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(1 - 6 of 6)
- Title
- Competing mechanisms in the perception of apparent motion: Effects of zero-hertz and time-varying energy.
- Creator
- Kogan, Kristine Marie, Florida Atlantic University, Hock, Howard S., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Anstis, et al. (1985) have reported that under certain conditions the visual system adapts and the perception of apparent motion breaks down. The present research indicates that breakdown is actually a result of same-place mechanisms successfully competing with motion-detecting mechanisms. Thus, the perception of stationarity (with flicker) can occur at the start of a trial and spontaneously switch to the perception of motion, or vice versa. The response of same-place mechanisms depends on...
Show moreAnstis, et al. (1985) have reported that under certain conditions the visual system adapts and the perception of apparent motion breaks down. The present research indicates that breakdown is actually a result of same-place mechanisms successfully competing with motion-detecting mechanisms. Thus, the perception of stationarity (with flicker) can occur at the start of a trial and spontaneously switch to the perception of motion, or vice versa. The response of same-place mechanisms depends on the zero-hertz energy at each location of an apparent motion stimulus, whereas the response of motion mechanisms depends on the time-varying energy. Average luminance, luminance contrast, the temporal symmetry of the apparent motion display, and relative phase are manipulated to investigate competition between same-place and motion-detecting mechanisms.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15234
- Subject Headings
- Motion perception (Vision), Perceptual-motor processes, Visual perception
- Format
- Document (PDF)
- Title
- Dynamic Grouping Motion and Amodal Completion.
- Creator
- Datta, Debarshi, Hock, Howard S., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
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Objects in a scene are likely to occlude other objects partially and are itself likely to be partially occluded. A central question, therefore, is how the visual system resolves the resulting surface correspondence problem by successfully determining which surfaces belong to which objects. To this end, a recently developed dynamic grouping methodology has determined whether pairs of adjacent surfaces are grouped (Hock & Nichols, 2012). The grouping of adjacent surfaces, which depends on their...
Show moreObjects in a scene are likely to occlude other objects partially and are itself likely to be partially occluded. A central question, therefore, is how the visual system resolves the resulting surface correspondence problem by successfully determining which surfaces belong to which objects. To this end, a recently developed dynamic grouping methodology has determined whether pairs of adjacent surfaces are grouped (Hock & Nichols, 2012). The grouping of adjacent surfaces, which depends on their affinity state, is indicated by the direction of perceived motion across one surface when its luminance is perturbed. In the current stimuli, which consists of a horizontal surface partially occluded by a vertical bar, dynamic grouping also can occur for nonadjacent surfaces, providing they are linked in two-dimensions by a connecting surface. Results indicate that the dynamic grouping motion is stronger for amodal completion entailing the perceptual grouping of nonadjacent surfaces behind an occluder.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004998, http://purl.flvc.org/fau/fd/FA00004988
- Subject Headings
- Dissertations, Academic -- Florida Atlantic University, Visual perception., Visual system., Dynamic grouping
- Format
- Document (PDF)
- Title
- Global feedback in hierarchical motion pattern formation.
- Creator
- Brownlow, Stacey W., Florida Atlantic University, Hock, Howard S., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
An array of four motion quartets (stimuli for which either horizontal or vertical motion is perceived depending on quartet aspect ratio) is arranged in a diamond configuration such that two global motion patterns are formed: (1) Rotation---alternating counterclockwise and clockwise motion is perceived, and (2) Parallel path motion---the perceived motions of all the elements are simultaneously horizontal or simultaneously vertical. The perception of rotation resulted in global feedback that...
Show moreAn array of four motion quartets (stimuli for which either horizontal or vertical motion is perceived depending on quartet aspect ratio) is arranged in a diamond configuration such that two global motion patterns are formed: (1) Rotation---alternating counterclockwise and clockwise motion is perceived, and (2) Parallel path motion---the perceived motions of all the elements are simultaneously horizontal or simultaneously vertical. The perception of rotation resulted in global feedback that biases the motion perceived for an individual component motion quartet to be more consistent with rotation than aspect ratio. Stronger rotation produced greater bias. Under certain conditions, the feedback-induced bias occurred even though global rotation was not perceived. The results were interpreted in the context of neurophysiological evidence regarding neurons in Areas MT and MSTd, and a dynamical theory of motion pattern formation (Hock, Schoner & Giese, 2003; Nichols, Hock & Schoner, 2006).
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13371
- Subject Headings
- Motion perception (Vision)--Mathematical models, Visual pathways, Neurophysiology, Nonlinear chemical kinetics
- Format
- Document (PDF)
- Title
- PERCEPTUAL SEGREGATION AND THE CATEGORY EFFECT.
