Perception of Self-Motion

Visually induced circular vection (CV) has been the subject of a wide range of functional brain and behavioral research. Participants in MRI or PET studies on CV were mostly in a supine viewing position, while participants in behavioral studies on CV were mostly in an upright viewing position. This study examines the effects of viewing positions (upright and supine) on roll CV reported by 16 participants while watching random dots (92 × 60 degrees field-of-view) rotating at different angular velocities (2, 4, 8, 16, 32, 64 deg/s) for 30 s. Viewing positions affected roll CV durations differently depending on the stimulation velocities. At slower velocities (2, 4, and 8 deg/s), participants exhibited significantly longer roll CV sensations when they were sitting in an upright position as opposed to lying in a supine position. The onset of roll CV was also significantly earlier with participants in an upright position despite similar roll CV intensities in both viewing positions. Sign...

In comparison to high level of knowledge of aircraft dynamics, the knowledge of a pilot in the human -aircraft system still appears to be insuffi cient. There have been a wide variety of studies and models describing the human's behavior and perception, especially in the fl ight environment. However, only few of them concern the dynamics of spatial orientation perception. This article deals with one of the most important aspects of aviation physiology. The aim of this paper is to consolidate information on the methods for modelling of the human perception of spatial orientation. This knowledge could be useful for further model's development. Systematic review, including publications, conference materials, chapters in books, diploma theses, doctoral dissertations and reports available in electronic databases. Most of the models of the human perception of spatial orientation currently use one of three techniques for perception estimating: state observer, Kalman's fi lter and Bayesian estimation. These models are able to mimic orientation perceptions, linear and circular vection, rotation and acceleration in the light, as well as estimate vestibular-ocular refl ex.

During the period of this grant, (June 1972 through February 1977), models quantifying our theories of vestibular and visual motion processing have been developed and are now'being'tested. New experimental results concerning visually induced motion and its relationship to vestibular responses have been obtained.. Most of this would not have been possible_ without the cooperation and help extended to us by the personnel of the Langley Research Center, especially our technical monitors, Dr. M.J.

A total of 60 children, 20 preschoolers, 20 first-graders, and 20 third-graders, participated in a game involving communication of spatial information. Subjects gave verbal directions to help another person find a hidden object, in this case, a small toy hidden under one of a number of cups. Two experimental conditions were set up, the first offering a relatively rich assortment of distinctive markings that could potentially be related to the array of cups, and the other not offering such distinctive markings. Generally, findings illustrate some aspects of developmental change. in children's use of spatial information and suggest that some unique task-related contextual effects exist in the communicative problem preseated to subjects. Major findings revealed that (1) the use of self-reference increased with age; (2) the use of listener as a reference point increased with age, and exceeded self-reference for the two youngest groups; (3) the third-grade children used a reference system near the hiding location more than a more remote reference system, whereas first-graders showed an opposite preference; and (4) the cup array itself was used often as a reference system by all subjects, regardless of their age or the availability of other differentiated environmental cues. (RH) *

We propose and test a method to reduce simulator sickness. Background: Prolonged work in driving simulators often leads to nausea and other symptoms summarized as simulator sickness. Visual/vestibular mismatches are a frequently addressed cause; we investigate another possibility, mismatch between actual distance to a screen and depicted distances in the simulator's graphics. Method: Drivers negotiated a figure-8 course in a photorealistic simulator. They reported discomfort and vection every 10 minutes up to 40 min. A correction group wore optometric test frames with +1.75 diopter lenses and prisms to converge parallel lines of sight on a screen 56 cm from the driver's eyes, preserving the normal accommodative convergence-to-accommodation (AC/A) ratio. A control group wore neutral lenses in the same test frames. In other experiments head tilt simulated vestibular experience on curves. Results: The optical correction significantly reduced simulator sickness measured on a 10-point discomfort scale, where 1 is no problem and 10 is about to vomit. Vection ratings were similar for correction and control groups. Some drivers failed to complete the course because of high discomfort ratings, crashes, or other causes. Head tilt in the direction opposite each curve while wearing the correction did not affect discomfort, while tilt in the same direction as each curve made simulator sickness worse. Conclusion: Optical corrections can significantly reduce simulator sickness, though they do not eliminate it. Head tilt while driving is not recommended. Application: Simple optical corrections in spectacle frames, easily purchased at any optical facility, should be used in screen-based driving simulators. Strength of the correction depends on distance from the driver to the screen.

