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The same object produces quite distinct images in the cortical representation, depending on whether it is looked at foveally or with the periphery, yet some form of size constancy prevents us from experiencing objects inflating or deflating as we move our eyes. According to the prominent sensorimotor account of vision by O'Regan and Noë [1], we constantly learn to discount the predictable sensory effects of motor actions, such as the projection of a stimulus on a larger cortical area as it gets foveated. Although previous studies have shown that foveal and parafoveal inputs can be associated in visual memory [2, 3], trans-saccadic prediction error could in principle re-calibrate even the appearance of peripheral and foveal stimuli. Here we introduce a new paradigm that induces such changes in the relative appearance of peripheral and foveal stimuli when directly compared. Repeated exposure to a trans-saccadic change in size, though unnoticed by most observers, induced a substantial modification of perceived size that lasted at least 1 day. Prediction is not limited to the motor system but can also occur for the sensory effects of external events, such as stimulus motion. We show that perceptual re-calibration can occur in the absence of eye movements if the change in size occurs predictably while objects move across the visual field. Perceptual uniformity emerges due to the continuously updated prediction of foveal appearance based on peripheral appearance.

Long tradition in philosophy and in empirical psychology has it that the perceptual recovery of enduring objective size and shape proceeds through initial spatial appearance experiences—like the sensed changing visual field size of a receding car, or the shifting shape appearance of a coin as it rotates in depth. The present paper carefully frames and then critically examines such proposals. It turns out that these are contingent, empirical matters, requiring close examination of relevant research in perception science in order to decide. The paper concludes with extended discussions of the empirical study of the perception of slant, size, and shape.

Our visual system can easily estimate the constant color and material of external objects despite dynamic changes in the retinal image across viewpoints and illuminations in natural scenes. It is commonly believed that this high-level visual function, called "perceptual constancy," is acquired through postnatal learning [1], building upon low-level functions that have developed earlier, such as image discrimination. However, we demonstrate here that before developing perceptual constancy, 3- to 4-month-old infants have a striking ability to discriminate slight image changes due to illumination that are not salient for adults. These young infants lose this ability after 5 months of age and then develop an ability to perceive distal surface properties (glossy or matte) at 7-8 months of age. Moreover, we identify the transition period between these two functions at 5-6 months of age, wherein infants show difficulty in both image and surface discrimination. These findings support the notion that acquiring perceptual constancy leads to a loss of sensitivity to variant information, which is negligible for constant surface material perception. We suggest that the immature visual system may initially directly access local image features and then develops a complementary constant neural representation of the properties of an object.

Vergence (the angular rotation of the eyes) is thought to provide essential distance information for size constancy (perceiving an object as having a constant physical size). Evidence for this comes from the fact that a target with a constant retinal size appears to shrink as the rotation of the eyes increases (indicating that the target has reduced in distance). This reduction in perceived size is supposed to maintain a constant perception of physical size in natural viewing conditions by cancelling out the increasing size of the retinal image as an object moves closer. Whilst this hypothesis has been extensively tested over the last 200 years, it has always been tested in the presence of confounding cues such as a changing retinal image or cognitive cues to distance. Testing members of the public with normal vision, we control for these confounding cues and find no evidence of vergence size constancy. Statement of Relevance This work has important implications for the neural basis of size constancy and for multisensory integration. First, leading work on the neural basis of size constancy cannot differentiate between recurrent processes in V1 (based on triangulation cues, such as vergence) and top-down processing (based on pictorial cues). Since our work challenges the existence of vergence size constancy, and therefore much of the basis of the recurrent processing account, our work indicates that top-down processing is likely to have a much more important role in size constancy than previously thought. Second, vergence size constancy is thought to be largely responsible for the apparent integration of the retinal image with proprioceptive distance information from the hand in the Taylor illusion (an afterimage of the hand viewed in darkness appears to shrink as the observer’s hand is moved closer). This explanation for the Taylor illusion is challenged, and a cognitive account proposed instead.

Successful categorization requires listeners to represent the incoming sensory information, resolve the “blooming, buzzing confusion” inherent to noisy sensory signals, and leverage the accumulated evidence towards making a decision. Despite decades of intense debate, the neural systems underlying speech categorization remain unresolved. Here we assessed the neural representation and categorization of lexical tones by native Mandarin speakers (N = 31) across a range of acoustic and contextual variabilities (talkers, perceptual saliences, and stimulus-contexts) using functional magnetic imaging (fMRI) and an evidence accumulation model of decision-making. Univariate activation and multivariate pattern analyses reveal that the acoustic-variability-tolerant representations of tone category are observed within the middle portion of the left superior temporal gyrus (STG). Activation patterns in the frontal and parietal regions also contained category-relevant information that was differentially sensitive to various forms of variability. The robustness of neural representations of tone category in a distributed fronto-temporoparietal network is associated with trial-by-trial decision-making parameters. These findings support a hybrid model involving a representational core within the STG that operates dynamically within an extensive frontoparietal network to support the representation and categorization of linguistic pitch patterns.

Perception of a sound is influenced by spectral properties of surrounding sounds. When frequencies are absent in a preceding acoustic context before being introduced in a subsequent target sound, detection of those frequencies is facilitated via an auditory enhancement effect (EE). When spectral composition differs across a preceding context and subsequent target sound, those differences are perceptually magnified and perception shifts via a spectral contrast effect (SCE). Each effect is thought to receive contributions from peripheral and central neural processing, but the relative contributions are unclear. The present experiments manipulated ear of presentation to elucidate the degrees to which peripheral and central processes contributed to each effect in speech perception. In Experiment 1, EE and SCE magnitudes in consonant categorization were substantially diminished through contralateral presentation of contexts and targets compared to ipsilateral or bilateral presentations. In Experiment 2, spectrally complementary contexts were presented dichotically followed by the target in only one ear. This arrangement was predicted to produce context effects peripherally and cancel them centrally, but the competing contralateral context minimally decreased effect magnitudes. Results confirm peripheral and central contributions to EEs and SCEs in speech perception, but both effects appear to be primarily due to peripheral processing.

