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Radial bias for orientation and direction of motion modulates access to visual awareness during continuous flash suppression
Title
Radial bias for orientation and direction of motion modulates access to visual awareness during continuous flash suppression.
Creator
Hong, Sang Wook
Date Issued
2015-01-08
PURL
http://purl.flvc.org/fau/fd/FAUIR000149
Format
Citation
Color updating on the apparent motion path
Title
Color updating on the apparent motion path.
Creator
Chong, E., Hong, Sang Wook, Shim, W. M.
Date Issued
2014-12-19
PURL
http://purl.flvc.org/fau/fd/FAUIR000146
Format
Citation
Sex differences in perception of invisible facial expressions
Title
Sex differences in perception of invisible facial expressions.
Creator
Hong, Sang Wook, Yoon, K. Lira, Peaco, Sophia
Date Issued
2015-04-02
PURL
http://purl.flvc.org/fau/fd/FAUIR000150
Format
Citation
Semantic-based crossmodal processing during visual suppression
Title
Semantic-based crossmodal processing during visual suppression.
Creator
Cox, Dustin, Hong, Sang Wook
Date Issued
2015-06-02
PURL
http://purl.flvc.org/fau/fd/FAUIR000147
Format
Citation
Motion Alters Color Appearance
Title
Motion Alters Color Appearance.
Creator
Hong, Sang Wook, Kang, Min-Suk
Abstract/Description
Chromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show that when one colored object moves around an identical stationary object, the perceived saturation of the stationary object decreases dramatically whereas the saturation of the moving object increases. These color appearance shifts in the opposite directions suggest that normalization induced by the object’s motion may mediate...
Show moreChromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show that when one colored object moves around an identical stationary object, the perceived saturation of the stationary object decreases dramatically whereas the saturation of the moving object increases. These color appearance shifts in the opposite directions suggest that normalization induced by the object’s motion may mediate the shift in color appearance. We ruled out other plausible alternatives such as local adaptation, attention, and transient neural responses that could explain the color shift without assuming interaction between color and motion processing. These results demonstrate that the motion of an object affects both its own color appearance and the color appearance of a nearby object, suggesting a tight coupling between color and motion processing.
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Date Issued
2016-12-08
PURL
http://purl.flvc.org/fau/fd/FAUIR000022
Format
Citation
Visual context processing in bipolar disorder: a comparison with schizophrenia
Title
Visual context processing in bipolar disorder: a comparison with schizophrenia.
Creator
Yang, Eunice, Tadin, Duje, Glasser, Davis M., Hong, Sang Wook, Blake, Randolph, Park, Sohee
Date Issued
2013
PURL
http://purl.flvc.org/fau/fd/FAUIR000145
Format
Citation
Acute Alcohol Drinking Promotes Piecemeal Percepts during Binocular Rivalry
Title
Acute Alcohol Drinking Promotes Piecemeal Percepts during Binocular Rivalry.
Creator
Cao, Dingcai, Zhuang, Xiaohua, Kang, Para, Hong, Sang Wook, King, Andrea C.
Date Issued
2016-04-06
PURL
http://purl.flvc.org/fau/fd/FAUIR000148
Format
Citation
Traveling Waves of Dominance in Motion-Induced Blindness
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)
Investigating the Temporal Dynamics of Advanced Information Processing During Interocular Suppression Using Electroencephalography and Pattern Classification
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)
THE DETERMINANTS OF GROUPING DURING BINOCULAR RIVALRY
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)
THE CAUSAL ROLE OF THETA OSCILLATIONS IN THE FRONTOPARIETAL NETWORK ON COGNITIVE FLEXIBILITY
Title
THE CAUSAL ROLE OF THETA OSCILLATIONS IN THE FRONTOPARIETAL NETWORK ON COGNITIVE FLEXIBILITY.
Creator
Yoon, Yosun, Hong, Sang Wook, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
Cognitive flexibility is crucial for efficient goal-directed behavior, especially in rapidly changing environments. While recent studies have consistently shown enhanced theta power and synchronization in the frontoparietal network during flexible task-switching, direct evidence establishing a causal link between theta-rhythm brain oscillation and cognitive flexibility remains limited. In this study, we applied transcranial alternating current stimulation (tACS) to the frontoparietal network...
