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Brain and Behavior Sep 2019The perception of a target stimulus can be impaired by a subsequent mask stimulus, even if they do not overlap temporally or spatially. This "backward masking" is...
INTRODUCTION
The perception of a target stimulus can be impaired by a subsequent mask stimulus, even if they do not overlap temporally or spatially. This "backward masking" is commonly used to modulate a subject's awareness of a target and to characterize the temporal dynamics of vision. Masking is most apparent with brief, low-contrast targets, making detection difficult even in the absence of a mask. Although necessary to investigate the underlying neural mechanisms, evaluating masking phenomena in animal models is particularly challenging, as the task structure and critical stimulus features to be attended must be learned incrementally through rewards and feedback. Despite the increasing popularity of rodents in vision research, it is unclear if they are susceptible to masking illusions.
METHODS
We characterized how spatially surrounding masks affected the detection of sine-wave grating targets.
RESULTS
In humans (n = 5) and rats (n = 7), target detection improved with contrast and was reduced by the presence of a mask. After controlling for biases to respond induced by the presence of the mask, a clear reduction in detectability was caused by masks. This reduction was evident when data were averaged across all animals, but was only individually significant in three animals.
CONCLUSIONS
While perceptual masking occurs in rats, it may be difficult to observe consistently in individual animals because the complexity of the requisite task pushes the limits of their behavioral capabilities. We suggest methods to ensure that masking, and similarly subtle effects, can be reliably characterized in future experiments.
Topics: Adult; Animals; Female; Humans; Male; Models, Animal; Orientation, Spatial; Perceptual Masking; Photic Stimulation; Rats
PubMed: 31444998
DOI: 10.1002/brb3.1368 -
Journal of Vision Aug 2016Static visual stimuli are smeared across the retina during saccades, but in normal conditions this smear is not perceived. Instead, we perceive the visual scene as... (Review)
Review
Static visual stimuli are smeared across the retina during saccades, but in normal conditions this smear is not perceived. Instead, we perceive the visual scene as static and sharp. However, retinal smear is perceived if stimuli are shown only intrasaccadically, but not if the stimulus is additionally shown before a saccade begins, or after the saccade ends (Campbell & Wurtz, 1978). This inhibition has been compared to forward and backward metacontrast masking, but with spatial relations between stimulus and mask that are different from ordinary metacontrast during fixation. Previous studies of smear masking have used subjective measures of smear perception. Here we develop a new, objective technique for measuring smear masking, based on the spatial localization of a gap in the smear created by very quickly blanking the stimulus at various points during the saccade. We apply this technique to show that smear masking survives dichoptic presentation (suggesting that it is therefore cortical in origin), as well as separations of as much as 6° between smear and mask.
Topics: Humans; Perceptual Masking; Retina; Saccades; Visual Perception
PubMed: 27479918
DOI: 10.1167/16.10.1 -
IEEE Transactions on Haptics 2018Future touch screen applications will include multiple tactile stimuli displayed simultaneously or consecutively to single finger or multiple fingers. These applications...
Future touch screen applications will include multiple tactile stimuli displayed simultaneously or consecutively to single finger or multiple fingers. These applications should be designed by considering human tactile masking mechanism since it is known that presenting one stimulus may interfere with the perception of the other. In this study, we investigate the effect of masking on the tactile perception of electrovibration displayed on touch screens. Through conducting psychophysical experiments with nine participants, we measured the masked thresholds of sinusoidal electrovibration bursts (125 Hz) under two masking conditions: simultaneous and pedestal. The masking signals were noise bursts, applied at five different sensation levels varying from 2 to 22 dB SL, also presented by electrovibration. For each participant, the thresholds were elevated as linear functions of masking levels for both masking types. We observed that the masking effectiveness was larger with pedestal masking than simultaneous masking. Moreover, in order to investigate the effect of tactile masking on our haptic perception of edge sharpness, we compared the perceived sharpness of edges separating two textured regions displayed with and without various types of masking stimuli. Our results suggest that sharpness perception depends on the local contrast between background and foreground stimuli, which varies as a function of masking amplitude and activation levels of frequency-dependent psychophysical channels.
