Although perceptual grouping has been widely studied, its mechanisms remain poorly understood. We propose a neural model of grouping that, through top-down control of its circuits, implements a grouping strategy involving both a connection strategy (which elements to connect) and a selection strategy (that defines spatiotemporal properties of a selection signal to segment target elements and facilitate identification). We apply the model to a letter discrimination task that investigated relationships among uniform connectedness and the grouping (...) principles of proximity and shape similarity. Participants reported whether small circles formed a global letter E or H, and these circles could be connected by a line or be embedded in a matrix of squares. In the model, a good grouping strategy for this task consists of a connection strategy that connects circles but not squares for all conditions and a selection strategy that uses a selection signal of varying size, depending on whether squares were present. Consistent with empirical results, which were verified in two replication studies, model performance is worse with distractor squares, and line connectors improve performance only in the condition with squares. Rather than relying on abstract grouping principles, we show how the empirical results can be explained in terms of observers implementing a task-dependent grouping strategy that promotes overall performance. (shrink)

A fundamental characteristic of human visual perception is the ability to group together disparate elements in a scene and treat them as a single unit. The mechanisms by which humans create such groupings remain unknown, but grouping seems to play an important role in a wide variety of visual phenomena. I propose a neural model of grouping; through top-down control of its circuits, the model implements a grouping strategy that involves both a connection strategy (which elements to (...) connect) and a selection strategy (spatiotemporal properties of a selection signal that segments target elements to facilitate identification). With computer simulations I explain how the circuits work and show how they can account for a wide variety of Gestalt principles of perceptual grouping. Additionally, I extend the model so that it can simulate visual search tasks. I show that when the model uses particular grouping strategies, simulated results closely match empirical results from replication experiments of three visual search tasks. In these experiments, perceptual grouping was induced by proximity and shape similarity (Palmer & Beck, 2007), by the spacing of irrelevant distractors and size similarity (Vickery, 2008), or by the proximity of dots and the proximity and shape similarity of line figures (Trick & Enns, 1997). Thus, I show that the model accounts for a variety of grouping effects and indicates which grouping strategies were likely used to promote performance in three visual search tasks. (shrink)

Perceptual grouping has traditionally been thought to be governed by innate, universal principles. However, recent work has found differences in Japanese and English speakers' non-linguistic perceptual grouping, implicating language in non-linguistic perceptual processes (Iversen, Patel, & Ohgushi, 2008). Two experiments test Japanese- and English-learning infants of 5-6 and 7-8 months of age to explore the development of grouping preferences. At 5-6 months, neither the Japanese nor the English infants revealed any systematic perceptual biases. (...) However, by 7-8 months, the same age as when linguistic phrasal grouping develops, infants developed non-linguistic grouping preferences consistent with their language's structure (and the grouping biases found in adulthood). These results reveal an early difference in non-linguistic perception between infants growing up in different language environments. The possibility that infants' linguistic phrasal grouping is bootstrapped by abstract perceptual principles is discussed. (shrink)

In a series of articles, Jacob Beck proposed that a variety of texture segmentation phenomena occurs due to emergent features that arise from “links” between elements with appropriate local properties, such as alignment, orientation, and proximity. His findings and ideas guided theoretical and computational models, and some of his demonstrations became textbook knowledge about visual perception. We build on this work in two ways. First, we provide a modern replication of a classic texture segmentation study using a much larger sample (...) size. Overall, the replication agrees with Beck’s original findings, although there are some quantitative differences. Second, we show how to apply a quantitative model of visual cortex to Beck’s experiment and demonstrate that the model can explain many aspects of Beck’s findings. Key to the model’s success is cognitive control of connections between individual elements (akin to Beck’s “links” between elements) and a selection mechanism that makes it easy to identify how well elements within a region connect and how well different regions are disconnected. Overall, the model supports Beck’s claim that local properties can facilitate patterns of connections between stimulus elements and that some connection patterns allow an observer to easily distinguish textures. (shrink)