La perception du mouvement visuel modélisé par des modèles connexionnistes fournit différents axes de recherche pour le développement de modèles de perception-action en temps réel appliqués à la perception visuelle dynamique du mouvement. Nous présentons dans cet article les bases d'une approche connexionniste bio-inspirée avec une adaptation particulière des filtres de Gabor spatio-temporels que nous utilisons en vue d'une approche plus modulaire et fortement localisée pour la perception visuelle du mouvement. Summary : The visual perception of motion modeled by connectionist models offers various areas of research for the development of models of real-time perception-action applied to the dynamic visual perception of motion. We present in this article the bases of a bio-inspired connectionist approach with a particular adaptation of the spatiotemporal Gabor filters that we use within a more modular and strongly localized approach for the visual perception of motion. Mots clés : Perception du mouvement, réseau de neurones bio-inspirés, flot optique, filtres de Gabor.

Modeling visual perception of motion by connectionist networks offers various areas of research for the development of real-time models of dynamic perception-action. In this paper we present the bases of a bio-inspired connectionist approach that is part of our development of neural networks applied to autonomous robotics. Our model of visual perception of motion is based on a causal adaptation of spatiotemporal Gabor filters. We use our causal spatiotemporal filters within a modular and strongly localized architecture that performs a shunting inhibition mechanism. This model has been evaluated on artificial as well as natural image sequences.

I would firstly like to thank my primary supervisor, Stephen Palmisano, for his guidance and patience and for encouraging me to grow as a researcher. I would also like to thank my secondary supervisor, Julie Steele, for her support and encouragement. To my co-authors and collaborators-Juno Kim, Robert Allison, Donovan Govan and Deborah Apthorp-thank you for your contributions and advice throughout my thesis. In particular, I would like to thank Juno Kim for his programming support and expertise. I would like to thank anonymous reviewers from Perception and ASEM for their helpful suggestions on published aspects of this thesis. A special thank you should also go to staff from the School of Psychology who helped to keep me sane toward the end of my thesis-Emma Barkus, Paul Smith, Len McAlear, Peter Caputi, Gerard Stoyles and, in particular, Nadia Crittenden who guided to the end. To my fellow postgraduate students: thank you for allowing me to vent and for picking me up when it all felt too hard. I would especially like to thank my coffee buddy, Stewart Vella, my office mates, Lisa-Marie Greenwood and Brad Parkinson, and those who cheered me over the finish line-Louise Turner,

This study examined the contributions of low-, mid-and high-level visual motion information to vection. We compared the vection experiences induced by hand-drawn and computer-generated animation clips to those induced by versions of these movies that contained only their pure optic flow. While the original movies were found to induce longer and stronger vection experiences than the pure optic flow, vection onsets were not significantly altered by removing the mid-and high-level information. We conclude that low-level visual motion information appears to be important for vection induction, whereas mid-and higher-level display information appears to be important for sustaining and strengthening this vection after its initial induction.

Younger adults integrate visual and vestibular cues to self-motion in a manner consistent with optimal integration; however, little is currently known about whether this process changes with older age. Our objective was to determine whether older adults, like younger adults, display evidence of optimal visual-vestibular integration, including reductions in bimodal variance (Visual + Vestibular) compared with unimodal variance (visual or vestibular alone), and reliability-based cue weighting. We used a motion simulator and a head-mounted display to introduce a 2-interval forced-choice heading estimation task. Older (65+ years) and younger adults (18-35 years) judged which of two movements was more rightward. Movements consisted of vestibular cues (passive movement in darkness), visual cues (optic flow), or both cues combined. The combined condition contained either congruent cues or incongruent cues (either a subtle 5° or larger 20° conflict). Results demonstrated that older adults h...

The illusion of self-motion (vection) is a multisensory phenomenon elicited by visual, auditory, tactile, or other sensory cues. Aging is often associated with changes in sensory acuity, visual motion perception, and multisensory integration, processes which may influence vection perception. However, age-related differences in vection have received little study to date. Thus, the objective of the present study was to investigate age-related differences in vection during multisensory stimulation. Nineteen younger adults and 19 older adults were exposed to rotating visual, auditory, and tactile stimuli (separately or in combination) at a speed of 45°/s inside a VR laboratory inducing circular vection. The size of the field-of-view (FOV) was large (240°), medium (75°), small (30°), or contained no visuals. Vection intensity and duration were reported verbally after each trial. Overall, older adults experienced significantly stronger and longer vection compared to younger adults. Additionally, there were main effects of FOV and sensory cues, such that larger FOVs and the presence of auditory and tactile stimulation increased vection ratings for both age groups. These findings support the idea that vection is a multisensory experience that can be elicited by visual, auditory, and tactile stimuli and demonstrates these effects for the first time in older adults.

This experiment investigated the effect of walking without optic flow on subsequent vection induction and strength. Two groups of participants walked for 5 min (either wearing Ganzfeld goggles or with normal vision) prior to exposure to a vection-inducing stimulus. We then measured the onset latency and strength of vection induced by a radially expanding pattern of optic flow. The results showed that walking without optic flow transiently yielded later vection onsets and reduced vection strength. We propose that walking without optic flow triggered a sensory readjustment, which reduced the ability of optic flow to induce self-motion perception.

