Journal of Vision最新文献

In crowding, perception of a target deteriorates in the presence of nearby elements. As the entire stimulus configuration across large parts of the visual field influences crowding and not just nearby elements, low-level explanations, such as local pooling, do not suffice. To explain the effects of stimulus configuration, grouping was proposed as the key, and we implemented these ideas in a neural network model (LAMINART). In a recent publication, Moore and Zheng (2024) used a set of stimuli designed to induce surface completion cues, such as occlusion, and found that they had no effect on crowding. Based on these results, the authors questioned the role of grouping in crowding. Here we show that the stimuli Moore and Zheng used do not induce the intended perceptual occlusion effects. Hence, their conclusions are not warranted. Additionally, simulations of the LAMINART model explain the results of Moore and Zheng with the existing model characteristics.

In the Boynton Illusion, the perceived location of a low-contrast chromatic edge is altered by a nearby high-contrast luminance contour. Our study explores this color spreading effect across different chromatic directions using a position judgment task. We used the gap effect stimulus, which consists of a box evenly divided by a central contour, in half of the conditions. The suprathreshold chromatic test area embedded in the box provided a horizontal chromatic edge parallel to the central, high-contrast luminance contour that varied in its distance from the contour. An attraction effect of the nearest high-contrast contour on low-contrast chromatic and achromatic edges was observed. Specifically, when the test area is smaller than the region defined by the outer and middle contours, the edge is perceived to be closer to the middle contour (the colored area is perceived to be larger), a filling-in effect; conversely, when the test area extends beyond the middle contour, the edge is perceived to be closer to the middle contour (the colored area is perceived to be smaller), indicating a filling-out of color. Achromatic directions exhibit a relatively smaller effect than chromatic directions, whereas S-cone and equiluminant red and green edges show the same magnitude of positional displacement. The results can be interpreted as the visual system attempting to assign a single hue or brightness to a demarcated region.

Virtual reality (VR) can be used to design and create new types of psychophysical experiments. Its main advantage is that it frees us from the physical limitations of real-life experiments and the hardware and software limitations of experiments running on two-dimensional (2D) displays and computer graphics. However, color calibration of the displays is often required in vision science studies. Recent studies have shown that a standard color calibration of a head-mounted display (HMD) can be very challenging and comes with significant drawbacks. These drawbacks include the need to completely disable tone mapping or to use unlit materials when tone mapping is only partially disabled. In this article, we introduce a new approach that allows for successful color calibration of an HMD and overcomes the disadvantages associated with other solutions. We utilize a new VR engine, Three.js, which offers several advantages. This article details our setup and methodology and provides all the elements required to reproduce the method, including the source code. We also apply our method to evaluate and compare three different HMDs: HTC Vive Pro Eye, Meta Quest Pro, and Meta Quest 3. The results show that the HTC Vive Pro Eye performs excellently, the Meta Quest Pro performs well, and the Meta Quest 3 performs poorly.

Recent studies suggest that the efficiency of cones to detect photons can be evaluated by measuring the equivalent input noise (EIN; derived from contrast thresholds measured in the presence and absence of visual noise) under specific conditions in which the contrast threshold is limited by the variability in the number of photons detected by photoreceptors (i.e., photon noise). These conditions can be identified based on the known properties of photon noise: spatially and temporally white and inversely proportional to the luminance intensity. The present study aims to adapt this psychophysical paradigm to evaluate the efficiency of rods to detect photons. A motion direction discrimination task was used to evaluate the EIN over a wide range of luminance intensities for various spatial and temporal frequencies when the display was blue or red (to which rods have little sensitivity). The target was either a Gabor patch presented at 20 degrees of eccentricity (first experiment) or a rotating sine-wave annulus with a radius of 10 degrees of eccentricity (second experiment). In both experiments, the EIN was found to be inversely proportional to luminance intensity over a limited range of luminance intensities for both display colors. At these luminance intensities, the EIN was roughly independent of the spatial and temporal frequencies, matching the properties of photon noise. Furthermore, under these conditions, contrast thresholds were lower (i.e., better) when the display was blue rather than red, which suggests that vision was mediated by rods when the display was blue. We conclude that the efficiency of rods to detect photons can be evaluated by measuring contrast thresholds in the presence and absence of visual noise over a limited range of luminance intensities with a blue display.

An algorithm is described that for the first time accurately computes the true object-color solid. Previous methods have computed only approximations to the true object-color solid since they have been based on Schrödinger's (partially incorrect) assumption that optimal reflectances contain only two transitions. There are, however, three- and four-transition optimal reflectances and these additional reflectances lead to a larger object-color solid than one based on two-transition reflectances alone. The differences between the approximate and true object-color solids have now been quantified. It is further shown that-despite there being optimal reflectances with up to four transitions-the object-color solid can, nonetheless, be parametrized in terms of only two variables. Finally, a method for solving a previously unsolved problem that Schrödinger posed a century ago is presented. Namely, for any given direction in color space, the algorithm determines the corresponding optimal reflectance.

