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The field of consciousness studies has yielded various—sometimes contradicting—accounts regarding the function of consciousness, ranging from denying it has such function to claiming that any high-level cognitive function requires consciousness. Empirical findings supporting both accounts were reported, yet some of them have been recently revisited based on failures to replicate. Here, we aimed at replicating a remarkable finding reported by Ric and Muller (2012); participants were able to follow an unseen instruction, integrate it with a subsequently presented pair of unseen digits, and accordingly either add the digits (resulting in a priming effect), or simply represent them. This finding thus demonstrates unconscious task-switching, temporal integration (involving mental chaining), and arithmetic operation. Finding such high-level processes in the absence of awareness is of pivotal importance to our understanding of consciousness, as it challenges prominent theories in the field (e.g., the global neuronal workspace). Accordingly, in light of the self-correction wave in psychological science in general and in the field of consciousness studies in particular, we report here a preregistered replication aimed at testing the reproducibility of this finding, while also better controlling for subjects' awareness of both the instruction and the digits. Across two highly powered experiments, our results failed to replicate the original effect. We, therefore, conclude that the current evidence does not support the claim that arithmetic operations (specifically, addition) can be flexibly initiated without awareness, in line with the current arguments for a more limited scope of unconscious processing. Public Significance Statement: A major open question in psychology is why we developed consciousness. Why did evolution grant us the ability to experience some processes, and is there any functional benefit to having such conscious experiences? One way to study the latter question focuses on characterizing what cannot be done without consciousness. Here, we re-visit a finding from 2012 showing that people can do math unconsciously in a flexible manner (i.e., following invisible instructions). In two highly powered experiments, we failed to find the same effect. We conclude that consciousness may indeed be necessary for tasks that require integrating different kinds of information in a complex and flexible manner, in line with several theories of consciousness. [ABSTRACT FROM AUTHOR]

Our ability to identify an object is often impaired by the presence of preceding and/or succeeding task-irrelevant items. Understanding this temporal interference is critical for any theoretical account of interference across time and for minimizing its detrimental effects. Therefore, we used the same sequences of 3 orientation items, orientation estimation task, and computational models, to examine temporal interference over both short (<150  ms; visual masking) and long (175–475  ms; temporal crowding) intervals. We further examined how inter-item similarity modifies these different instances of temporal interference. Qualitatively different results emerged for interference of different scales. Interference over long intervals mainly degraded the precision of the target encoding while interference over short intervals mainly affected the signalto-noise ratio. Although both interference instances modulated substitution errors (reporting a wrong item) and were alleviated with dissimilar items, their characteristics were markedly disparate. These findings suggest that different mechanisms mediate temporal interference of different scales. [ABSTRACT FROM AUTHOR]

Divisive Normalization and the Wilson–Cowan equations are well-known influential models of nonlinear neural interaction (Carandini and Heeger in Nat Rev Neurosci 13(1):51, 2012; Wilson and Cowan in Kybernetik 13(2):55, 1973). However, they have been always treated as different approaches and have not been analytically related yet. In this work, we show that Divisive Normalization can be derived from the Wilson–Cowan dynamics. Specifically, assuming that Divisive Normalization is the steady state of the Wilson–Cowan differential equations, we find that the kernel that controls neural interactions in Divisive Normalization depends on the Wilson–Cowan kernel but also depends on the signal. A standard stability analysis of a Wilson–Cowan model with the parameters obtained from our relation shows that the Divisive Normalization solution is a stable node. This stability suggests the appropriateness of our steady state assumption. The proposed theory provides a mechanistic foundation for the suggestions that have been done on the need of signal-dependent Divisive Normalization in Coen-Cagli et al. (PLoS Comput Biol 8(3):e1002405, 2012). Moreover, this theory explains the modifications that had to be introduced ad hoc in Gaussian kernels of Divisive Normalization in Martinez-Garcia et al. (Front Neurosci 13:8, 2019) to reproduce contrast responses in V1 cortex. Finally, the derived relation implies that the Wilson–Cowan dynamics also reproduce visual masking and subjective image distortion, which up to now had been explained mainly via Divisive Normalization. [ABSTRACT FROM AUTHOR]

Visual masking plays a crucial role in optimizing distortion position and intensity in information hiding. However, existing studies on stereoscopic visual masking effects are insufficient and may not align with human perceptual thresholds. This paper aims to fill this research gap by conducting psychophysical experiments to investigate binocular target-to-target visual masking effects that leverage the perceptual mechanisms of the human eye, leading to precise determination of masking thresholds. The experiments involve adjusting the orientation of noise gratings in two scenarios: binocular combination and binocular rivalry, and quantitatively measure the masking thresholds for various binocular noise orientations. Experiment I focuses on investigating the intraocular target-to-target orientation modulation effects in binocular combination, while Experiments II and III explore the interocular target-to-target masking effects and orientation modulation effects in binocular rivalry. The findings indicate that the target-to-target masking effects can increase stereoscopic visual masking thresholds by 23% to 65% compared to previous context-to-target masking effects, while ensuring the noise remains invisible. These findings have practical implications for information hiding technologies related to stereoscopic images and videos. By selecting the orientation, position, and intensity for distortion, improvements can be made in metrics such as embedding strength and capacity while ensuring high-quality display. [ABSTRACT FROM AUTHOR]

Our ability to identify an object is often impaired by the presence of preceding and/or succeeding task-irrelevant items. Understanding this temporal interference is critical for any theoretical account of interference across time and for minimizing its detrimental effects. Therefore, we used the same sequences of 3 orientation items, orientation estimation task, and computational models, to examine temporal interference over both short (