- Creator
- ROSENTHAL, ALAN., Florida Atlantic University, Hock, Howard S., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
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A category effect of alphanumeric characters in a visual search paradigm was examined to see whether the effect could be accounted for by the number of memory comparisons or by an early stage of perceptual processing. In Experiments 1 and 2, subjects searched for targets in either a within-category or between-category condition. The two experiments differed by the point in the trials where "catch trials" were presented. Experiment 3 used new configurations based on Gestalt principles which...
Show moreA category effect of alphanumeric characters in a visual search paradigm was examined to see whether the effect could be accounted for by the number of memory comparisons or by an early stage of perceptual processing. In Experiments 1 and 2, subjects searched for targets in either a within-category or between-category condition. The two experiments differed by the point in the trials where "catch trials" were presented. Experiment 3 used new configurations based on Gestalt principles which had been shown to influence target detection times at an early level of perceptual processing. The results of Experiments 1 and 2 favored a perceptual explanation mediating the effect. In Experiment 3, the critical interaction of category and Gestalt factors which would have demonstrated a competition in perceptually parsing the display fell short of significance.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14036
- Subject Headings
- Human information processing, Perception
- Format
- Document (PDF)
- Title
- Potential stimulus contributions to counterchange determined motion perception.
- Creator
- Park, Cynthia Louise Smith, Hock, Howard S., Barenholtz, Elan, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Prior research has explored the counterchange model of motion detection in terms of counterchanging information that originates in the stimulus foreground (or objects). These experiments explore counterchange apparent motion with regard to a new apparent motion stimulus where the necessary counterchanging information required for apparent motion is provided by altering the luminance of the background. It was found that apparent motion produced by background-counterchange requires longer frame...
Show morePrior research has explored the counterchange model of motion detection in terms of counterchanging information that originates in the stimulus foreground (or objects). These experiments explore counterchange apparent motion with regard to a new apparent motion stimulus where the necessary counterchanging information required for apparent motion is provided by altering the luminance of the background. It was found that apparent motion produced by background-counterchange requires longer frame durations and lower levels of average stimulus contrast compared to foreground-counterchange. Furthermore, inter-object distance does not influence apparent motion produced by background-counterchange to the degree it influences apparent motion produced by foreground-counterchange.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004313
- Subject Headings
- Motion perception (Vision), Perceptual motor processes, Visual analysis, Visual discrimination, Visual pathways, Visual perception
- Format
- Document (PDF)
- Title
- TOP-DOWN EFFECTS OF PERCEPTUAL GROUPING ON THE PERCEPTION OF MOTION.
- Creator
- Datta, Debarshi, Hock, Howard S., Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
- Abstract/Description
-
Ullman (1979) has proposed a measurement metric, which he termed “affinity." He described affinity as a certain similarity measure between successively presented surfaces as it affects the perception of apparent motion between the surfaces. Later, the concept of “affinity” has been extended; it entails that how the perception of motion within a surface is affected by its grouping strength with adjacent surfaces (Hock and Nichols, 2012). It has been found that the more attributes, that are...
Show moreUllman (1979) has proposed a measurement metric, which he termed “affinity." He described affinity as a certain similarity measure between successively presented surfaces as it affects the perception of apparent motion between the surfaces. Later, the concept of “affinity” has been extended; it entails that how the perception of motion within a surface is affected by its grouping strength with adjacent surfaces (Hock and Nichols, 2012). It has been found that the more attributes, that are shared by the adjacent surfaces, the greater the likelihood of their being grouped together. However, Ullman (1979) suggested that the relative affinities of pairs of surfaces could determine the solutions for the motion correspondence problem (when more than one motion path is possible). However, it has remained unknown whether the effects of affinity on solutions to the correspondence problem are due to its effects on a single surface apparent motion strength or pre-selection biases; i.e., the top-down effects of perceptual grouping favoring the perception of motion in one direction as opposed to other competing directions. In the current study, it has been confirmed that motion within a surface is affected by its affinity with adjacent surfaces. The current study also confirmed that affinity has a small, but significant effect on motion strength when motion surfaces are presented in a single surface apparent motion configuration, evidence for top-down effects in which motion strength can be affected by affinity. In motion correspondence problem, affinity affects the perceived motion direction due to competition is consistent with the solution to the motion correspondence problem being affected by the relative affinity-determined strength of competing motion signals. But it is seen that there is strong affinity is due to preselection identity biases. To conclude, in motion correspondence problem, stronger motion is perceived between the two similar surfaces is due to pre-selection biases resulting from the perceptual grouping of surfaces with the greatest affinity; i.e., the top-down effects favoring the perception of motion in one direction as opposed to other competing directions.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013567
- Subject Headings
- Motion Perception, Perceptual grouping
- Format
- Document (PDF)
