In time perception research, we typically measure how an observer perceives time intervals by collecting data from multiple trials with a single estimate recorded on each. However, this gives us limited information about the observer's uncertainty for each estimate, which we usually measure from the variability across trials. Our study tested the potential of a modified reproduction task to provide a duration estimate as well as a measure of uncertainty on a single-trial basis. Participants were instructed to press and hold a key to temporally bracket the end of a learned duration (0.6-4 s) as narrowly as possible. Therefore, we expected the bracket's length to indicate the level of uncertainty. We compared this method to a conventional reproduction task. Taking the mid-point of the bracket as the duration estimate, we found that both methods produced equivalent data. Critically, the bracket length predicted reproduction variability, indicating that a single bracket obtained in an individual trial could potentially provide as much information as multiple reproductions. Additionally, relative variability in bracket start and end positions suggests a combination of additive and multiplicative noise components. Our findings highlight the bracket method as a more efficient and nuanced approach to measure time estimates and their associated uncertainty, expanding the methodological toolkit and opening new avenues in time perception research.

We investigated the influence of the medium on the perception of depicted objects and materials. Oil paintings and their reproductions in engravings were chosen because they are vastly distinctive media while having completely identical content. A total of 15 pairs were collected, consisting of 88 fragments depicting different materials, including fabric, skin, wood and metal. Besides the original condition, we created three manipulations to understand the effect of colour (a greyscale version) and contrast (equalised histograms towards both painting and engraving). We performed rating experiments on five attributes: three-dimensionality, glossiness, convincingness, smoothness and softness. An average of 25 participants finished each of the 20 online experimental sessions (five attributes X four conditions). Besides clear correlations between the two media, the differences mainly show in their means (different levels of perceived attributes) and standard deviations (perceived range). In most sessions, paintings depict a wider range than engravings. In addition, it was the histogram equalisation (global contrast) that made the most impact on perceived attributes, rather than colour removal. This suggests that engravers compensated for the lack of colour by exploiting the possibilities of local contrast.

Predicting the timing of incoming information allows brain to optimize information processing in dynamic environments. However, the effects of temporal predictions on tactile perception are not well established. In this study, two experiments were conducted to determine how temporal predictions interact with conditional probabilities in tactile perceptual processing. In Experiment 1, we explored the range of the interval between preceding ready cues and imperative targets in which temporal prediction effects can be observed. This prediction effect was observed for intervals of 500 and 1,000 ms. In Experiment 2, we investigated the benefits of temporal predictions on tactile perception while manipulating the conditional probability (setting the stimulus onset earlier or later than the predicted moment in short and long intervals). Our results revealed that this effect became stronger as the probability of the stimulus at the predicted time point increased under short-interval conditions. Together, our results show that the difficulty of transferring processing resources increases in temporally dynamic environments, suggesting a greater subjective cost associated with maladaptive responses to temporally uncertain events.

The experiment combined the spatial Stroop paradigm to examine the effect of background location on the perception of arrow or gaze direction in the vertical dimension by manipulating the congruence between the target direction and background location, and to validate a possible cognitive mechanism for gaze direction specificity - inhibiting background location. The results showed that when subjects were required to identify the target direction in a Stroop task (Experiment 1), the gaze cue failed to induce the Stroop effect. However, when subjects were required to judge the congruence between the target direction and the background location (Experiment 2), the gaze cue and the arrow cue both induced the Stroop effect. This suggests that " inhibiting background location" is responsible for the elimination of the spatial Stroop effect by gaze direction, which may one of the mechanisms for gaze direction specificity.

An important aspect to an immersive experience in Virtual Reality is vection, defined as the illusion of self-motion. Much of the literature to date has explored strategies to maximize vection through manipulations of the visual stimulus (e.g., increasing speed) or the experimental context (e.g., framing of the study instructions). However, the role of individual differences (e.g., age, biological sex) in vection susceptibility has received little attention. The objective of the current study was to investigate the influence of individual-difference factors on vection perception in younger and older adults. Forty-six younger adults ( = 25.1) and 39 older adults ( = 72.4) completed assessments of personality traits, field dependence, and visual attention prior to observing a moving visual stimulus aimed at inducing circular vection. Vection was measured using self-reports of onset latency, duration, and intensity. Results indicated that, in both age groups, females experienced longer-lasting vection compared to males. Additionally, the level of field dependence was related to vection intensity and duration in males but not in females. Variability in vection intensity was best explained by a mixture of biological, perceptual, cognitive, and personality variables. Taken together, these findings suggest that individual factors are important for understanding differences in vection susceptibility.