Chinese citrus fly, Bactrocera minax (Enderlein; Diptera: Tephritidae), which attacks citrus fruits in China is one of the most important international quarantine pests. Understanding the function of visual organs is the basis of trapping and prevention for management of pests such as B. minax. In this study, take-off ability and crawling experiments were conducted using 5 groups of B. minax all with different visual blinding treatments (blind ocelli, blind left compound eye, blind right compound eye, blind compound eyes, blind ocelli and compound eyes) and a corresponding control that was not blinded. We found that both the left and right compound eyes played a critical role in the vertical and horizontal crawling behavior of B. minax, while the ocelli did not. However, the perception of ambient light by ocelli or either compound eye had a significant influence on take-off of B. minax. Elucidating the monocular and compound eye functions of B. minax will help us to develop better visual traps for this important pest of citrus. La mosca china de los cítricos, Bactrocera minax (Enderlein; Diptera: Tephritidae), que ataca las frutas de cítricos en China es una de las plagas cuarentenarias internacionales más importantes. El comprender la función de los órganos visuales es la base del trampeo y la prevención para el manejo de plagas como B. minax. En este estudio, se realizaron pruebas de capacidad de despegue y experimentos de rastreo utilizando 5 grupos de B. minax, todos con diferentes tratamientos de cegamiento visual (ocelli ciego, ojo compuesto izquierdo ciego, ojo compuesto derecho ciego, ojos compuestos ciegos, ocelli ciego y ojos compuestos) y un control correspondiente que no fue cegado. Descubrimos que tanto el ojo compuesto izquierdo como el derecho desempeñaron un papel fundamental en el comportamiento de rastreo vertical y horizontal de B. minax, mientras que el ocelli no lo hizo. Sin embargo, la percepción de la luz ambiental por parte del ocelli o del ojo compuesto tuvo una influencia significativa en el despegue de B. minax. El esclarecer las funciones oculares monoculares y compuestas de B. minax nos ayudará a desarrollar mejores trampas visuales para esta importante plaga de los cítricos. [ABSTRACT FROM AUTHOR]

Within the realm of consciousness research, different methods of measuring the content of visual awareness are used: On the one hand, subjective measures require a report of sensory experiences related to a stimulus. On the other hand, objective measures rely on the observer’s performance to accurately detect or discriminate the stimulus. The most appropriate measure of awareness is currently debated. To contribute to this debate, we review findings on the relation between subjective and objective measures of awareness. Although subjective measures sometimes lag behind objective measures, a substantial number of studies demonstrates a convergence of measures. Based on the reviewed studies, we identify five aspects relevant for achieving a convergence of measures. Future research could then identify and empirically test the boundary conditions, under which a convergence or divergence of subjective and measures of awareness is observed.

• Attentional load and masking lead to modulations in early and late ERP components correlated with the changes in behavioral performance values. • The modulations in each component were not uniform and distinct in terms of dependency on masking and attentional load. • The diverse nature of masking and attentional influences on sensory processing. Visual masking and attentional selection play important roles in controlling information processing for perception. Using an experimental design combining metacontrast with attentional load, we investigated the time course of changes in event-related potentials under different attentional load and masking conditions. The behavioral results indicated significant effects of attentional load on masking functions (i.e., masking strength as a function of stimulus onset asynchrony between target and mask). The analyses of neural activities revealed significant effects of masking and attentional load on early components located over occipital and parieto-occipital scalp sites. There were also significant modulations in the late positivity range centered over centro-parietal electrodes. However, the nature of modulations in early and late components was different. These findings overall highlight the diverse nature of masking and attentional influences on visual processing, particularly suggesting that attentional load in the visual field may have distinct effects at different stages of perceptual processing. [ABSTRACT FROM AUTHOR]

The existing temporal domain JND(just noticeable distortion) models are not sufficient to depict the interaction between temporal parameters and HVS characteristics, leading to insufficient accuracy of the spatial-temporal JND model.To solve this problem, feature parameters that can accurately describe the temporal characteristics of the video were explored and extracted, as well as a homogenization method for fusing heterogeneous feature parameters, and the temporal domain JND model based on this was improved.The feature parameters were investigated including foreground and background motion, temporal duration along the motion trajectory, residual fluctuation intensity along motion trajectory and adjacent inter-frame prediction residual, etc., which were used to characterize the temporal characteristics.Probability density functions for these feature parameters in the perception sense according to the HVS(human visual system) characteristics were proposed, and uniformly mapping the heterogeneous feature parameters to the scales of self-information and information entropy to achieve a homogeneous fusion measurement.The coupling method of visual attention and masking was explored from the perspective of energy distribution, and the temporal-domain JND weight model was constructed accordingly.On the basis of the spatial JND threshold, the temporal domain weights was integrated to develop a more accurate spatial-temporal JND model.In order to evaluate the performance of the spatiotemporal JND model, a subjective quality evaluation experiment was conducted.Experimental results justify the effectiveness of the proposed model.

The phrase "amari-akaghi" in my Akpoha, Igbo village, is tied around the metaphor of women and masking culture in Igbo society. This phrase alludes to women's knowledge of the workings of masquerades yet they cannot talk about it openly. I have weaved this paper around the perception of the "knowledge of the unknown" as touted and exemplified by Okonkwo's wives in Achebe's Things Fall Apart. Achebe in his seminal work revealed the position of the egwugwu masquerade tradition vis-à-vis women in Umuofia. Literatures on masquerade and women also suggest that women know much about the inner workings and secrecy associated with masquerade but cannot openly discuss it. However, no known effort has been dedicated to investigating this phenomenon in Achebe's Things Fall Apart against the reality of the concept of "amari-akaghi" in Akpoha, Igbo village. This paper, therefore, subjects Things Fall Apart to textual analyses through deconstruction of the narration. I conclude with valid interrogation of works, including the primary resource of this paper, that women in many Igbo villages of old and those represented in Achebe's Umuofia have always known and thought about the inscrutability of masquerades but have constantly kept to themselves to avoid upsetting the peace of their society and attracting ugly repercussions. This knowledge of the unknown exhibited by women in both societies, as investigated in this essay, had ensured cordial shared gender roles, which guaranteed peaceful coexistence in Igbo society. [ABSTRACT FROM AUTHOR]

Evoked response potentials are often divided up into numerous components, each with their own body of literature. But is there less variety than we might suppose? In this study, we nudge one component into looking like another. Both the N170 and recognition potential (RP) are N1 components in response to familiar objects. However, the RP is often measured with a forward mask that ends at stimulus onset whereas the N170 is often measured with no masking at all. This study investigates how inter‐stimulus interval (ISI) may delay and distort the N170 into an RP by manipulating the temporal gap (ISI) between forward mask and target. The results revealed reverse relationships between the ISI on the one hand, and the N170 latency, single‐trial N1 jitter (an approximation of N1 width) and reaction time on the other hand. Importantly, we find that scalp topographies have a unique signature at the N1 peak across all conditions, from the longest gap (N170) to the shortest (RP). These findings prove that the mask‐delayed N1 is still the same N170, even under conditions that are normally associated with a different component like the RP. In general, our results suggest greater synthesis in the study of event related potential components. [ABSTRACT FROM AUTHOR]

