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Title: AN EXAMINATION OF CONTEXT EFFECTS IN VISUAL PERCEPTION.
Creator: GORDON, GREGORY PETER, Florida Atlantic University
Abstract/Description: A "same-different" reaction time paradigm was used to investigate the influence of context on the perception of multiple object scenes consisting of "real-world" objects. The relationships among these objects were manipulated to compose four different contextual arrangements. This enabled an investigation of three aspects of context: familiarity, physical plausibility, and belongingness. Differences in reaction time between the four levels of context were significant for both same and...
Show moreA "same-different" reaction time paradigm was used to investigate the influence of context on the perception of multiple object scenes consisting of "real-world" objects. The relationships among these objects were manipulated to compose four different contextual arrangements. This enabled an investigation of three aspects of context: familiarity, physical plausibility, and belongingness. Differences in reaction time between the four levels of context were significant for both same and different responses. Furthermore, a correlational analysis indicated individual differences in the use of contextual effects. Those subjects who were most influenced by whether or not the objects belonged together, were least influenced by the disruption of the rules of physical plausibility, and vice versa. Correlational analyses concerned with the relationship between individual differences in context effects and emphasis on structural versus analytic processing (Hock, 1973) were insignificant, though in the predicted direction.
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Date Issued: 1973
PURL: http://purl.flvc.org/fcla/dt/13558
Subject Headings: Visual perception
Format: Document (PDF)

Title: THE PERCEPTION OF DISTANCE AND ANGLE RELATIONS FOR SIMPLE DOT PATTERNS.
Creator: O'ROURKE, GERALD., Florida Atlantic University
Abstract/Description: This research was concerned with the perception of inter-element distance and angle relations for pairs of dots arranged vertically, horizontally, oblique-left, and oblique-right. For each trial, a pair of dots was presented in different global locations, for five consecutive frames. The subject's task was to detect a change in the relative location of the dots, which could occur during one of the five frames. Each subject participated in three different conditions. One condition emphasized...
Show moreThis research was concerned with the perception of inter-element distance and angle relations for pairs of dots arranged vertically, horizontally, oblique-left, and oblique-right. For each trial, a pair of dots was presented in different global locations, for five consecutive frames. The subject's task was to detect a change in the relative location of the dots, which could occur during one of the five frames. Each subject participated in three different conditions. One condition emphasized the detection of changes in distance between the elements; the second emphasized the detection of changes in the angle formed by the elements. The third condition did not focus attention on either distance or angle changes. Results indicated that focussing attention on either distance or angle changes affected sensitivity to distance changes for rectilinear, but not for oblique arrangements. These results suggested that the vertical and horizontal components of Inter-element distance are perceptually fundamental, and that the Euclidean distance between two elements and the angle formed by the elements are internally computed from the perceptually fundamental distance components.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14288
Subject Headings: Visual perception
Format: Document (PDF)

Title: THE DETERMINANTS OF GROUPING DURING BINOCULAR RIVALRY.
Creator: Yoon, Yosun, Hong, Sang Wook, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description: Interocular grouping during binocular rivalry occurs when two images concurrently presented to two eyes are combined as a coherent pattern as if perceptual experience follows Gestalt grouping principles. The present study investigated what determines rivalry dynamics (perceptual experience of monocular stimuli and interocular grouping) by examining individual differences. Specifically, the effect of eye-of-origin and pattern coherence on percepts during rivalry were individually assessed...
Show moreInterocular grouping during binocular rivalry occurs when two images concurrently presented to two eyes are combined as a coherent pattern as if perceptual experience follows Gestalt grouping principles. The present study investigated what determines rivalry dynamics (perceptual experience of monocular stimuli and interocular grouping) by examining individual differences. Specifically, the effect of eye-of-origin and pattern coherence on percepts during rivalry were individually assessed using pairs of stimuli that induce either monocularly-driven (monocular coherence condition) or interocularly-driven (interocular coherence condition) coherent percepts. We found that the degree of perceiving complete, coherent stimuli was consistent within individuals regardless of conditions, indicating that individual differences in experiencing interocular grouping were explained by pattern coherence, rather than eye-of-origin information. In addition, we found that individuals who experience binocularly presented pattern motion more perceived interocularly-coherent stimuli more. This result suggests that a potential common mechanism may mediate binocular integration of visual information during binocular rivalry.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013815
Subject Headings: Binocular rivalry, Visual perception
Format: Document (PDF)