Topics: Adult; Female; Fingers; Humans; Male; Perceptual Masking; Touch Perception; User-Computer Interface; Vibration; Young Adult
PubMed: 30004890
DOI: 10.1109/TOH.2018.2855124 -
Perception Feb 2019Two experiments examined the effect of object substitution masking (OSM) on the perceptual errors in reporting the orientation of a target. In Experiment 1, a four-dot...
Two experiments examined the effect of object substitution masking (OSM) on the perceptual errors in reporting the orientation of a target. In Experiment 1, a four-dot trailing mask was compared with a simultaneous-noise mask. In Experiment 2, the four-dot and noise masks were factorially varied. Responses were modelled using a mixture regression model and Bayesian inference to deduce whether the relative impacts of OSM on guessing and precision were the same as those of a noise mask, and thus whether the mechanism underpinning OSM is based on increasing noise rather than a substitution process. Across both experiments, OSM was associated with an increased guessing rate when the mask trailed target offset and a reduction in the precision of the target representation (although the latter was less reliable across the two experiments). Importantly, the noise mask also influenced both guessing and precision, but in a different manner, suggesting that OSM is not simply caused by increasing noise. In Experiment 2, the effects of OSM and simultaneous-noise interacted, suggesting the two manipulations involve common mechanisms. Overall results suggest that OSM is often a consequence of a substitution process, but there is evidence that the mask increases noise levels on trials where substitution does not occur.
Topics: Acoustic Stimulation; Bayes Theorem; Humans; Orientation; Perceptual Masking; Photic Stimulation; Regression Analysis; Visual Perception
PubMed: 30799730
DOI: 10.1177/0301006619825782 -
Consciousness and Cognition Jul 2022Visual scenes typically contain redundant information. One mechanism by which the visual system compresses such redundancies is 'redundancy masking' - the reduction of...
Visual scenes typically contain redundant information. One mechanism by which the visual system compresses such redundancies is 'redundancy masking' - the reduction of the perceived number of items in repeating patterns. For example, when presented with three lines in the periphery, observers frequently report only two lines. Redundancy masking is strong in radial arrangements and absent in tangential arrangements. Previous studies suggested that redundancy-masked percepts predominate in stimuli susceptible to redundancy masking. Here, we investigated whether strong redundancy masking is associated with high confidence in perceptual judgements. Observers viewed three to seven radially or tangentially arranged lines at 10° eccentricity. They first indicated the number of lines, and then rated their confidence in their responses. As expected, redundancy masking was strong in radial arrangements and weak in tangential arrangements. Importantly, with radial arrangements, observers were more confident in their responses when redundancy masking occurred (i.e., lower number of lines reported) than when it did not occur (i.e., correct number of lines reported). Hence, observers reported higher confidence for erroneous than for correct judgments. In contrast, with tangential arrangements, observers were similarly confident in their responses whether redundancy masking occurred or not. The inversion of confidence in the radial condition (higher confidence when accuracy was low and lower confidence when accuracy was high) suggests that redundancy-masked appearance trumps 'veridical' perception. The often-reported richness of visual consciousness may partly be due to overconfidence in erroneous judgments in visual scenes that are subject to redundancy masking.
Topics: Consciousness; Humans; Judgment; Perceptual Masking; Visual Perception
PubMed: 35598518
DOI: 10.1016/j.concog.2022.103349 -
Perception 2001
Topics: Auditory Perception; Humans; Perceptual Masking; Sound Localization; Visual Perception
PubMed: 11383188
DOI: 10.1068/p3004ed -
Consciousness and Cognition May 2019Masked priming has been employed to study the role of consciousness for different levels of visual processing. However, masking procedures differ systematically between...