It has not been clarified if attention influences perception of targets in visual masking. Three forms of common masks (random pattern, para-/metacontrast, and four dots) were thus chosen in the present study and presented with character targets in three temporal sequences (forward, backward, and sandwiched mask or forward-backward mask combination). In order to pinpoint the level of processing where masking arises, character targets were varied in depth of processing from random arrangements of strokes up to real Chinese characters. The attentional influence was examined under perceptual discrimination and lexical decision tasks, respectively. The results revealed significant interactions among four factors (mask form, temporal sequence, depth of processing, and task). Identification of character targets in each form of mask sequence varied with task demand, with greater suppression in the perceptual discrimination task. These findings suggested that attentional demand can bias processing in favor of task-related information in visual masking. Variations in masking effects may be contributed by both attentional demand and spatio-temporal interaction. [ABSTRACT FROM AUTHOR]

The existing temporal domain JND(just noticeable distortion) models are not sufficient to depict the interaction between temporal parameters and HVS characteristics, leading to insufficient accuracy of the spatial-temporal JND model. To solve this problem, feature parameters that can accurately describe the temporal characteristics of the video were explored and extracted, as well as a homogenization method for fusing heterogeneous feature parameters, and the temporal domain JND model based on this was improved. The feature parameters were investigated including foreground and background motion, temporal duration along the motion trajectory, residual fluctuation intensity along motion trajectory and adjacent inter-frame prediction residual, etc., which were used to characterize the temporal characteristics. Probability density functions for these feature parameters in the perception sense according to the HVS(human visual system) characteristics were proposed, and uniformly mapping the heterogeneous feature parameters to the scales of self-information and information entropy to achieve a homogeneous fusion measurement. The coupling method of visual attention and masking was explored from the perspective of energy distribution, and the temporal-domain JND weight model was constructed accordingly. On the basis of the spatial JND threshold, the temporal domain weights was integrated to develop a more accurate spatial-temporal JND model. In order to evaluate the performance of the spatiotemporal JND model, a subjective quality evaluation experiment was conducted. Experimental results justify the effectiveness of the proposed model. [ABSTRACT FROM AUTHOR]

It is widely assumed that subliminal word priming is case insensitive and that a short SOA (< 100 ms) is required to observe any effects. Here we attempted to replicate results from an influential study with the inclusion of a longer SOA to re-examine these assumptions. Participants performed a semantic categorisation task on visible word targets that were preceded either 64 or 192 ms by a subliminal prime. The prime and target were either the same or different word and could appear in the same or different case. We confirmed the presence of subliminal word priming (same word < different word reaction times). The word priming effect did not differ when case was the same or different, which supports case insensitive word priming. However, there was a general facilitation effect driven by case (same case < different case). Finally, there was a significant difference between the two SOA conditions; however, there were no interactions between SOA and any other factor, demonstrating that subliminal priming did not differ between short and long SOAs. The results demonstrate that word priming is case insensitive but that there is nevertheless an overall facilitation when words, regardless if they are repeated or not, are presented in the same case. This facilitation in case may reflect modularity in the low-level processing of the visual characteristics of words. [ABSTRACT FROM AUTHOR]

Metacontrast masking is a powerful illusion to investigate the dynamics of perceptual processing and to control conscious visual perception. However, the neural mechanisms underlying this fundamental investigative tool are still debated. In the present study, we examined metacontrast masking across different contrast polarities by employing a contour discrimination task combined with EEG (Electroencephalography). When the target and mask had the same contrast polarity, a typical U-shaped metacontrast function was observed. A change in mask polarity (i.e., opposite mask polarity) shifted this masking function to a monotonic increasing function such that the target visibility was strongly suppressed at stimulus onset asynchronies less than 50 ms. This transition in metacontrast function has been typically interpreted as an increase in intrachannel inhibition of the sustained activities functionally linked to object visibility and identity. Our EEG analyses revealed an early (160–300 ms) and a late (300–550 ms) spatiotemporal cluster associated with this effect of polarity. The early cluster was mainly over occipital and parieto-occipital scalp sites. On the other hand, the later modulations of the evoked activities were centered over parietal and centro-parietal sites. Since both of these clusters were beyond 160 ms, the EEG results point to late recurrent inhibitory mechanisms. Although the findings here do not directly preclude other proposed mechanisms for metacontrast, they highlight the involvement of recurrent intrachannel inhibition in metacontrast masking. [ABSTRACT FROM AUTHOR]

It has not been clarified if attention influences perception of targets in visual masking. Three forms of common masks (random pattern, para-/metacontrast, and four dots) were thus chosen in the present study and presented with character targets in three temporal sequences (forward, backward, and sandwiched mask or forward-backward mask combination). In order to pinpoint the level of processing where masking arises, character targets were varied in depth of processing from random arrangements of strokes up to real Chinese characters. The attentional influence was examined under perceptual discrimination and lexical decision tasks, respectively. The results revealed significant interactions among four factors (mask form, temporal sequence, depth of processing, and task). Identification of character targets in each form of mask sequence varied with task demand, with greater suppression in the perceptual discrimination task. These findings suggested that attentional demand can bias processing in favor of task-related information in visual masking. Variations in masking effects may be contributed by both attentional demand and spatio-temporal interaction.

Within the realm of consciousness research, different methods of measuring the content of visual awareness are used: On the one hand, subjective measures require a report of sensory experiences related to a stimulus. On the other hand, objective measures rely on the observer's performance to accurately detect or discriminate the stimulus. The most appropriate measure of awareness is currently debated. To contribute to this debate, we review findings on the relation between subjective and objective measures of awareness. Although subjective measures sometimes lag behind objective measures, a substantial number of studies demonstrates a convergence of measures. Based on the reviewed studies, we identify five aspects relevant for achieving a convergence of measures. Future research could then identify and empirically test the boundary conditions, under which a convergence or divergence of subjective and measures of awareness is observed., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Image quality assessment is a critical problem for image compression, which can be utilized as a guidance for image compression and codec evaluation. In this paper, we propose a full reference image quality assessment (IQA) algorithm to measure the perceptual quality of compressed images. The proposed IQA model utilizes a data-driven transform, multi-stage Karhunen-Loeve Transform (MS-KLT), as a feature extractor to decompose both reference and compressed images into feature domain, where the importance of feature distortions in different spectral components to human visual system (HVS) is easy to distinguish. Accordingly, an efficient weighting strategy is proposed to reflect the importance of feature distortions based on the energy of transformed coefficients. Considering HVS characteristics, weighted spatial masking effect is derived from both local and global perspectives. In addition, to avoid influences of random noises, a local adaptive low-pass filtering process is applied as a pre-processing operation. Extensive experimental results on popular datasets show that our proposed method correlates better with the subjective results compared with the state-of-the-art algorithms. Moreover, the proposed method behaves more robustly compared with existing methods, and achieves top-ranking performance on different IQA datasets. [ABSTRACT FROM AUTHOR]