The "Color Circle" is an important chromatic Gestalt in the visual arts. There is not really a formal equivalent in conventional colorimetry. The fact that the hues can be linearly ordered and that such an order is necessarily periodic was intuited by artists in the early 19th century, but only formally explained by Ostwald and later Schrödinger a century later. As with musical keys, various metrical orders are in common use. Is there such a thing as a "well tempered" order? We consider this an issue for experimental phenomenology. We discuss an attempt based on observations by 30 (nonartist) observers.

We introduce a new illusory color phenomenon. The illusion is evoked by two alternating displays comprising various colored disks. Although the colors in the alternating displays are the same, the color appearance of the two displays are quite different. We suggest that apparent motion of the disks modulates the color percepts.

Skin color is one of the colors we are most frequently exposed to. It contains information, such as ethnic group and health status, and numerous studies have demonstrated the influence of various facial attributes on the formation of impressions. However, no research has specifically explored the repercussions of treating changes in skin color as a singular variable. We cross-culturally examined skin color changes along with the red-yellow axis and how they influence facial impressions across six face shapes from three types of ethnicities. A 7-point scale was used for evaluation, and the observers evaluated the impression of face images according to the following six evaluation items: healthiness, preference, brightness, whiteness, transparency, and skin tone. The observers were divided into the following four groups: Japan, China, Thailand, and the Caucasus. Differences in the evaluation and association of skin color with various traits emerged between cultures. For instance, East Asian cultures associated positive attributes with reddish skin colors, whereas Caucasians often linked positive traits with yellowish skin colors. These cultural disparities emphasize the dynamic interplay between culture and perception in assessing facial impressions.

There are two main characteristics of visual information processing when viewing an image by scrolling on a small screen: viewing the image sequentially, section by section, owing to the limited visible area, and moving the image to view the desired section of the image. In this study, we investigated the effects of these characteristics on the encoding of object location. The participants were required to observe an image containing 10 objects under three viewing conditions without a time limit and to recall the location of the target object. The viewing conditions were a scrolling condition, a moving-window condition in which a fixed image was viewed by moving the window, and a no-window condition in which the entire image was viewed without a window. The results showed that although the recall accuracy did not differ among the conditions, the observation time increased in the order of scrolling, moving-window, and no-window conditions. These results indicate that in a scrolling view, the object location can be encoded with the same accuracy as that in a full view; however, more time is required for encoding. This finding suggests that viewing the image sequentially and moving the image degrade the encoding of object location.

We describe a new phenomenon-partial object doubling-in which the perceived contours of peripherally viewed moving targets become distorted and duplicated. The effect appears to arise due to interactions between physically drawn contours and the strong negative afterimages that are dynamically released during stable viewing of the displays. An online demo is provided where the effect can be experienced and relevant parameters manipulated.

Transient-induced fading is a phenomenon where a peripheral target perceptually fades when a surrounding object is flashed. It has been suggested that the transient-induced fading could be affected not only by the lower-level factors such as the luminance contrast change, but also by the higher-level factors such as Gestalt grouping by similarity. In the present study, Experiment 1 investigated whether the perceptual fading of a visual target could be strongly induced when a ring area surrounding the target with high luminance contrast disappeared rather than appeared. Experiment 2 examined the effect of the (dis)appearance of a higher-level object (Kanizsa-type subjective contour) on the fading perception. Experiment 3 further investigated whether the rating of the perceived effortlessness of a subjective contour could be positively correlated with the fading duration of the target. Our results revealed that perceptual fading was mainly induced by the disappearance of fan areas inside black disks producing a subjective contour surrounding the target. Disappearance of a perceptual object at the representation level does not trigger the transient-induced fading even if a higher-level factor (e.g., grouping by similarity) affects the fading objects.

Previous research on haptic search using sandpaper with different roughness levels as a target and distractors showed that rough sandpaper among fine "pops out" and can be searched for in a shorter time than when the roles of the target and distractors are reversed. However, it is not clear whether the same search asymmetry occurs with differences in the shapes of tactile symbols on capsule paper. To explore this possibility, we conducted a haptic search experiment using circles with or without a dot on capsule paper as a target and distractors, which are often used as point symbols in tactile maps for the blind. Contrary to our expectations, haptic search asymmetry did not occur between these two tactile symbols. Regardless of target type, the search times increased in proportion to the number of items (distractors plus target), as participants tended to adopt serial search strategy in which they placed their index or middle finger on the tactile symbol to distinguish it every time they found a new one. The ratio of the search times for target-absent to target-present trials is precise alignment with the occurrence rate of repetitive search trials.

