Proximal Stimulus Research Articles

Alpha-Band Frequency and Temporal Windows in Perception: A Review and Living Meta-analysis of 27 Experiments (and Counting).

Temporal windows in perception refer to windows of time within which distinct stimuli interact to influence perception. A simple example is two temporally proximal stimuli fusing into a single percept. It has long been hypothesized that the human alpha rhythm (an 8- to 13-Hz neural oscillation maximal over posterior cortex) is linked to temporal windows, with higher frequencies corresponding to shorter windows and finer-grained temporal resolution. This hypothesis has garnered support from studies demonstrating a correlation between individual differences in alpha-band frequency (IAF) and behavioral measures of temporal processing. However, nonsignificant effects have also been reported. Here, we review and meta-analyze 27 experiments correlating IAF with measures of visual and audiovisual temporal processing. Our results estimate the true correlation in the population to be between .39 and .53, a medium-to-large effect. The effect held when considering visual or audiovisual experiments separately, when examining different IAF estimation protocols (i.e., eyes open and eyes closed), and when using analysis choices that favor a null result. Our review shows that (1) effects have been internally and independently replicated, (2) several positive effects are based on larger sample sizes than the null effects, and (3) many reported null effects are actually in the direction predicted by the hypothesis. A free interactive web app was developed to allow users to replicate our meta-analysis and change or update the study selection at will, making this a "living" meta-analysis (randfxmeta.streamlit.app). We discuss possible factors underlying null reports, design recommendations, and open questions for future research.

Mean orientation discrimination based on proximal stimuli.

Ensemble perception refers to the ability to accurately and rapidly perceive summary statistical representations of specific features from a group of similar objects. However, the specific type of representation involved in this perception within a three-dimensional (3-D) environment remains unclear. In the context of perspective viewing with stereopsis, distal stimuli can be projected onto the retina as different forms of proximal stimuli based on their distances, despite sharing similar properties, such as object size and spatial frequency. This study aimed to investigate the effects of distal and proximal stimuli on the perception of summary statistical information related to orientation. In our experiment, we presented multiple Gabor patches in a stereoscopic environment, allowing us to measure the discrimination threshold of the mean orientation. The object size and spatial frequency were fixed for all patches regardless of depth. However, the physical angular size and absolute spatial frequency covaried with the depth. The results revealed the threshold elevation with depth expansion, especially when the patches formed two clusters at near and far distances, leading to large variations in their retinotopic representations. This finding indicates a minor contribution of similarity of the distal stimuli. Subsequent experiments demonstrated that the variability in physical angular size of the patches significantly influenced the threshold elevation in contrast to that of binocular disparity and absolute spatial frequency. These findings highlight the critical role of physical angular size variability in perceiving mean orientations within the 3-D space.

The role of purpose in the stress process: A homeostatic account

The accumulation of evidence that having a sense of purpose contributes to greater health and well-being has vastly outpaced investigations into why this is so. Here, we offer a novel functional account for the demonstrated benefits of purpose by characterizing it as a resource that maintains psychological homeostasis. We posit that a sense of purpose recenters conscious attention toward prospective and overarching aims, thereby limiting the magnitude of disruption to well-being caused by the proximal stimuli. By attenuating reactivity to proximal events both stressful and uplifting, a sense of purpose facilitates greater stability in health and functioning over time. We leverage this mechanistic account with specific examples found across areas of psychological science and outline questions to guide future research.

Illusion as a Cognitive Clash Rooted in Perception.

Illusions are important 'tools' in the study of perceptual processes. Their conception is typically linked to the notion of veridicality in a dual-world framework, in which we either see the macro physical world as it is (ecological approaches) or we derive a faithful representation (cognitive approaches) of it. Within such theoretical views, illusions are errors caused by inadequate sensory information (because of poor quality, insufficient quantity, contradictory, etc.). From a phenomenological stance, however, experiencing an illusion does not relate to the physical quality of the distal or proximal stimulus; rather, it depends on a comparison between the actual perception and what one believes should be perceived given the knowledge s/he has gained about the physical stimulus. Within such a framework, illusions are still considered of extreme importance in the study of the processes underpinning perception, but they are not conceived as errors. They represent instead a cognitive clash between actual perception and hypothesized perception based on some sort of comparison, thus also showing their potential as a tool for studying the underpinnings of cognitive processes.

Loudness constancy for noise and speech: How instructions and source information affect loudness of distant sounds.