Our visual system affords a distance-invariant percept of object size by integrating retinal image size with viewing distance (size constancy). Single-unit studies with animals have shown that real changes in distance can modulate the firing rate of neurons in primary visual cortex and even subcortical structures, which raises an intriguing possibility that the required integration for size constancy may occur in the initial visual processing in V1 or even earlier. In humans, however, EEG and brain imaging studies have typically manipulated the apparent (not real) distance of stimuli using pictorial illusions, in which the cues to distance are sparse and not congruent. Here, we physically moved the monitor to different distances from the observer, a more ecologically valid paradigm that emulates what happens in everyday life. Using this paradigm in combination with electroencephalography (EEG), we were able for the first time to examine how the computation of size constancy unfolds in real time under real-world viewing conditions. We showed that even when all distance cues were available and congruent, size constancy took about 150 ms to emerge in the activity of visual cortex. The 150-ms interval exceeds the time required for the visual signals to reach V1, but is consistent with the time typically associated with later processing within V1 or recurrent processing from higher-level visual areas. Therefore, this finding provides unequivocal evidence that size constancy does not occur during the initial signal processing in V1 or earlier, but requires subsequent processing, just like any other feature binding mechanisms.

This article explores ways in which modern experimental psychology can provide information about aspects of the processes involved in the creation of visual art. Many areas of research in the fields of neuroscience and cognitive neuropsychology yield information that can be used to develop techniques to benefit the production of art. Several phenomena are discussed to provide a comprehensive perspective on the psychological, behavioural and physiological processes that influence the creation of artwork. Keywords: paradoxical facilitation, cognitive psychology, system 1, system 2, verbal overshadowing, perceptual constancy, categorical, coordinate, TMS

Vision is suppressed during saccadic eye movements. To create a stable perception of the visual world we must compensate for the gaps in visual input caused by this suppression. Some theories of perceptual stability, such as the Saccade Target Object Theory (McConkie & Currie, 1996), propose that stability relies on object correspondence across saccades. According to these views, the visual system encodes features of the saccade target into visual working memory (VWM) before a saccade is made. After the saccade, participants attempt to locate those features within a small region near the fovea. If this locating process succeeds, perceptual stability is maintained. The present study investigated directly whether perceptual stability relies on VWM. If it does, perceived stability should be impaired when VWM is loaded with other visual information. Participants detected saccade target displacements while simultaneously maintaining a VWM or verbal working memory (AWM) load. In three experiments, a VWM load negatively impacted participants' ability to detect saccade target displacements and the saccade target displacement task negatively impacted memory for VWM task items. Neither of these effects were apparent when AWM was loaded, suggesting that performance on VWM and saccade target displacement detection tasks, and thus perceptual stability, relies on VWM resources. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Detection of a target tone in a simultaneous multi-tone masker can be improved by preceding the stimulus with the masker alone. The mechanisms underlying this auditory enhancement effect may enable the efficient detection of new acoustic events and may help to produce perceptual constancy under varying acoustic conditions. Previous work in cochlear-implant (CI) users has suggested reduced or absent enhancement, due perhaps to poor spatial resolution in the cochlea. This study used a supra-threshold enhancement paradigm that in normal-hearing listeners results in large enhancement effects, exceeding 20 dB. Results from vocoder simulations using normal-hearing listeners showed that near-normal enhancement was observed if the simulated spread of excitation was limited to spectral slopes no shallower than 24 dB/oct. No significant enhancement was observed on average in CI users with their clinical monopolar stimulation strategy. The variability in enhancement between CI users, and between electrodes in a single CI user, could not be explained by the spread of excitation, as estimated from auditory nerve evoked potentials. Enhancement remained small, but did reach statistical significance, under the narrower partial-tripolar stimulation strategy. The results suggest that enhancement may be at least partially restored by improvements in the spatial resolution of current CIs.

Properties like shape, size, and colour exhibit perceptual constancy: they appear to remain constant throughout variations in the conditions under which they are perceived. A number of writers have suggested that “apparent properties”, mind-independent relational properties that vary with the perceptual conditions, play an essential role in explaining perceptual constancy. On this view, when we see, e.g. a penny from an oblique angle, we see the circularity of the penny by or in virtue of seeing a mind-independent relational apparent property (its elliptical look). This chapter argues that views which explain the perception of constant properties of objects by appealing to perception of mind-independent apparent properties are structurally similar to sense-datum theories of perception; as such, they face many of the same challenges. It concludes that apparent properties play at best a modest explanatory role, functioning as the objects of awareness when we direct our attention in the appropriate ways.

The long-term spectrum of a preceding sentence can alter the perception of a following speech sound in a contrastive manner. This speech context effect contributes to our ability to extract reliable spectral characteristics of the surrounding acoustic environment and to compensate for the voice characteristics of different speakers or spectral colorations in different listening environments to maintain perceptual constancy. The extent to which such effects are mediated by low-level "automatic" processes, or require directed attention, remains unknown. This study investigated spectral context effects by measuring the effects of two competing sentences on the phoneme category boundary between /i/ and /e/ in a following target word, while directing listeners' attention to one or the other context sentence. Spatial separation of the context sentences was achieved either by presenting them to different ears, or by presenting them to both ears but imposing an interaural time difference (ITD) between the ears. The results confirmed large context effects based on ear of presentation. Smaller effects were observed based on either ITD or attention. The results, combined with predictions from a two-stage model, suggest that ear-specific factors dominate speech context effects but that the effects can be modulated by higher-level features, such as perceived location, and by attention. (PsycINFO Database Record

Common sense takes the physical world to be populated by mind-independent particulars. Why and with what right do we hold this view? Early phenomenologists argue that the common sense view is our natural starting point because we experience objects as mind-independent. While it seems unsurprising that one can perceive an object being red or square, the claim that one can experience an object as mind-independent is controversial. In this paper I will articulate and defend the claim that we can experience mind-independence by mainly drawing on the work of the Gestalt psychologist Karl Duncker who, in turn, built on Husserl’s work. In the development of this claim the notion of a limit – either a maximum or minimum – of perception will play an important role.