A rotating stimulus of alternating red and white sectors generates a faint pink fill throughout the image. The trailing cyan after images of the red sectors quickly become the brightest regions in the image, providing an index of the overall illumination that triggers a shift of the white point. Actual white areas then shift in the opposite direction and appear pink.

It has been suggested that caricaturing enhances esthetic appeal, by making an image more strongly stimulate those areas of the brain encoding the subject's distinctive features than does the subject itself. However, some experimental work suggests that people prefer faces with proportions closer to average, or closer to a particular template. It might be that familiarity with the face is important if caricaturing is to increase the esthetic appeal of a likeness. Here we examined how automated caricaturing of photographs of nominal celebrities influenced judgments of esthetic appeal, and how familiarity with the celebrities affected these. Caricaturing monotonically decreased the esthetic appeal of the celebrity photographs, with subjects' familiarity with the celebrity not influencing this relationship. The degree to which caricaturing influenced esthetic appeal was not correlated with judgments of relative spatial dimensions for a simple shape, either in a discrimination threshold experiment or a peak-shift experiment.

Pictorial awareness is addressed through experimental phenomenology involving over 90 naïve participants. Since one can't look at the "same" picture twice the study uses one-shot trials. The participant's fascination for the duration of a session is held through the artistic principle of theme and variation. Six variations focus on the theme of pictorial geometry, both two-dimensional and three-dimensional. Major findings are: Idiosyncratic deviations from veridical are huge as compared to common textbook "effects." Observers wield arbitrary heuristics for tasks that are "formally related." The assumption of a common formal framework is apparently unsound. The notion of "inverse optics" is misleading. A fair fraction of the population appears to lack monocular stereopsis as intuitive awareness. It suggests an as-yet unrecognized, but perhaps common variety of aphantasia.

In this narrative review, we take a critical look at the various attempts that have been made to augment home (or personal) entertainment experiences via the addition of some form of digitally controlled tactile stimulation. There has been an explosive growth in the market for home entertainment in recent years, and a majority of smartphones and other wearable electronic devices are now touch-enabled. As such, it is important to consider the challenges and potential opportunities for enhanced multisensory entertainment that may result from the introduction of tactile/haptic stimulation in the context of audiovisual digital storytelling and/or gaming. The key technological, financial (and legal), cognitive, and creative/artistic, challenges associated with the tactile augmentation of home entertainment experiences are outlined. Tactile augmentation, in the sphere of both public and personal entertainment, is more likely to succeed when it goes beyond the merely pleonastic vibrotactile reproduction of those interactions/events than can already be seen and/or heard on screen. At the same time, however, it remains uncertain under what conditions immersion in an entertainment experience will be enhanced by the addition of some form of primitive digital tactile stimulation. Ultimately, until a clear usage case can be made for the benefits of introducing a tactile element to home entertainment, it is unlikely to gain traction and switch from being merely a gimmick to more of a valuable element of multisensory storytelling.

The rubber hand illusion involves the sense of body ownership of a fake hand. We showed that concurrent visuotactile stimuli to rubber and real hands can induce the embodiment of rubber hands when both rubber hands are positioned on the table. This phenomenon indicates that the brain has an integrated representation of the sense of body ownership for both hands.

There has long been interest in augmenting cinematic and other forms of public entertainment through tactile and/or bodily (i.e., vestibular) stimulation. In this narrative historical review, the early history of touch (or haptics, as it is sometimes called) and other forms of bodily stimulation (e.g., motion platforms) in the context of entertainment is critically reviewed, with a focus on early cinema as well as other early examples of immersive virtual reality travel experiences. Critically, various challenges have limited the introduction of such additional channels of sensory stimulation. These include technological, financial, cognitive, creative, ethical/artistic, and also legal considerations, given the many patents that currently exist covering commercial digital tactile stimulation (e.g., in the gaming context). Taken together, these challenges help to explain why it is that despite the early interest in "the feelies" (e.g., an envisioning of film that includes tactile sensations by Aldous Huxley, in his novel Brave New World), touch-enhanced cinema and storytelling have never really caught on in the mainstream in the way that, say, the talkies so obviously did following the introduction of sound into cinema in the early decades of the 20th century. Nevertheless, identifying the potential successful use cases that have emerged from previous attempts to augment public entertainments with tactile/bodily stimulation will likely provide useful guidelines for the future tactile augmentation of home entertainment.