Linguistic labels exert a particularly strong top-down influence on perception. The potency of this influence has been ascribed to their ability to evoke category-diagnostic features of concepts. In doing this, they facilitate the formation of a perceptual template concordant with those features, effectively biasing perceptual activation towards the labelled category. In this study, we employ a cueing paradigm with moving, point-light stimuli across three experiments, in order to examine how the number of biological motion features (form and kinematics) encoded in lexical cues modulates the efficacy of lexical top-down influence on perception. We find that the magnitude of lexical influence on biological motion perception rises as a function of the number of biological motion-relevant features carried by both cue and target. When lexical cues encode multiple biological motion features, this influence is robust enough to mislead participants into reporting erroneous percepts, even when a masking level yielding high performance is used. [ABSTRACT FROM AUTHOR]

Due to its provable security and remarkable device-independence, masking has been widely accepted as a noteworthy algorithmic-level countermeasure against side-channel attacks. However, relatively high cost of masking severely limits its applicability. Considering the high tackling complexity of non-linear operations, most masked AES implementations focus on the security and cost reduction of masked S-boxes. In this paper, we focus on linear operations, which seems to be underestimated, on the contrary. Specifically, we discover some security flaws and redundant processes in popular first-order masked AES linear operations, and pinpoint the underlying root causes. Then we propose a provably secure and highly efficient masking scheme for AES linear operations. In order to show its practical implications, we replace the linear operations of state-of-the-art first-order AES masking schemes with our proposal, while keeping their original non-linear operations unchanged. We implement four newly combined masking schemes on an Intel Core i7-4790 CPU, and the results show they are roughly 20% faster than those original ones. Then we select one masked implementation named RSMv2 due to its popularity, and investigate its security and efficiency on an AVR ATMega163 processor and four different FPGA devices. The results show that no exploitable first-order side-channel leakages are detected. Moreover, compared with original masked AES implementations, our combined approach is nearly 25% faster on the AVR processor, and at least 70% more efficient on four FPGA devices. [ABSTRACT FROM AUTHOR]

Conventional objective image assessment metrics, such as mean squared error and peak signal-to-noise ratio, which only calculates pixel-based differences between the original and the degraded images, are not in agreement with the human vision. In this paper, we present an improved objective full-reference image quality assessment method, called the multiscale and multidirectional visibility differences (MMVD) predictor. The proposed MMVD metric considers multiscale and multidirectional visibility differences in the domain of the discrete nonseparable shearlet transform, which emulates the multichannel structure of information processing of the human vision system. In the process of constructing the visual just noticeable difference threshold in the shearlet domain, the contrast sensitivity function and the visual masking effect which are important properties of the human visual perception are considered simultaneously to approximate the sensitivities of human visual responses. Both contrast masking and entropy masking are considered to tackle the visual masking issue. All subbands of the shearlet transform are evaluated, and perceptual errors of subbands are pooled together to yield the objective quality index of a distorted image. The extensive validation experiments are conducted on five public image databases, namely, TID2008, TID2013, CSIQ, IVC, and LIVE. The experimental results demonstrate the proposed method is well coherent with human perception and has better performance compared to the several state-of-the-art image quality metrics.

The ability to process facial expressions can be modified by altering the spatial frequency of the stimuli, an effect that has been attributed to differential properties of visual pathways that convey different types of information to distinct brain regions at different speeds. While this effect suggests a potential influence of spatial frequency on the processing speed of facial emotion, this hypothesis has not been examined directly. We addressed this question using a facial emotion identification task with photographs containing either high spatial frequency (HSF), low spatial frequency (LSF), or broadband spatial frequency (BSF). Temporal processing of emotion perception was manipulated by suppressing visual perception with a single-pulse transcranial magnetic stimulation (TMS), delivered to the visual cortex at six intervals prior to (forward masking) or following (backward masking) stimulus presentation. Participants performed best in the BSF, followed by LSF, and finally HSF condition. A spatial frequency by forward/backward masking interaction effect demonstrated reduced performance in the forward masking component in the BSF condition and a reversed performance pattern in the HSF condition, with no significant differences between forward and backward masking in the LSF condition. Results indicate that LSF information may play a greater role than HSF information in emotional processing, but may not be sufficient for fast conscious perception of emotion. As both LSF and HSF filtering reduced the speed of extracting emotional information from faces, it is possible that intact BSF faces have an inherent perceptual advantage and hence benefit from faster temporal processing.

Perception of a briefly presented target is impaired when a sparse surrounding mask (e.g., four‐dot) persists after target offset compared to when the target and mask offset together (i.e., object substitution masking [OSM]). Previous studies have reported a mask preview effect in which OSM is largely attenuated by prior presentation of the mask. Here, we investigated how breaking object continuity of the previewed mask affects the mask preview effect. Introducing an abrupt surface color change of the previewed mask at target onset disrupted the beneficial effect of mask preview, that is, OSM was reinstated (Experiment 1). The masking induced by mask color change exhibited the same two characteristics as conventional OSM: target location specificity and non‐necessity of voluntary attention to the mask (Experiment 2). These results suggest that a sudden change in surface color breaks object continuity of the previewed mask and causes the mask to be represented as a new one, which triggers OSM anew. [ABSTRACT FROM AUTHOR]

Cognitive neuroscience and its applied developments have revolutionized marketing. With advances in neuroscientific techniques, marketing has needed to refocus toward understanding issues like the area of the brain that should be stimulated to transform the consumer’s intention to purchase into a real decision, how information is processed when making a decision, and how personality traits affect the purchase decision. Neuroscience has opened the door to the consumer’s brain. For many years, scientists have investigated the role of subliminal messages in marketing, with their findings generating a significant controversy. Many have shown that making sound decisions based on intuition rather than conscious reasoning is more common than previously thought. In fact, many studies have shown that sound intuitive decision-making depends on the association of the subliminal messages of a given situation with the limbic brain structures formed. Scientists have concluded that the brain does not consciously need to know contextual information to learn the value of this information and make the necessary linkages to make productive decisions. In this study, we consider whether unconscious perceptual processing influences decision-making and explore the influence of aspects of personality that are related to unconscious processing, such as the degree of neuroticism, extroversion, and gender of the individual, applied to the demographic cohort Generation Z, distinguishing between whether the stimuli are verbal or pictorial. The backward masking visual paradigm has been used to assess unconscious perceptual processing. To test these processes, a set of ANOVA models and logistic regressions were run where the dependent variable is whether the people perceived the stimuli or not and the independent variables were gender, the form of the stimuli (pictorial or verbal), and the personality traits extroversion, introversion, and neuroticism. The results suggest that verbal stimuli work better than pictorial stimuli, although a possible explanation is that the pictures require modification to be more effective. In the case of verbal stimuli, gender and level of neuroticism are found to be important variables that influence unconscious perceptual decision-making processes. Specifically, a female with a high level of neuroticism shows greater permeability in its unconscious perceptual processes.