When referring to a target object in a visual scene, speakers are assumed to consider certain distractor objects to be more relevant than others. The current research predicts that the way in which speakers come to a set of relevant distractors depends on how they perceive the distance between the objects in the scene. It reports on the results of two language production experiments, in which participants referred to target objects in photo-realistic visual scenes. Experiment 1 manipulated three factors that (...) were expected to affect perceived distractor distance: two manipulations of perceptual grouping (region of space and type similarity), and one of presentation mode (2D vs. 3D). In line with most previous research on visually-grounded reference production, an offline measure of visual attention was taken here: the occurrence of overspecification with color. The results showed effects of region of space and type similarity on overspecification, suggesting that distractors that are perceived as being in the same group as the target are more often considered relevant distractors than distractors in a different group. Experiment 2 verified this suggestion with a direct measure of visual attention, eye tracking, and added a third manipulation of grouping: color similarity. For region of space in particular, the eye movements data indeed showed patterns in the expected direction: distractors within the same region as the target were fixated more often, and longer, than distractors in a different region. Color similarity was found to affect overspecification with color, but not gaze duration or the number of distractor fixations. Also the expected effects of presentation mode (2D vs. 3D) were not convincingly borne out by the data. Taken together, these results provide direct evidence for the close link between scene perception and language production, and indicate that perceptual grouping principles can guide speakers in determining the distractor set during reference production. (shrink)

A fundamental characteristic of human visual perception is the ability to group together disparate elements in a scene and treat them as a single unit. The mechanisms by which humans create such groupings remain unknown, but grouping seems to play an important role in a wide variety of visual phenomena, and a good understanding of these mechanisms might provide guidance for how to improve machine vision algorithms. Here, we build on a proposal that some groupings are the result of (...) connections in cortical area V2 that join disparate elements, thereby allowing them to be selected and segmented together. In previous instantiations of this proposal, connection formation was based on the anatomy (e.g., extent) of receptive fields, which made connection formation obligatory when the stimulus conditions stimulate the corresponding receptive fields. We now propose dynamic circuits that provide greater flexibility in the formation of connections and that allow for top-down control of perceptual grouping. With computer simulations we explain how the circuits work and show how they can account for a wide variety of Gestalt principles of perceptual grouping, texture segmentation tasks, amodal illusory contours, and ratings of perceived groupings. We propose that human observers use such top-down control to implement task-dependent connection strategies that encourage particular groupings of stimulus elements in order to promote performance on various visual tasks. (shrink)

The laws and principles which predict how perceptual qualities can be extracted from the most elementary visual signals were discovered by the Gestalt psychologists(e.g., Wertheimer,1923; Metzger,1930, translated and re-editedbySpillmann in 2009 and2012, respectively). Their seminal work has inspired visual science ever since, andhas led to exciting discoveries which have confirmed the Gestalt idea that the human brain would have an astonishing capacity for selecting and combining critical visual signals to generate output representations for decision making and action. This capacity (...) of selection and integration enables the perception of form and space, and the correct estimation of relative positions, trajectories, and distances of objects represented in planar images. This paper addresses problems of perceptual organization with critical implications for visual interfaces, and the design of surgical simulator platforms in particular. (shrink)

Previous studies making use of indirect processing measures have shown that perceptual grouping can occur outside the focus of attention. However, no previous study has examined the possibility of subliminal processing of perceptual grouping. The present work steps forward in the study of perceptual organization, reporting direct evidence of subliminal processing of Gestalt patterns. In two masked priming experiments, Gestalt patterns grouped by proximity or similarity that induced either a horizontal or vertical global orientation of (...) the stimuli were presented as masked primes and followed by visible targets that could be congruent or incongruent with the orientation of the primes. The results showed a reliable priming effect in the complete absence of prime awareness for both proximity and similarity grouping principles. These findings suggest that a phenomenal report of the Gestalt pattern is not mandatory to observe an effect on the response based on the global properties of Gestalt stimuli. (shrink)