A common form of the Ponzo illusion involves two test probes of equal size, embedded in a planar linear perspective painting depicting a three-dimensional (3D) scene, where the probe perceived to be farther is judged to be larger than the probe perceived closer to the viewer. In this paper, the same perspective 3D scene was painted on three surfaces: (a) A 2D surface incongruent with the 3D painted scene (flat perspective). (b) A 3D surface with a geometry congruent with the 3D scene (proper perspective). (c) A 3D surface with an opposite depth arrangement to the 3D scene (reverse perspective). This last stimulus was bistable and could be perceived veridically, as it physically existed, or as a depth-inverting illusion. For all experiments, observers relied on perspective gradients to estimate the size of a test probe placed within the scene; objects placed in a ‘far’ position as defined by perspective cues were perceived to be larger regardless of their physical distance. Further, illusion strength was tied to retinal size; small retinal-size differences (Experiments 1 and 2) did not affect illusion strength, whereas larger retinal-size differences (Experiment 3) did play a minor role.

The interception of the action-perception loop in virtual reality [VR] causes that understanding the effects of different display factors in spatial perception becomes a challenge. For example, studies have reported that there is not size-constancy, the perceived size of an object does not remain constant as its distance increases. This phenomenon is closely related to the reports of underestimation of distances in VR, which causes remain unclear. Despite the efforts improving the spatial cues regarding display technology and computer graphics, some interest has started to focus on the human side. In this study, we propose a perceptual calibration method which can ameliorate the effects of non-size-constancy in heterogeneous VR displays. The method was validated in a perceptual matching experiment comparing the performance between an HTC Vive HMD and a four-walls CAVE system. Results show that perceptual calibration based on interpupillary distance increments can solve partially the phenomenon of non-size-constancy in VR.

If the perceived transmittances of transparent objects are matched across illuminants, only incomplete constancy is found. This implies that physically identical objects may appear different. Nevertheless, it was reported in the literature that subjects could almost perfectly identify such objects across illuminants, even if a transparency impression was suppressed by violating geometric transparency conditions. A potential interpretation of these findings is that (a) identification and matching rely on different criteria and processes and that (b) identification is solely based on low-level color information. We here present evidence against these hypotheses. Our results show that the best match, that is, the transparent object under the test illuminant that appears most similar to the standard, is also the preferred object in the identification task. Furthermore, we found that the degree of constancy increases in both tasks, if figural cues support a transparency impression and the accompanying color scission. We discuss the relation between matching and identification suggested by these findings.

Recent studies on visuomotor processes using virtual setups have suggested that actions are affected by similar biases as perceptual tasks. In particular, a strong lack of depth constancy is revealed, resembling biases in perceptual estimates of relative depth. With this study we aim to understand whether these findings are mostly caused by a lack of metric accuracy of the visuomotor system or by the limited cues provided by the use of virtual reality. We addressed this issue by comparing grasping movements towards a spherical object located at four distances (420, 450, 480, and 510 mm) performed in three conditions: 1) virtual, in which the target was a virtual object defined by binocular cues, 2) glow-in-the-dark, in which the object was painted with luminous paint but no other cue was provided, and 3) full-cue, in which the movement was performed with the lights on and all the environmental information was available. Results revealed a striking effect of object distance on grip aperture equally in all three conditions. Specifically, grip aperture gradually decreased with increase in object distance, proving a consistent lack of depth constancy. These findings clearly demonstrate that systematic biases in grasping actions are not induced by the use of virtual environments and that action and perception may involve the same visual information, which does not engage a metric reconstruction of the scene.

A primary goal for models of speech perception is to describe how listeners achieve reliable comprehension given a lack of invariance between the acoustic signal and individual speech sounds. For example, individual talkers differ in how they implement phonetic properties of speech. Research suggests that listeners attain perceptual constancy by processing acoustic variation categorically while maintaining graded internal category structure. Moreover, listeners will use lexical information to modify category boundaries to learn to interpret a talker's ambiguous productions. The current work examines perceptual learning for talker differences that signal well-defined, unambiguous category members. Speech synthesis techniques were used to differentially manipulate talkers' characteristic productions of the stop voicing contrast for two groups of listeners. Following exposure to the talkers, internal category structure and category boundary were examined. The results showed that listeners dynamically adjusted internal category structure to be centered on experience with the talker's voice, but the category boundary remained fixed. These patterns were observed for words presented during training as well as novel lexical items. These findings point to input-driven constraints on functional plasticity within the language architecture, which may help to explain how listeners maintain stability of linguistic knowledge while simultaneously demonstrating flexibility for phonetic representations.

The perceptual constancy of shape, including view invariance, is an amazing property of the visual system. Cortical representation by the medial axis (MA) is an attractive candidate for maintaining the constancy of a wide range of arbitrary shapes. Recent physiological studies have reported that neurons in the primary visual cortex (V1) show a response to two-dimensional (2D) MAs, and those in the inferior temporal cortex (IT) are selective to three-dimensional (3D) MAs. However, little is known about the neural mechanisms underlying the transformation of 2D to 3D MAs. As a first step toward investigating the cortical mechanism, we have proposed as a hypothesis that a pair of monocular 2D MAs is fused to generate a 3D MA. We examined the computational plausibility of the hypothesis; specifically, whether an energy-based fusion model is capable of generating 3D MAs. We generated blob-like, physiologically plausible 2D MAs, and used a standard energy model to detect the disparity between a pair of 2D MAs. The model successfully generated 3D MAs for a variety of objects that included typical shape characteristics. A reconstruction test showed that the computed 3D MAs captured the essential structure of the objects with reasonable accuracy and view invariance. These results indicate that the fusion of monocular blob-like 2D MAs is capable of generating a reasonable 3D MA within the framework of the energy model.

This paper explores by means of extensive numerical simulation how unidirectional and bidirectional symmetric dispersal can affect the mean total population size and the fluctuation range in a two-patch population model described by coupled difference equations. The obtained results show that the response to dispersal varies not only with the type of connection between subpopulations, but also with the intrinsic dynamics in each subpopulation. We find that the mean total population size increases monotonically with unidirectional dispersal from a region with local complicated dynamics to a region with an attracting equilibrium, whereas in the other studied scenarios the response is generically unimodal. Constancy and persistence are considered by relating them to the fluctuation range. Our results show that dispersal is capable of enhancing constancy and persistence only in certain situations. Additionally, we show that multistability affects the behaviour of the mean total population size and its fluctuation range. Hence it can be concluded that, in contrast to other control strategies, only if there is a good knowledge of the local population dynamics, then a modification of the natural dispersal rate between regions might be used as a way to control the size and stability of the population.