Show moreCognitive flexibility is crucial for efficient goal-directed behavior, especially in rapidly changing environments. While recent studies have consistently shown enhanced theta power and synchronization in the frontoparietal network during flexible task-switching, direct evidence establishing a causal link between theta-rhythm brain oscillation and cognitive flexibility remains limited. In this study, we applied transcranial alternating current stimulation (tACS) to the frontoparietal network at a theta frequency (6 Hz) with a phase difference of either 0° (inphase) or 180° (antiphase) to explore its impact on task-switching performance. The results showed no significant tACS modulation effects on switch costs or neural oscillatory synchronization in the frontoparietal network. However, a consistent negative correlation was observed between frontoparietal theta power in the early time window of cue-target interval and task switching performance, implying the close relationship between proactive control in task switching and frontoparietal theta activities.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014340
Subject Headings
Theta Rhythm, Cognition, Cognitive psychology
Format
Document (PDF)
FACIAL EXPRESSION PROCESSING IN AUTISM SPECTRUM DISORDER AS A FUNCTION OF ALEXITHYMIA: AN EYE MOVEMENT STUDY
Title
FACIAL EXPRESSION PROCESSING IN AUTISM SPECTRUM DISORDER AS A FUNCTION OF ALEXITHYMIA: AN EYE MOVEMENT STUDY.
Creator
Escobar, Brian, Hong, Sang Wook, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
The perception and interpretation of faces provides individuals with a wealth of knowledge that enables them to navigate their social environments more successfully. Prior research has hypothesized that the decreased facial expression recognition (FER) abilities observed in autism spectrum disorder (ASD) may be better explained by comorbid alexithymia, the alexithymia hypothesis. The present study sought to further examine the alexithymia hypothesis by collecting data from 59 participants and...
Show moreThe perception and interpretation of faces provides individuals with a wealth of knowledge that enables them to navigate their social environments more successfully. Prior research has hypothesized that the decreased facial expression recognition (FER) abilities observed in autism spectrum disorder (ASD) may be better explained by comorbid alexithymia, the alexithymia hypothesis. The present study sought to further examine the alexithymia hypothesis by collecting data from 59 participants and examining FER performance and eye movement patterns for ASD and neurotypical (NT) individuals while controlling for alexithymia severity. Eye movement-related differences and similarities were examined via eye tracking in conjunction with statistical and machine-learning-based pattern classification analysis. In multiple different classifying conditions, where the classifier was fed 1,718 scanpath images (either at spatial, spatial-temporal, or spatial temporal-ordinal levels) for high-alexithymic ASD, high-alexithymicvi NT, low-alexithymic ASD, and low-alexithymic NT, we could accurately decode significantly above chance level. Additionally, in the cross-decoding analysis where the classifier was fed 1,718 scanpath images for high- and low alexithymic ASD individuals and tested on high- and low-alexithymic NT individuals, results showed that classification accuracy was significantly above chance level when using spatial images of eye movement patterns. Regarding FER performance results, we found that ASD and NT groups performed similarly, but at lower intensities of expressions, ASD individuals performed significantly worse than NT individuals. Together, these findings suggest that there may be eye-movement related differences between ASD and NT individuals, which may interact with alexithymia traits.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014358
Subject Headings
Autism Spectrum Disorder, Machine learning, Facial expression, Alexithymia, Eye tracking
Format
Document (PDF)
The Effects of Dichoptic and Isoluminant-Chromatic Stimuli on the Perception of Object and Objectless Motion
Title
The Effects of Dichoptic and Isoluminant-Chromatic Stimuli on the Perception of Object and Objectless Motion.
Creator
Seifert, Matthew S., Hong, Sang Wook, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
Visual motion can be conveyed by a variety of information sources in the environment, and those types of information may be detected at various levels by different motion-perceiving mechanisms in the visual system. High-level visual information has been demonstrated to have 3rd order, or salience-based properties (Lu & Sperling, 1995). The perceptual system they describe that computes motion from these types of information shares several characteristics with Hock and colleagues' counterchange...
Show moreVisual motion can be conveyed by a variety of information sources in the environment, and those types of information may be detected at various levels by different motion-perceiving mechanisms in the visual system. High-level visual information has been demonstrated to have 3rd order, or salience-based properties (Lu & Sperling, 1995). The perceptual system they describe that computes motion from these types of information shares several characteristics with Hock and colleagues' counterchange detection system, notably flexibility with respect to types of input from which motion can be computed, which comes at the cost of diminished processing speed. The mechanism of counterchange detection is well suited to processing visual features often present in environmental scenes, e.g., objects and surfaces, and may be a mechanism of 3rd order motion. Consistent with reported properties of 3rd order motion, the current experiments tested count erchange-, luminance-, and color-based motion stimuli with 3 objectives: to identify whether the 3 systems framework generalizes beyond the stimulus type with which it was defined, to test whether counterchange shares similarities with the 3rd order system with respect to dichoptic integration, and perception of isoluminant color-based motion, and to test subjectively objectless sources of motion-defining information (spreading luminance and hue) to see if they display properties of the 1st order system derived from sine wave gratings. Results indicate that counterchange-based stimuli displayed predicted properties of dichoptic integration, and perception at isoluminance, but putative 1st order (spreading) stimuli also displayed these properties. This may suggest that object-like surfaces, even when not directly the source of motion information, can contribute to computation of motion. Further, these results highlight the difficulty of generalizing from one theoretical framework to another, and specifically, of psychophysically testing high-level information while isolating contributions from low level information upon which high level visual stimuli are built.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00004545, http://purl.flvc.org/fau/fd/FA00004545
Subject Headings
Movement, Psychology of, Perceptual motor processes, Physiological optics, Space and time, Visual perception
Format
Document (PDF)
THE ASSESMENT OF THE ROLE OF MICROSACCADIC EYE MOVEMENTS IN BISTABLE MOTION PERCEPTION
Title
THE ASSESMENT OF THE ROLE OF MICROSACCADIC EYE MOVEMENTS IN BISTABLE MOTION PERCEPTION.