Interpersonal distance, an essential component of social interaction, is modulated by the emotion conveyed by others and associated physiological response. However, in modern societies with overcrowded and hyperstimulating environments, we can only surreptitiously glimpse the faces of others in order to quickly make behavioral adjustments. How this impacts social interactions is not yet well understood. In the present study, we investigated this issue by testing whether facial expressions that are difficult to identify modify the physiological response (Electrodermal Activity, EDA) and subsequent judgment of interpersonal comfort distance. We recorded participants' EDA while they provided comfort judgments to interpersonal distances with a Point‐Light Walker (PLW). The PLW, with an emotionally neutral gait, moved toward and crossed participants at various distances after the latter were exposed to a negative (anger), positive (happiness) or neutral facial expression presented at the perceptual threshold. Bayesian analyses of the data revealed an increase versus decrease of interpersonal comfort distance with the PLW depending on the negative versus positive emotional valence of the facial expression. They also showed an increase in EDA when the approaching PLW violated interpersonal comfort distance after participants were exposed to an angry facial expression. These effects correlated with the subjective assessment of the arousal of facial expressions. Thus, previous exposure to barely visible facial expressions can alter the representation of social comfort space and the physiological response associated with a violation of interpersonal comfort distances, depending on the valence and arousal of the emotional social stimuli. Others' facial expressions (FE) contribute to the specification of interpersonal distance in social interactions. Here, we demonstrate that FE with poor visibility alter comfort interpersonal distance depending on the valence of FE. Furthermore, EDA increased after exposition to angry FE, but only in case of violation of comfort social space. [ABSTRACT FROM AUTHOR]

Cognitive neuroscience and its applied developments have revolutionized marketing. With advances in neuroscientific techniques, marketing has needed to refocus toward understanding issues like the area of the brain that should be stimulated to transform the consumer's intention to purchase into a real decision, how information is processed when making a decision, and how personality traits affect the purchase decision. Neuroscience has opened the door to the consumer's brain. For many years, scientists have investigated the role of subliminal messages in marketing, with their findings generating a significant controversy. Many have shown that making sound decisions based on intuition rather than conscious reasoning is more common than previously thought. In fact, many studies have shown that sound intuitive decision-making depends on the association of the subliminal messages of a given situation with the limbic brain structures formed. Scientists have concluded that the brain does not consciously need to know contextual information to learn the value of this information and make the necessary linkages to make productive decisions. In this study, we consider whether unconscious perceptual processing influences decision-making and explore the influence of aspects of personality that are related to unconscious processing, such as the degree of neuroticism, extroversion, and gender of the individual, applied to the demographic cohort Generation Z, distinguishing between whether the stimuli are verbal or pictorial. The backward masking visual paradigm has been used to assess unconscious perceptual processing. To test these processes, a set of ANOVA models and logistic regressions were run where the dependent variable is whether the people perceived the stimuli or not and the independent variables were gender, the form of the stimuli (pictorial or verbal), and the personality traits extroversion, introversion, and neuroticism. The results suggest that verbal stimuli work better than pictorial stimuli, although a possible explanation is that the pictures require modification to be more effective. In the case of verbal stimuli, gender and level of neuroticism are found to be important variables that influence unconscious perceptual decision-making processes. Specifically, a female with a high level of neuroticism shows greater permeability in its unconscious perceptual processes. [ABSTRACT FROM AUTHOR]

In visual backward masking paradigms, the visibility of a target is reduced using various kinds of mask stimuli presented immediately after the target. Four-dot masking is one such kind of backward masking, caused by four surrounding dots neither spatially adjacent nor similar to the target. Four-dot masking is often considered to involve object-level interferences. However, low-level contributions such as lateral inhibition and motion detection are also possible. To elucidate the loci of the underlying mechanism within the visual hierarchy, we compared the masking effect between monoptic and dichoptic viewing conditions. A target and a four-dot mask, which also served as a spatial cue to the target location, were presented to the same eye in monoptic viewing, whereas they were presented to different eyes in dichoptic viewing. Observers were then asked to discriminate the target shape. We found a significant decline in the correct response rate compared to the baseline condition in which the four-dot mask was not presented, and the masking effect was equivalent between the monoptic and dichoptic viewings. These results demonstrate that four-dot masking stems exclusively from processing within the binocular pathway. [ABSTRACT FROM AUTHOR]

With explosive increase of internet video services, perceptual modeling for video quality has attracted more attentions to provide high quality-of-experience (QoE) for end-users subject to bandwidth constraints, especially for compressed video quality. In this paper, a novel perceptual model for satisfied-user-ratio (SUR) on compressed video quality is proposed by exploiting compressed video bitrate changes and spatial-temporal statistical characteristics extracted from both uncompressed original video and reference video. In the proposed method, an efficient video feature set is explored and established to model SUR curves against bitrate variations by leveraging the Gaussian Processes Regression (GPR) framework. In particular, the proposed model is based on the recently released large-scale video quality dataset, VideoSet, and takes both spatial and temporal masking effects into consideration. To make it more practical, we further optimize the proposed method from three aspects including feature source simplification, computation complexity reduction and video codec adaption. Based on experimental results on VideoSet, the proposed method can accurately model SUR curves for various video contents and predict their required bitrates at given SUR values. Subjective experiments are conducted to further verify the generalization ability of the proposed SUR model. [ABSTRACT FROM AUTHOR]

In amblyopia, there is an interocular suppressive imbalance that results in the fixing eye dominating perception. In this study, we aimed to determine whether these suppressive interactions were narrowband and tuned for spatial frequency or broadband and independent of spatial frequency. We measured the contrast sensitivity and masking functions of fifteen amblyopic subjects and seventeen control subjects using the quick Contrast Sensitivity Function (qCSF) approach (Lesmes, Lu, Baek, & Albright, 2010). We first measured the monocular sensitivity functions of each participant and thereafter corrected for it. We then measured masking sensitivity functions for low, mid and high spatial frequency masks, normalized to their visibility. In the control group, we observed that the strength of dichoptic masking is equivalent between the two eyes. It is also tuned such that masking by low spatial frequencies in one eye mainly affects low spatial frequencies in the other eye and masking by high spatial frequencies mainly affects high spatial frequencies. In amblyopes, although the interocular masking is also tuned for spatial frequency, it is not equivalent between the two eyes: the masking effect from the amblyopic to fixing eye is weaker than the other way around. The asymmetry observed in the strength of masking between the two eyes in amblyopia is tuned for spatial frequency. It is not the consequence of the contrast sensitivity deficit of the amblyopic eye nor is it the consequence of abnormally strong masking from the fixing eye. Rather it is due to an abnormally weak masking strength by the amblyopic eye per se. [ABSTRACT FROM AUTHOR]

