When motion appears stopped: Stereo motion standstill

Abstract

Motion standstill is different from the usual perceptual experiences associated with objects in motion. In motion standstill, a pattern that is moving quite rapidly is perceived as being motionless, and yet its details are not blurred but clearly visible. We revisited motion standstill in dynamic random-dot stereograms similar to those first used by Julesz and Payne [Julesz B, Payne R (1968) Vision Res 8:433-444]. Three improvements were made to their paradigm to avoid possible confounds: The temporal frequency of the motion stimuli was manipulated independently from that of individual stereo gratings so that the failure of motion perception is not due to inability to compute stereo. The motion of the stereo gratings was continuous across the visual field so that the perceived pattern in motion standstill was not a simple average of a back-and-forth display wobble over time. Observers discriminated three spatial frequencies to demonstrate pattern recognition. Three objective psychophysical methods, instead of merely selfreport, were used to objectively demonstrate motion standstill. Our results confirm that motion standstill occurs in dynamic random-dot stereogram motion displays at 4 -6 Hz. Motion standstill occurs when the stimulus spatiotemporal frequency combination exceeds that of the salience-based third-order motion system in a spatiotemporal frequency range in which the shape and depth systems still function. The ability of shape systems to extract a representative image from a series of moving samples is a significant component of a biological system's ability to derive a stable perceptual world from a constantly changing visual environment.illusions ͉ perception ͉ psychophysics ͉ stereopsis ͉ vision

Reaction Time Improvements by Neural Bistability

“…If such training is done adequately, assessments [2,46] show that improvements may occur in nine tested abilities of students and stamina of the visual system. Positive results also appeared for toss-to-wall [46], baseball [2,13,47,48], basketball [49,50], cricket, football [9,51,52], fencing, frisbee [9], hockey [15,53], rugby [54], softball [55,56], tennis, table tennis [57], volleyball [49], and water-polo [49]. Outside of sports, improvements are known for motion sickness [58], older adults [59], and visually impaired youth [60].…”

Efficiency of extracting stereo-driven object motions

“…Observers performed better at slower presentation rates, which is in agreement with previous findings for third-order motion stimuli (Lu & Sperling, 1995), and consistent with the fact that stereo-motion perception declines at higher temporal frequencies. Alternately, the possibility of a decline in stereo-shape extraction at faster presentation rates (Foley & Tyler, 1976) cannot be ruled out as a cause, although Tseng et al (2006) showed that observers are sometimes unable to discriminate motion direction of stereo-defined gratings, even when they clearly perceive the grating. Performance declined for both grating and motion detection at higher temporal frequencies.…”

Contribution of the slow motion mechanism to global motion revealed by an MAE technique

“…It is theoretically possible that the different static and flicker MAE directions are due to the different contributions of the first-order and second-order motion mechanisms. Luminance gratings can stimulate the second-order, as well as the first-order and third-order motion systems 65 – 70 . If we assume that second-order motion mechanism is responsible to flicker MAE, we can still explain the results with replacing the fast motion mechanism by the second-order motion system.…”