Vection (illusion of self-motion) is known to be induced by watching large field-of-view (FOV) moving scenes. In our study, we investigated vection induced by small FOV stimuli. Three experiments were conducted in 45 sessions to analyze vection provoked by moving scenes covering total FOVs as small as 10 square-degrees. Results indicated that 88% of the participants reported vection while watching two small patches of moving dots (1°horizontal by 5°vertical, each) placed on the left and right sides of the observers. This is less than a quarter of the total visual area of two Apple Watches viewed at a distance of 40 cm. Occlusion of the visual field between the two display patches significantly increased the levels of rated vection. Similarly, increasing the speed of the moving dots of the two display patches from about 5 to 25°/sec increased the levels of rated vection significantly. The location of the two patches in the horizontal visual field did not affect the vection perception significantly. When the two straight stripes of dots were moving in opposite directions, participants perceived circular vection. The observers connected the two stimuli in their minds and perceived them as parts of a single occluded background. The findings of this study are relevant to the design of mobile devices (e.g., smartphones) and wearable technology (e.g., smart watches) with small display areas.

Visually induced circular vection (CV) has been the subject of a wide range of functional brain and behavioral research. Participants in MRI or PET studies on CV were mostly in a supine viewing position, while participants in behavioral studies on CV were mostly in an upright viewing position. This study examines the effects of viewing positions (upright and supine) on roll CV reported by 16 participants while watching random dots (92 × 60 degrees field-of-view) rotating at different angular velocities (2, 4, 8, 16, 32, 64 deg/s) for 30 s. Viewing positions affected roll CV durations differently depending on the stimulation velocities. At slower velocities (2, 4, and 8 deg/s), participants exhibited significantly longer roll CV sensations when they were sitting in an upright position as opposed to lying in a supine position. The onset of roll CV was also significantly earlier with participants in an upright position despite similar roll CV intensities in both viewing positions. Significant two-way interactions between effects of viewing positions and dot rotating velocities for some conditions were noted. Consistency between current findings and the hypothesis predicting a weaker roll CV in upright positions based upon perceived gravity by the otolith organs is discussed.

Paper presented at the Australasian Experimental Psychology Conference 2015, 8-11 April 2015, Sydney, Australia. Keywords without, visual, motion, reduces, subsequent, vection, walking Disciplines Education | Social and Behavioral Sciences Publication Details Palmisano, S., Seno, T., Riecke, B. & Nakamura, S. (2015). Walking without visual motion reduces subsequent vection. Australasian Experimental Psychology Conference 2015 This conference paper is available at Research Online: http://ro.uow.edu.au/sspapers/1585 apply two standard accumulation models – the diffusion (Ratcliff & McKoon, 2008) and the LBA (Brown & Heathcote, 2008) – to the detection of heterogeneous multi-­‐attribute targets in a simulated unmanned-­‐aerial-­‐vehicle operator task. Despite responses taking two seconds or more and complications added by realistic features such as a complex target classification rule, interruptions from a simultaneous navigation task and time pressured choices about several simultaneo...

Typically it takes up to 10 seconds or more to induce a visual illusion of self-motion ("vection"). However, for this vection to be most useful in virtual reality and vehicle simulation, it needs to be induced quickly, if not immediately. This study examined whether vection onset latency could be reduced towards zero using visual display manipulations alone. In the main experiments, visual self-motion simulations were presented to observers via either a large external display or a head-mounted display (HMD). Priming observers with visually simulated viewpoint oscillation for just ten seconds before the main self-motion display was found to markedly reduce vection onset latencies (and also increase ratings of vection strength) in both experiments. As in earlier studies, incorporating this simulated viewpoint oscillation into the self-motion displays themselves was also found to improve vection. Average onset latencies were reduced from 8-9s in the no oscillating control condition to as little as 4.6 s (for external displays) or 1.7 s (for HMDs) in the combined oscillation condition (when both the visual prime and the main self-motion display were oscillating). As these display manipulations did not appear to increase the likelihood or severity of motion sickness in the current study, they could possibly be used to enhance computer generated simulation experiences and training in the future, at no additional cost.

Visually induced illusions of self-motion are often referred to as . This article developed and tested a model of responding to visually induced vection. We first constructed a mathematical model based on well-documented characteristics of vection and human behavioral responses to this illusion. We then conducted 10,000 virtual trial simulations using this (OPVM) OPVM was used to generate simulated vection onset, duration, and magnitude responses for each of these trials. Finally, we compared the properties of OPVM's simulated vection responses with real responses obtained in seven different laboratory-based vection experiments. The OPVM output was found to compare favorably with the empirically obtained vection data.