Creator
Romulus, Darwin, Hong, Sang Wook, Florida Atlantic University, Center for Complex Systems and Brain Sciences, Charles E. Schmidt College of Science
Abstract/Description
Even during fixation, the eye is rarely still, as miniature eye movements continue to occur within fixational periods of the eye. These miniature movements are referred to as fixational eye movements. Microsaccades are one of the three types of fixational eye movements that have been identified. Microsaccades have been attributed to different visual processes/phenomena such as fixation stability, perceptual fading, and multistable perception. Still, debates surrounding the functional role of...
Show moreEven during fixation, the eye is rarely still, as miniature eye movements continue to occur within fixational periods of the eye. These miniature movements are referred to as fixational eye movements. Microsaccades are one of the three types of fixational eye movements that have been identified. Microsaccades have been attributed to different visual processes/phenomena such as fixation stability, perceptual fading, and multistable perception. Still, debates surrounding the functional role of microsaccades in vision ensued, as many of the findings from earlier microsaccade reports contradict one another and the polarity in the field caused by these debates led many to believe that microsaccades do not hold a necessary/specialized role in vision. To gain a deeper understanding of microsaccades and its relevance in vision, we sought out to assess the role of microsaccades in bistable motion perception in our behavioral/eye-tracking study. Observers participated in an eye-tracking experiment where they were asked to complete a motion discrimination task while viewing a bistable apparent motion stimuli. The collected eye-tracking data was then used to train a classification model to predict directions of illusory motion perceived by observers. We found that small changes in gaze position during fixation, occurring within or outside microsaccadic events, predicted the direction of motion pattern imposed by the motion stimuli. Our findings suggest that microsaccades and fixational eye movements are correlated with motion perception and that miniature eye movements occurring during fixation may have relevance in vision.
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Date Issued
2021
PURL
http://purl.flvc.org/fau/fd/FA00013799
Subject Headings
Eye--Movements, Saccadic eye movements, Eye tracking
Format
Document (PDF)
TEMPORAL DYNAMICS OF NEGATIVE AND POSITIVE FACIAL EXPRESSION PROCESSING
Title
TEMPORAL DYNAMICS OF NEGATIVE AND POSITIVE FACIAL EXPRESSION PROCESSING.
Creator
Escobar, Brian E., Hong, Sang Wook, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
The perception and interpretation of faces provides individuals with a wealth of knowledge that enables them to navigate their social environments more successfully. The present study examined the temporal dynamics of valence information from emotional facial expressions using electroencephalogram (EEG) in conjunction with multi-variate pattern analysis (MVPA). In multiple different classifying conditions, it was demonstrated that when decoding for a positively- vs. a negatively- vs. a...
Show moreThe perception and interpretation of faces provides individuals with a wealth of knowledge that enables them to navigate their social environments more successfully. The present study examined the temporal dynamics of valence information from emotional facial expressions using electroencephalogram (EEG) in conjunction with multi-variate pattern analysis (MVPA). In multiple different classifying conditions, it was demonstrated that when decoding for a positively- vs. a negatively- vs. a neutrally-valenced expression, above chance level decoding accuracy occurs sooner when compared to instances of decoding for a negatively- vs. a negatively- vs. a neutrally-valenced expression. Additionally, results showed that classification accuracy as measured by percentage of correct responses was higher in the classification condition with the positively-valenced expression versus the one with two negatively-valenced expressions. Together, these finding suggest that neural processing of facial expression may occur hierarchical manner, in that categorization between between-valence (positive vs. negative) facial expressions precedes categorization among within-valence.
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Date Issued
2021
PURL
http://purl.flvc.org/fau/fd/FA00013862
Subject Headings
Facial expression, Electroencephalography, Facial expression--Research
Format
Document (PDF)