The influence of visual experience on spatial imagery is still not fully understood. Although numerous experiments have been interpreted as showing considerable limitations in the functioning of imagery processes in people who are totally blind, especially those who were born blind or had early onset of blindness, there are studies suggesting that no significant differences in this area can be detected between blindfolded sighted and nonsighted individuals. There are claims that in some cases persons deprived of visual experience perform better than blindfolded sighted individuals (for a review, see Cattaneo et al., 2008). The differences in the results of the experiments reported in this and in other sources seem to follow from the specificity of the imagery task rather than from the imagery operation (mental imagery activity) being tested (see, for example, Cornoldi & Vecchi, 2003). Testing imagery scaling operations may serve as an example. Mental scaling transformation is an operation that involves changing the size of an image found, for example, when sighted persons compare objects (Larsen & Bundesen, 1978). The reaction time increased with the size ratio of objects (see also Bennett & Warren, 2002; Craddock & Lawson, 2009). Some research suggests that adults without prior visual experience do not understand that the size of an object imagined to be moving away must be reduced in accordance with the principle of perspective (Arditi, Holtzman, & Kosslyn, 1988; Vanlierde & Wanet-Defalque, 2005). There is, however, research providing evidence that it is unlikely that these difficulties result from an inability to perform the operation of mental scaling (Kennedy, 1993; Wnuczko & Kennedy, 2014). For clarity of argumentation, it is important to distinguish between linear size (which can, for example, be measured in centimeters), and angular size. The linear size of a particular object is an objective property that does not change over time. The ability to evaluate the linear size can therefore be treated as an indication of conceptual knowledge related to typical sizes of objects encountered in the real world. These sizes may change only in fantasy (for example, in Alice in Wonderland). In visual perception, the angular size--that is, the angle at which the observed object subtends at the eye--changes with the distance between the object and the observer. Angular size is usually measured in degrees of the arc, although in some research it was shown by pointing to the ends of the imagined object. In those cases the pointing span indicated the angular size (see, for example, Arditi et al., 1988). In visual perception, identical objects placed at different distances from the observer create images on the retina that differ in size. It is also possible to determine the changing pointing span for these objects. The size differences are reflected in verbal descriptions: a lake observed from an airplane may be compared to a puddle, and a dog observed from a distance may seem as small as an ant. We get this impression despite being aware that the linear size of these objects does not change (this is the mechanism of size constancy). Visual angular size has its analogy in imagery. Kosslyn (1978) defines angular size as the visual angle of the mind's eye, and provides empirical evidence that sighted persons imagine objects as being a certain distance away from the mind's eye. Sighted persons first experience size constancy in infancy (Slater, Mattock, & Brown, 1990). This constancy, functioning as automatic inference, makes it possible to assess the linear size of an object on the basis of its optical size and the distance. The accuracy of the inference involved in the process of visual perception improves gradually, and at early school age is not yet fully developed (Granrud & Schmechel, 2006). Developmental progress in understanding the relationship between angular and linear size can be observed in drawings made by sighted children. …

In this paper, we propose a novel algorithm for high-definition displays to enlarge low-resolution images while maintaining perceptual constancy (i.e., the same field-of-view, perceptual blur radius, and the retinal image size in viewer's eyes). We model the relationship between a viewer and a display by considering two main aspects of visual perception, i.e., scaling factor and perceptual blur radius. As long as we enlarge an image while adjust its image blur levels on the display, we can maintain viewer's perceptual constancy. We show that the scaling factor should be set in proportion to the viewing distance and the blur levels on the display should be adjusted according to the focal length of a viewer. Toward this, we first refer to edge directions to interpolate a low-resolution image with the increasing of viewing distance and the scaling factor. After images are interpolated, we utilize a local contrast to estimate the spatially varying image blur levels of the interpolated image. We then further adjust the image blur levels using a parametric deblurring method, which combines L1 as well as L2 reconstruction errors, and Tikhonov with total variation regularization terms. By taking these factors into account, high-resolution images adaptive to viewing distance on a display can be generated. Experimental results on both natural image metric and user subjective studies across image scales demonstrate that the proposed super-resolution algorithm for high-definition displays performs favorably against the state-of-the-art methods.

We seldom mistake a closer object as being larger, even though its retinal image is bigger. One underlying mechanism could be to calculate the size of the retinal image relative to that of another nearby object. Here we set out to investigate whether single neurons in the monkey inferotemporal cortex (IT) are sensitive to the relative size of parts in a display. Each neuron was tested on shapes containing two parts that could be conjoined or spatially separated. Each shape was presented in four versions created by combining the two parts at each of two possible sizes. In this design, neurons sensitive to the absolute size of parts would show the greatest response modulation when both parts are scaled up, whereas neurons encoding relative size would show similar responses. Our main findings are that 1) IT neurons responded similarly to all four versions of a shape, but tuning tended to be more consistent between versions with proportionately scaled parts; 2) in a subpopulation of cells, we observed interactions that resulted in similar responses to proportionately scaled parts; 3) these interactions developed together with sensitivity to absolute size for objects with conjoined parts but developed slightly later for objects with spatially separate parts. Taken together, our results demonstrate for the first time that there is a subpopulation of neurons in IT that encodes the relative size of parts in a display, forming a potential neural substrate for size constancy.

Some experiments in perceptual psychology measure perceivers’ phenomenal experiences of objects versus their cognitive assessments of object properties. Analyzing such experiments, this article responds to Pizlo’s claim that much work on shape constancy before 1985 confused problems of shape ambiguity with problems of shape constancy. Pizlo fails to grasp the logic of experimental designs directed toward phenomenal aspects of shape constancy. In the domain of size perception, Granrud’s studies of size constancy in children and adults distinguish phenomenal from cognitive factors.