In comparison to high level of knowledge of aircraft dynamics, the knowledge of a pilot in the human-aircraft system still appears to be insuffi cient. There have been a wide variety of studies and models describing the human's behavior and perception, especially in the fl ight environment. However, only few of them concern the dynamics of spatial orientation perception. This article deals with one of the most important aspects of aviation physiology. The aim of this paper is to consolidate information on the methods for modelling of the human perception of spatial orientation. This knowledge could be useful for further model's development. Systematic review, including publications, conference materials, chapters in books, diploma theses, doctoral dissertations and reports available in electronic databases. Most of the models of the human perception of spatial orientation currently use one of three techniques for perception estimating: state observer, Kalman's fi lter and Bayesian estimation. These models are able to mimic orientation perceptions, linear and circular vection, rotation and acceleration in the light, as well as estimate vestibular-ocular refl ex.

Just noticeable difference (JND) for stereoscopic 3D content reflects the maximum tolerable distortion, it corresponds to the visibility threshold of the asymmetric distortions in the left and right contents. The 3D-JND models can be used to improve the efficiency of the 3D compression or the 3D quality assessment. Compared to 2D-JND models, the 3D-JND models appeared recently and related literature is rather limited. In this paper, we give a deep and comprehensive study of the pixel-based 3D-JND models. To our best knowledge, this is the first review on 3D-JND models. Each model is briefly described by giving its rationale and main components in addition to providing exhaustive information about the targeted application, the pros, and cons. Moreover, we present the characteristics of the human visual system (HVS) presented in these models. In addition, we analyze and compare the 3D-JND models thoroughly using qualitative and quantitative performance evaluation based on Middlebury stereo datasets. Besides, we measure the JND thresholds of the asymmetric distortion based on psychophysical experiments and compare these experimental results to the estimates from the 3D-JND models in order to evaluate the accuracy of each model. INDEX TERMS Human visual system, just noticeable difference (JND), 3D compression, 3D-JND models, 3D quality assessment.

Modeling visual perception of motion by connectionist networks offers various areas of research for the development of real-time models of dynamic perception-action. In this paper we present the bases of a bio-inspired connectionist approach that is part of our development of neural networks applied to autonomous robotics. Our model of visual perception of motion is based on a causal adaptation of spatiotemporal Gabor filters. We use our causal spatiotemporal filters within a modular and strongly localized architecture that performs a shunting inhibition mechanism. This model has been evaluated on artificial as well as natural image sequences.

This experiment investigated the effect of walking without optic flow on subsequent vection induction and strength. Two groups of participants walked for 5 min (either wearing Ganzfeld goggles or with normal vision) prior to exposure to a vection-inducing stimulus. We then measured the onset latency and strength of vection induced by a radially expanding pattern of optic flow. The results showed that walking without optic flow transiently yielded later vection onsets and reduced vection strength. We propose that walking without optic flow triggered a sensory readjustment, which reduced the ability of optic flow to induce self-motion perception.

Vision is important for estimating self-motion, which is thought to involve optic-flow processing. Here, we investigated the fMRI response profiles in visual area V6, the precuneus motion area (PcM), and the cingulate sulcus visual area (CSv)-three medial brain regions recently shown to be sensitive to optic-flow. We used wide-view stereoscopic stimulation to induce robust self-motion processing. Stimuli included static, randomly moving, and coherently moving dots (simulating forward self-motion). We varied the stimulus size and the presence of stereoscopic information. A combination of univariate and multi-voxel pattern analyses (MVPA) revealed that fMRI responses in the three regions differed from each other. The univariate analysis identified optic-flow selectivity and an effect of stimulus size in V6, PcM, and CSv, among which only CSv showed a significantly lower response to random motion stimuli compared with static conditions. Furthermore, MVPA revealed an optic-flow specific...

Visually induced motion sickness (VIMS) can occur via prolonged exposure to visual stimulation that generates the illusion of self-motion (vection). Not everyone is susceptible to VIMS and the neural mechanism underlying susceptibility is unclear. This study explored the differences of electroencephalographic (EEG) signatures between VIMS-susceptible and VIMS-resistant groups. Thirty-two-channel EEG data were recorded from 12 VIMSsusceptible and 15 VIMS-resistant university students while they were watching two patterns of moving dots: (1) a coherent rotation pattern (vection-inducing and potentially VIMS-provoking pattern), and (2) a random movement pattern (non-VIMS-provoking control). The VIMS-susceptible group exhibited a significantly larger increase in the parietal N2 response when exposed to the coherent rotating pattern than when exposed to control patterns. In members of the VIMS-resistant group, before vection onset, global connectivity from all other EEG electrodes to the right-temporal-parietal and to the right-central areas increased, whereas after vection onset the global connectivity to the right-frontal area reduced. Such changes were not observed in the susceptible group. Further, the increases in N2 amplitude and the identified phase synchronization index were significantly correlated with individual motion sickness susceptibility. Results suggest that VIMS susceptibility is associated with systematic impairment of dynamic cortical coordination as captured by the phase synchronization of cortical activities. Analyses of dynamic EEG signatures could be a means to unlock the neural mechanism of VIMS.

