reversed advantages for vection were both due to effects on perceived motion-in-depth. The current findings clearly demonstrate that stereoscopic information does not need to be consistent with monocular motion signals in order to improve vection. When taken together with past findings, they suggest that stereoscopic information only needs to be dynamic (as opposed to static) in order to improve vection-in-depth.
Publisher: Frontiers Media SA
Date: 11-11-2014
Publisher: Frontiers Media SA
Date: 27-02-2015
Publisher: Frontiers Media SA
Date: 12-11-2020
Publisher: SPIE
Date: 27-04-2007
DOI: 10.1117/12.719892
Publisher: Springer New York
Date: 2010
Publisher: Elsevier BV
Date: 11-2001
DOI: 10.1016/S0042-6989(01)00183-3
Abstract: Stereoscopic corrugation detection in the presence of horizontal- and vertical- additive disparity noise was examined using a signal detection paradigm. Random-dot stereograms either represented a 3-D square-wave surface with various amounts of Gaussian-distributed additive disparity noise or had the same disparity values randomly redistributed. Stereoscopic detection of 2 arcmin peak litude corrugations was found to tolerate significantly greater litudes of vertical-disparity noise than horizontal-disparity noise--irrespective of whether the corrugations were horizontally or vertically oriented. However, this directional difference in tolerance to disparity noise was found to reverse when the corrugation and noise litudes were increased (so as to produce equivalent signal-to-noise ratios). These results suggest that horizontal- and vertical-disparity noise pose different problems for dot-matching and post-matching surface reconstruction as corrugation and noise litudes increase.
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.VISRES.2006.07.020
Abstract: We report a novel illusory distortion of the visual scene, which became apparent during both: (i) observer rotation inside a furnished stationary room and (ii) room rotation about the stationary observer. While this distortion had several manifestations, the most common experience was that scenery near fixation appeared to sometimes lead and other times lag more peripheral scenery. Across a series of experiments, we eliminated explanations based on eye-movements, distance misperception, peripheral aliasing, differential motion sensitivity and adaptation. We found that these illusory scene distortions occurred only when the observer perceived (real or illusory) changes in self-tilt and maintained a stable fixation.
Publisher: SAGE Publications
Date: 2008
DOI: 10.1068/P5806
Abstract: We examined the vection in depth induced when simulated random self-accelerations (jitter) and periodic self-accelerations (oscillation) were added to radial expanding optic flow (simulating constant-velocity forward self-motion). Contrary to the predictions of sensory-conflict theory frontal-plane jitter and oscillation were both found to significantly decrease the onsets and increase the speeds of vection in depth. Depth jitter and oscillation had lesser, but still significant, effects on the speed of vection in depth. A control experiment demonstrated that adding global perspective motion which simulated a constant-velocity frontal-plane self-motion had no significant effect on vection in depth induced by the radial component of the optic flow. These results are incompatible with the notion that constant-velocity displays produce optimal vection. Rather, they indicate that displays simulating self-acceleration can often produce more compelling experiences of self-motion in depth.
Publisher: SAGE Publications
Date: 20-01-2016
Abstract: Interchanging the left and right eye views of a scene (pseudoscopic viewing) has been reported to produce vivid stereoscopic effects under certain conditions. In two separate field studies, we examined the experiences of 124 observers (76 in Study 1 and 48 in Study 2) while pseudoscopically viewing a distant natural outdoor scene. We found large in idual differences in both the nature and the timing of their pseudoscopic experiences. While some observers failed to notice anything unusual about the pseudoscopic scene, most experienced multiple pseudoscopic phenomena, including apparent scene depth reversals, apparent object shape reversals, apparent size and flatness changes, apparent reversals of border ownership, and even complex illusory foreground surfaces. When multiple effects were experienced, patterns of co-occurrence suggested possible causal relationships between apparent scene depth reversals and several other pseudoscopic phenomena. The latency for experiencing pseudoscopic phenomena was found to correlate significantly with observer visual acuity, but not stereoacuity, in both studies.