Title: HEMISPHERIC DIFFERENCES IN THE EFFECT OF STIMULUS FAMILIARITY ON PERCEIVED DURATION.
Creator: MURPHY, ARTHUR LORD, Florida Atlantic University
Abstract/Description: A paired-comparisons procedure was used to obtain relative duration judgements of identical pairs of normal (e.g. A vs. A) or rotated (e.g.V vs.V) letters. Each pair of letters was presented simultaneously for a duration of 50msec, with one letter in the LVF (left visual field, right hemisphere), and one in the RVF (right visual field, left hemisphere). It was hypothesized that LVF presentations of rotated letters would have a greater apparent duration . This was based on Hock, Kronseder, and...
Show moreA paired-comparisons procedure was used to obtain relative duration judgements of identical pairs of normal (e.g. A vs. A) or rotated (e.g.V vs.V) letters. Each pair of letters was presented simultaneously for a duration of 50msec, with one letter in the LVF (left visual field, right hemisphere), and one in the RVF (right visual field, left hemisphere). It was hypothesized that LVF presentations of rotated letters would have a greater apparent duration . This was based on Hock, Kronseder, and Corcoran's (1975) demonstration that rotated letters presented in the LVF produce longer reaction times than RVF presentations on a visual comparisons task. The results were that subjects' "left" vs. "right" responses did not differ significantly for any of the conditions. Methodological considerations were cited as a possible reason for the failure to confirm the present hypo thesis.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13810
Subject Headings: Time perception, Visual perception, Human information processing
Format: Document (PDF)

Title: The attentional control of spatial perception.
Creator: Balz, Gunther William, Florida Atlantic University, Hock, Howard S.
Abstract/Description: When perceivers examine a visual scene, they can control the extent to which their attention is either narrowly focused or spread over a larger spatial area. The experiments reported in this dissertation explore the consequences of narrow vs. broad attention for simple spatial discriminations as well as more complex cooperative interactions that are the basis for the self-organization of coherent motion patterns. Subjects' attentional spread (narrow or broad) is manipulated by means of a...
Show moreWhen perceivers examine a visual scene, they can control the extent to which their attention is either narrowly focused or spread over a larger spatial area. The experiments reported in this dissertation explore the consequences of narrow vs. broad attention for simple spatial discriminations as well as more complex cooperative interactions that are the basis for the self-organization of coherent motion patterns. Subjects' attentional spread (narrow or broad) is manipulated by means of a primary, luminance detection task. In conjunction with the luminance detection task is a secondary, spatial discrimination or detection task, which differs in the four reported experiments. In Experiment 1, the discrimination of misalignment of two visual elements is enhanced by narrowly focused attention. In Experiment 2, discrimination of horizontal spatial separation of two visual elements is improved for small inter-element distances by narrow attention and for relatively large inter-element distances by broad attention. Experiment 3 shows that the inter-element distance among counterphase-presented visual elements for which unidirectional and oscillatory motion patterns are observed with equal frequency depends on subjects' attentional spread. Narrow attention favors the oscillatory pattern and broad attention favors the unidirectional pattern. Experiment 4 shows that attentional spread has a minimal effect on the detection of motion, and, additionally that attentional effects on simple spatial judgments (Experiments 1 and 2) are too small to account for the large shift in the equi-probable boundary of reported unidirectional and oscillatory motion patterns found in Experiment 3. Therefore, it is concluded in conjunction with Hock and Balz's (1994) differential gradient model, that attentional spread influences the self-organization of unidirectional and oscillatory motion patterns through its effects on the relative strength of facilitating and inhibiting interactions among directionally selective motion detectors.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/12392
Subject Headings: Attention, Selectivity (Psychology), Visual perception, Space perception
Format: Document (PDF)