• Both supraliminal and subliminal cues can affect response times and modulate brain activity. • Supraliminal CNV originates from temporal and mesio-frontal (Supplementary Motor Areas) neural sources. • Subliminal CNV originates from temporal lobe sources. The scope of unconscious cognition stretched its limits dramatically during the last 40 years, yet most unconscious processes and representations that have been described so far are fleeting and very short-lived, whereas conscious representations can be actively maintained in working memory for a virtually unlimited period. In the present work we aimed at exploring conscious and unconscious lasting (>1 second) expectancy effects. In a series of four experiments we engaged participants in the foreperiod paradigm while using both unmasked and masked cues that were informative about the presence/absence of an upcoming target. We recorded behavioral responses, high-density scalp EEG (Exp. 2a), and intra-cranial EEG (Exp. 2b). While conscious expectancy was associated with a large behavioral effect (~150 ms), unconscious expectancy effect was significant but much smaller (4 ms). Both conscious and unconscious expectancy Contingent Negative Variations (CNVs) originated from temporal cortices, but only the late component of conscious CNV originated from an additional source located in the vicinity of mesio-frontal areas and supplementary motor areas. Finally, only conscious expectancy was accessible to introspection. Both unmasked and masked cues had an impact on response times and on brain activity. These results support a two-stage model of the underlying mechanisms of expectancy. [ABSTRACT FROM AUTHOR]

In a novel integration of research designs, we tested for unconscious perception effects at an unattended stimulus location using a focused attention paradigm (Lachter, J., Forster, K. I., & Ruthruff, E. 2004. Forty-five years after Broadbent (1958): Still no identification without attention. Psychological Review, 111(4), 880–913. https://doi.org/10.1037/0033-295X.111.4.880). Target-masked word or nonword prime stimuli were briefly displayed for 14, 28, or 56 ms at an experimentally-defined attended or unattended location, followed by a lexical decision task. At the briefest prime durations (14 and 28 ms), we failed to find any evidence for unattended priming effects, consistent with Lachter et al., but there were some small priming (i.e., congruency) effects at the attended location. The 14 ms primes could not be discriminated above chance, but could be detected. Our results support the claim that perceptual processing is strongest with focal attention. For the 14 ms primes at the attended location, results could support an unconscious perception claim, but the effect was weak and awareness of the primes was unlikely to have been completely eliminated. [ABSTRACT FROM AUTHOR]

Adaptation is the process that changes a neuron's response based on recent inputs. In the traditional model, a neuron's state of adaptation depends on the recent input to that neuron alone, whereas in a recently introduced model (Hebbian normalization), adaptation depends on the structure of neural correlated firing. In particular, increased response products between pairs of neurons leads to increased mutual suppression. We test a psychophysical prediction of this model: adaptation should depend on 2nd-order statistics of input stimuli. That is, if two stimuli excite two distinct sub-populations of neurons, then presenting those stimuli simultaneously during adaptation should strengthen mutual suppression between those subpopulations. We confirm this prediction in two experiments. In the first, pairing two gratings synchronously during adaptation (i.e., a plaid) rather than asynchronously (interleaving the two gratings in time) leads to increased effectiveness of one pattern for masking the other. In the second, pairing the gratings in a center-surround configuration results in reduced apparent contrast for the central grating when paired with the same surround (as compared with a condition in which the central grating appears with a different surround at test than during adaptation). These results are consistent with the prediction that an increase in response covariance leads to greater mutual suppression between neurons. This effect is detectable both at threshold (masking) and well above threshold (apparent contrast). [ABSTRACT FROM AUTHOR]

Based upon evidence that vision for action has quicker access to visual information than vision for perception, we hypothesized that the two systems may have differentiated visual thresholds. There is also evidence that, unlike vision for perception, vision for action is insensitive to cognitive dual-task interference. Using visual masking, we determined the visual thresholds of 15 participants in a perception task, an action task and an action plus concurrent cognitive secondary task. There was no difference in threshold between the perception task and the action task, but the action plus concurrent secondary task was accompanied by a greater visual threshold than both the perception task and the action task alone, indicating dual-task interference. The action task was thus most likely informed by vision for perception. The implications of these results are reviewed in the context of recent discussions of the two visual systems model. [ABSTRACT FROM AUTHOR]

Retinal and cortical mechanisms provide for persistence of visual information across intervals of many hundreds of milliseconds, which supports the integration of partial shape cues. The present experiments displayed unknown shapes in a match recognition task, wherein a target shape was quickly followed by a comparison shape; the task was to specify whether the comparison shape was the same or different from the target. The target and comparison shapes were displayed as sparse dots that marked boundary locations. The first experiment successively displayed the target shape as two complementary subsets and found that the probability of correct match remained above chance with up to 500 ms of subset separation. The second experiment demonstrated masking of the target by a random pattern of dots when the target and mask were displayed simultaneously, but with much less or no masking when the two were separated by 100 ms. The third experiment displayed the target subsets with 200 ms of separation and found that match recognition was disrupted when the random-dot mask was displayed midway between the two subsets. Much less masking of an intact target was produced with that amount of temporal separation, which suggests that mechanisms for integration of shape cues have a special vulnerability to masking. The third experiment also found very little impairment of match recognition when the mask was displayed simultaneous with one of the subsets. We hypothesize that there is embedding of the subset pattern within the mask pattern, but additional display of the other subset effectively disembeds the buried partial shape cues.

