The independence of dynamic spatial orientation from luminance and refractive error

Leibowitz, Herschel W.; Rodemer, C. Shupert; Dichgans, J.

doi:10.3758/bf03198789

Cited by 103 publications

(47 citation statements)

References 23 publications

(22 reference statements)

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“…The distance between the subject's eyes and the screens of the monitors was 25 em. Leibowitz, Rodemer, and Dichgans (1979) have shown that vection is independent of the refractive error. Consequently, the small distance between the monitors and the subject's eyes should not have had an effect on the perceived vection.…”

Section: Apparatusmentioning

confidence: 99%

Spatiotemporal boundaries of linear vection

Sauvan

Brunet

1995

Perception & Psychophysics

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Thresholds for the perception of linear vection were measured. These thresholds allowed us to define the spatiotemporal contrast surface sensitivity and the spatiotemporal domain of the perception of rectilinear vection (a visually induced self-motion in a straight line). Moreover, a Weber's law was found, such that a mean relative differential threshold in angular velocity of about 41% is necessary to perceive curvilinear vection. This visually induced self-motion corresponds to the sensation of moving in a curved path. It is proposed that curvilinear vection is induced when the apparent velocity difference is detectable. The spatiotemporal domain of perception of rectilinear vection and its spatiotemporal contrast surface sensitivity are centered on low spatial frequencies. Concurrently, the values which correspond to the relative differential thresholds of curvilinear vection are low spatial frequencies. Accordingly, the peripheral ambient visual system seems to be involved in perceiving linear veetion. It is argued further that the central ambient system might also be involved in the processing of linear vection.

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Section: Apparatusmentioning

confidence: 99%

Spatiotemporal boundaries of linear vection

Sauvan

Brunet

1995

Perception & Psychophysics

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“…Scotopic!Ambient System Reports of experiments with other aspects of egocentric localization and orientation have indicated major control by the peripheral visual field (Brandt, Dichgans, & Koenig, 1973;Dichgans & Brandt, 1974;Trevarthen, 1968), insensitivity to the accommodative stimulus (Leibowitz, Rodemer, & Dichgans, 1979), at most a low level of sensitivity to change in stimulus intensity (Leibowitz et al, 1979), and control by large visual fields (Dichgans & Brandt, 1974;Trevarthen, 1968). This has led to the suggestion (Leibowitz, Post, Brandt, & Dichgans, 1982;Trevarthen, 1968) that visual processing of localization and orientation is under control of an "ambient" system, whereas the processing of fine detail and form is under control of a "focal" system, whose main control is by more central (i.e., foveal and near foveal) pro-cesses, involves perception of fine detail, and is sensitive to the accommodative stimulus.…”

Section: Adaptation Ofvpel Within Amentioning

confidence: 99%

Light and dark adaptation of visually perceived eye level controlled by visual pitch

Matin

1995

Perception & Psychophysics

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The pitch of a visual field systematically influences the elevation at which a monocularly viewing subject sets a target so as to appear at visually perceived eye level (VPEL). The deviation of the setting from true eye level averages approximately 0.6 times the angle of pitch while viewing a fully illuminated complexly structured visual field and is only slightly less with one or two pitched-fromvertical lines in a dark field (Matin & Li, 1994a). The deviation of VPEL from baseline following 20 min of dark adaptation reaches its full value less than 1 min after the onset of illumination of the pitched visual field and decays exponentially in darkness following 5 min of exposure to visual pitch, either 30°topbackward or 20°topforward. The magnitude of the VPEL deviation measured with the dark-adapted right eye following left-eye exposure to pitch was 85%ofthe deviation that followed pitch exposure of the right eye itself. Time constants for VPEL decay to the dark baseline were the same for same-eye and cross-adaptation conditions and averaged about 4 min. The time constants for decay during dark adaptation were somewhat smaller, and the change during dark adaptation extended over a 16% smaller range following the viewing of the dim two-line pitched-from-vertical stimulus than following the viewing of the complex field. The temporal course of light and dark adaptation ofVPEL is virtually identical to the course oflight and dark adaptation of the scotopic luminance threshold following exposure to the same luminance. We suggest that, following rod stimulation along particular retinal orientations by portions of the pitched visual field, the storage of the adaptation process resides in the retinogeniculate system and is manifested in the focal system as a change in luminance threshold and in the ambient system as a change in VPEL.The linear model previously developed to account for VPEL, which was based on the interaction of influences from the pitched visual field and extraretinal influences from the body-referenced mechanism, was employed to incorporate the effects of adaptation. Connections between VPEL adaptation and other cases of perceptual adaptation of visual direction are described.The physical elevation of visually perceived eye level (VPEL) changes linearly with the pitch! of an illuminated visual field (Matin & Fox, 1986Matin, Fox, & Doktorsky, 1987;Matin & Li, 1989b, 1992b, 1992c, 1994a, 1994bMatin, Li, & Doktorsky, 1988;Stoper & Cohen, 1989). Employing the normally illuminated and complexly structured pitchroom shown in Figure 1a, average VPEL values for different groups of 8 subjects in two separate experiments deviated from true eye level by 0.61 and 0.63 times the angle of visual pitch over pitch ranges of 65°and 50°, respectively; one of the experiments involved monocular viewing, and the second involved binocular viewing. The slope of each subject's VPEL-versus-pitch function was linear, with individual slopes that ranged from +0.44 to +0.84. These individual slopes have demonstrated a great deal ...

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“…As documented, features of aging that contribute to the use of conservative strategies during obstacle crossing by older adults include the deterioration of muscle strength and vision (Chou et al, 2003;Leibowitz et al, 1979;Brandt et al, 1986). In order to reduce the risks of tripping and falling, older adults decrease crossing speed, decrease crossing step length, and increase the step width over the obstacle (Chen et al, 1991).…”

Section: Success Ratementioning

confidence: 99%