Title: A visual rotation invariant in fixated motion.
Creator: Ozery, Nissim Jossef., Florida Atlantic University, Raviv, Daniel, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: This thesis studies the 2-D-based visual invariant that exists during relative motion between a camera and a 3-D object. We show that during fixation there is a measurable nonlinear function of optical flow that produces the same value for all points of a stationary environment regardless of the 3-D shape of the environment. During fixated camera motion relative to a rigid object, e.g., a stationary environment, the projection of the fixated point remains (by definition) at the same location...
Show moreThis thesis studies the 2-D-based visual invariant that exists during relative motion between a camera and a 3-D object. We show that during fixation there is a measurable nonlinear function of optical flow that produces the same value for all points of a stationary environment regardless of the 3-D shape of the environment. During fixated camera motion relative to a rigid object, e.g., a stationary environment, the projection of the fixated point remains (by definition) at the same location in the image, and all other points located on the 3-D rigid object can only rotate relative to that 3-D fixation point. This rotation rate of the points is invariant for all points that lie on the particular environment, and it is measurable from a sequence of images. This new invariant is obtained from a set of monocular images and is expressed explicitly as a closed form solution.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15095
Subject Headings: Invariants, Visual perception, Motion perception (Vision)
Format: Document (PDF)

Title: Autonomous landing and road following using two-dimensional visual cues.
Creator: Yakali, Huseyin Hakan., Florida Atlantic University, Raviv, Daniel, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: This dissertation deals with vision-based perception-action closed-loop control systems based on 2-D visual cues. These visual cues are used to calculate the relevant control signals required for autonomous landing and road following. In the landing tasks it has been shown that nine 2-D visual cues can be extracted from a single image of the runway. Seven of these cues can be used to accomplish parallel flight and glideslope tracking tasks of the landing. For the road following task, three...
Show moreThis dissertation deals with vision-based perception-action closed-loop control systems based on 2-D visual cues. These visual cues are used to calculate the relevant control signals required for autonomous landing and road following. In the landing tasks it has been shown that nine 2-D visual cues can be extracted from a single image of the runway. Seven of these cues can be used to accomplish parallel flight and glideslope tracking tasks of the landing. For the road following task, three different algorithms based on two different 2-D visual cues are developed. One of the road following algorithms can be used to generate steering and velocity commands for the vehicle. Glideslope tracking of the landing task has been implemented in real-time on a six-degree-of-freedom flight simulator. It has been shown that the relevant information computed from 2-D visual cues is robust and reliable for the landing tasks. Road following algorithms were tested successfully up to 50km/h on a US Army High Mobility and Multipurpose Wheeled Vehicle (HMMWV) equipped with a vision system and on a Denning mobile robot. The algorithms have also been tested successfully using PC-based software simulation programs.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/12365
Subject Headings: Visual perception, Landing aids (Aeronautics)
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.
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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: Traveling Waves of Dominance in Motion-Induced Blindness.
Creator: Cox, Dustin, Hong, Sang Wook, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: In the present study, it was examined whether the spatiotemporal dynamics of transitions towards target dominance in motion-induced blindness (MIB) were wave-like, similar to those in binocular rivalry. The spatiotemporal dynamics of transitions towards dominance in MIB were further compared with those in binocular rivalry to reveal a potential neural locus of MIB. Across a series of experiments, the relationship between target length, stimulus structure, presentation location and the latency...
Show moreIn the present study, it was examined whether the spatiotemporal dynamics of transitions towards target dominance in motion-induced blindness (MIB) were wave-like, similar to those in binocular rivalry. The spatiotemporal dynamics of transitions towards dominance in MIB were further compared with those in binocular rivalry to reveal a potential neural locus of MIB. Across a series of experiments, the relationship between target length, stimulus structure, presentation location and the latency for circular arc segment-shaped targets to reappear was examined, respectively. It was found that target reappearance durations increase with target length, as if they reappear in a gradual, wavelike fashion. Target reappearance durations were decreased for collinear compared to radial targets, but they were not influenced by the location of target presentation. The results suggest MIB target reappearances are associated with traveling waves of dominance, and early visual cortex is a likely neural substrate in which these wave-like transitions occur.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004704, http://purl.flvc.org/fau/fd/FA00004704
Subject Headings: Binocular rivalry, Binocular vision, Visual pathways, Visual perception
Format: Document (PDF)