Vision is important for estimating self-motion, which is thought to involve optic-flow processing. Here, we investigated the fMRI response profiles in visual area V6, the precuneus motion area (PcM), and the cingulate sulcus visual area (CSv)—three medial brain regions recently shown to be sensitive to optic-flow. We used wide-view stereoscopic stimulation to induce robust self-motion processing. Stimuli included static, randomly moving, and coherently moving dots (simulating forward self-motion). We varied the stimulus size and the presence of stereoscopic information. A combination of univariate and multi-voxel pattern analyses (MVPA) revealed that fMRI responses in the three regions differed from each other. The univariate analysis identified optic-flow selectivity and an effect of stimulus size in V6, PcM, and CSv, among which only CSv showed a significantly lower response to random motion stimuli compared with static conditions. Furthermore, MVPA revealed an optic-flow specific multi-voxel pattern in the PcM and CSv, where the discrimination of coherent motion from both random motion and static conditions showed above-chance prediction accuracy, but that of random motion from static conditions did not. Additionally, while area V6 successfully classified different stimulus sizes regardless of motion pattern, this classification was only partial in PcM and was absent in CSv. This may reflect the known retinotopic representation in V6 and the absence of such clear visuospatial representation in CSv. We also found significant correlations between the strength of subjective self-motion and univariate activation in all examined regions except for primary visual cortex (V1). This neuro-perceptual correlation was significantly higher for V6, PcM, and CSv when compared with V1, and higher for CSv when compared with the visual motion area hMT+. Our convergent results suggest the significant involvement of CSv in self-motion processing, which may give rise to its percept.

There are at least two possible binocular cues to motionin-depth, namely disparity change over time and interocular velocity differences. There has been significant controversy about their relative contributions to the perception of motion-in-depth. In the present study, we used the technique of selective adaptation to address this question. In Experiment 1, we found that adaptation to motion-in-depth depicted by temporally correlated random-dot stereograms, which contained coherent interocular velocity difference, produced motion aftereffect in the depth direction irrespective of the adaptors' interocular correlation for any adaptation duration tested. This suggests that coherent changing disparity does not contribute to motion-in-depth adaptation. Because the aftereffect duration did not saturate in the tested range of adaptation duration, it is unlikely that the lack of the effect of changing disparity was due to a ceiling effect. In Experiment 2, we used a novel adaptor that contained a unidirectional coherent interocular velocity difference signal and a bidirectional changing disparity signal that should not induce a motion aftereffect in depth. Following the adaptation, motion aftereffect in depth occurred in the opposite direction to the adaptor's motion-in-depth based on interocular velocity difference. Experiment 3 demonstrated that these results generalized in 12 untrained subjects. These experiments suggest that the contribution of interocular velocity difference to the perception of motion-in-depth is substantial, while that of changing disparity is very limited (if any), at least at the stages of direction-selective mechanisms subject to an aftereffect phenomenon.

We examined whether a negative motion aftereffect occurs in the depth direction following adaptation to motion in depth based on changing disparity and/or interocular velocity differences. To dissociate these cues, we used three types of adapters: random-element stereograms that were correlated (1) temporally and binocularly, (2) temporally but not binocularly, and (3) binocularly but not temporally. Only the temporally correlated adapters contained coherent interocular velocity differences while only the binocularly correlated adapters contained coherent changing disparity. A motion aftereffect in depth occurred after adaptation to the temporally correlated stereograms while little or no aftereffect occurred following adaptation to the temporally uncorrelated stereograms. Interestingly, a monocular test pattern also showed a comparable motion aftereffect in a diagonal direction in depth after adaptation to the temporally correlated stereograms. The lack of the aftereffect following adaptation to pure changing disparity was also confirmed using spatially separated random-dot patterns. These results are consistent with the existence of a mechanism sensitive to interocular velocity differences, which is adaptable (at least in part) at binocular stages of motion-in-depth processing. We did not find any evidence for the existence of an "adaptable" mechanism specialized to see motion in depth based on changing disparity.

Modeling visual perception of motion by connectionist networks offers various areas of research for the development of real-time models of dynamic perception-action. In this paper we present the bases of a bio-inspired connectionist approach that is part of our development of neural networks applied to autonomous robotics. Our model of visual perception of motion is based on a causal adaptation of spatiotemporal Gabor filters. We use our causal spatiotemporal filters within a modular and strongly localized architecture that performs a shunting inhibition mechanism. This model has been evaluated on artificial as well as natural image sequences.

Past research has found that following passive rotation to the opposite side of a table (or some other testing apparatus), 6-to 1 l-month olds make egocentric perseverative errors in motor tasks in which they are required to reach or turn their heads towards a target hidden prior to the passive rotation. These errors have been interpreted as evidence of infants' limited ability to form accurate allocentric representations of space. The current experiment uses a habituation procedure to explore the possibility that these perseverative errors are, in part, a consequence of poor motor planning rather than poor representational ability.

