Amodal Representation of Occluded Surfaces: Role of Invisible Stimuli in Apparent Motion Correspondence

Perception ◽  
1990 ◽  
Vol 19 (3) ◽  
pp. 285-299 ◽  
Author(s):  
Shinsuke Shimojo ◽  
Ken Nakayama
Keyword(s):  
Apparent Motion ◽  
Motion Correspondence

Local-Level and Global-Level Form Characteristics in Apparent-Motion Correspondence

Perception ◽  
1995 ◽  
Vol 24 (11) ◽  
pp. 1233-1245 ◽  
Author(s):  
Terry Palmer ◽  
Ovid J L Tzeng ◽  
Sheng He
Keyword(s):  
Apparent Motion ◽  
Motion Detection ◽  
Local Level ◽  
The Other ◽  
Correspondence Problem ◽  
Global Level ◽  
Global Precedence ◽  
Detection Mechanism ◽  
Motion Display ◽  
Motion Correspondence

This study addressed the ‘correspondence’ problem of apparent-motion (AM) perception in which parts of a scene must be matched with counterparts separated in time and space. Given evidence that AM correspondence can be mediated by two distinct processes—one based on a low-level motion-detection mechanism (the Reichardt process), the other involving the tracking of objects by visual attention (the attention-based process)—the present study explored how these processes interact in the perception of apparent motion between hierarchically structured figures. In three experiments, hierarchical figures were presented in a competition motion display so that, across frames, figures were identical at either the local or the global level. In experiment 1 it was shown that AM occurred between locally identical figures. Furthermore, with the Reichardt AM component eliminated in experiments 3 and 4, no preference was obtained for either level. While evidence from previous studies suggests that form extraction for hierarchically structured figures proceeds from the global to the local level, the present results indicate the irrelevance of such a global precedence in AM correspondence. In addition, it is suggested that Reichardt AM correspondence between local elements constrains attention-based AM correspondence between global figures so that both components move in the same direction. It is argued that this constraining process represents an elegant means of achieving AM correspondence between objects undergoing complex transformations.

The role of brachial muscle spindle signals in assignment of visual direction

1993 ◽  
Vol 70 (4) ◽  
pp. 1578-1584 ◽  
Author(s):  
P. DiZio ◽  
C. E. Lathan ◽  
J. R. Lackner
Keyword(s):  
Apparent Motion ◽  
Muscle Spindle ◽  
Target Location ◽  
Biceps Brachii ◽  
Visual Target ◽  
Visual Direction ◽  
Muscle Vibration ◽  
Illusory Motion ◽  
The Stability

1. In the oculobrachial illusion, a target light attached to the unseen stationary hand is perceived as moving and changing spatial position when illusory motion of the forearm is elicited by brachial muscle vibration. Our goal was to see whether we could induce apparent motion and displacement of two retinally fixed targets in opposite directions by the use of oculobrachial illusions. 2. We vibrated both biceps brachii, generating illusory movements of the two forearms in opposite directions, and measured any associated changes in perceived distance between target lights on the unseen stationary hands. The stability of visual fixation of one of the targets was also measured. 3. The seen distance between the stationary targets increased significantly when vibration induced an illusory increase in felt distance between the hands, both with binocular and monocular viewing. 4. Subjects maintained fixation accuracy equally well during vibration-induced illusory increases in visual target separation and in a no-vibration control condition. Fixation errors were not correlated with the extent or direction of illusory visual separation. 5. These findings indicate that brachial muscle spindle signals can contribute to an independent representation of felt target location in head-centric coordinates that can be interrelated with a visual representation of target location generated by retinal and oculomotor signals. 6. A model of how these representations are interrelated is proposed, and its relation to other intersensory interactions is discussed.

scholarly journals Deciding what to see: The role of intention and attention in the perception of apparent motion

2008 ◽  
Vol 48 (8) ◽  
pp. 1096-1106 ◽  
Author(s):  
Axel Kohler ◽  
Leila Haddad ◽  
Wolf Singer ◽  
Lars Muckli
Keyword(s):  
Apparent Motion