The Delboeuf illusion occurs when two circles (test figures) of equal radius are placed side by side and surrounded by concentric circles (inducers) of varying radii, resulting in the test figure being misestimated depending on the size of the surrounding inducer. This study conducted three experiments to explore the impact of shape and the contour attraction and parallel attraction on the Delboeuf illusion for different shapes. In Experiment 1 (= 64), the test figures remained as circles while the inducers varied in shape. Experiment 2 (= 64) involved simultaneous changes in the shape of both the test figures and the inducers. Experiment 3 (= 64) replicated Experiment 2, with the exception that the areas of the inducers were equal and the distances between the inducers and the test figures were also equal. We conclude that the shape of the inducer and the test figure had an impact on the visual size perception, and in the magnitude of the Delboeuf illusion, varied depending on contour attraction. Configurations with circles or shapes resembling circles exhibit contour attraction, while configurations with shapes possessing longer parallel lines shift toward parallel attraction, both attractions enhance the perceived magnitude of the Delboeuf illusion.

The spread of COVID-19 has drastically increased the number of people wearing masks in public areas and the opportunities to evaluate others' faces based on limited information. This study investigates the cognitive bias in judging the attractiveness of faces partially hidden by sanitary masks. Experiment 1 revealed that men rated women's faces as more attractive when wearing masks, specifically in the context of rating women as romantic partners; however, this mask bias was absent when men rated women as friends. On the other hand, women did not show the mask bias irrespective of the assumed social relationship. Experiment 2 demonstrated that the mask bias among elderly men was less affected by the assumed social relationship (or the possibility of reproduction), compared to young men, though they showed the bias itself. These results suggest that the cognitive strategies related to reproduction underlie the attractiveness judgment of the partial faces.

Looking leads gaze to objects; seeing recognizes them. Visual crowding makes seeing difficult or impossible before looking brings objects to the fovea. Looking before seeing can be guided by saliency mechanisms in the primary visual cortex (V1). We have proposed that looking and seeing are mainly supported by peripheral and central vision, respectively. This proposal is tested in an observer with central vision loss due to macular degeneration, using a visual search task that can be accomplished solely through looking, but is actually impeded through seeing. The search target is an uniquely oriented, salient, bar among identically shaped bars. Each bar, including the target, is part of an " " shape. The target's is identical to, although rotated from, the other 's in the image, which normally causes confusion. However, this observer exhibits no such confusion, presumably because she cannot see the 's shape, but can look towards the target. This result demonstrates a critical dichotomy between central and peripheral vision.

This paper provides an overview of the many different ways that light interacts with surfaces in the natural environment to provide useful information for visual perception. It begins with a discussion of how the concept of light has evolved over the course of human history. It then considers a wide variety of optical phenomena including Lambert's laws of illumination, the effects of microscopic surface structure on patterns of reflection, the bidirectional reflectance distribution function, the refraction of transmitted light, chromatic dispersion, thin film interference, sub-surface scattering, the Fresnel effects, indirect illumination from multiple reflections, caustics, and the structure of the light field. The primary goal of this discussion is to provide the necessary background information to help students and young researchers more easily understand the scientific literature on the perception of 3D shape and material properties from patterns of image shading.

The classical body ownership illusion, such as the rubber hand illusion, is achieved through appropriate proprioceptive displacement within temporal and spatial constraints that do not exceed the limits of proprioceptive flexibility. In the 2023 Best Illusion of the Year Contest, we introduced (BEI), which creates the illusion of owning a dramatically deformed earlobe through immediate visuotactile stimulation and seemingly challenges classical proprioceptive boundaries. The laboratory experiment examined the mechanics of this illusion, revealing a significant interaction between tactile earlobe pulling and visual miming that contributed to the enhanced perception of earlobe stretch. Importantly, 88% of the participants confirmed the illusory earlobe stretch (a rating of +4 or higher on a 7-point scale). More than half reported an earlobe descent of >10 cm within a 10-s visuotactile stimulation. The findings suggest that BEI operates on a distinct principle separate from proprioceptive modulation in contrast to classical ownership illusions.

Evolutionary psychology suggests that we are attuned to relevant information in the environment. For example, attention may be attracted by physical beauty because it is important for finding a partner with good reproductive health. Consistently, previous studies found that attention stayed longer on attractive than unattractive faces. We asked whether this tendency was automatic and varied participants' implicit search intentions to be either consistent or inconsistent with the presumably automatic tendency to attend to attractive faces. To create an implicit intention to look at attractive faces, participants searched for a happy face in an array of neutral faces because happy faces are rated as more attractive than neutral faces. To create the opposite intention to look at unattractive faces, participants searched for a disgusted or sad face because disgusted or sad faces are rated as less attractive than neutral faces. We found longer fixation durations on attractive faces when participants searched for happy faces. When participants searched for disgusted or sad faces, however, fixation durations were longer on unattractive faces. Thus, the search task determined whether attractive faces were looked at longer. The tendency to attend to attractive faces is therefore not automatic but can be overruled by search intentions.

