Journal of Vision最新文献

Perception and decision-making in the present are not solely driven by the current inputs reaching sensory organs, but are also influenced by previous stimuli and decisions (i.e., task responses). This "serial dependence" effect is not limited to the immediately preceding stimulus or response, but it has been shown to extend several trials back in the past. However, owing to potential correlations across past responses, effects from more remote trials may be inflated, even when assessing the effect of past stimuli. In this work, we assess the potential role of response autocorrelation as a potential source of spurious results. We first show that, in serial dependence models, the effect of responses decays slowly across trials, and that such a slow decay increases the probability of observing spurious effects, even when considering past stimuli. We then provide an analytical tool to contain such spurious results. Finally, we apply our approach to a real dataset from a previous study, showing that the effect from two trials back may indeed be inflated. Our results suggest that serial dependence may be more limited in time than previously thought, and that caution is in order when assessing effects from multiple trials back in the past.

Pervasive gaps in sensory information are completed in perception. Interestingly, humans are unaware of that perceptual completion in cases of proximal gaps, which are caused by properties of their own sensory system, and report high confidence for the inferred information in those gaps. Here, we investigated whether such overconfidence is also observed in perceptual completion of visual information in distal gaps (i.e., those caused by the properties of the stimulus). In three experiments, we asked participants to perform a perceptual (type 1) task and report their confidence (type 2 task) using stimuli that were either intact (full stimulus), with a partial cutout (stimulus with gap), partially occluded (amodal completion) or induced (modal completion). We examined whether participants report high confidence for amodal and modal completion in comparison to a full stimulus or stimulus with gap. Over three experiments, participants had the highest confidence for full stimuli, whereas amodal and modal completion led to comparable confidence as stimuli with gap. These findings demonstrate that there was low confidence for stimuli whose distal gaps are perceptually filled in. In combination with previous research, our results suggest that visibility of the gaps in information influences confidence judgments.

The human visual system is tasked with perceiving stable and moving objects despite ever-present eye movements. Normally, our visual system performs this task exceptionally well; indeed, under conditions with frames of reference, our ability to detect relative motion exceeds the sampling limits of foveal cones. However, during fixational drift, if an image is programmed to move in a direction consistent with retinal slip, little to no motion is perceived, even if this motion is amplified. We asked: Would a stimulus moving in a direction consistent with retinal slip, but with a smaller magnitude across the retina, also appear relatively stable? We used an adaptive optics scanning light ophthalmoscope to deliver stimuli that moved contingent to retinal motion and measured subjects' perceived motion under conditions with world-fixed background content. We also tested under conditions with background content closer to and farther from the stimuli. We found a sharp discontinuity in motion perception. Stimuli moving in a direction consistent with retinal slip, no matter how small, appear to have relatively little to no motion, whereas stimuli moving in the same direction as eye motion appear to be moving. Displacing background content to greater than 4° from the stimuli diminishes the effects of this phenomenon.

Visual adaptation and attention are two processes that help manage the limited bioenergetic resources of the brain for perception. Visual perception is heterogeneous around the visual field: It is better along the horizontal than the vertical meridian (horizontal-vertical anisotropy [HVA]), and better along the lower than the upper vertical meridian (vertical meridian asymmetry [VMA]). Recently, we showed that visual adaptation is more pronounced at the horizontal than the vertical meridian, but whether and how this differential adaptation modulates the effects of covert spatial attention remain unknown. In this study, we investigated whether and how the effects of endogenous (voluntary) and exogenous (involuntary) covert attention on an orientation discrimination task vary at the cardinal meridians, with and without adaptation. We manipulated endogenous (Experiment 1) or exogenous (Experiment 2) attention via an informative central or uninformative peripheral cue, respectively. Results showed that (a) in the non-adapted condition, the typical HVA and VMA emerged in contrast thresholds; (b) the adaptation effect was stronger at the horizontal than the vertical meridian; and (c) regardless of adaptation, both endogenous and exogenous attention enhanced and impaired performance at the attended and unattended locations, respectively, to a similar degree at both cardinal meridians. Together, these findings reveal that, despite differences between endogenous and exogenous attention, their effects remain uniform across cardinal meridians-even under differential adaptation that reduces intrinsic asymmetries of visual field representations.

