I-Perception最新文献

The search for stereograms that reveal depth features to two eyes that are concealed from each alone commenced with announcement of the invention of the stereoscope by Wheatstone in 1838. The paired figures he presented to the eyes were mostly simple outline drawings of geometrical objects, in order to reduce or remove monocular indications of depth. One stereogram, consisting of dots, yielded depth without monocular recognition; later others did so with more complex stereograms. Most notably in 1960, Julesz achieved this with computer-generated random-dot stereograms. Prior to Julesz similar patterns were hand-made, photographed and paired to yield stereograms by Cajal, Mobbs, Kompaneysky, and Aschenbrenner. Wheatstone did not recognise the significance of his simple dot stereogram possibly because he was interested in representing objects rather than surfaces stereoscopically. Thus, it can be argued that the precursors of random-dot stereograms were produced by Wheatstone in his article describing the invention of the stereoscope.

When a green/blue object is presented on a red background and viewed in peripheral vision, the object is seen to flash twice or to flicker (the peripheral flicker illusion). We showed that the ratio of photopic luminances of the object and the red background determines the optimal photopic luminance of the green/blue object required for the illusion to occur. The results were analyzed using scotopic luminance to investigate the role of rod responses. It was found that the scotopic luminance of the green/blue object should be higher than that of the red background for the illusion to occur. This suggests that the red background enhances the flickering impression of the object when there is a sudden increase in the rod responses.

Human observers can sometimes attribute animacy or agency to non-living objects, such as robots, perceiving them as if they were alive. In particular, the movement pattern of non-living things is a key feature for perceiving life. It is also well known that the pattern of the eyes is also an important feature for the perception of the sense of life. The present study investigated how the animacy impression of a cube-shaped robot moving along the Perlin noise trajectory could be influenced by the visual patterns of the eyes, such as eye positions and gaze directions. The eyes were presented on the top surface of the cube-shaped robot. Participants were asked to rate animacy impressions of the robot. These impressions included the impression of a live animal, having intention and moving in a self-propelled manner. These impressions were consistently higher when the eyes were presented on the side of the robot's direction of motion than when they were presented on the side orthogonal to, or opposite to, the robot's direction of motion. In general, the animacy impressions were largely comparable regardless of whether the robot's gaze direction aligned with, was orthogonal to, or opposed its motion direction. However, the impression of intention was stronger when the gaze direction at the front side of the object was consistent with the motion direction than when it was inconsistent. We discuss the evolutionary role of eye position in determining animacy impressions.

When a stationary ring of points precedes or follows an "inducing ring" of points that spins so rapidly it appears to be a steady outline circle the stationary ring often appears to momentarily rotate in the direction of the inducing ring's spin. In previous studies of this "motion bridging effect" (MBE) the start and stop positions of the inducing ring points were spatially aligned with the points of the stationary ring. Here we report that as these start and stop positions are progressively displaced across the spaces separating the points of the stationary test ring the MBE direction congruency effect decreases and then reverses, so that the illusory rotation is predominantly opposite to the direction of the inducing ring spin. This reverse congruency effect peaks when the points of the inducing ring start and stop midway between the points of the stationary test ring, with congruency returning as further displacements bring the point positions back into alignment. We conclude that the MBE is not only determined by the inducing ring's rotation direction, but also by an interaction between the inducing and test ring points at the moment the inducing ring starts or stops. We consider various ways of accounting this effect. Explanations based on direction cuing by apparent motion steps, the motion aftereffect, and biphasic impulse responses are ruled out. A speculative explanation based on perceptual heuristics that interpret the competing motion direction signals generated by a transformation of contour segments of the spinning ring into the points of the stationary ring (or vice-versa) is proposed.

During WWI, dazzle camouflage involved painting allied shipping with bold geometric patterns to disrupt the perceptions of enemy submariners. The first experiment to provide quantitative results on this (Blodgett, 1919; MIT Libraries, MA) used scale models and mechanical simulation, and reported enormous perceptual errors for their perceived direction of travel (up to ∼60°), possibly due to a "twist" effect from forced perspective. However, Blodgett's work did not meet modern standards and the organisation of his report complicates evaluation. Here, we produce (i) reformatted and (ii) heavily edited versions of the original report to improve readability, and (iii) provide a critical reappraisal of the work including (iv) a detailed reanalysis of Blodgett's data and (v) a new control experiment on edited images of the original stimuli. After addressing problems with Blodgett's analysis and control experiment, we found results indicating a twist of only about 7°, but a much larger "hysteresis" effect (∼19-23°) where perceived direction was drawn to the horizon regardless of dazzle. This effect combined both constructively and destructively with "twist", depending on the direction of the target ship. These reappraised findings resolve an apparent conflict with the second quantitative experiment on dazzle ships conducted over a century later using computer displays online (Lovell et al., 2024; Royal Society Open Science). We conclude that Blodgett's approach and data remain of interest today, but his conclusions substantially overestimated the effectiveness of dazzle camouflage in biasing the perceived directions of ships. However, other potential benefits of dazzle, including perceptual variance, await systematic investigation.