Smooth pursuit eye movements are used to volitionally track moving objects, keeping their image near the fovea. Pursuit gain, the ratio of eye to stimulus speed, is used to quantify tracking accuracy and is usually close to 1 for healthy observers. Although previous studies have shown directional asymmetries such as horizontal gain exceeding vertical gain, the temporal stability of these biases and the correlation between oculomotor metrics for tracking in different directions and speeds have not been investigated. Here, in testing sessions 4 to 10 days apart, 45 human observers tracked targets moving along two-dimensional trajectories. Horizontal, vertical, and radial pursuit gain had high test-retest reliability (mean intraclass correlation 0.84). The frequency of all saccades and anticipatory saccades during pursuit also had high test-retest reliability (intraclass correlation coefficients = 0.66 and 0.73, respectively). In addition, gain metrics showed strong intermetric correlation, and saccade metrics separately showed strong intercorrelation; however, gain and saccade metrics showed only weak intercorrelation. These correlations are likely to originate from a mixture of sensory, motor, and integrative mechanisms. The test-retest reliability of multiple distinct pursuit metrics represents a "pursuit identity" for individuals, but we argue against this ultimately contributing to an oculomotor biomarker.

A single psychophysical experiment evaluated observers' ability to detect visual patterns embedded in noise; effects of stimulus complexity and observer age were also evaluated. Eighteen younger and older observers participated in the experiment (mean ages were 20.3 and 72.6 years, respectively). On any given trial, observers were presented with two successive temporal intervals; a dotted visual pattern embedded in noise appeared in one temporal interval, whereas a completely random spatial distribution of dots appeared in the other. The observers' task was to indicate which temporal interval contained the pattern. For all observers, there were large effects of both stimulus complexity and amount of noise. Plots of pattern detection accuracy as a function of complexity were determined for both younger and older adults. As a group, the younger adults were able to tolerate higher amounts of complexity (than older adults) and still perform at a threshold level of performance (d' = 1.0). Despite this overall difference in performance between the age groups, there was a large amount of interobserver variability, such that the pattern detection performance of some individual older adults matched or exceeded that of a sizeable number of younger adults-aging is therefore not accompanied by a uniform or necessary decline in pattern detection.

A decade of research has demonstrated that the reported perception of a new stimulus can be biased by task-irrelevant prior stimuli. However, existing studies have primarily focused on explaining the direction and magnitude of this bias effect, often neglecting other relevant aspects of perceptual behavior that may also be influenced by prior stimuli. In this study, we examined how decision speed for a new stimulus might be influenced by prior stimuli in motion-direction estimation tasks. We found that direction reports exhibited a repulsive serial bias along with a systematic response time (RT) effect, where reports were faster when the prior motion direction was more dissimilar to the current motion direction. Follow-up experiments replicated this RT effect and showed that it occurred only when repulsive serial bias was evident. Subsequent analyses revealed that the RT effect was positively correlated with repulsive serial bias, indicating that both effects are driven by common underlying mechanisms. Together, these results demonstrate that prior stimuli not only bias but also modulate response speed to new stimuli, suggesting that existing theories should incorporate decisional mechanisms that influence response speed to fully account for the serial bias phenomenon.

Vision science imposes rigorous requirements for the design and execution of psychophysical studies and experiments. These requirements ensure precise control over variables, accurate measurement of perceptual responses, and reproducibility of results, which are essential for investigating visual perception and its underlying mechanisms. Because different experiments have different requirements, not all aspects of a display system are critical for a given setting. Therefore, some display systems may be suitable for certain types of experiments but unsuitable for others. An additional challenge is that the performance of consumer systems is often highly dependent on specific monitor settings and firmware behavior. Here, we evaluate the performance of four display systems: a consumer LCD gaming monitor, a consumer OLED gaming monitor, a consumer OLED TV, and a VPixx PROPixx projector system. To allow the reader to assess the suitability of these systems for different experiments, we present a range of different metrics: luminance behavior, luminance uniformity across display surface, estimated gamma values and linearity, channel additivity, channel dependency, color gamut, pixel response time, and pixel waveform. In addition, we exhaustively report the monitor firmware settings used. Our analyses show that current consumer-level OLED display systems are promising and adequate to fulfill the requirements of some critical vision science experiments, allowing laboratories to run their experiments even without investing in high-quality professional display systems. For example, the tested Asus OLED gaming monitor shows excellent response time, a sharp square waveform even at 240 Hz, a color gamut that covers 94% of DCI-P3 color space, and the best luminance uniformity among all four tested systems, making it a favorable option on price-to-performance ratio.