It is proposed that Homo sapiens’ biological adaptation was accomplished to survive under the environmental conditions that existed during the Paleolithic time. Recent man’s evolution, to a significant extent, corresponds to a cultural type of evolution, not necessarily requiring further overt biological changes. Strategies used for spatial orientation are reviewed; perceptual constancy, reference systems, and cross-cultural differences in visuoperceptual abilities are emphasized. It is pointed out that males usually perform better than females in spatial tests, even though there is not a clear explanation for this difference. The neurological bases of spatial cognition are further discussed, emphasizing the two brain areas supporting spatial cognition: the right parietal lobe and the hippocampus; some neuroimaging studies approaching the pattern of brain activation during different spatial tasks are examined. Finally, visuospatial impairments resulting from brain damage are discussed; it is explained that spatial agnosia represents an impairment in perception and the use of spatial-dependent information resulting from brain pathology. This type of disorder is generally associated with right parietal or parietal-occipital damage.

Ever since the days of René Descartes, in the seventeenth century, the search for the relationship between subjective perception and neural activity has been an ongoing challenge. In neuroscience, an approach to the problem via the visual system has produced a paradigm using perceptual suppression, changing with time. Cortical areas in which the neural activity was modulated in temporal correlation with this percept could be traced. Although these areas may lead directly to perception, such temporal correlation of neural activity does not suffice as ultimate proof that they actually do so. In this article, I will use a different method to show that, for the perception of our own retina, any brain area leading directly to this perception also needs to represent the retina without distortion. Furthermore, I will demonstrate that the phenomenon of size constancy must be realized in this area.

We can estimate the veridical size of nearby objects reasonably well irrespective of their viewing distance. This perceptual capability, termed size constancy, is accomplished by combining information about retinal image size together with the viewing distance, or using the relational information available in the scene, via direct perception [1]. A previous study [2] showed that children typically underestimate the size of a distant object. This underestimation is reduced with time, suggesting that years of visual experience may be essential for attaining true size constancy. But what if you have had very limited vision during the early years of life? We studied 23 Ethiopian children suffering from bilateral, early-onset cataract, who were surgically treated only years after birth. Surprisingly, most children were able to estimate object size reasonably well irrespective of distance; in fact, they usually tended to overestimate the far-object size. Closer examination indicated that, although before surgery the patients were diagnosed as having a full, mature bilateral cataract, they nevertheless had some residual form of vision, typically limited to very close range. Gandhi et al.[3] earlier reported immediate susceptibility to geometric visual illusions in a similar group of newly-sighted children, concluding that size constancy was probably innate. We suggest that their immediate ability to judge physical size irrespective of distance is more likely to result from their previous visual experience.

The perceived size of an object remains relatively constant although its retinal size keeps decreasing as the object moves away along the depth dimension of the 3D space, i.e. size constancy. Neural mechanisms generating size constancy in virtual 3D space, however, remain poorly understood. By constructing a virtual 3D world in the MR scanner, we positioned the same 3D objects either near or far from the observers so that the near and far objects were perceived as having the same physical size despite their differences in retinal size. To control for the effect of differential retinal size, an additional 2D condition was introduced: a large and a small object, with matched retinal images as the near and far objects in the 3D condition, respectively, were presented on a 2D screen. Differences in retinal size activated overlapped areas in bilateral inferior occipital gyrus (IOG) in both experiments. The overlapped areas in IOG, however, showed different patterns of functional connectivity with different neural networks, depending on the perceived size of objects. In particular, IOG showed enhanced connectivity with bilateral superior parietal cortex in the 2D condition, but with inferior temporal and prefrontal cortex in the virtual 3D condition, i.e., size constancy.

Humans perceive speech as being relatively stable despite acoustic variation caused by vocal tract (VT) differences between speakers. Humans use perceptual 'vocal tract normalisation' (VTN) and other processes to achieve this stability. Similarity in vocal apparatus/acoustics between birds and humans means that birds might also experience VT variation. This has the potential to impede bird communication. No known studies have explicitly examined this, but a number of studies show perceptual stability or 'perceptual constancy' in birds similar to that seen in humans when dealing with VT variation. This review explores similarities between birds and humans and concludes that birds show sufficient evidence of perceptual constancy to warrant further research in this area. Future work should 1) quantify the multiple sources of variation in bird vocalisations, including, but not limited to VT variations, 2) determine whether vocalisations are perniciously disrupted by any of these and 3) investigate how birds reduce variation to maintain perceptual constancy and perceptual efficiency.

Face identification is reliable for viewers who are familiar with the face, and unreliable for viewers who are not. One account of this contrast is that people become good at recognising a face by learning its configuration-the specific pattern of feature-to-feature measurements. In practice, these measurements differ across photos of the same face because objects appear more flat or convex depending on their distance from the camera. Here we connect this optical understanding to face configuration and identification accuracy. Changing camera-to-subject distance (0.32m versus 2.70m) impaired perceptual matching of unfamiliar faces, even though the images were presented at the same size. Familiar face matching was accurate across conditions. Reinstating valid distance cues mitigated the performance cost, suggesting that perceptual constancy compensates for distance-related changes in optical face shape. Acknowledging these distance effects could reduce identification errors in applied settings such as passport control.

In our auditory environment, we rarely experience the exact acoustic waveform twice. This is especially true for communicative signals that have meaning for listeners. In speech and music, the acoustic signal changes as a function of the talker (or instrument), speaking (or playing) rate, and room acoustics, to name a few factors. Yet, despite this acoustic variability, we are able to recognize a sentence or melody as the same across various kinds of acoustic inputs and determine meaning based on listening goals, expectations, context, and experience. The recognition process relates acoustic signals to prior experience despite variability in signal-relevant and signal-irrelevant acoustic properties, some of which could be considered as “noise” in service of a recognition goal. However, some acoustic variability, if systematic, is lawful and can be exploited by listeners to aid in recognition. Perceivable changes in systematic variability can herald a need for listeners to reorganize perception and reorient their attention to more immediately signal-relevant cues. This view is not incorporated currently in many extant theories of auditory perception, which traditionally reduce psychological or neural representations of perceptual objects and the processes that act on them to static entities. While this reduction is likely done for the sake of empirical tractability, such a reduction may seriously distort the perceptual process to be modeled. We argue that perceptual representations, as well as the processes underlying perception, are dynamically determined by an interaction between the uncertainty of the auditory signal and constraints of context. This suggests that the process of auditory recognition is highly context-dependent in that the identity of a given auditory object may be intrinsically tied to its preceding context. To argue for the flexible neural and psychological updating of sound-to-meaning mappings across speech and music, we draw upon examples of perceptual categories that are thought to be highly stable. This framework suggests that the process of auditory recognition cannot be divorced from the short-term context in which an auditory object is presented. Implications for auditory category acquisition and extant models of auditory perception, both cognitive and neural, are discussed.