It is well known that aging affects fundamental perceptual functions. Numerous studies have investigated age-related changes in visual motion perception and demonstrated that aging impairs motion processing. However, limited studies have explored age-related changes in auditory motion perception, and whether aging influences auditory motion perception based on interaural level differences remains unknown. This study examined age-related differences in the discrimination of auditory motion direction based on interaural level differences. We conducted two experiments to estimate the signal-to-noise ratio and motion coherence thresholds required to discriminate auditory motion and visual motion directions, respectively, in younger and older adults. Results showed that age significantly impairs visual motion discrimination; however, it does not impair auditory motion discrimination. These findings suggest that aging does not affect auditory motion perception based on interaural level differences, at least with the broadband noise used in this experiment.

When a photograph of the back of a hand with the fingers extended to the depth is observed upside-down, the hand appears vertically squashed, with extremely short fingers. The first aim of this study was to quantitatively measure the "frog hand illusion (FHI)", named after its bizarre appearance, and the second aim was to examine whether the dominant hand affects the strength of FHI. We measured the apparent shortening of the fingers using the method of constant stimuli. The results showed that the fingers of the inverted hand appeared to be shorter than those of the upright hand by about 5% on average. No effect of the dominant hand was observed. We propose the hypothesis that FHI occurs because of the attenuation of perceptual constancy, which might stem from observing the hand image from an atypical viewpoint.

Monocular blur sometimes impairs locomotion; however, it is not always clear when this will happen. Optic flow (the apparent motion of scene texture elements that occurs during self-motion) provides powerful signals about the direction of travel. Here, we test whether monocular blur impairs heading perception from optic flow compared to full vision under various levels of optic flow degradation. Participants (N = 52, mean age = 30 years) completed contrast sensitivity, visual acuity, and heading perception tasks with rich or degraded optic flow, with or without monocular blur (0.4 logMAR Bangerter filter over the non-dominant eye, full vision in the dominant eye). Heading perception was assessed using a browser-based task where the participants viewed a 3-second video consistent with self-motion over a textured ground plane (moving towards the horizon at an offset heading ranging from -20 to +20°) and identified the point on the horizon towards which they were travelling. The measures of each participant's performance were the absolute and directional angular error between the heading offset and their response. Monocular blur and degraded flow were associated with an increase in absolute heading error and a larger underestimation of heading angle, with the worst performance observed when monocular blur and degraded flow were combined. These results suggest that the impact of monocular blur on heading perception becomes apparent only when optic flow signals are weak (e.g., night-time driving). These findings support the theory that monocular blur and the richness of visual information interact to produce deficits in heading perception.

Two experiments were conducted to explore the impact of the distance of a visual scale employed in the crossmodal matching method dubbed See What You Feel (SWYF) used to study the Uznadze haptic aftereffect. Previous studies reported that SWYF leads to a general underestimation of out-of-sight handheld spheres, which seems to increase with visual scale distance. Experiment 1 tested the effect of visual scale distance in haptic-to-visual crossmodal matching. A 19-step visual scale, made of actual 3D spheres (diameters ranging from 2.0 to 5.6 cm), was set at one of three possible distances (30, 160, 290 cm); participants' task was to find the matching visual spheres for four out-of-sight handheld test spheres (diameters 3.0, 3.8, 4.6, 5.0 cm). Results confirmed the underestimation effect and only partially confirmed the role of scale distance. Experiment 2 investigated the role of scale distance in a visual-to-visual matching task in which the same visual scale was employed, set at one of three distances (37, 160, 290 cm). Participants' task was to find a match for the same four test stimuli. Results showed no statistical difference between matched and actual sphere sizes with distance 37 cm; underestimations were observed with the far distances, thus reflecting overestimations of scale sphere sizes. Results from both experiments allow us to conclude that the underestimation effect observed with SWYF is a general feature of haptic-to-visual crossmodal matching, and that the SWYF method is a valuable tool for measuring haptic size perception with handheld stimuli when the visual scale is set at a visually comfortable peripersonal distance.

This study introduces pictorial technique (PT) as an innovative method in empirical aesthetics to assess aesthetic impressions of visual artworks. Forty participants, drawn from general and artistic populations, evaluated nine paintings representing abstract, traditional figural, and modern figural styles using the PT and aesthetic rating scales. The PT enabled participants to mark impactful areas within artworks, transforming subjective impressions into spatial data visualized as heatmaps. Results showed that, on average, participants marked 17% of the painting's surface, with notable stylistic differences in attention distribution. Abstract paintings exhibited dispersed attention, focusing on geometric shapes and color contrasts, while traditional figural works concentrated on narrative elements. Modern figural paintings demonstrated a hybrid pattern, emphasizing both individual details and broader compositions. The study also tested the hypothesis that dimensional characteristics of marked areas correspond to aesthetic preferences. Findings revealed that the size of marked regions modestly predicted ratings on Interestingness and Comprehensibility scales, though the explained variance was limited. The study highlights the PT's potential for visualizing aesthetic engagement and suggests its integration with physiological methods like eye-tracking to explore the interaction between spontaneous attention and reflective aesthetic judgments. These findings underscore PT's adaptability and value as a tool for investigating aesthetic experiences across diverse art forms and cultural contexts.