Contour erasure describes the phenomenon that after brief flicker adaptation at the edge of an object, the object disappears and is replaced by the background - highlighting the importance of edges in perceiving a surface. The underlying mechanism remains unknown. The current study investigates the characteristics and functional properties of contour erasure, and its relationship with related phenomena such as perceptual filling-in, forward masking, and contrast adaptation. We used a homogeneous disk as a target, and circles that corresponded to the outline of the target disk as the adapter. Using a two-alternative forced choice (2AFC) paradigm, each trial began with a counterphase flickering adapter, followed by the target randomly presented in one of the two locations. Participants indicated the target location with a button press. The target detection threshold elevation relative to the no adaptation condition was used as an index of the adaptation effect. We manipulated two spatial properties (eccentricity and the adapter size) plus three temporal properties (adapter flickering rate, adaptation duration, and interstimulus interval [ISI]). Results indicated that the adaptation effect increased with eccentricity, flickering rate (plateauing at 6 hertz [Hz]) and adaptation duration, but decreased with longer ISI and for adapter sizes that were larger than the target. The target threshold first increased then decreased as the adapter size decreased from that of the target, indicating a size tuning that is slightly smaller than the target. Our results indicate that contour erasure shares some of the key features of other well-known perceptual phenomena like filling in and contrast adaptation.

Multisensory information can help resolve perceptual ambiguity in situations such as the alternating visual experience during binocular rivalry. Across four experiments, participants viewed dichoptically presented spiky and round rival targets while simultaneously touching spiky, neutral, or round shapes in three-dimensional (3D) printed form. The primary aim was to investigate the influence of visuotactile shape congruence in the curvature dimension. In addition, the roles of voluntary action and spatial colocalization on successful crossmodal integration were investigated. Voluntary action was tested between active touch (Experiments 1 and 2) and passive touch (Experiments 3 and 4) conditions. Visual stimulus type differed between rapid successions of 3D-rendered images (Experiments 1 and 3) and real-world video recordings (Experiments 2 and 4), with the latter involving bodily cues to promote visuotactile colocalization. In general, the results showed that tactile shape congruence can lead to relative dominance of the corresponding visual target, especially when visuotactile colocalization was encouraged with video recordings as visual targets. The results suggest beneficial effects of crossmodal shape congruence on disambiguation, which seems to be generally comparable between the two modes of active versus passive touch. Using 3D stimuli and including free voluntary action, the study provides novel and connecting insights into the naturalistic object processing behavior of humans.

The ability to quickly and precisely follow another person's gaze reflects critical evolutionary mechanisms underlying social interactions, such as attention modulation and the prediction of others' future actions. Recent studies show that observers use another person's gaze direction and peripheral scene information to make anticipatory saccades toward the gaze goal. However, it remains unclear how these eye movements are influenced by complex features of natural scenes, such as a foveal gazer, multiple peripheral gaze goals, and the relative distance between gazer and goal. We presented dynamic stimuli (videos) of real-world scenes with or without a gazer shifting their head to gaze at other individuals (gaze goals). Participants were instructed to search for a specific target individual in the videos while their eye movements were recorded. We measured the accuracy of the first saccade in locating the gaze goal. First, we found that the absence of a foveal gazer significantly increased saccade error, but only when the goal was at least approximately 9 degrees of visual angle from the initial fixation. First saccade amplitude and onset latency were higher in the gazer-present condition. Second, when there were multiple potential gaze goals in the periphery, the first saccade was directed to the individual closer to the initial fixation (gazer) location. Finally, the presence of multiple peripheral gaze goals shortened saccade latencies and increased the frequency of anticipatory saccades made before the gazer completed their head movement. These findings extend our understanding of gaze following in complex, naturalistic scenes and inform theories of attention and real-world decision-making.