La perception du mouvement visuel modélisé par des modèles connexionnistes fournit différents axes de recherche pour le développement de modèles de perception-action en temps réel appliqués à la perception visuelle dynamique du mouvement. Nous présentons dans cet article les bases d'une approche connexionniste bio-inspirée avec une adaptation particulière des filtres de Gabor spatio-temporels que nous utilisons en vue d'une approche plus modulaire et fortement localisée pour la perception visuelle du mouvement. Summary : The visual perception of motion modeled by connectionist models offers various areas of research for the development of models of real-time perception-action applied to the dynamic visual perception of motion. We present in this article the bases of a bio-inspired connectionist approach with a particular adaptation of the spatiotemporal Gabor filters that we use within a more modular and strongly localized approach for the visual perception of motion. Mots clés : Perception du mouvement, réseau de neurones bio-inspirés, flot optique, filtres de Gabor.

Visually induced illusory self-motion perception is termed vection. We measured vection strength in participants wearing either wooden or iron clogs together with or without a weight-jacket (four conditions). We hypothesized that the heavier items would inhibit vection more because they make locomotion difficult. Results partially showed that the iron clogs could inhibit vection. We concluded that cognition of the fact that the heavier iron clogs made locomotion difficult might function as an inhibitor of vection, suggesting that cognition can alter vection strength.

There are two types of binocular cues available for perception of motion in depth. One is the binocular disparity change in time and the other is the velocity difference between the left and the right retinal images (interocular velocity differences). We measured the luminance contrast threshold for seeing motion in depth while isolating either of the cues at various temporal modulations of velocity in the stimulus. To isolate disparity cues, dynamic random-dot stereograms were used (the disparity condition) while binocularly uncorrelated random-dot kinematograms were used to isolate velocity cues (the velocity condition). Results showed that sensitivity peaked at a temporal frequency ͑ϳ1 cps͒ in the velocity condition while the peak in the disparity condition was at the lowest frequency ͑0.35 cps͒ or at least at a frequency lower than that in the velocity condition. This suggests that the visual system has different temporal frequency properties for the velocity and disparity cues for motion in depth.

Highlights d Monovision induces interocular blur differences and a mismatch in processing speed d The speed mismatch means a common lens correction can cause dramatic motion illusions d Drivers may misperceive the distance of cyclists by the width of a narrow street lane d Novel combinations of non-invasive ophthalmic interventions can abolish the illusion

Two theories are considered to account for the perception of motion of depth-defined objects in random-dot stereograms (stereomotion). In the Lu-Sperling three-motion-systems theory [J. Opt. Soc. Am. A 18, 2331 (2001)], stereomotion is perceived by the third-order motion system, which detects the motion of areas defined as figure (versus ground) in a salience map. Alternatively, in his comment [J. Opt. Soc. Am. A 19, 2142 (2002)], Patterson proposes a low-level motion-energy system dedicated to stereo depth. The critical difference between these theories is the preprocessing (figure-ground based on depth and other cues versus simply stereo depth) rather than the motion-detection algorithm itself (because the motion-extraction algorithm for third-order motion is undetermined). Furthermore, the ability of observers to perceive motion in alternating feature displays in which stereo depth alternates with other features such as texture orientation indicates that the third-order motion system can perceive stereomotion. This reduces the stereomotion question to ''Is it third-order alone or third-order plus dedicated depth-motion processing?'' Two new experiments intended to support the dedicated depth-motion processing theory are shown here to be perfectly accounted for by thirdorder motion, as are many older experiments that have previously been shown to be consistent with thirdorder motion. Cyclopean and rivalry images are shown to be a likely confound in stereomotion studies, rivalry motion being as strong as stereomotion. The phase dependence of superimposed same-direction stereomotion stimuli, rivalry stimuli, and isoluminant color stimuli indicates that these stimuli are processed in the same (third-order) motion system. The phase-dependence paradigm [Lu and Sperling, Vision Res. 35, 2697 (1995)] ultimately can resolve the question of which types of signals share a single motion detector. All the evidence accumulated so far is consistent with the three-motion-systems theory.

Visually induced self-motion (vection) affects the speed at which actions are performed. However, it has been unclear whether this speedy action induced by vection is based on the modulation of mental tempo. To clarify this issue, we tested whether the speed of vection influenced an observer's cyclic action related to mental tempo. Observers viewed fast and slow moving optic flow stimuli and dynamic random dots, whilst handclapping at their preferred tempo. The results revealed that the clapping rate was the fastest in the fastest optic flow condition. This effect vanished when optic flow stimuli moved fast but did not induce vection. Fast optic flow stimuli also induced larger pupil dilation, suggesting that it increased the observer's arousal level. These results suggest that illusory self-motion increased arousal levels, thereby modulating mental tempo.