SummaryPerceptual constancy requires neural representations that are selective for object identity, but also tolerant for identity-preserving transformations. How such representations arise in the brain and contribute to perception remains unclear. Here we studied tolerant representations of sound identity in the auditory system by recording multi-unit activity in tonotopic auditory cortex of ferrets discriminating the identity of vowels which co-varied across orthogonal stimulus dimensions (fundamental frequency, sound level, location and voicing). We found that neural decoding of vowel identity was most successful across the same orthogonal dimensions over which animals generalized their behavior. We also decoded orthogonal sound features and behavioral variables including choice and accuracy to show a behaviorally-relevant, multivariate and multiplexed representation of sound, with each variable represented over a distinct time-course. Finally, information content and timing of sound feature encoding was modulated by task-engagement and training, suggesting that tolerant representations during perceptual constancy are attentionally and experience-dependent.

In Origins of Objectivity Burge advances a theory of perception according to which perceptions are, themselves, objective representations. The possession of veridicality conditions by perceptual states—roughly, non-propositional analogues of truth-conditions—is central to Burge’s account of how perceptual states differ, empirically and metaphysically, from sensory states. Despite an impressive examination of the relevant empirical literatures, I argue here that Burge has not succeeded in securing a distinction between perception and “mere” sensation.

In this paper, I first want to vindicate Wollheim’s idea that seeing-in, taken as the twofold phenomenologically sui generis experience which picture perception consists in, accounts for the phenomenon of perceptual constancy. Following Wollheim’s usage himself, by “perceptual constancy” I will mean a particular phenomenon of perceptual robustness, namely the fact that a picture’s subject is experienced as undistorted from any point of view in which a spectator may regard a picture. Moreover, I will properly take into consideration the specific impression of “being followed” by the gaze of a picture’s subject in portraits (and alike pictures), which in these cases is a consequence of perceptual constancy. For this impression corroborates a particular reading of what the seeing-in experience really consists in. According to such a reading, in the configurational fold of that experience one experiences both the merely visible surface properties and the design properties of the picture’s vehicle, where such design properties also include the so-called grouping properties of the vehicle. On the basis of such a fold, moreover, in the recognitional fold of the seeing-in experience one knowingly illusorily sees the picture as its subject. In questo paper, voglio prima di tutto rivendicare l’idea di Wollheim per cui il vedere-in, l’esperienza in cui consiste la percezione pittorica - un’esperienza fenomenologicamente sui generis fatta da due momenti percettivi - spiega il fenomeno della costanza percettiva. Per “costanza percettiva” intendo qui con Wollheim un particolare fenomeno di robustezza percettiva, cioè il fatto che il soggetto di una raffigurazione è esperito come non distorto, in quanto dato dalla stessa prospettiva, da qualunque punto di vista in cui lo spettatore si collochi per guardare la raffigurazione. Inoltre, voglio in particolar modo considerare l’impressione specifica di ‘essere seguito’ dallo sguardo del soggetto raffigurato che hanno gli spettatori di ritratti, o di tipi simili di raffigurazioni; un’impressione che consegue al fenomeno della costanza percettiva. Questa impressione, infatti, corrobora una particolare lettura di ciò in cui l’esperienza di vedere-in effettivamente consiste. Secondo tale lettura, nel momento configurativo di tale esperienza lo spettatore percepisce sia le proprietà meramente visibili di superficie sia le proprietà di design del veicolo raffigurativo. Tra queste proprietà di design vanno incluse anche le cosiddette proprietà di raggruppamento del veicolo, le proprietà per gli elementi di tale veicolo di essere ordinati lungo una certa direzione entro una determinata dimensione. Sulla base di tale momento, poi, nel momento ricognitivo dell’esperienza di vedere-in lo spettatore vede, in una maniera consapevolmente illusoria, tale veicolo raffigurativo come il soggetto della raffigurazione.

Europe's Journal of Psychology, 2014, Vol. 10(1), 204–207, doi:10.5964/ejop.v10i1.731 Published (VoR): 2014-02-28. *Corresponding author at: Baharan Street Moali Abad Street, Shiraz, Iran. E-mail: pazhoohi@gmail.com This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Auditory enhancement is the increase in salience of a target embedded in a simultaneous masker that occurs when a copy of the masker, termed the precursor, is presented first. The effect reflects the general principle of contrast enhancement and may help in the perceptual constancy of speech under varying acoustic conditions. The physiological mechanisms underlying auditory enhancement remain unknown. This study investigated EEG responses under conditions that elicited perceptual enhancement. The target tone was amplitude-modulated at two modulation frequencies to target cortical (~40 Hz) and subcortical (100–200 Hz) responses. Measurements were made in either passive conditions or under active tasks to examine the potential effects of attention on the neural correlates of enhancement. Robust effects of enhancement were observed at the cortical level, replicating our earlier findings. Preliminary data under passive conditions also suggest a trend towards increased neural response to the enhanced target tone at frequencies exceeding 200 Hz, suggesting a subcortical contribution. The results suggest that this paradigm can be used to tap into the neural correlates of auditory enhancement at both cortical and subcortical levels simultaneously and show the potential for tapping into attentional modulation of auditory enhancement. [Work supported by NIH grant R01DC012262.]