The physical properties of a sound evolve when traveling away from its source. As an example, the sound pressure level at the listener's ears will vary according to their respective distance and azimuth. However, several studies have reported loudness to remain constant when varying the distance between the source and the listener. This loudness constancy has been reported to occur when the listener focused attention on the sound as emitted by the source (namely the distal stimulus). Instead, the listener can focus on the sound as reaching the ears (namely the proximal stimulus). The instructions given to the listener when assessing loudness can drive focus toward the proximal or distal stimulus. However, focusing on the distal stimulus requires to have sufficient information about the sound source, which could be provided by either the environment or by the stimulus itself. The present study gathers three experiments designed to assess loudness when driving listeners' focus toward the proximal or distal stimuli. Listeners were provided with different quality and quantity of information about the source depending on the environment (visible or hidden sources, free field or reverberant rooms) and on the stimulus itself (noise or speech). The results show that listeners reported constant loudness when asked to focus on the distal stimulus only, provided enough information about the source was available. These results highlight that loudness relies on the way the listener focuses on the stimuli and emphasize the importance of the instructions that are given in loudness studies.

Zebrafish larvae use stimulus intensity and contrast to estimate distance to prey

The ability to determine the distance to objects is an important feature of most visual systems, but little is known about the neuronal mechanisms for distance estimation. Larval zebrafish execute different visual behaviors depending on distance; at medium distances, they converge their eyes and approach, but when the prey is close enough, they execute a strike and suck the prey into their mouths. To study distance estimation, we developed a head-fixed strike assay. We found that we could evoke strike behavior in head-fixed larvae and quantify head movements to classify the behavior as a strike. Strikes were dependent on distance to prey, allowing us to use them to study distance estimation. Light intensity is rapidly attenuated as it travels through water, so we hypothesized that larvae could use intensity as a distance cue. We found that increasing stimulus intensity could cause larvae to strike at prey that would normally be out of range, and decreasing the intensity could lower the strike rate even for very proximal stimuli. In addition, stimulus contrast is a key parameter, and this could allow larvae to estimate distance over the range of natural illumination. Finally, we presented prey in the binocular vs. monocular visual field and found that monocular prey did evoke strikes, although the binocular input produced more. These results suggest that strike behavior is optimally evoked by bright UV dots in the binocular zone with minimal UV background light and provide a foundation to study the neuronal mechanisms of distance estimation.

Shape, perspective, and what is and is not perceived: Comment on Morales, Bax, and Firestone (2020).

Psychology and philosophy have long reflected on the role of perspective in vision. Since the dawn of modern vision science-roughly, since Helmholtz in the late 1800s-scientific explanations in vision have focused on understanding the computations that transform the sensed retinal image into percepts of the three-dimensional environment. The standard view in the science is that distal properties-viewpoint-independent properties of the environment (object shape) and viewpoint-dependent relational properties (3D orientation relative to the viewer)-are perceptually represented and that properties of the proximal stimulus (in vision, the retinal image) are not. This view is woven into the nature of scientific explanation in perceptual psychology, and has guided impressive advances over the past 150 years. A recently published article suggests that in shape perception, the standard view must be revised. It argues, on the basis of new empirical data, that a new entity-perspectival shape-should be introduced into scientific explanations of shape perception. Specifically, the article's centrally advertised claim is that, in addition to distal shape, perspectival shape is perceived. We argue that this claim rests on a series of mistakes. Problems in experimental design entail that the article provides no empirical support for any claims regarding either perspective or the perception of shape. There are further problems in scientific reasoning and conceptual development. Detailing these criticisms and explaining how science treats these issues are meant to clarify method and theory, and to improve exchanges between the science and philosophy of perception. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Perception needs modular stimulus-control

Perceptual processes differ from cognitive, this paper argues, in functioning to be causally controlled by proximal stimuli, and being modular, at least in a modest sense that excludes their being isotropic in Jerry Fodor's sense. This claim agrees with such theorists as Jacob Beck and Ben Phillips that a function of stimulus-control is needed for perceptual status. In support of this necessity claim, I argue, inter alia, that E.J. Green's recent architectural account misclassifies processes deploying knowledge of grammar as perceptual. Pace Beck and Phillips, however, I argue a function of stimulus-control is insufficient for perceptual as opposed to cognitive status. One consideration in favour of such insufficiency, noted but (I argue) not convincingly rebutted by these theorists, concerns perpetually grounded demonstrative thought. Two other considerations trade on the fact that a function of stimulus-control can arise not from blind nature but intentional design or social institutions, where so-functioning processes may but need not be perceptual. I offer two cases where such processes are cognitive, viz. skilful play-by-play announcing of ongoing events, and voluntary visualizing of ongoing events under the guidance of apt play-by-play announcements, dubbed announcement-driven visualizing (ADV). The cognitive status of these three diverse phenomena cannot be explained by an absence of a perception-like representational format or content (for ADV has such) or by a presence of personal-level mental states causally mediating between stimuli and outputs (for perception has such). A bettter explanation invokes, I argue, the non-modular character of the generating process.