Masked priming has been employed to study the role of consciousness for different levels of visual processing. However, masking procedures differ systematically between studies. To examine these procedural differences we contrasted priming effects with metacontrast masking, which is often applied in the context of perceptual priming, and priming effects with sandwich pattern masking, frequently used in studies on semantic priming. Results indicate that the amount of masking neither affects perceptual nor semantic priming effects in a semantic categorization task when a metacontrast masking paradigm was used. However, perceptual and semantic priming effects increased with increasing prime visibility when a sandwich pattern masking paradigm was used. Findings suggest that different types of masking procedures affect the processing of the masked stimuli in substantially different ways even if the masking effect on conscious perception of these stimuli is comparable.
Topics: Adult; Color Perception; Consciousness; Female; Humans; Male; Pattern Recognition, Visual; Perceptual Masking; Psychomotor Performance; Semantics; Young Adult
PubMed: 31003074
DOI: 10.1016/j.concog.2019.03.009 -
Schizophrenia Bulletin 1987The present article reviews and evaluates 20 studies of susceptibility to visual masking among individuals within the schizophrenia spectrum using a neurophysiological... (Review)
Review
The present article reviews and evaluates 20 studies of susceptibility to visual masking among individuals within the schizophrenia spectrum using a neurophysiological framework provided by a multichannel model of masking. Particular emphasis is placed upon methodological considerations within the context of the current experimental visual masking literature. While there is ample evidence to suggest that individuals within the schizophrenia spectrum frequently exhibit a backward masking deficit, very little can be understood about the specific nature of the deficit. To gain increased understanding of the specific nature of this deficit, researchers need to use some contemporary theory of masking and derive a theoretical design rationale that facilitates a priori predictions in addition to the more typical post hoc theorizing.
Topics: Brain; Humans; Perceptual Masking; Schizophrenia; Schizophrenic Psychology; Visual Perception
PubMed: 3326163
DOI: 10.1093/schbul/13.4.679 -
Journal of Vision Sep 2009Can practice effects on unconscious stimuli lead to awareness? Can we "learn to see"? Recent evidence suggests that blindsight patients trained for an extensive period...
Can practice effects on unconscious stimuli lead to awareness? Can we "learn to see"? Recent evidence suggests that blindsight patients trained for an extensive period of time can learn to discriminate and consciously perceive stimuli that they were previously unaware of. So far, it is unknown whether these effects generalize to normal observers. Here we investigated practice effects in metacontrast masking. Subjects were trained for five consecutive days on the stimulus onset asynchrony (SOA) that resulted in chance performance. Our results show a linear increase in sensitivity (d') but no change in bias (c) for the trained SOA. This practice effect on sensitivity spreads to all tested SOAs. Additionally, we show that subjects rate their perceptual awareness of the target stimuli differently before and after training, exhibiting not only an increase in sensitivity, but also in the subjective awareness of the percept. Thus, subjects can indeed "learn to see."
Topics: Adult; Awareness; Consciousness; Female; Humans; Male; Perceptual Masking; Photic Stimulation; Problem-Based Learning; Visual Perception; Young Adult
PubMed: 19810799
DOI: 10.1167/9.10.18 -
Journal of Vision Feb 2021How are visual sensory representations that are acquired peripherally from a saccade target related to sensory representations generated foveally after the saccade? We...
How are visual sensory representations that are acquired peripherally from a saccade target related to sensory representations generated foveally after the saccade? We tested the hypothesis that, when the two representations are perceived to belong to the same object, the post-saccadic value tends to overwrite the pre-saccadic value. Participants executed a saccade to a colored target object, which sometimes changed during the saccade by ±15°, 30°, or 45° in color space. They were post-cued to report either the pre-saccadic or post-saccadic color in a continuous report procedure. Substantial overwriting of the pre-saccadic color by the post-saccadic color was observed. Moreover, the introduction of a brief post-saccadic blank interval (which disrupted the perception of object correspondence) led to a substantial reduction in overwriting. The results provide the first direct evidence for an object-mediated overwriting mechanism across saccades, in which post-saccadic values automatically replace pre-saccadic values.
Topics: Adolescent; Adult; Female; Humans; Male; Perceptual Masking; Saccades; Visual Perception; Young Adult
PubMed: 33538771
DOI: 10.1167/jov.21.2.3