Citation: Allen B, Haun AM, Hanley T, Green CS, Rokers B. Optimal combination of the binocular cues to 3D motion. Invest Ophthalmol Vis Sci. 2015;56:7589–7596. DOI:10.1167/ iovs.15-17696 PURPOSE. Perception necessarily entails combining separate sensory estimates into a single coherent whole. The perception of three-dimensional (3D) motion, for instance, can rely on two binocular cues: one related to the change in binocular disparity over time (CD) and the other related to interocular velocity differences (IOVD). Although previous work has shown that neither cue is strictly necessary for the perception of 3D motion, observers are able to judge 3D motion in displays in which one or the other cue has been eliminated, it is unclear whether or how the two cues are combined in situations in which both are present. METHODS. We tested the visual performance of a sample of 81 individuals (Mage 1⁄4 20.34, 49 females) in four main conditions that measured, respectively, static stereoacuity, C...

We investigated the effect of reduced contrast on speed perception for two types of tasks: (a) the speed of a rotating image, an example of "object-motion," and (b) speed of travel when viewing wide-screen videos recorded from inside a car, an example of "self-motion." Both types of stimuli were presented over a range of spatial contrasts. The results showed that reduced contrast caused significant decreases of perceived speed for the rotating disk, replicating the well known Thompson Effect. Reduced contrast had inconsistent effects on perceived speed of self-motion, however, resulting in perception of faster self-motion at the lowest speed, slower self-motion at higher speeds, and no effect at intermediate speed. Although further research is needed, the differential effects of reduced contrast on perceived speed of object-motion vs. self-motion are consistent with evidence for two modes of vision.

Visually induced motion sickness (VIMS) can occur via prolonged exposure to visual stimulation that generates the illusion of self-motion (vection). Not everyone is susceptible to VIMS and the neural mechanism underlying susceptibility is unclear. This study explored the differences of electroencephalographic (EEG) signatures between VIMS-susceptible and VIMS-resistant groups. Thirty-two-channel EEG data were recorded from 12 VIMSsusceptible and 15 VIMS-resistant university students while they were watching two patterns of moving dots: (1) a coherent rotation pattern (vection-inducing and potentially VIMS-provoking pattern), and (2) a random movement pattern (non-VIMS-provoking control). The VIMS-susceptible group exhibited a significantly larger increase in the parietal N2 response when exposed to the coherent rotating pattern than when exposed to control patterns. In members of the VIMS-resistant group, before vection onset, global connectivity from all other EEG electrodes to the right-temporal-parietal and to the right-central areas increased, whereas after vection onset the global connectivity to the right-frontal area reduced. Such changes were not observed in the susceptible group. Further, the increases in N2 amplitude and the identified phase synchronization index were significantly correlated with individual motion sickness susceptibility. Results suggest that VIMS susceptibility is associated with systematic impairment of dynamic cortical coordination as captured by the phase synchronization of cortical activities. Analyses of dynamic EEG signatures could be a means to unlock the neural mechanism of VIMS.

In comparison to high level of knowledge of aircraft dynamics, the knowledge of a pilot in the human -aircraft system still appears to be insuffi cient. There have been a wide variety of studies and models describing the human's behavior and perception, especially in the fl ight environment. However, only few of them concern the dynamics of spatial orientation perception. This article deals with one of the most important aspects of aviation physiology. The aim of this paper is to consolidate information on the methods for modelling of the human perception of spatial orientation. This knowledge could be useful for further model's development. Systematic review, including publications, conference materials, chapters in books, diploma theses, doctoral dissertations and reports available in electronic databases. Most of the models of the human perception of spatial orientation currently use one of three techniques for perception estimating: state observer, Kalman's fi lter and Bayesian estimation. These models are able to mimic orientation perceptions, linear and circular vection, rotation and acceleration in the light, as well as estimate vestibular-ocular refl ex.

Two experiments were carried out to test speed perception dependency on field of view (FoV), virtual road markings (VRMs), and presentation orders. The primary purpose was to examine how the extent of the optic flow (foremost peripherally-vertically) informs the driver about egospeed. A second purpose was to examine different task demands and stimulus characteristics supporting rhythm-based versus energy-based processing. A third purpose was to examine speed changes indicative of changes in motion sensitivity. Participants were tested in a car simulator, with FoV resembling low front-door windows, and with VRMs inside the car. Three main results were found. Larger FoV, both horizontally and peripherally-vertically, significantly reduced participants' speed, as did VRMs. Delineator posts and road center lines were used for participants' rhythm-based processing, when the task was to drive at target speeds. Rich motion-flow cues presented initially resulted in lower egospeed in subsequent conditions with relatively less motion-flow cues. The practical implication is that non-iconic, naturalistic and intuitive interfaces can effectively instill spontaneous speed adaptation in drivers.