Mental object rotation based on two-dimensional visual representations

The discovery of mental rotation was one of the most significant landmarks in experimental psychology, leading to the ongoing assumption that to visually compare objects from different three-dimensional viewpoints, we use explicit internal simulations of object rotations, to 'mentally adjust' one object until it matches the other1. These rotations are thought to be performed on three-dimensional representations of the object, by literal analogy to physical rotations. In particular, it is thought that an imagined object is continuously adjusted at a constant three-dimensional angular rotation rate from its initial orientation to the final orientation through all intervening viewpoints2. While qualitative theories have tried to account for this phenomenon3, to date there has been no explicit, image-computable model of the underlying processes. As a result, there is no quantitative account of why some object viewpoints appear more similar to one another than others when the three-dimensional angular difference between them is the same4,5. We reasoned that the specific pattern of non-uniformities in the perception of viewpoints can reveal the visual computations underlying mental rotation. We therefore compared human viewpoint perception with a model based on the kind of two-dimensional 'optical flow' computations that are thought to underlie motion perception in biological vision6, finding that the model reproduces the specific errors that participants make. This suggests that mental rotation involves simulating the two-dimensional retinal image change that would occur when rotating objects. When we compare objects, we do not do so in a distal three-dimensional representation as previously assumed, but by measuring how much the proximal stimulus would change if we watched the object rotate, capturing perspectival appearance changes7.

Critical Role of Osteopontin in Maintaining Urinary Phosphate Solubility in CKD.

Nephron loss dramatically increases tubular phosphate to concentrations that exceed supersaturation. Osteopontin (OPN) is a matricellular protein that enhances mineral solubility in solution; however, the role of OPN in maintaining urinary phosphate solubility in CKD remains undefined. Here, we examined (1) the expression patterns and timing of kidney/urine OPN changes in CKD mice, (2) if tubular injury is necessary for kidney OPN expression in CKD, (3) how OPN deletion alters kidney mineral deposition in CKD mice, (4) how neutralization of the mineral-binding (ASARM) motif of OPN alters kidney mineral deposition in phosphaturic mice, and (5) the in vitro effect of phosphate-based nanocrystals on tubular epithelial cell OPN expression. Tubular OPN expression was dramatically increased in all studied CKD murine models. Kidney OPN gene expression and urinary OPN/Cr ratios increased before changes in traditional biochemical markers of kidney function. Moreover, a reduction of nephron numbers alone (by unilateral nephrectomy) was sufficient to induce OPN expression in residual nephrons and induction of CKD in OPN-null mice fed excess phosphate resulted in severe nephrocalcinosis. Neutralization of the ASARM motif of OPN in phosphaturic mice resulted in severe nephrocalcinosis that mimicked OPN-null CKD mice. Lastly, in vitro experiments revealed calcium-phosphate nanocrystals to induce OPN expression by tubular epithelial cells directly. Kidney OPN expression increases in early CKD and serves a critical role in maintaining tubular mineral solubility when tubular phosphate concentrations are exceedingly high, as in late-stage CKD. Calcium-phosphate nanocrystals may be a proximal stimulus for tubular OPN production.

Reexamining nodality in equivalence classes.

Equivalence classes are defined according to the substitutability, or functional similarity, of the stimuli within a stimulus class. Several studies have demonstrated that the degree of functional similarity between stimuli in a class is dependent, in part, upon the number of nodes (intervening stimuli) between the stimuli. Higher nodal number is related to lower functional similarity. This effect is referred to as "nodality." There are three key factors that have not been simultaneously controlled for in the relevant studies: priming effects, reinforcement during training, and multiple stimulus functions of stimuli (sample, comparison, or both). In the present experiment, controlling for these factors, two 6-member, 4-node equivalence classes were established, and a within-class preference assessment was used to evaluate nodality. Of 12 participants, five achieved criterion accuracy (90%) during testing. These participants demonstrated nodality, showing preference for stimuli that were nodally proximal to a sample in the preference test. When distal comparisons were chosen, participants took longer, on average, to make the selection compared to selections of proximal stimuli. These findings are consistent with earlier studies demonstrating nodality, which suggests that nodality is a robust phenomenon and not an artifact of the factors that were controlled for in the present study.

Serial dependence occurs at the level of both features and integrated object representations.