Speech categories are defined by multiple acoustic dimensions and their boundaries are generally fuzzy and ambiguous in part because listeners often give differential weighting to these cue dimensions during phonetic categorization. This study explored how a listener's perception of a speaker's socio-indexical and personality characteristics influences the listener's perceptual cue weighting. In a matched-guise study, three groups of listeners classified a series of gender-neutral /b/-/p/ continua that vary in VOT and F0 at the onset of the following vowel. Listeners (...) were assigned to one of three prompt conditions and rated the talker in terms of vocal gender prototypicality, attractiveness, friendliness, confidence, trustworthiness, and gayness. Male listeners and listeners who saw a male face showed less reliance on VOT compared to listeners in the other conditions. Listeners' visual evaluation of the talker also affected their weighting of VOT and onset F0 cues, although the effects of facial impressions differ depending on the gender of the listener. The results demonstrate that individual differences in perceptual cue weighting are modulated by the listener's gender and his/her subjective evaluation of the talker. These findings lend support for exemplar-based models of speech perception and production where socio-indexical features are encoded as a part of the episodic traces in the listeners' mental lexicon. This study also shed light on the relationship between individual variation in cue weighting and community-level sound change by demonstrating that VOT and onset F0 co-variation in North American English has acquired a certain degree of socio-indexical significance. (shrink)

Research on language production has focused on the process of utterance planning and involved studying the synchronization between visual gaze and the production of sentences that refer to objects in the immediate visual environment. However, it remains unclear how the visual grouping of these objects might influence this process. To shed light on this issue, the present research examined the effects of the visual grouping of objects in a visual display on utterance planning in two experiments. Participants produced (...) utterances of the form “The snail and the necklace are above/below/on the left/right side of the toothbrush” for objects containing these referents (e.g., a snail, a necklace and a toothbrush). These objects were grouped using classic Gestalt principles of color similarity (Experiment 1) and common region (Experiment 2) so that the induced perceptual grouping was congruent or incongruent with the required phrasal organization. The results showed that speech onset latencies were shorter in congruent than incongruent conditions. The findings therefore reveal that the congruency between the visual grouping of referents and the required phrasal organization can influence speech production. Such findings suggest that, when language is produced in a visual context, speakers make use of both visual and linguistic cues to plan utterances. (shrink)

People are remarkably smart: They use language, possess complex motor skills, make nontrivial inferences, develop and use scientific theories, make laws, and adapt to complex dynamic environments. Much of this knowledge requires concepts and this study focuses on how people acquire concepts. It is argued that conceptual development progresses from simple perceptual grouping to highly abstract scientific concepts. This proposal of conceptual development has four parts. First, it is argued that categories in the world have different structure. Second, (...) there might be different learning systems that evolved to learn categories of differing structures. Third, these systems exhibit differential maturational course, which affects how categories of different structures are learned in the course of development. And finally, an interaction of these components may result in the developmental transition from perceptual groupings to more abstract concepts. This study reviews a large body of empirical evidence supporting this proposal. (shrink)

Perceptual organization comprises a wide range of processes such as perceptual grouping, figure-ground organization, filling-in, completion, and perceptual switching. The Oxford Handbook of Perceptual Organization provides a broad and extensive review of the current literature, written in an accessible form for scholars and students.

This article identifies the structural and conceptual aspects of a visual construction often used in advertisements to establish a metaphoric or associative relation, that is, symmetric object alignment (SOA). It offers an account of the formal ingredients of SOA, which fall into two groups: object-constitutive factors (like size, shape, and color) and object-depictment factors (like perspective, orientation, and distance from viewing point). Both factors allow us to treat SOA as a visual rhetorical scheme. We also discuss how SOA relates to (...) conceptual structure, metaphoric or otherwise. Four types of relations are distinguished, based on the way in which perceptual and conceptual characteristics interact. Finally, we discuss the way in which these characteristics relate to the processing of such visual messages. One depictment factor will be focused on in particular: one-to-one versus one-to-many alignments. An attempt is made to connect these 2 patterns to the much-discussed topic in verbal metaphor theory, object comparison versus categorization. (shrink)