Particle-based simulations are used across many science domains, and it is well known that stereoscopic viewing and kinetic depth enhance our ability to perceive the 3D structure of such data. But the relative advantages of stereo and kinetic depth have not been studied for point cloud data, although they have been studied for 3D networks. This article reports two experiments assessing human ability to perceive 3D structures in point clouds as a function of different viewing parameters. In the first study, the number of discrete views was varied to determine the extent to which smooth motion is needed. Also, half the trials had stereoscopic viewing and half had no stereo. The results showed kinetic depth to be more beneficial than stereo viewing in terms of accuracy and so long as the motion was smooth. The second experiment varied the amplitude of oscillatory motion from 0 to 16 degrees. The results showed an increase in detection rate with amplitude, with the best amplitudes being...

The relationship between vection (illusory self-motion) and cybersickness is complex. This pilot study examined whether only unexpected vection provokes sickness during head-mounted display (HMD) based virtual reality (VR). 20 participants ran through the tutorial of Mission: ISS (an HMD VR app) until they experienced notable sickness (maximum exposure was 15 minutes). We found that: 1) cybersickness was positively related to vection strength; and 2) cybersickness appeared to be more likely to occur during unexpected vection. Given the implications of these findings, future studies should attempt to replicate them and confirm the unexpected vection hypothesis with larger sample sizes and rigorous experimental designs. CCS CONCEPTS • Human-centered computing → Visualization; Visualization theory, concepts and paradigms.

Geometric constraints for the perception of three-dimensional (3D) binocular motion are discussed in a probabilistic framework. Two alternative Bayesian models of binocular integration are put forward to explain perceptual bias under uncertainty. The models exploit biologically plausible constraints of local motion and disparity processing in a binocular viewing geometry. Results from computer simulations and model selection support the idea that disparity processing rather than motion processing introduces perceptual bias in 3D motion. This suggests that the binocular motion system combines motion and disparity constraints relatively late when establishing a 3D motion percept.

Quantification of perceptual sensitivity to latency in virtual environments (VEs) and elucidation of the mechanism by which latency is perceived is essential for development of countermeasures by VE designers. We test the hypothesis that observers use "image slip" @e., motion of the VE scene caused by system time lags) to detect the consequences of latency rather than explicitly detecting time delay. Our presumption is that forcing observers to change from constant rate to randomly paced head motion will disrupt their ability to discriminate latency based on perceived image slip. This study indicates that the disruption in motion pattern causes a shift in latency detection criteria and a minor degradation in discrimination ability. It is likely therefore that observers make at least some use of image slip in discriminating VE latency. It can also be inferred that when observers learn to discriminate latency, their Just Noticeable Difference (JND) remains below 17 ms.

Most research on texture density has utilized textures rendered as two-dimensional (2D) planar surfaces, consistent with the conventional definition of density as the number of texture elements per unit area. How the brain represents texture density information in the three-dimensional (3D) world is not yet clear. Here we tested whether binocular information affects density processing using simultaneous density contrast (SDC), in which the perceived density of a texture region is changed by a surround of different density. We considered the effect on SDC of two types of binocular information: the stereoscopic depth relationships and the interocular relationships between the center and surround textures. Observers compared the perceived density of two random dot patterns, one with a surround (test stimulus) and one without (match), using a 2AFC staircase procedure. In Experiment 1 we manipulated the stereo-depth of the surround plane systematically from near to far, relative to the c...

Language and spatial reasoning are two primary abstract representational systems in humans. Language acquisition has been much studied, while the ontogeny of spatial navigation is comparatively less well understood, as is the relationship between early language and space. This study explored emergent place learning and language in 16-to 24-month-old children using a spatial task adapted from the Morris water maze, and the MacArthur Communicative Development Inventory. Children were placed in a circular enclosure and a puzzle was hidden under the floor at one location. Before each trial children were disoriented and placed in the maze from a different starting position. Their search strategies and success at finding the puzzle were coded. Older children demonstrated more spatial searching and more goal-finding success, as well as greater overall expressive vocabulary. Place learning and expressive language both significantly correlated with age, but place learning and language did not correlate with each other once age was partialled, with one crucial exception: a theoretically-predicted correlation between prepositions and goal localization.

The value of a dynamic motion platform to the flight simulator is a controversial issue within the flight training community. The motion of the flight simulator platform has been shown to affect pilot performance and behavior. Performance studies show that the operator’s performance is enhanced when introducing motion which might indicate that the operator experiences a sensation closer to real flight which should reflect positively on the pilot’s training. However, most transfer of training studies show no major benefit after being trained in a flight simulator with or without a motion system. Resolving these discrepancies and testing for flight simulator training effectiveness requires very time consuming and expensive testing of human performance, both in the aircraft and the simulator. This research aims to tackle this problem by developing a control theoretic approach with novel ideas that include; developing a novel structural model of a human-in-the-loop control system, devel...