Object perception depends on mechanisms that transform the information received by our sensory receptors into a coherent and meaningful experience. Visual objects are made up of visual features (e.g., shape, color, orientation), which are, in large part, processed in parallel across different brain areas. The experience of unified objects thus requires binding features and brain signals. Our perception of objects is remarkably stable and constant, despite changes in the proximal stimulus caused by eye and body movements or changes in ambient lighting. Such spurious changes are not perceived. Object perception thus also depends on a mechanism that smooths perceptual samples across time, which has been called the continuity field and is quantified by serial dependence. In two studies, the relative levels of feature binding and serial dependence were examined. Participants reported perceived shape or emotional expression; reports were attracted to stimuli seen in the recent past. Results further show that serial dependence occurs both at the level of features and at the level of objects defined by a conjunction of features. The relative level of serial dependence depends on the type of feature or object: Serial dependence of shape occurs mostly independently of other features that define an object, whereas serial dependence of emotional expression occurs on the object-level representation that integrates several features. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Gestalt Theory and the Network of Traditional Hypotheses

Summary Since at least the time of Helmholtz, the process of visual perception has been regarded as a two-stage affair consisting of an initial sensory stage corresponding to the proximal stimulus and a subsequent cognitive stage corresponding to the distal object. This construction amounts to an awkward mind body dualism wherein part of perception is done by the body and the other part is done by the mind. Gestalt theory rejected both raw sensations and their cognitive interpretation, offering a single unified perceptual process that responds to an extended pattern of stimulation. They proposed organizational rules that describe how objects arise from the indifferent retinal mosaic. The same grouping principles by which objects are segmented also function to segregate regions of uniform illumination. Lightness values can then be computed by comparing luminance values within each such framework of illumination, with no need for the mystical concept of taking the illumination into account.

Close facial emotions enhance physiological responses and facilitate perceptual discrimination

Accumulating evidence indicates that the peripersonal space (PPS) constitutes a privileged area for efficient processing of proximal stimuli, allowing to flexibly adapt our behavior both to the physical and social environment. Whether and how behavioral and physiological signatures of PPS relate to each other in emotional contexts remains, though, elusive. Here, we addressed this question by having participants to discriminate male from female faces depicting different emotions (happiness, anger or neutral) and presented at different distances (50 cm–300 cm) while we measured the reaction time and accuracy of their responses, as well as pupillary diameter, heart rate and heart rate variability. Results showed facilitation of participants' performances (i.e., faster response time) when faces were presented close compared to far from the participants, even when controlling for retinal size across distances. These behavioral effects were accompanied by significant modulation of participants' physiological indexes when faces were presented in PPS. Interestingly, both PPS representation and physiological signals were affected by features of the seen faces such as the emotional valence, its sex and the participants' sex, revealing the profound impact of social context onto the autonomic state and behavior within PPS. Together, these findings suggest that both external and internal signals contribute in shaping PPS representation.

System Design and Experimental Research of Neural Signal Blocking based on Spike Trapping Principle.

Different neural signal blocking technologies provide potential therapy for various diseases caused by pathological or involuntary neural activities. In this paper, a novel neural signal blocking concept based on spike-trapping principle is introduced. The blocking system was designed and implemented. In the system, a compound action potential was induced by a proximal stimulus, and a blocking signal was generated after a neural signal was detected, which was applied to the distal end of the nerve to block the nerve conduction. The reliability of the system was verified on bullfrog sciatic nerve gastrocnemius muscle specimens. The optimal blocking signal parameters, the relationship between nerve diameter and blocking threshold voltage, and the nerve safety of blocking signals were explored. The experimental results show that the system is possible to block a pathological or involuntary neural signal automatically. The average voltage of block threshold and the minimum pulse width are -1.66 V and 120 ms, respectively. The blocking threshold decreases as the diameter of the nerve increases. The blocking signals at the threshold level are safe for the stimulated nerve.

BET Epigenetic Reader Proteins in Cardiovascular Transcriptional Programs.