A signature problem in our understanding of spoken language processing is listeners’ perceptual constancy in the face of considerable variability in the instantiation of linguistic form. Abundant evidence now suggests that listeners are sensitive to the fine-grained structure of linguistic units that signal differences among talkers and track and adapt to this structure during the perception of speech. This talk will present data from a perceptual learning paradigm addressing both the constraints and flexibility of speech perceptual mechanisms. The aim was to address the degree to which exposure to variation in and expectations about talker- and group-specific attributes influence the degree of specificity and generalization in the perceptual adaptation process. Listeners were exposed to talker-dependent variation in a linguistic form, and expectations about talker characteristics were manipulated. The results suggest that listeners dynamically adapt to and encode systematic changes in the linguistic category structure as a function of expectation and appear to flexibly integrate talker- and group-dependent sources of variation into linguistic representation and processing.A signature problem in our understanding of spoken language processing is listeners’ perceptual constancy in the face of considerable variability in the instantiation of linguistic form. Abundant evidence now suggests that listeners are sensitive to the fine-grained structure of linguistic units that signal differences among talkers and track and adapt to this structure during the perception of speech. This talk will present data from a perceptual learning paradigm addressing both the constraints and flexibility of speech perceptual mechanisms. The aim was to address the degree to which exposure to variation in and expectations about talker- and group-specific attributes influence the degree of specificity and generalization in the perceptual adaptation process. Listeners were exposed to talker-dependent variation in a linguistic form, and expectations about talker characteristics were manipulated. The results suggest that listeners dynamically adapt to and encode systematic changes in the linguistic cate...

A central topic in discussions about qualia concerns their purported transparency. According to transparency theorists, an experience is transparent in the sense that the subject having the experience is aware of nothing but the intended object of the experience. In this paper this notion is criticized for failing to account for the dynamical aspects of perception. A key assumption in the paper is that perceptual content has a certain temporal depth, in the sense that each act of perception can present an object as extended in time and that objects can be perceived as persisting through time. An object that is seen as persisting through time is often seen as constant and unchanging, even though the presentation of it is changing. In this paper it is argued that in order to account for these cases of perceptual constancy, we must distinguish between the awareness of having perceived that an object has a property at a certain point in time, and perceptually intending that it has that property at that point in time. Consequently, we must in at least some instances be aware of something more than the object of the experience. But precisely this distinction is rejected by the transparency theory.

We explored size–distance scaling with a demonstration based on the classic Holway–Boring experiment. Undergraduate psychology majors estimated the sizes of two glowing paper circles under two conditions. In the first condition, the environment was dark and, with no depth cues available, participants ranked the circles according to their angular sizes. In the second condition, the environment was illuminated and, with depth cues available, the students ranked the circles according to actual physical size. The demonstration replicated the key elements of the original experiment, and objective and subjective measures indicated that it improved understanding of size–distance scaling. We also describe variants of the experiment suitable for different instructional environments.

This article proposes an account of color constancy based on an examination of the relevant scientific literature. Differences in experimental settings and task instructions that lead to variation in subject performance are given particular attention. Based on the evidence discussed, the core of the proposal made is that there are two different forms of color constancy, one phenomenal and the other projective. This follows the hypothesis of Reeves et al. (Perception & Psychophysics 70:219–228, 2008). Unlike Reeves et al. (Perception & Psychophysics 70:219–228, 2008), it is argued that projective color constancy is crucially dependent upon phenomenal color constancy and certain aspects of scene perception. Additionally, it is hypothesized that capacities that support projective color constancy have an important role to play in facilitating our ability to quickly recognize scenes with diagnostic chromatic properties independently of assignments of colors to object surfaces.

Cohen (IEEE Trans. Signal Processing, 41, 3275-3292, 1993) suggested that a signal’s scale can beregarded as a ‘physical attribute’ that decouples the size of a phenomenon from its shape. His idea, incombination with invariant signal representations, has clear ramifications for the phenomenon of sizeconstancy in vision science. In the visual system, it is hoped that size constancy might be derived fromthe collected responses of a distribution of isotropic spatial filters whose underlying spatial extentare systematically varied from coarse to fine scales according to a diffusion model of image blur: theso-called scale-space representation (eg Koenderink, Biol. Cyb. 50, 363-370, 1984). We demonstratethat this ‘blurring’ approach is flawed. The reason is because scaling and blurring are fundamentallydifferent image operations – application of linear filters whose degrees of blur are different beforeattempting to extract scale information can seriously impair one’s ability to extract the physical attributeof scale. We show that local scale (and position) invariant signal representations can be derived byfinding unknown coefficients that allow one to predict the image intensity signal from a power seriesexpansion. We further show that the inverse of this power series is a Taylor expansion of discretelocal image derivatives whose coefficients are invariant of position and scale. The expansion retainsthe benefit of efficiency when representing 2D shape. Finally, we show how our ideas link scaling,fractional orders of differentiation and pyramid sampling as a means for determining the scale of a 2Dshape. We suggest that similar computations underpin position and scale invariant computations in the visual system.

Deformable objects such as cloth exhibit their mechanical properties (e.g. stiffness) through shape deformation over time under external forces. Mechanical properties are important because they tell us the affordance of the object and helps us predict what type of action can be done upon it. Previous research shows that motion statistics can be used to develop computer vision algorithms to estimate mechanical properties of cloth under an unknown wind force. It is unclear what motion cues human use to estimate mechanical properties. Estimating mechanical properties is difficult because both the intrinsic properties of the fabric and the external force contribute to the apparent motion of the fabric. However, in order to achieve invariant material perception, the visual system needs to discount the effects of external force. In this paper, we investigate whether humans have an invariant representation of mechanical properties of fabrics under varying external forces in dynamic scenes. Then we study what visual cues allow humans to achieve this perceptual constancy. The stimuli are animated videos containing a hanging fabric moving under oscillating wind. We vary both intrinsic mechanical properties such as mass and stiffness of the cloth as well as the strength of the wind force. We discuss our results in the context of optical flow statistics. This advances the current understanding of the role of motion in perception of material properties in dynamic scenes.