Title: The effect of spatial attention on pupil dynamics.
Creator: Daniels, Lori B., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Although it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the...
Show moreAlthough it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the rate of attention variation, dilating with broadly spread attention and contracting with narrowly focused attention, and 2) pupillary differences required changes in attentional spread; there were no differences in pupil diameter between sustained broad and sustained spread attention. Given that broadly spread attention increases the relative activation of large receptive fields and narrowly focused attention increases the relative activation of small receptive fields (Balz & Hock, 1997), the results of this study indicate that these attentional effects on receptive field activation can be mediated by changes in pupil diameter. That is, under broad attention, the corresponding pupillary dilation observed would increase spherical aberration, blurring the image thereby reducing high spatial frequency information and decreasing the activation of relatively small cortical receptive fields compared to relatively large receptive fields. This increased perception of low spatial frequencies would be beneficial in cases where attention is spread over a large area. Alternatively, under narrow attention the resulting pupillary constriction reduces spherical aberration sharpening the image and preserving high spatial frequency information resulting in a relatively increased response of small receptive fields.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1870692
Subject Headings: Visual perception, Eye, Physiology, Optics, Adaptive, Visual pathways
Format: Document (PDF)

Title: Investigating the Temporal Dynamics of Advanced Information Processing During Interocular Suppression Using Electroencephalography and Pattern Classification.
Creator: Cox, Dustin, Hong, Sang Wook, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: A thorough delineation of the extent of processing possible without visual awareness is necessary to elucidate the neural mechanisms of visual awareness. Despite extensive research, it is presently unclear whether invisible stimuli can undergo advanced processing. To introduce existing work on this topic, previous behavioral efforts to investigate the extent of processing possible without visual awareness and the psychophysical methods used to render stimuli invisible, such as visual masking...
Show moreA thorough delineation of the extent of processing possible without visual awareness is necessary to elucidate the neural mechanisms of visual awareness. Despite extensive research, it is presently unclear whether invisible stimuli can undergo advanced processing. To introduce existing work on this topic, previous behavioral efforts to investigate the extent of processing possible without visual awareness and the psychophysical methods used to render stimuli invisible, such as visual masking and interocular suppression-based techniques, are discussed. Physiological evidence that provide support for and against the possibility that advanced information processing can occur without visual awareness are addressed. The basics of multivariate pattern classification techniques are outlined. The potential of using multivariate pattern classification analyses in conjunction with neuroimaging in the temporal domain to investigate whether advanced processing can occur without visual awareness is discussed. An original study using electroencephalography (EEG) and pattern classification techniques to investigate the extent of processing possible without visual awareness is outlined. The results of the analyses reveal that a pattern classifier did not extract neural signatures of categorical processing from EEG recordings when participants viewed an image that remained invisible for the duration of its presentation. In contrast, the results from a second experiment reveal that the pattern classifier was able to decode the category of invisible images from the EEG time series when the images would eventually become visible. The results provide support for the idea that under certain circumstances, such as when the depth of interocular suppression is reduced, advanced processing for invisible stimuli can occur.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013193
Subject Headings: Advanced information processing, Electroencephalography, Neuroimaging, Visual perception
Format: Document (PDF)

Title: VISUAL CONCEPTS: PROTOTYPE ABSTRACTION AND SPECIFIC REPRESENTATION.
Creator: TROMLEY, CHERYL LYNN., Florida Atlantic University
Abstract/Description: Prototype abstraction and specific representations were examined using two acquisition procedures (paired-associate and concept formation) for concept members generated by applying one of two distortion rules (form preserving and form destroying) to eight-dot base patterns. One distortion rule maximized the configurational similarity between concept members and minimized their elemental similarity (form preserving). The other maximized the elemental similarity between concept members and...
Show morePrototype abstraction and specific representations were examined using two acquisition procedures (paired-associate and concept formation) for concept members generated by applying one of two distortion rules (form preserving and form destroying) to eight-dot base patterns. One distortion rule maximized the configurational similarity between concept members and minimized their elemental similarity (form preserving). The other maximized the elemental similarity between concept members and minimized their configurational similarity (form destroying). Either immediately following acquisition or after a two-week delay, subjects were given a classification test which included the concept members learned during acquisition and novel members of the concepts. Evidence for prototype abstraction was found only for form preserving concepts. This result was interpreted as evidence for the configurational nature of a prototypical representation. Evidence for long-term retention of specific representations was found only for form destroying concepts. This result was explained by a model involving a network of partially overlapping features.
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Date Issued: 1978
PURL: http://purl.flvc.org/fcla/dt/13941
Subject Headings: Visual perception--Testing, Concepts, Abstraction
Format: Document (PDF)