Epigenetic mechanisms involve the placing (writing) or removal (erasing) of histone modifications that allow heterochromatin to transition to the open, activated euchromatin state necessary for transcription. A third, less studied epigenetic pathway involves the reading of these specific histone marks once placed. The BETs (bromodomain and extraterminal-containing protein family), which includes BRD2, BRD3, and BRD4 and the testis-restricted BRDT, are epigenetic reader proteins that bind to specific acetylated lysine residues on histone tails where they facilitate the assembly of transcription complexes including transcription factors and transcriptional machinery like RNA Polymerase II. As reviewed here, considerable recent data establishes BETs as novel determinants of induced transcriptional programs in vascular cells, like endothelial cells and vascular smooth muscle cells, cardiac myocytes and inflammatory cells, like monocyte/macrophages, cellular settings where these epigenetic reader proteins couple proximal stimuli to chromatin, acting at super-enhancer regulatory regions to direct gene expression. BET inhibition, including the use of specific chemical BET inhibitors like JQ-1, has many reported effects in vivo in the cardiovascular setting, like decreasing atherosclerosis, angiogenesis, intimal hyperplasia, pulmonary arterial hypertension, and cardiac hypertrophy. At the same time, data in endothelial cells, adipocytes, and elsewhere suggest BETs also help regulate gene expression under basal conditions. Studies in the cardiovascular setting have highlighted BET action as a means of controlling gene expression in differentiation, cell identity, and cell state transitions, whether physiological or pathological, adaptive, or maladaptive. While distinct BET inhibitors are being pursued as therapies in oncology, a large prospective clinical cardiovascular outcome study investigating the BET inhibitor RVX-208 (now called apabetalone) has already been completed. Independent of this specific agent and this one trial or the numerous unanswered questions that remain, BETs have emerged as novel epigenetic players involved in the execution of coordinated transcriptional programs in cardiovascular health and disease.

Effects of light map orientation and shape on the visual perception of canonical materials

We previously presented a systematic optics-based canonical approach to test material-lighting interactions in their full natural ecology, combining canonical material and lighting modes. Analyzing the power of the spherical harmonics components of the lighting allowed us to predict the lighting effects on material perception for generic natural illumination environments. To further understand how material properties can be brought out or communicated visually, in the current study, we tested whether and how light map orientation and shape affect these interactions in a rating experiment: For combinations of four materials, three shapes, and three light maps, we rotated the light maps in 15 different configurations. For the velvety objects, there were main and interaction effects of lighting and light map orientation. The velvety ratings decreased when the main light source was coming from the back of the objects. For the specular objects, there were main and interaction effects of lighting and shape. The specular ratings increased when the environment in the specular reflections was clearly visible in the stimuli. For the glittery objects, there were main and interaction effects of shape and light map orientation. The glittery ratings correlated with the coverage of the glitter reflections as the shape and light map orientation varied. For the matte objects, results were robust across all conditions. Last, we propose combining the canonical modes approach with so-called importance maps to analyze the appearance features of the proximal stimulus, the image, in contradistinction to the physical parameters as an approach for optimization of material communication.

Does perceptual psychology rule out disjunctivism in the theory of perception?

Disjunctivist views in the theory of perception hold that genuine perceptions differ in some relevant kind from misperceptions, such as illusions and hallucinations. In recent papers, Tyler Burge has argued that such views conflict with the basic tenets of perceptual psychology. According to him, perceptual psychology is committed to the view that genuine perceptions and misperceptions produced by the same proximal stimuli must be or involve perceptual states of the same kind. This, he argues, conflicts with disjunctivism. In this paper, I defend epistemological disjunctivism from Burge’s inconsistency charge. To this end, I survey the perceptual psychological literature, and reveal that the perceptual kinds they tend to employ differ from and imply nothing about the kinds at issue for the epistemological disjunctivist. I then argue that Burge’s concerns with epistemological disjunctivism are best interpreted as motivated not by his commitment to empirical science, but instead by his views in epistemology and about human rationality.

Seeing Seeing

AbstractI argue that we can visually perceive others as seeing agents. I start by characterizing perceptual processes as those that are causally controlled by proximal stimuli. I then distinguish between various forms of visual perspective‐taking, before presenting evidence that most of them come in perceptual varieties. In doing so, I clarify and defend the view that some forms of visual perspective‐taking are “automatic”—a view that has been marshalled in support of dual‐process accounts of mindreading.

Perceptual Pluralism

AbstractPerceptual systems respond to proximal stimuli by forming mental representations of distal stimuli. A central goal for the philosophy of perception is to characterize the representations delivered by perceptual systems. It may be that all perceptual representations are in some way proprietarily perceptual and differ from the representational format of thought (Dretske 1981; Carey 2009; Burge 2010; Block ms.). Or it may instead be that perception and cognition always trade in the same code (Prinz 2002; Pylyshyn 2003). This paper rejects both approaches in favor ofperceptual pluralism, the thesis that perception delivers a multiplicity of representational formats, some proprietary and some shared with cognition. The argument for perceptual pluralism marshals a wide array of empirical evidence in favor of iconic (i.e., image‐like, analog) representations in perception as well as discursive (i.e., language‐like, digital) perceptual object representations.