Статья посвящена исследованию проблемы константности восприятия и ее роли в процессе адаптации человека к социокультурному окружению. Цель работы заключалась в установлении психологических детерминант, оказывающих влияние на точность восприятия заданных образцов испытуемыми. В качестве гипотетического выдвинуто предположение о том, что психоэмоциональное состояние испытуемого и локальные межполушарные взаимодействия влияют на точность восприятия и последующее воспроизведение заданного образца.Описано исследование, в котором приняли участие 19 студентов четвертого курса психолого-педагогического факультета Смоленского государственного университета. Исследование проводилось в марте 2014 г. В ходе эксперимента осуществлялись измерения точности воспроизведения заданного образца с помощью вначале попеременного, а затем одновременного надавливания правой и левой руками испытуемых на клавиши измерительного прибора. Измерения проводились на специально изготовленном для обследования приборе, позволяющем устанавливать величину ошибки воспроизведения автоматически непосредственно в процессе работы. Серии измерений проводились в разных психоэмоциональных состояниях испытуемых: спокойного бодрствования и в состоянии психоэмоционального возбуждения (после интенсивной физической нагрузки).Компаративное соотнесение полученных результатов подтвердило выдвинутую автором гипотезу о влиянии психоэмоционального состояния испытуемого и локальных межполушарных взаимодействий на точность восприятия и последующего воспроизведения заданного образца, а также уточнило «вклад» межполушарной асимметрии в точность воспроизведения перцептивного образца. В ходе исследования было установлено, что наиболее информативным измерением, позволяющим установить перцептивную зрелость испытуемого, является величина ошибки при восприятии и последующем воспроизведении образца ведущей рукой в состоянии спокойного бодрствования.

In the oculomotor system‎, ‎spatial updating is the ability to aim a saccade toward a remembered visual target position despite intervening eye movements‎. ‎Although this has been the subject of extensive experimental investigation‎, ‎there is still no unifying theoretical framework to explain the neural mechanism for this phenomenon‎, ‎and how it influences visual signals in the brain‎. ‎Here‎, ‎we propose a unified state-space model (SSM) to account for the dynamics of spatial updating during two types of eye movement; saccades and smooth pursuit‎. ‎Our proposed model is a nonlinear SSM and implemented through a recurrent radial-basis-function neural network in a dual Extended Kalman filter (EKF) structure‎. ‎The model parameters and internal states (remembered target position) are estimated sequentially using the EKF method‎. ‎The proposed model replicates two fundamental experimental observations‎: ‎continuous gaze-centered updating of visual memory-related activity during smooth pursuit‎, ‎and predictive remapping of visual memory activity before and during saccades‎. ‎Moreover‎, ‎our model makes the new prediction that‎, ‎when uncertainty of input signals is incorporated in the model‎, ‎neural population activity and receptive fields expand just before and during saccades‎. ‎%This study suggests that visual remapping phenomena‎ -‎and thus subjective space constancy- ‎originates from the requirements of motor behavior‎. These results suggest that visual remapping and motor updating are part of a common visuomotor mechanism‎, ‎and that subjective perceptual constancy arises in part from training the visual system on motor tasks.

Perceptual constancy refers to the ability to stabilize the representation of an object even though the retinal image of the object undergoes variations. In previous studies, we proposed a General Object Constancy (GOC) hypothesis to demonstrate a common stabilization mechanism for perception of an object's features, such as size, contrast and depth, as the perceived distance varies. In the present study, we report another depth illusion supporting the GOC model. The stimuli comprised pairs of disks moving in a pattern of radial optic flow. Each pair consisted of a white disk positioned upper left to a dark disk, creating a percept of the white disk casting a shadow. As the pairs contracted towards the center of the screen in accordance with motion away from the observer, the two disks in each pair appeared to increase in contrast and separate farther away from each other both in the fronto-parallel plane (angular separation illusion) and in depth (depth separation illusion). While the contrast illusion and the angular separation illusion, which is a variant of the size illusion, replicated our previous findings, the illusion of depth separation revealed a depth constancy phenomenon. We further confirmed that the size and depth perception were related, e.g., the depth separation and the angular separation illusions were highly correlated across observers. Whereas the illusory increase in the angular separation between a disk and its 'shadow' could not be canceled by modulation of depth, decreasing the angular separation could offset the illusory increase in depth separation. The results can be explained by the GOC hypothesis: the visual system uses the same scaling factor to account for contrast, size (angular separation), and depth variations with distance; additionally, the perceived size of the object is used to scale its depth and contrast signals in order to achieve constancy.

A key challenge for the visual system is to extract constant object properties from incoming sensory information. This information is ambiguous because the same sensory signal can arise from many combinations of object properties and viewing conditions and noisy because of the variability in sensory encoding. The competing accounts for perceptual constancy of surface lightness fall into two classes of model: One derives lightness estimates from border contrasts, and another explicitly infers surface reflectance. To test these accounts, we combined a novel psychophysical task with probabilistic implementations of both models. Observers compared the lightness of two stimuli under a memory demand (a delay between the stimuli), a context change (different surround luminance), or both. Memory biased perceived lightness toward the mean of the whole stimulus ensemble. Context change caused the classical simultaneous lightness contrast effect, in which a target appears lighter against a dark surround and darker against a light surround. These effects were not independent: Combined memory load and context change elicited a bias smaller than predicted assuming an independent combination of biases. Both models explain the memory bias as an effect of prior expectations on perception. Both models also produce a context effect, but only the reflectance model correctly describes the magnitude. The reflectance model, finally, captures the memory-context interaction better than the contrast model, both qualitatively and quantitatively. We conclude that (a) lightness perception is more consistent with reflectance inference than contrast coding and (b) adding a memory demand to a perceptual task both renders it more ecologically valid and helps adjudicate between competing models.

Visual neurons typically receive information from a limited portion of the retina, and such receptive fields are a key organizing principle for much of visual cortex. At the same time, there is strong evidence that receptive fields transiently shift around the time of saccades. The nature of the shift is controversial: Previous studies have found shifts consistent with a role for perceptual constancy; other studies suggest a role in the allocation of spatial attention. Here we present evidence that both the previously documented functions exist in individual neurons in primate cortical area V4. Remapping associated with perceptual constancy occurs for saccades in all directions, while attentional shifts mainly occur for neurons with receptive fields in the same hemifield as the saccade end point. The latter are relatively sluggish and can be observed even during saccade planning. Overall these results suggest a complex interplay of visual and extraretinal influences during the execution of saccades., Visual receptive fields are known to change positions around the time of a saccade, but the nature of this remapping is unclear. Here Neupane and colleagues show that neurons in area V4 of the visual cortex exhibit two types of remapping, one consistent with a role in maintaining perceptual stability, and a second that seems to reflect shifts of attention.