Older adults with age-related hearing loss often use hearing aids to compensate. However, certain challenges in speech perception, especially in noise still exist, despite today’s HA technology. The current study presents an evaluation of a home-based auditory exercises program that can be used during the adaptation process for HA use. The home-based program was developed at a time when telemedicine became prominent in part due to the COVID-19 pandemic. The study included 53 older adults with age-related symmetrical sensorineural hearing loss. (...) They were divided into three groups depending on their experience using HAs. Group 1: Experienced users. Group 2: New users. Group 3: Non-users. These three groups underwent auditory exercises for 3 weeks. The auditory tasks included auditory detection, auditory discrimination, and auditory identification, as well as comprehension with basic and more complex stimuli, presented in quiet and in noisy listening conditions. All participants completed self-assessment questionnaires before and after the auditory exercises program and underwent a cognitive test at the end. Self-assessed improvements in hearing ability were observed across the HA users groups, with significant changes described by new users. Overall, speech perception in noise was poorer than in quiet. Speech perception accuracy was poorer in the non-users group compared to the users in all tasks. In sessions where stimuli were presented in quiet, similar performance was observed among new and experienced uses. New users performed significantly better than non-users in all speech in noise tasks; however, compared to the experienced users, performance differences depended on task difficulty. The findings indicate that HA users, even new users, had better perceptual performance than their peers who did not receive hearing aids. (shrink)

An efficient representation of the environment requires both the selection of a fraction of the information that reaches our senses and the organization of this information into coherent and meaningful elements. Here we discuss the dynamic interplay between selective attention and perceptual organization, important processes that allow us to perceive a seamless, integrated world. Based on evidence from behavioral and neuroimaging studies with normal observers and neuropsychological patients, we examine whether: perceptual grouping constrains visual attention, determining which (...) objects will be selected and be candidates for explicit report; visual attention modulates perceptual grouping, determining how elements are grouped to form meaningful wholes. The data suggest that, whilst not being necessary for at least some forms of perceptual grouping, visual attention can nevertheless modulate grouping. We conclude that selection is dynamically set by bottom-up stimulus factors, top-down knowledge and the allocation of attention to space and within grouped regions of objects. (shrink)

We report on rapid perceptual learning of intonation contour categories in adults and 9- to 11-year-old children. Intonation contours are temporally extended patterns, whose perception requires temporal integration and therefore poses significant working memory challenges. Both children and adults form relatively abstract representations of intonation contours: Previously encountered and novel exemplars are categorized together equally often, as long as distance from the prototype is controlled. However, age-related differences in categorization performance also exist. Given the same experience, adults form narrower (...) categories than children. In addition, adults pay more attention to the end of the contour, while children appear to pay equal attention to the beginning and the end. The age range we examine appears to capture the tail-end of the developmental trajectory for learning intonation contour categories: There is a continuous effect of age on category breadth within the child group, but the oldest children are adult-like. (shrink)

Developmental coordination disorder is a heterogeneous condition. Besides motor impairments, children with DCD often exhibit poor visual perceptual skills and executive functions. This study aimed to characterize the motor, perceptual, and cognitive profiles of children with DCD at the group level and in terms of subtypes. A total of 50 children with DCD and 31 typically developing peers underwent a comprehensive neuropsychological and motor assessment. The percentage of children with DCD showing impairments in each measurement was first described. (...) Hierarchical agglomerative and K-means iterative partitioning clustering analyses were then performed to distinguish the subtypes present among the complete sample of children in a data-driven way. Moderate to large percentages of children with DCD showed impaired executive functions and praxis, as well as attentional, visual perceptual, and visuomotor skills. Clustering analyses identified five subtypes, four of them mainly consisting of children with DCD and one of TD children. These subtypes were characterized by: generalized impairments, impaired manual dexterity, poor balance, planning, and alertness, impaired manual dexterity, cognitive inhibition, and poor visual perception, impaired manual dexterity and cognitive inhibition, and no impairment. Besides subtle differences, the motor and praxis measures did not enable to discriminate between the four subtypes of children with DCD. The subtypes were, however, characterized by distinct perceptual or cognitive impairments. These results highlight the importance of assessing exhaustively the perceptual and cognitive skills of children with DCD. (shrink)

Perceptual grouping is fundamental to many auditory processes. The Iambic–Trochaic Law (ITL) is a default grouping strategy, where rhythmic alternations of duration are perceived iambically (weak‐strong), while alternations of intensity are perceived trochaically (strong‐weak). Some argue that the ITL is experience dependent. For instance, French speakers follow the ITL, but not as consistently as German speakers. We hypothesized that learning about prosodic patterns, like word stress, modulates this rhythmic grouping. We tested this idea by training French (...) adults on a German‐like stress contrast. Individuals who showed better phonological learning had more ITL‐like grouping, particularly over duration cues. In a non‐phonological condition, French adults were trained using identical stimuli, but they learned to attend to acoustic variation that was not linguistic. Here, no learning effects were observed. Results thus suggest that phonological learning can modulate low‐level auditory grouping phenomena, but it is constrained by the ability of individuals to learn from short‐term training. (shrink)