Auditory branding is undoubtedly becoming more important across a range of sectors. One area, in particular, that has recently seen significant growth concerns the introduction of music and soundscapes that have been specifically designed to match a particular scent (what one might think of as "audio scents" or "sonic scents"). This represents an exciting new approach to the sensory marketing of fragrance and for industries with strategic sensory goals, such as cosmetics. Crucially, techniques such as the semantic differential technique, as well as the emerging literature on crossmodal correspondences, offer both a mechanistic understanding of, and a practical framework for, those wishing to rigorously align the connotative meaning and conceptual/emotional/sensory associations of sound and scent. These developments have enabled those working in the creative industries to start moving beyond previously popular approaches to matching, or translating between the senses, that were traditionally often based on the idiosyncratic phenomenon of synaesthesia, toward a more scientific approach while nevertheless still enabling/requiring a healthy dose of artistic inspiration. In this narrative historical review, we highlight the various approaches to the systematic matching of sound with scent and review the various marketing activations that have appeared in this space recently.

The face-cube illusion was made by Jean Beuchet in 1966 (as indicated in the device) and this effect was not published. For this reason, it seems important to present this visual phenomenon. The effect is obtained from connected curved wire construction presented in three-dimensional space. The orientation of wires can be modified, and it can be perceived as either a cube or a face depending on one's viewing point.

We present a practical example for the phenomenon of color assimilation. We describe the advances in research on color assimilation from von Bezold, to Albers and Munker, and provide a compelling example of the recently described "Confetti-illusion" by Novick. Our research introduces a novel aspect by showing how unripe and greenish looking oranges can be perceived as ripe and vibrantly colored when viewed through an orange net. These findings highlight the significant implications of color assimilation in everyday consumer environments, offering a fresh perspective on how visual perception can be manipulated.

The lightness of an object is an intrinsic property that depends on its surface reflectance spectrum. The visual system estimates an object's lightness from the light reflected off its surface. However, the reflected light also depends on object extrinsic properties of the scene, such as the light source. For stable perception, the visual system needs to discount the variations due to the object extrinsic properties. We characterize this perceptual stability for variation in two spectral properties of the scene: the reflectance spectra of background objects and the intensity of light sources. We measure human observers' thresholds of discriminating computer-generated images of 3D scenes based on the lightness of a spherical target object in the scene. We measured change in discrimination thresholds as we varied the reflectance spectra of the objects and the intensity of the light sources in the scene, both individually and simultaneously. For small amounts of extrinsic variations, the discrimination thresholds remained nearly constant indicating that the thresholds were dominated by observers' intrinsic representation of lightness. As extrinsic variation increased, it started affecting observers' lightness judgment and the thresholds increased. We estimated that the effects of extrinsic variations were comparable to observers' intrinsic variation in the representation of object lightness. Moreover, for simultaneous variation of these spectral properties, the increase in threshold squared compared to the no-variation condition was a linear sum of the corresponding increase in threshold squared for the individual properties, indicating that the variations from these independent sources combine linearly.

When one walks toward a crowd of pedestrians, dealing with their biological motion while controlling one's own self-motion is a difficult perceptual task. Limb articulation of a walker is naturally coupled to the walker's translation through the scene and allows the separation of optic flow generated by self-motion from the biological motion of other pedestrians. Recent research has shown that if limb articulation and translation mismatch, such as for walking in place, self-motion perception becomes biased. This bias may reflect an illusory motion attributed to the pedestrian crowd from the articulation of their limbs. To investigate this hypothesis, we presented observers with a simulation of forward self-motion toward a laterally moving crowd of point-light walkers and asked them to report the perceived lateral speed of the crowd. To investigate the dependence of the crowd speed percept on biological motion, we also included conditions in which the points of the walker were spatially scrambled to destroy body form and limb articulation. We observed illusory crowd speed percepts that were related to the articulation rate of the biological motion. Scrambled walkers also produced illusory motion but it was not related to articulation rate. We conclude that limb articulation induces percepts of crowd motion that can be used for interpreting self-motion toward crowds.

Backward masking is a powerful phenomenon that can reduce, often to zero, the visibility of targets. Here, we show that when the masking is less than completely effective so that the target remains visible, the masking has other effects, specifically reducing the perceived size of the target.