Characteristics of the flux dimension cue in apparent motion correspondence

1992 ◽  
Vol 6 (1) ◽  
pp. 11-24
Author(s):  
Sima Shechter ◽  
Shaul Hochstein
Keyword(s):  
Apparent Motion ◽  
Motion Correspondence

Individual Differences in Responses of Untrained Observers to Stroboscopic Apparent Motion

Perception ◽  
1987 ◽  
Vol 16 (5) ◽  
pp. 573-581 ◽  
Author(s):  
David C Finlay ◽  
Mark L Manning ◽  
Barney Fenelon
Keyword(s):  
Individual Differences ◽  
Small Group ◽  
Long Range ◽  
Apparent Motion ◽  
Peak Frequency ◽  
Intersubject Variability ◽  
Once Daily ◽  
Large Groups

Two large groups of inexperienced subjects ( n = 208 and n = 50) and a small group of experienced subjects ( n = 5) were tested using time-till-breakdown as a measure of long-range apparent motion across a range of temporal frequencies. One group of inexperienced subjects was retested after one week and demonstrated quite stable patterns of response. Large intersubject variability was observed in terms of the amount of motion seen, with most inexperienced subjects reporting very little apparent motion. A raster display produced a peak frequency 1 Hz higher than a standard tachistoscope display. The role of experience was also examined with a small group of inexperienced subjects ( n = 8) tested once daily over five consecutive days. There was high intersubject variability and intrasubject consistency, demonstrating little influence of learning and experience. The results are discussed in terms of current ideas on the breakdown effect.

Visual figure–ground discrimination in the honeybee: the role of motion parallax at boundaries

1990 ◽  
Vol 238 (1293) ◽  
pp. 331-350 ◽  
Keyword(s):  
Apparent Motion ◽  
Motion Parallax ◽  
The Other ◽  
Neural Models ◽  
Height Difference ◽  
Sugar Water ◽  
Different Types ◽  
Series Of Experiments ◽  
The Difference

Free flying bees were trained to collect a reward of sugar-water from a structured figure, placed at a randomly varying location on a sheet of transparent Perspex, positioned 5 cm above a structured Background. During subsequent tests, done in the absence of a reward, the bees’ landings on the boundaries of the figure, as well as within the figure and outside it, were recorded. The same bees were also tested with the figure placed directly on the background, thus eliminating the difference in height between the figure and the background. The results of both types of tests were then compared to identify and investigate the cues that bees use to detect a structured figure, when presented over a structured background. The structure of both the figure and the background were varied in a series of experiments, training a fresh group of bees in each experiment. A randomly structured figure presented against a randomly structured background cannot be detected by the bees unless it is raised above the background. A height difference of 2 cm is sufficient to elicit a rate of landings on the figure that is significantly higher than the chance level. The detectability of the figure does not depend upon the shape of the figure or on differences in density between the structures of the figure and the background. Thus, in detecting the raised figure, the only cue used by the bees appears to be the apparent motion of the figure relative to the background. The majority of landings on a raised figure occur at its boundaries. This shows that the visual stimulus that is crucial in detecting the figure is the local discontinuity in apparent motion that occurs at the boundary. We refer to this as ‘boundary parallax ’. In a series of experiments that used a striped background and a variety of structured figures, three different types of boundary parallax were offered to the bees. These were: (i) ‘covering parallax’, at a boundary in which stripes on either side of the boundary are parallel to the boundary; (ii) ‘shearing parallax’, in which stripes on either side are perpendicular to the boundary and (iii) ‘orthogonal parallax’, in which the stripes on one side are perpendicular to those on the other side. The bees performed very well at detecting raised boundaries that offered covering or shearing parallax, despite the fact that such boundaries are not readily discernible on the basis of their static geometry. On the other hand, bees performed poorly in detecting raised boundaries that offered orthogonal parallax, despite the fact that such boundaries are geometrically quite vivid to the human eye. We propose two neural models for the detection of boundary parallax that account for the sensitivity of bees to covering and shearing parallax and their insensitivity to orthogonal parallax.

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