Title: Visual threat cues for autonomous navigation.
Creator: Kundur, Sridhar Reddy, Florida Atlantic University, Raviv, Daniel, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: This dissertation deals with novel vision-based motion cues called the Visual Threat Cues (VTCs), suitable for autonomous navigation tasks such as collision avoidance and maintenance of clearance. The VTCs are time-based and provide some measure for a relative change in range as well as clearance between a 3D surface and a moving observer. They are independent of the 3D environment around the observer and need almost no a-priori knowledge about it. For each VTC presented in this dissertation,...
Show moreThis dissertation deals with novel vision-based motion cues called the Visual Threat Cues (VTCs), suitable for autonomous navigation tasks such as collision avoidance and maintenance of clearance. The VTCs are time-based and provide some measure for a relative change in range as well as clearance between a 3D surface and a moving observer. They are independent of the 3D environment around the observer and need almost no a-priori knowledge about it. For each VTC presented in this dissertation, there is a corresponding visual field associated with it. Each visual field constitutes a family of imaginary 3D surfaces attached to the moving observer. All the points that lie on a particular imaginary 3D surface, produce the same value of the VTC. These visual fields can be used to demarcate the space around the moving observer into safe and danger zones of varying degree. Several approaches to extract the VTCs from a sequence of monocular images have been suggested. A practical method to extract the VTCs from a sequence of images of 3D textured surfaces, obtained by a visually fixation, fixed-focus moving camera is also presented. This approach is based on the extraction of a global image dissimilarity measure called the Image Quality Measure (IQM), which is extracted directly from the raw data of the gray level images. Based on the relative variations of the measured IQM, the VTCs are extracted. This practical approach to extract the VTCs needs no 3D reconstruction, depth information, optical flow or feature tracking. This algorithm to extract the VTCs was tested on several indoor as well as outdoor real image sequences. Two vision-based closed-loop control schemes for autonomous navigation tasks were implemented in a-priori unknown textured environments using one of the VTCs as relevant sensory feedback information. They are based on a set of IF-THEN fuzzy rules and need almost no a-priori information about the vehicle dynamics, speed, direction of motion, etc. They were implemented in real-time using a camera mounted on a six degree-of-freedom flight simulator.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/12476
Subject Headings: Computer vision, Robot vision, Visual perception
Format: Document (PDF)

Title: INDIVIDUAL DIFFERENCES IN REPRODUCTIVE MEMORY.
Creator: WHITEHURST, ROBERT EUGENE, Florida Atlantic University
Abstract/Description: Individual differences were obtained in a task requiring the reproduction of familiar and unfamiliar dot patterns. These individual differences were related to Hock's (1973) distinction between Ss emphasizing analytic vs. structural processes. For some Ss (structural), reproductive performance was facilitated by past experience, presumably because these Ss acquired a structural organizational scheme of knowledge. For the other Ss (analytic), reproductive performance was retarded by past...
Show moreIndividual differences were obtained in a task requiring the reproduction of familiar and unfamiliar dot patterns. These individual differences were related to Hock's (1973) distinction between Ss emphasizing analytic vs. structural processes. For some Ss (structural), reproductive performance was facilitated by past experience, presumably because these Ss acquired a structural organizational scheme of knowledge. For the other Ss (analytic), reproductive performance was retarded by past experience, presumably because these Ss acquired a knowledge of "distinctive" features.
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Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13748
Subject Headings: Reproduction (Psychology), Visual perception, Recognition (Psychology)
Format: Document (PDF)