In this paper we claim, first, that there are high-level visual experiences of grouping properties, i.e., properties that an array of elements we see can have to be organised in a certain way. Second, we argue that there are auditory experiences of groupings that share certain important properties with visual experiences of groupings, thereby being perceptual and high-level as well. Third, these results enable us to understand the nature and structure of our meaning experiences. We claim that, although (...) meaning experiences depend on the auditory experiences we discuss, they are not perceptual, for they lack one of the features that make those auditory experiences perceptual; namely, being holistically attended to. (shrink)

In sport, perceptual skill training software is intended to assist tactical training in the field. The aim of this field study was to test whether ‘laboratory-based’ pattern recall training would augment tactical skill training performed on the field. Twenty-six soccer players between 14-16 years of age from a single team participated in this study and were divided into three groups. The first received field training on a specific tactical skill plus cognitive training sessions on the pattern recall task. The (...) second performed only the field training while the third group served as a control group and had field training on other topics. The task on the pre-, post- and retention tests was to recall specific soccer patterns displayed on a computer screen. Results showed significant changes between pre- to post-test performance. There was no significant interaction between groups and tests but the effect size was large. From pre- to retention-test, there was a significant difference between tests and an interaction between groups and tests, but no main effect difference between groups. On the basis of significance testing only retention was affected by the additional training, however, descriptive results and effect sizes from pre- to post-test were as expected and suggested there were learning benefits. Together these results indicate that augmented perceptual-cognitive training might be beneficial, but some limitations in our study design (e.g., missing field test, missing placebo group, etc.) need to be improved in future work. (shrink)

The universality, invariance, and elegance of principles governing the universe may be reflected in principles of the minds that have evolved in that universe – provided that the mental principles are formulated with respect to the abstract spaces appropriate for the representation of biologically significant objects and their properties. (1) Positions and motions of objects conserve their shapes in the geometrically fullest and simplest way when represented as points and connecting geodesic paths in the six-dimensional manifold jointly determined by the (...) Euclidean group of three-dimensional space and the symmetry group of each object. (2) Colors of objects attain constancy when represented as points in a three-dimensional vector space in which each variation in natural illumination is canceled by application of its inverse from the three-dimensional linear group of terrestrial transformations of the invariant solar source. (3) Kinds of objects support optimal generalization and categorization when represented, in an evolutionarily-shaped space of possible objects, as connected regions with associated weights determined by Bayesian revision of maximum-entropy priors. Key Words: apparent motion; Bayesian inference; cognition; color constancy; generalization; mental rotation; perception; psychological laws; psychological space; universal laws. (shrink)

Some philosophers have suggested that certain shifts in perceptual organization are counterexamples to representationalism about phenomenal character. Representationalism about phenomenal character is, roughly, the view that there can be no difference in the phenomenal character of experience without a difference in the representational content of experience. In this paper, I examine three of these alleged counterexamples: the dot array (Peacocke 1983), the intersecting lines (Speaks 2010), and the 3 X 3 grid (Nickel 2007). I identify the two features of (...) their phenomenology that call for explanation: grouping and prominence. I then argue that representationalists can adequately account for both of these features. I also critique some previous treatments of grouping and prominence. (shrink)