Object individuation is the process whereby the brain infers that dynamic input reflects multiple discrete objects, rather than a single, continuing object over time. Object substitution masking is a popular method for operationalizing object individuation inferences in the laboratory. Although object substitution masking was historically thought to interact with attentional processes, an emerging body of literature indicates that this form of visual masking is impervious to some attentional manipulations. However, one form of attention that has not been systematically studied in relation to object-substitution masking is endogenous attentional orienting. This is important because in other domains, endogenous attentional orienting has been found to have qualitatively distinct effects from other forms of attention, including impacting visual perception when other forms of attention do not. Therefore, if attention does interact with object individuation processes, then endogenous attentional orienting is the most likely candidate mechanism for such a relationship. Here, therefore, the impact of endogenous attentional on object-substitution masking was tested. Across 2 experiments, although endogenous attentional orienting impacted overall target perception, it had no impact on object substitution masking. This implies that object individuation inferences are indeed independent of attention. This article investigates two important visual processes and determines whether they interact or are independent. One is voluntary visual attention, the process of strategically selecting certain aspects of visual scene for privileged perceptual processing, and the other is object-individuation, the process whereby the human brain determines that dynamic visual input reflects multiple objects rather than a single object continuing over time. Here, it was found that these processes, although each having a strong impact on perception in their own right, operate completely independently of one another. [ABSTRACT FROM AUTHOR]

The level of processing (LoP) hypothesis proposes that low-level stimulus perception (i.e., stimulus energy and features) is a graded process whereas high-level (i.e., letters, words, meaning) stimulus perception is all-or-none. In the present study, we set up a visual masking design in order to examine the nature of visual awareness at stimulus energy (i.e., detection task) and feature levels (identification task) at specific individual target durations (13, 27, 40, 53, and 80 ms). We manipulated the strength of the masking to produce different visibility conditions and gathered participants' subjective (across a 4-point awareness scale) and objective (accuracy levels) awareness performances. We found that intermediate ratings (i.e., ratings 2 and 3, which index graded awareness experiences) were used in more than 50% of the trials for target presentations of 27, 40, 53, and 80 ms. In addition, objective accuracy performances for target presentations of 27 and 80 ms produced linearly increasing detection and identification accuracies across the awareness scale categories, respectively. Overall, our results suggest that visual awareness at energy and feature levels of stimulus perception may be graded. Furthermore, we found a divergence in detection and identification performance results, which emphasizes the need for an adequate election of target durations when studying different perceptual processes such as detection versus more complex stimulus identification processes. Finally, "clarity" in the perceptual awareness scale should be exhaustively defined depending on the level of processing of the stimulus, as participants may recalibrate the meaning of the different awareness categories depending on task demands. [ABSTRACT FROM AUTHOR]

• A model based energy minimization algorithm for pairwise camera selection. • A symmetry-aware energy term to compensate camera projection errors. • A masking method to limit the effect of occlusions during the mesh refinement stage. Many Multi-View-Stereo algorithms extract a 3D mesh model of a scene, after fusing depth maps into a volumetric representation of the space. Due to the limited scalability of such representations, the estimated model does not capture fine details of the scene. Therefore a mesh refinement algorithm is usually applied; it improves the mesh resolution and accuracy by minimizing the photometric error induced by the 3D model into pairs of cameras. The choice of these pairs significantly affects the quality of the refinement and usually relies on sparse 3D points belonging to the surface. Instead, in this paper, to increase the quality of pairs selection, we exploit the 3D model (before the refinement) to compute five metrics: scene coverage, mutual image overlap, image resolution, camera parallax, and a new symmetry term. To improve the refinement robustness, we also propose an explicit method to manage occlusions, which may negatively affect the computation of the photometric error. The proposed method takes into account the depth of the model while computing the similarity measure and its gradient. We quantitatively and qualitatively validated our approach on publicly available datasets against state of the art reconstruction methods. [ABSTRACT FROM AUTHOR]

In this paper, a new personal identification method based on unconstrained iris recognition is presented. We apply a nontraditional step for feature extraction where a new circular contourlet filter bank is used to capture the iris characteristics. This idea is based on a new geometrical image transform called the circular contourlet transform (CCT). An efficient multilevel and multidirectional contourlet decomposition method is needed to form a reduced-length quantized feature vector with improved performance. The CCT transform provides both multiscale and multioriented analysis of iris features. Circular contourlet-like mask filters can be used with shapes just like the 2D circular-support regions in different scales and directions. A reduced recognition system is realized using a single branch of the whole decomposition bank, highlighting a system realization with lower complexity and fewer computations. In the proposed recognition system, only five out of seven elements of the gray level cooccurrence matrix are required in the creation of the feature vector, which leads to a further reduction in computations. In addition, the highly discriminative frequency regions due to the use of circular-support decompositions can result in highly accurate feature vectors, reflecting good recognition rates for the proposed system. It is shown that the proposed system has encouraging performance in terms of high recognition rates and a reduced number of elements of the feature vector. This reflects reliable and rapid recognition properties. In addition, some promising characteristics of the system are apparent since it can efficiently be realized with lower computation complexity. [ABSTRACT FROM AUTHOR]

Abstract Does the human brain elicit patterns of activity associated with the meaning of words in the absence of conscious awareness? Do such non-conscious semantic representations generalize across languages? This study aimed to address these questions using fMRI-based multivariate pattern analysis (MVPA) in a masked word paradigm. Animal and non-animal words were visually presented in two different languages (i.e. Spanish and Basque). Words were presented very briefly and were masked. On each trial, participants identified the semantic category and provided a visibility rating of the word. A support vector machine (SVM) was used to decode word category from multivoxel patterns of BOLD responses in seven canonical semantic regions of a left-lateralized network that were prespecified based on a previous meta-analysis. We show that the semantic category of non-conscious words (i.e. associated with null visual experience and chance-level discrimination performance) can be significantly decoded from BOLD response patterns. For Spanish, such discriminative patterns of BOLD responses were consistently found in inferior parietal lobe, dorsomedial prefrontal cortex, inferior frontal gyrus and posterior cingulate gyrus. While for Basque, these were found in ventromedial temporal lobe and posterior cingulate gyrus. All of the areas identified have previously been associated with semantic processing in studies involving animals-tools and animals-artifacts contrasts. In conscious trials, such patterns were found to be distributed over all seven regions of the semantic network in both Spanish and Basque. However, we found no evidence of across-language generalization. These results demonstrate that even in the absence of conscious awareness and lack of behavioural sensitivity to the words, putative semantic brain areas carry information related to the meanings of the words. The generalization of semantic representations across languages, however, may require deeper conscious semantic access. Highlights • Masked words were visually presented in Spanish and Basque. • SVM classifiers were used to decode the semantic category from BOLD activity patterns. • The category of non-conscious words can be decoded in key substrates of the semantic network. • Across-language generalization of semantic representations may however require conscious access. [ABSTRACT FROM AUTHOR]