Title: Squirrel Monkeys, Discrimination Learning and Sequential Testing: The Redundancy, Relative Position and Complexity of Random Shapes.
Creator: McNab, Levie J., Michels, Kenneth M., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: This study was a partial replication of one previously reported by Nash and Michels (1966). The purpose was to investigate perceptual form discrimination behavior of young squirrel monkeys as affected by contextual variables of the stimulus. The variables examined were Redundancy, Position and, of the form itself, Complexity. In addition, a sequential method of testing and recording was compared with the conventional 50-trial block procedure. Two 17 month old monkeys were tested on eight...
Show moreThis study was a partial replication of one previously reported by Nash and Michels (1966). The purpose was to investigate perceptual form discrimination behavior of young squirrel monkeys as affected by contextual variables of the stimulus. The variables examined were Redundancy, Position and, of the form itself, Complexity. In addition, a sequential method of testing and recording was compared with the conventional 50-trial block procedure. Two 17 month old monkeys were tested on eight twochoice problems in a Purdue General Test Apparatus. The problems each consisted of two slides on which pairs of random shapes were presented. The shapes within each pair of slides were held constant on the parameters investigated. One slide was designated as the positive stimulus and presented in either the right or left position in random order. The number of correct responses for the 50-trial blocks, as examined by an analysis of variance, failed to reach statistical significance for any of the variables investigated. However, graphic inspection of the data suggests general agreement with the findings of Nash and Michels (1966). In comparing the two methods of testing, the sequential test of performance (STOP) was equally as effective as the conventional method and could have provided a substantial savings in test time. Comparison of scores obtained by the two procedures shows good correlation. Although no strong conclusions can be drawn from the data, they do lead to the speculation that there is a relationship between effect and extent of redundancy, and that failure of S to make a correct response in the test situation may be the result of cue sampling rather than a failure to discriminate.
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Date Issued: 1968
PURL: http://purl.flvc.org/fau/fd/FA00012593
Subject Headings: Form perception, Visual discrimination, Monkeys--Behavior
Format: Document (PDF)

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.
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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: THE SPATIAL FRAMEWORK OF FORM PERCEPTION: INDIVIDUAL DIFFERENCES WITH RESPECT TO PHENOMENAL AND RETINAL DETERMINATION OF SPATIAL REFERENCE.
Creator: GOLD, LEON SAMUEL, Florida Atlantic University
Abstract/Description: Rock's procedure for separating the effect of objective and retinal spatial reference by varying stimulus orientation and body posture was used in conjunction with the "same-different" reaction time paradigm. It was predicted that the individual differences in perceptual processing (analytic and structural) obtained by Hock (1973) would involve different determinants of spatial reference, these being retinal reference for analytic processing and objective reference for structural processing....
Show moreRock's procedure for separating the effect of objective and retinal spatial reference by varying stimulus orientation and body posture was used in conjunction with the "same-different" reaction time paradigm. It was predicted that the individual differences in perceptual processing (analytic and structural) obtained by Hock (1973) would involve different determinants of spatial reference, these being retinal reference for analytic processing and objective reference for structural processing. The results show that analytic subjects as hypothesized, referenced perceptual information to a retinal coordinate system. Structural subjects however, seemed to reference perceptual information to both objective and retinal coordinates. The results for structural subjects were attributed to the unexpected finding that subjects who were structural while upright, became analytic when in a reclining position. The latter finding suggested that Rock's methodology for separating the effects of retinal and objective orientation relies on the subjects employing the same mode of processing in all bodily postures.
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Date Issued: 1974
PURL: http://purl.flvc.org/fcla/dt/13649
Subject Headings: Form perception, Orientation (Psychology), Recognition (Psychology), Visual perception
Format: Document (PDF)