This study investigates whether listeners’ cue weighting predicts their real‐time use of asynchronous acoustic information in spoken word recognition at both group and individual levels. By focusing on the time course of cue integration, we seek to distinguish between two theoretical views: the associated view (cue weighting is linked to cue integration strategy) and the independent view (no such relationship). The current study examines Seoul Korean listeners’ (n = 62) weighting of voice onset time (VOT, available earlier in time) and (...) onset fundamental frequency of the following vowel (F0, available later in time) when perceiving Korean stop contrasts (Experiment 1: cue‐weighting perception task) and the timing of VOT integration when recognizing Korean words that begin with a stop (Experiment 2: visual‐world eye‐tracking task). The group‐level results reveal that the timing of the early cue (VOT) integration is delayed when the later cue (F0) serves as the primary cue to process the stop contrast, supporting a relationship between cue weighting and the timing of cue integration (the associated view). At the individual level, listeners with greater reliance on F0 than VOT exhibited a further delayed integration of VOT. These findings suggest that the real‐time processing of asynchronously occurring acoustic cues for lexical activation is modulated by the weight that listeners assign to those cues, providing evidence for the associated view of cue integration. This study offers insights into the mechanisms of cue integration and spoken word recognition, and they shed light on variability in cue integration strategies among listeners. (shrink)

Object files are mental representations that enable perceptual systems to keep track of objects as numerically the same. How is their reference fixed? A prominent approach, championed by Zenon Pylyshyn and John Campbell, makes room for a non-satisfactional use of properties to fix reference. This maneuver has enabled them to reconcile a singularist view of reference with the intuition that properties must play a role in reference fixing. This paper examines Campbell’s influential defense of this strategy. After criticizing it, (...) a new approach is sketched. The alternative view introduces representational contents to explain perceptual individuation. After arguing that those contents are not satisfactional, it is concluded that there is room for a third view of reference fixing that does not fit into the singularist/descriptivist dichotomy. (shrink)

Abilities such as peripheral reaction are of special importance in soccer. Whether these abilities can be improved by sport-specific on-field interventions remains unclear. The aim of the present controlled trial was to investigate the effect of a soccer-specific perceptual-cognitive on-field training on peripheral reaction of highly talented soccer players aged 12 to 13 years. N = 38 male elite athletes from young talent centers were allocated to an intervention (n = 19) and a control group (n = 19). Computer-based (...) peripheral perception tests were conducted pre- and post-intervention. Combining a sport-specific and a juggling task, the intervention was performed once a week (8 weeks, 20 min. per week) in addition to team training. The control group exclusively underwent usual team training. Analyzes show significant differences between the two groups for Peripheral Reaction Time, with significant improvements for the intervention group and none for the control group. Furthermore, results indicate that improvements in peripheral reaction might be due to changes in the reaction time of right-footed players. Future studies should be conducted to clarify the effect of sport-specific on-field training approaches on peripheral reaction time. These analyzes should consider the influence of lateralization on effectivity of perceptual-cognitive on-field training approaches. (shrink)

We present the first neurophysiological signatures showing distinctive effects of group social context and emotional arousal on cultural perceptions, such as the efficacy of religious rituals. Using a novel protocol, EEG data were simultaneously recorded from ethnic Chinese religious believers in group and individual settings as they rated the perceived efficacy of low, medium, and high arousal spirit-medium rituals presented as video clips. Neural oscillatory patterns were then analyzed for these perceptual judgements, categorized as low, medium, and high efficacy. (...) The results revealed distinct neural signatures and behavioral patterns between the experimental conditions. Arousal levels predicted ratings of ritual efficacy. Increased efficacy was marked by suppressed alpha and beta power, regardless of group or individual setting. In groups, efficacy ratings converged. Individual setting showed increased within-participant phase synchronization in alpha and beta bands, while group setting enhanced between-participant theta phase synchronization. This reflected group participants' orientation toward a common perspective and social coordination. These findings suggest that co-presence in groups leads to a social-tuning effect supported by between-participant theta phase synchrony. Together these neural synchrony patterns reveal how collective rituals have both individual and communal dimensions. The emotionality of spirit-medium rituals drives individual perceptions of efficacy, while co-presence in groups signals the significance of an event and socially tunes enhanced agreement in perceptual ratings. In other words, mass gatherings may foster social cohesion without necessarily requiring group-size scaling limitations of direct face-to-face interaction. This could have implications for the scaling computability of synchrony in large groups as well as for humanistic studies in areas such as symbolic interactionism. (shrink)