Highlights • Configuring can occur in the absence of visual awareness induced by masking. • Visual awareness strengthen configural representation. • Sensitivity to grouping cues is evident in unconscious processing. Abstract We examined whether configuring, which determines the appearance of grouped elements as a global shape, requires visual awareness, using a priming paradigm and two invisibility-inducing methods, CFS and sandwich masking. The primes were organized into configurations based on closure, collinearity, and symmetry (collinear primes), or on closure and symmetry (noncollinear primes). The prime-target congruency could be in configuration or in elements. During CFS, no significant response-priming was observed for invisible primes. When masking induced invisibility, a significant configuration response-priming was found for collinear and noncollinear primes, visible and invisible, with larger magnitude for the former. An element response-priming of equal magnitude was evident for visible and invisible noncollinear primes. Our results suggest that configuring can be accomplished in the absence of visual awareness when stimuli are rendered invisible by sandwich masking, but it benefits from visual awareness. Our results also suggest sensitivity to the available grouping cues in unconscious processing. [ABSTRACT FROM AUTHOR]

Retinal and cortical mechanisms provide for persistence of visual information across intervals of many hundreds of milliseconds, which supports the integration of partial shape cues. The present experiments displayed unknown shapes in a match recognition task, wherein a target shape was quickly followed by a comparison shape; the task was to specify whether the comparison shape was the same or different from the target. The target and comparison shapes were displayed as sparse dots that marked boundary locations. The first experiment successively displayed the target shape as two complementary subsets and found that the probability of correct match remained above chance with up to 500 ms of subset separation. The second experiment demonstrated masking of the target by a random pattern of dots when the target and mask were displayed simultaneously, but with much less or no masking when the two were separated by 100 ms. The third experiment displayed the target subsets with 200 ms of separation and found that match recognition was disrupted when the random-dot mask was displayed midway between the two subsets. Much less masking of an intact target was produced with that amount of temporal separation, which suggests that mechanisms for integration of shape cues have a special vulnerability to masking. The third experiment also found very little impairment of match recognition when the mask was displayed simultaneous with one of the subsets. We hypothesize that there is embedding of the subset pattern within the mask pattern, but additional display of the other subset effectively disembeds the buried partial shape cues. [ABSTRACT FROM AUTHOR]

We analyzed the accuracy and reaction time (RT) of basic and superordinate image categorization under forward masking conditions in 41 healthy subjects. Images of man-made objects and animals were used as target stimuli, while images of man-made objects, animals, faces, and buildings were used as masks. The comparison of the psychometric characteristics of the basic and superordinate categorization showed the influence of mask and stimulus semantic similarity on the forward masking effectiveness, which depended on the type of experimental task performed by the subject (the level of categorization of the target stimulus). The masking effect at the basic-level categorization was more pronounced at a greater semantic similarity between the mask and the target stimulus. In contrast, a greater masking effect at the superordinate-level categorization was observed when the mask and the stimulus belonged to different categories. The images of faces and buildings had a less pronounced masking effect compared to the images of animals and man-made objects, regardless of the type of task. For basic-level categorization, the increase in RT under semantically related conditions was caused by distributional skewing. In contrast, for superordinate categorization, semantically unrelated conditions led to distributional shifting towards greater values. The results of this study suggest a hypothesis of temporal and spatial division of cognitive processes of the basic and superordinate categorization. [ABSTRACT FROM AUTHOR]

• Do local elements group into global shapes in the absence of awareness? • Masked priming study with both objective and subjective awareness measures. • Priming results evaluated using Bayesian analyses and generative regression models. • Assessing prime visibility trial-wise interferes with masked priming. • Strong evidence for local elements grouping into global shapes without awareness. To investigate whether local elements are grouped into global shapes in the absence of awareness, we introduced two different masked priming designs (e.g., the classic dissociation paradigm and a trial-wise probe and prime discrimination task) and collected both objective (i.e., performance based) and subjective (using the perceptual awareness scale [PAS]) awareness measures. Prime visibility was manipulated using three different prime-mask stimulus onset asynchronies (SOAs) and an unmasked condition. Our results showed that assessing prime visibility trial-wise heavily interfered with masked priming preventing any prime facilitation effect. The implementation of Bayesian regression models, which predict priming effects for participants whose awareness levels are at chance level, provided strong evidence in favor of the hypothesis that local elements group into global shape in the absence of awareness for SOAs longer than 50 ms, suggesting that prime-mask SOA is a crucial factor in the processing of the global shape without awareness. [ABSTRACT FROM AUTHOR]

Objective: Forward masking is a commonly used paradigm to investigate the temporal dynamics of visual processing. The neural correlates of this paradigm, however, are not fully understood. In particular, there is no study to our knowledge that systematically investigated the associated ERP components. Methods: We designed two experiments using the paracontrast masking paradigm. In both experiments, EEG (Electroencephalography) activity was recorded while the participants performed a contour discrimination task. In addition to the mask-to-target onset timing (SOA), the mask-to-target (M/T) contrast ratio was manipulated in the first experiment, and the contrast polarity (same and opposite polarities) of the mask was manipulated in the second experiment. Results: Behavioral results showed that the perceived visibility was dependent on SOA, and the mask caused strong brief-inhibition on target visibility at short SOA values. The brief-inhibition was also found to be significantly modulated by the M/T contrast ratio and polarity. The EEG analyses revealed SOAdependent non-linear interactions between the target and mask in the P1, N1, and late components. Moreover, the M/T contrast ratio significantly modulated the interactions in the N1 component range. Conclusion: In summary, this study points to the neurophysiological correlates of forward masking and particularly provides important insights into the ERP components associated with brief inhibition. The findings also contribute to our understanding of cortical dynamics underlying perceived visibility. This work was supported by The Scientific and Technological Research Council of Türkiye (TUBITAK Project Number. 119K368). [ABSTRACT FROM AUTHOR]

In visual perception, human only perceive discrete-scale quality levels over a wide range of coding bitrate. More clearly, the videos compressed with a series of quantization parameters (QPs) only have limited perceived quality levels. In this paper, perceptual quantization is transformed into the problem of how to determine the just perceived QP for each quality level, and a just noticeable coding distortion (JNCD) based perceptual quantization scheme is proposed. Specifically, multiple visual masking effects are analyzed and a linear regression (LR) based JNCD model is proposed to predict JNCD thresholds for all quality levels at first. According to the JNCD prediction model, the frame-level perceptual QPs for all quality levels are then derived on the premise of that coding distortions are infinitely close to the predicted JNCD thresholds. Based on the predicted frame-level perceptual QPs, the perceived QPs of all quality levels for each coding unit (CU) are finally determined according to a perceptual modulation function. Experimental results show that the proposed quality-wise perceptual quantization scheme is superior to the existing perceptual video coding algorithms significantly, i.e., the proposed perceptual quantization could save more bitrate with better quality. [ABSTRACT FROM AUTHOR]