Attentive and predictive mechanisms crucially shape perception, but the interplay between these fundamental processes remains poorly understood. Studies on interactions between attention and prediction have yielded discrepant results, potentially because of differences in task demands. The present study examined whether the perceptual load (i.e., task difficulty) affects predictive processing in task-relevant and task-irrelevant hemifields. To this end, we developed a novel delayed match-to-reference task that orthogonally manipulated task-relevance, prediction, and perceptual load. We hypothesized that a low-load condition should facilitate the processing of prediction violations (oddball effects) in task-irrelevant space because of the availability of spare processing resources. We analyzed accuracy and response time (RT) data from 28 healthy young participants with separate repeated measures analyses of variance. The results confirmed the effectiveness of the load manipulation because a high perceptual load significantly increased RTs and decreased accuracy. Notably, the accuracy analysis yielded a significant three-way interaction between task-relevance, prediction, and load. Post-hoc tests revealed that load modulated the processing of prediction violations in the task-irrelevant hemifield. Importantly, the prediction violation, induced by a low-frequency and task-irrelevant feature (orientation), reduced accuracy in the low-load but not in the high-load condition. This finding suggests that predictive processing in task-irrelevant space is contingent on the availability of processing resources, with high perceptual load inhibiting the processing of unexpected events in task-irrelevant regions. The present study shows that load is a crucial factor in the interaction between task-relevance and prediction.

Organizing visual input into coherent percepts requires dynamic grouping and segmentation mechanisms that operate across both spatial and temporal domains. Crowding occurs when nearby elements interfere with target perception, but specific flanker configurations can alleviate this effect through Gestalt-based grouping, a phenomenon known as uncrowding. Here, we examined the temporal dynamics underlying these spatial organization processes using a Vernier discrimination task. In Experiment 1, we varied stimulus duration and found that uncrowding emerged only after 160 ms, suggesting a time-consuming process. In Experiment 2, we manipulated the stimulus onset asynchrony (SOA) between the target and flankers. We found that presenting good-Gestalt flankers briefly before the target (as little as 32 ms) significantly boosted uncrowding, even in the absence of temporal overlap between the two stimuli. This effect was specific to conditions in which flankers preceded the target, ruling out pure temporal integration and masking accounts. These findings suggest that spatial segmentation can be dynamically facilitated when the temporal order of presentation allows grouping mechanisms to engage prior to target processing. Moreover, the observed time course indicates that segmentation is not purely feedforward, particularly for stimuli that are likely to recruit higher level visual areas, pointing instead to the involvement of recurrent or feedback processes.

To interact with the world effectively, the human visual system must extract meaningful features from visual scenes. One key feature are edges, luminance or texture discontinuities in two-dimensional (2D) images that often correspond to object boundaries in three-dimensional scenes. Edge sensitivity has traditionally been studied with well-controlled stimuli and binary choice tasks, but it is unclear how well these insights transfer to real-world behavior. Recent studies have extended this approach using natural images but typically retained binary button presses. In this study, we extend the approach further and ask observers (N = 20) to trace edges in natural scenes, presented with or without 2D visual noise. To quantify edge detection performance, we use a signal detection theory-inspired approach. Participants' edge traces in the noise-free condition serve as an individualized "ground-truth" or signal, used to categorize edge traces from noise conditions into hits, false alarms, misses, and correct rejections. Observers produce remarkably consistent edge traces across conditions. Noise interference patterns mirror results from traditional edge sensitivity studies, especially for edges with spectral properties similar to natural scenes. This suggests that insights from controlled paradigms can transfer to naturalistic ones. We also examined edge traces to identify which image features drive edge perception, using interindividual variability as a pointer to relevant features. We conclude that line drawings are a powerful tool to investigate edge sensitivity and potentially other aspects of visual perception, enabling nuanced exploration of real-world visual behavior with few experimental trials.