Expertise in Chinese character recognition is marked by reduced holistic processing, which depends mainly on writing rather than reading experience. Here we show that, while simplified and traditional Chinese readers demonstrated a similar level of HP when processing characters shared between the simplified and traditional scripts, simplified Chinese readers were less holistic than traditional Chinese readers in perceiving simplified characters; this effect depended mainly on their writing rather than reading performance. However, the two groups did not differ in HP of (...) traditional characters, regardless of their difference in reading and writing performances. Our image analysis showed high visual similarity between the two character types, with a larger variance among simplified characters; this may allow simplified Chinese readers to interpolate and generalize their skills to traditional characters. Thus, transfer of perceptual expertise may be constrained by both the similarity in feature and the difference in exemplar variance between the categories. (shrink)

As he recalls in his book Naive Physics, Paolo Bozzi’s experiments on naïve or phenomenological physics were partly inspired by Aristotle’s spokesman Simplicio in Galileo’s Dialogue. Aristotle’s ‘naïve’ views of physical reality reflect the ways in which we are disposed perceptually to organize the physical reality we see. In what follows I want to apply this idea to the notion of a group, a term which I shall apply as an umbrella expression embracing ordinary visible collections (of pieces of fruit (...) in the fruit bowl), but also families, populations, kinds, categories, species and genera. I will try to determine to what extent we can understand what groups, in this broad sense, have in common and how they are distinguished from two sorts of entities with which they are standardly confused, namely sets and wholes. (shrink)

Shepard's analysis of how shape, motion, and color are perceptually represented can be generalized. Apparent motion and shape may be associated with a group of spatial transformations, accounting for rigid and plastic motion, and perceived object color may be associated with a group of illuminant transformations, accounting for the discriminability of surface-reflectance changes and illuminant changes beyond daylight. The phenomenological and mathematical parallels between these perceptual domains may indicate common organizational rules, rather than specific ecological adaptations. [Barlow; Hecht; Kubovy (...) & Epstein; Schwartz; Shepard; Todorovic]. (shrink)

We explore experimental methods used to study the phenomena of perceptual organization, first studied by the Gestalt psychologists. We describe an application of traditional psychophysics to perceptual organization and offer alternative methods. Among these, we distinguish two approaches that use multistable stimuli: (1) phenomenological psychophysics, in which the observer's response is assumed to accurately and directly reflect perceptual experience; and (2) the interference paradigm, in which an observer's response is evaluated as correct or incorrect because it pertains (...) to a corrigible task, but does not directly reflect the observer's experience. We show that phenomenological psychophysics can yield valuable information about perceptual organization and lends itself to the development of quantitative theory. We discuss some criticisms of the method and argue that the two approaches that use multistable stimuli are complementary. We also compare each of the approaches with traditional psychophysics. We conclude that the several methods are convergent. (shrink)

Much research on color representation and categorization has assumed that relations among color terms can be proxies for relations among color percepts. We test this assumption by comparing the mapping of color words with color appearances among different observer groups performing cognitive tasks: an invariance of naming task; and triad similarity judgments of color term and color appearance stimuli within and across color categories. Observer subgroups were defined by perceptual phenotype and photopigment opsin genotype analyses. Results suggest that individuals (...) rely on at least two different representational models of color experience: one lexical, conforming to the culture's normative linguistic representation, and another individual perceptual representation organizing each observer's color sensation experiences. Additional observer subgroup analyses suggest that perceptual phenotype variation within a language group may play a greater role in the shared color naming system than previously thought. A reexamination of color naming data in view of these findings may reveal influences on color naming important to current theories. (shrink)

This article introduces an experimental paradigm to selectively probe the multiple levels of visual processing that influence the formation of object contours, perceptual boundaries, and illusory contours. The experiments test the assumption that, to integrate contour information across space and contrast sign, a spatially short-range filtering process that is sensitive to contrast polarity inputs to a spatially long-range grouping process that pools signals from opposite contrast polarities. The stimuli consisted of thin subthreshold lines, flashed upon gaps between collinear (...) inducers which potentially enable the formation of illusory contours. The subthreshold lines were composed of one or more segments with opposite contrast polarities. The polarity nearest to the inducers was varied to differentially excite the short-range filtering process. The experimental results are consistent with neurophysiological evidence for cortical mechanisms of contour processing and with the Boundary Contour System model, which identifies the short-range filtering process with cortical simple cells, and the long-range grouping process with cortical bipole cells. (shrink)