Title: COLLISION FREE NAVIGATION IN 3D UNSTRUCTURED ENVIRONMENTS USING VISUAL LOOMING.
Creator: Yepes, Juan David Arango, Raviv, Daniel, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
Abstract/Description: Vision is a critical sense for many species, with the perception of motion being a fundamental aspect. This aspect often provides richer information than static images for understanding the environment. Motion recognition is a relatively simple computation compared to shape recognition. Many creatures can discriminate moving objects quite well while having virtually no capacity for recognizing stationary objects. Traditional methods for collision-free navigation require the reconstruction of...
Show moreVision is a critical sense for many species, with the perception of motion being a fundamental aspect. This aspect often provides richer information than static images for understanding the environment. Motion recognition is a relatively simple computation compared to shape recognition. Many creatures can discriminate moving objects quite well while having virtually no capacity for recognizing stationary objects. Traditional methods for collision-free navigation require the reconstruction of a 3D model of the environment before planning an action. These methods face numerous limitations as they are computationally expensive and struggle to scale in unstructured and dynamic environments with a multitude of moving objects. This thesis proposes a more scalable and efficient alternative approach without 3D reconstruction. We focus on visual motion cues, specifically ’visual looming’, the relative expansion of objects on an image sensor. This concept allows for the perception of collision threats and facilitates collision-free navigation in any environment, structured or unstructured, regardless of the vehicle’s movement or the number of moving objects present.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014239
Subject Headings: Motion perception (Vision), Collision avoidance systems, Visual perception
Format: Document (PDF)

Title: Temporal and spatial determinants of induced shifts in perceived position.
Creator: Eastman, Kathleen E., Florida Atlantic University, Hock, Howard S.
Abstract/Description: The effects of the onset, offset, and sustained presence of inducing lines on the perceived position of test lines were independently investigated in a vernier alignment task. For spatial separations larger than 2.3 min, repulsion effects were always observed. For the smallest spatial separation, 2.3 min, the effect of the inducing lines was attraction for 0 and 195 SOAs. Minimal attraction was observed for a 3000 SOA. However, when the offset effect was isolated using the 3000 SOA and a 0...
Show moreThe effects of the onset, offset, and sustained presence of inducing lines on the perceived position of test lines were independently investigated in a vernier alignment task. For spatial separations larger than 2.3 min, repulsion effects were always observed. For the smallest spatial separation, 2.3 min, the effect of the inducing lines was attraction for 0 and 195 SOAs. Minimal attraction was observed for a 3000 SOA. However, when the offset effect was isolated using the 3000 SOA and a 0 ISI, a large repulsion effect was observed for the 2.3 min spatial separation, as well as for the larger spatial separations. These results indicate that the temporal separation between visual elements is as important in determining perceived position as their spatial separation, which has been demonstrated in earlier studies (Badcock & Westheimer, 1985). A differential gradient model is proposed which accounts for these findings in terms of excitatory and inhibitory interactions within an ensemble of position-sensitive units.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14897
Subject Headings: Visual perception, Space perception, Motion perception (Vision), Figure-ground perception
Format: Document (PDF)

Title: Cyclical Variations in Object and Spatial-based Attention.
Creator: Ray, Subhosit, Sheremata, Summer, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description: Spatial-based attention is shown to vary in strength over short intervals of time. Whether object-based selection also has similar temporal variability is not known. Egly, Driver and Rafal (1994) demonstrated using 2-rectangle displays how both spatial and object-based selection engages in processing of a visual scene. In Experiment-1 using the 2-rectangle paradigm we measured temporal variability of target detection by presenting targets at a variable SOA. In Experiment-2, we used 4-squares...
Show moreSpatial-based attention is shown to vary in strength over short intervals of time. Whether object-based selection also has similar temporal variability is not known. Egly, Driver and Rafal (1994) demonstrated using 2-rectangle displays how both spatial and object-based selection engages in processing of a visual scene. In Experiment-1 using the 2-rectangle paradigm we measured temporal variability of target detection by presenting targets at a variable SOA. In Experiment-2, we used 4-squares to preclude any object-based selection and measured temporal variability in target detection at similar locations as in Experiment-1. We found target detection to be periodic in delta and theta hertz rhythm in both Experiment-1 and Experiment-2 upon comparing corresponding cue-valid and same-object locations. Similar spectral profiles across experiments indicate a split-spotlight of spatial attention that rhythmically monitors cue-valid and other invalid locations. Future experiments are needed to determine whether object-based selection is periodic in nature.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013563
Subject Headings: Attention, Visual Perception, Space perception, Selective attention, Selectivity (Psychology), Visual system
Format: Document (PDF)

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