Publisher: Elsevier BV
Date: 04-2002
Publisher: SAGE Publications
Date: 2003
DOI: 10.1068/P3468
Abstract: Palmisano et al (2000 Perception29 57–67) found that adding coherent perspective jitter to constant-velocity radial flow improved visually induced illusions of self-motion (vection). This was a surprising finding, because unlike pure radial flow, this jittering radial flow should have generated sustained visual–vestibular conflicts—previously thought to always reduce/impair vection. We attempted to ascertain the essential stimulus features for this jitter advantage for vection by examining three novel types of jitter display. While adding incoherent jitter to radial flow was found to impair vection, adding coherent non-perspective jitter had little effect on this subjective experience (contrary to the notion that jitter improves vection by reducing adaptation to radial flow). Importantly, we found that coherent perspective jitter not only improves the vection induced by radial flow, but it also appears to induce modest vection by itself (demonstrating that vection can still occur when there is an extreme mismatch between actual and expected vestibular activity). These results suggest that the previously demonstrated advantage for coherent perspective jitter was due (in part at least) to jittering vection combining with forwards vection in depth to produce a more compelling overall vection experience.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 24-06-2010
DOI: 10.1167/10.6.19
Abstract: There has been no direct examination of stereoscopic depth perception at very large observation distances and depths. We measured perceptions of depth magnitude at distances where it is frequently reported without evidence that stereopsis is non-functional. We adapted methods pioneered at distances up to 9 m by R. S. Allison, B. J. Gillam, and E. Vecellio (2009) for use in a 381-m-long railway tunnel. Pairs of Light Emitting Diode (LED) targets were presented either in complete darkness or with the environment lit as far as the nearest LED (the observation distance). We found that binocular, but not monocular, estimates of the depth between pairs of LEDs increased with their physical depths up to the maximum depth separation tested (248 m). Binocular estimates of depth were much larger with a lit foreground than in darkness and increased as the observation distance increased from 20 to 40 m, indicating that binocular disparity can be scaled for much larger distances than previously realized. Since these observation distances were well beyond the range of vertical disparity and oculomotor cues, this scaling must rely on perspective cues. We also ran control experiments at smaller distances, which showed that estimates of depth and distance correlate poorly and that our metric estimation method gives similar results to a comparison method under the same conditions.
Publisher: Brill
Date: 2017
DOI: 10.1163/22134808-00002593
Abstract: Behavioural studies have consistently found stronger vection responses for oscillating, compared to smooth/constant, patterns of radial flow (the simulated viewpoint oscillation advantage for vection). Traditional accounts predict that simulated viewpoint oscillation should impair vection by increasing visual–vestibular conflicts in stationary observers (as this visual oscillation simulates self-accelerations that should strongly stimulate the vestibular apparatus). However, support for increased vestibular activity during accelerating vection has been mixed in the brain imaging literature. This fMRI study examined BOLD activity in visual (cingulate sulcus visual area — CSv medial temporal complex — MT+ V6 precuneus motion area — PcM) and vestibular regions (parieto-insular vestibular cortex — PIVC osterior insular cortex — PIC ventral intraparietal region — VIP) when stationary observers were exposed to vection-inducing optic flow (i.e., globally coherent oscillating and smooth self-motion displays) as well as two suitable control displays. In line with earlier studies in which no vection occurred, CSv and PIVC/PIC both showed significantly increased BOLD activity during oscillating global motion compared to the other motion conditions (although this effect was found for fewer subjects in PIVC/PIC). The increase in BOLD activity in PIVC/PIC during prolonged exposure to the oscillating (compared to smooth) patterns of global optical flow appears consistent with vestibular facilitation.
Publisher: Brill
Date: 2011
Abstract: Sensory conflict has been used to explain the way we perceive and control our self-motion, as well as the aetiology of motion sickness. However, recent research on simulated viewpoint jitter provides a strong challenge to one core prediction of these theories — that increasing sensory conflict should always impair visually induced illusions of self-motion (known as vection). These studies show that jittering self-motion displays (thought to generate significant and sustained visual–vestibular conflict) actually induce superior vection to comparable non-jittering displays (thought to generate only minimal/transient sensory conflict). Here we review viewpoint jitter effects on vection, postural sway, eye-movements and motion sickness, and relate them to recent behavioural and neurophysiological findings. It is shown that jitter research provides important insights into the role that sensory interaction plays in self-motion perception.
Start Date: 07-2006
End Date: 06-2008
Amount: $36,960.00
Funder: Australian Research Council
View Funded ActivityStart Date: 05-2021
End Date: 12-2024
Amount: $199,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 12-2013
Amount: $200,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2008
End Date: 12-2011
Amount: $225,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2007
End Date: 12-2009
Amount: $135,000.00
Funder: Australian Research Council
View Funded Activity