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sj-vid-3-ipe-10.1177_2041669518801029 - Supplemental material for Crowding and the Furrow Illusion
No full textSupplemental material, sj-vid-3-ipe-10.1177_2041669518801029 for Crowding and the Furrow Illusion by Stuart Anstis and Patrick Cavanagh in i-Perception</p
sj-vid-1-ipe-10.1177_2041669518801029 - Supplemental material for Crowding and the Furrow Illusion
No full textSupplemental material, sj-vid-1-ipe-10.1177_2041669518801029 for Crowding and the Furrow Illusion by Stuart Anstis and Patrick Cavanagh in i-Perception</p
sj-vid-2-ipe-10.1177_2041669518801029 - Supplemental material for Crowding and the Furrow Illusion
No full textSupplemental material, sj-vid-2-ipe-10.1177_2041669518801029 for Crowding and the Furrow Illusion by Stuart Anstis and Patrick Cavanagh in i-Perception</p
Supplemental material for Motion-Induced Scotoma
No full textSupplementary Material for Motion-Induced Scotoma by Tatjana Seizova-Cajic, Nika Adamian, Marianne Duyck and Patrick Cavanagh in Perception</p
Stimulus sequence of the “intra-retinal” and “extra-retinal remapping” conditions.
No full text<p>Each panel shows the sequence of the stimuli with a view from above the observer (represented by a single eye). The front screen and the side screen are shown as grey rectangles. The visual fields are shown as a green or red half circle when the observer fixates respectively the left or right fixation marker on the front screen. Each panel also represents the projections on the retina of the currently presented probe (black lines), of previously presented probe (gray lines) and of the predicted post-saccadic position of a probe (remapping) following the saccade (brown lines). (a) In the sequence of the extra-retinal remapping condition, probes were sequentially presented on the side screen, at the edge of observers’ visual field, 150 ms before and 150 ms after the fixation markers exchange locations. Observers were instructed to follow the green fixation marker, making rightward saccades while the peripheral probe move in the same direction. Observers report after each trial whether they saw motion on the side screen. Probes distance matched the fixation markers distance, such that the two probes fell closely at the same position on the retina even if they had two distinct positions in space. Under these conditions, to perceive motion between probes, the first probe should be remapped at its post-saccadic position on the retina, falling then outside observer’s visual field (see brown line), on extra-retinal visual space. (b) In the sequence of the intra-retinal remapping, observers made leftward saccades while probes moved in the same direction. The first probe is again remapped at its post-saccadic position, falling now inside observer’s visual field, on intra-retinal visual space.</p
Demonstration of effects of grouping, screenshots of Movies S1 to S3.
No full text<p>Please see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071188#pone.0071188.s001" target="_blank">Movies S1</a> to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071188#pone.0071188.s003" target="_blank">S3</a> and instructions in the Supporting Information section. A) Matched condition, B) Unmatched condition, C) Baseline.</p
Illustration of stimulus and data presentation method.
No full text<p>(A) In experiment 1, binocular rivalry was induced with foveal presentation of red and green orthogonal gratings to the left or right eye respectively. The rivaling targets were red and green sinusoidal grating patches that subtended 2.5° of visual angle. The gratings had a spatial frequency of 1.6 cycles/deg oriented obliquely at either 45° or 135°. Targets were presented for either 60sec of continual presentation or for 60×1sec presentations over 600 sec (i.e. 1sec on 9sec off). In experiment 2, the same targets were presented in one of 8 locations spaced equally around a circular path with a radius of 4.5° around a 0.3° central fixation point. During the intermittent stimulus conditions targets were presented for 1sec with an inter-stimulus interval 250ms (all 8 locations visited every 10sec). In both conditions the targets were presented on a gray background within a 13.5° white square frame 0.2° thick. (B) Schematic illustration of results for an idealized case of random and strongly biased perceptual dominance (note that any switch in perception is only temporary, suggesting the dominance reflects an onset bias rather than stabilization). For foveal rivalry the data are graphically represented as a sequence of 60 adjacent colored bars corresponding (from left to right) with the perceptual dominance for each of the 60×1sec presentation (in the intermittent case the gap interval is not depicted). In experiment 2, perceptual dominance at each location is illustrated by a color patch corresponding to each of the 8 peripheral target locations. Each successive target loop is represented in increasingly outward rings. In this way, each color patch represents the subject's perceptual dominance at a single point in time and space for the entire trial. The left column represents idealized case for random allocation of dominance, while the right column shows complete localized biases.</p
Apparatus and visual field.
No full text<p>Two screens positioned at a distance of 60 cm from observers’ head were used, a front screen displaying the fixation (green dot) and saccade (red dot) markers and a side screen displaying the apparent motion probes. Eye and head position are monitored using an eye tracker combined with a head tracker and a chin rest with the left support removed in order to leave the side screen visible. (a) The green parabolic field represents observer’s visual field when fixating on the left fixation marker. The side screen is positioned such that the leftmost apparent motion probe falls just within the observer’s visual field when he or she is fixating the left marker on the front screen. (b) The red parabolic field represents observer’s visual field when he or she fixates the right fixation marker on the front screen. When fixating the rightmost marker, the right motion probe on the side screen falls at approximately the same position on the observer’s retina as the left probe does when fixating the left marker, even though the two probes do not have the same position in space. Note, however, that the position of left motion probe falls outside observer’s visual field when he or she fixates the right marker (at which time the left probe is no longer present).</p
Motion: the long and short of it
No full textSeveral authors have proposed that motion is analyzed by two separate processes: short-range and long-range. We claim that the differences between short-range and long-range motion phenomena are a direct consequence of the stimuli used in the two paradigms and are not evidence for the existence of two qualitatively different motion processes. We propose that a single style of motion analysis, similar to the well known Reichardt and Marr-Ullman motion detectors, underlies all motion phenomena. Although there are different detectors of this type specialized for different visual attributes (namely first-order and second-order stimuli), they all share the same mode of operation. We review the studies of second-order motion stimuli to show that they share the basic phenomena observed for first-order stimuli. The similarity across stimulus types suggests, not parallel streams of motion extraction, one short-range and passive and the other long-range and intelligent, but a concatenation of a common mode of initial motion extraction followed by a general inference process.</p
Results of Experiment 2, sensitivity.
No full text<p>In the Near condition, no difference in sensitivity (d′) between the Matched and Unmatched condition was found. Also in the Far condition there was no difference between the Matched and Unmatched condition. Gray squares are placeholders for the target letters of varying orientations; the squares were not presented. The dashed line indicates performance on a target presented with only Horizontal flankers. Error bars indicate standard errors of the mean. Stimuli are not drawn to scale.</p
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