When we perceive an object, we perceive the object from a perspective. As a consequence of the perspectival nature of perception, when we perceive, say, a circular coin from different angles, there is a respect in which the coin looks circular throughout, but also a respect in which the coin's appearance changes. More generally, perception of shape and size properties has both a constant aspect—an aspect that remains stable across changes in perspective—and a perspectival aspect—an aspect that changes (...) depending on one's perspective on the object. How should we account for the perspectival aspect of spatial perception? We present a framework within which to discuss the perspectival aspect of perception and put forward three desiderata that any account of the perspectival aspect of perception should satisfy. We discuss views on which the perspectival aspect of perception is analyzed in terms of constitutively mind-dependent appearance properties as well as views on which the perspectival aspect of perception is analyzed in terms of representations of mind-independent perspectival properties. (shrink)

It remains controversial whether touch is a truly spatial sense or not. Many philosophers suggest that, if touch is indeed spatial, it is only through its alliances with exploratory movement, and with proprioception. Here we develop the notion that a minimal yet important form of spatial perception may occur in purely passive touch. We do this by showing that the array of tactile receptive fields in the skin, and appropriately relayed to the cortex, may contain the (...) same basic informational building blocks that a creature navigating around its environment uses to build up a perception of space. We illustrate this point with preliminary evidence that perception of spatiotemporal patterns on the human skin shows some of the same features as spatial navigation in animals. We argue (a) that the receptor array defines a ‘tactile field’, (b) that this field exists in a minimal form in ‘skin space’, logically prior to any transformation into bodily or external spatial coordinates, and (c) that this field supports tactile perception without integration of concurrent proprioceptive or motor information. The basic cognitive elements of space perception may begin at lower levels of neural and perceptual organisation than previously thought. (shrink)

Tools do not just expand our capabilities. They change what we can do, and in doing so, they change who we are. Serena is Serena because of what she can do with a tennis racket. Tiger is Tiger because of what he can do with a golf club. In changing what we can do, tools also change the very way we perceive the spatial layout of the world. Objects beyond arm's reach appear closer when we wield a tool that (...) can expand out to the object. Catchable objects seem to move faster when we wield a tool that is less effective for catching the object. These examples illustrate how the basic processes of spatial vision are impacted by tool use. (shrink)

This paper examines Helmholtz's attempt to use empirical psychology to refute certain of Kant's epistemological positions. Particularly, Helmholtz believed that his work in the psychology of visual perception showed Kant's doctrine of the a priori character of spatial intuition to be in error. Some of Helmholtz's arguments are effective, but this effectiveness derives from his arguments to show the possibility of obtaining evidence that the structure of physical space is non-Euclidean, and these arguments do not depend on his (...) theory of vision. Helmholtz's general attempt to provide an empirical account of the "inferences" of perception is regarded as a failure. (shrink)

Ballard et al. model eye position as a deictic pointer for spatial perception. Evidence from research on gaze control indicates, however, that shifts in actual eye position are neither necessary nor sufficient to produce shifts in spatial perception. Deictic context is instead provided by the interaction between two deictic pointers; one representing actual eye position, and the other, intended eye position.

Our perception of where touch occurs on our skin shapes our interactions with the world. Most accounts of cutaneous localisation emphasise spatial transformations from a skin-based reference frame into body-centred and external egocentric coordinates. We investigated another possible method of tactile localisation based on an intrinsic perception of ‘skin space’. The arrangement of cutaneous receptive fields (RFs) could allow one to track a stimulus as it moves across the skin, similarly to the way animals navigate using path (...) integration. We applied curved tactile motions to the hands of human volunteers. Participants identified the location midway between the start and end points of each motion path. Their bisection judgements were systematically biased towards the integrated motion path, consistent with the characteristic inward error that occurs in navigation by path integration. We thus showed that integration of continuous sensory inputs across several tactile RFs provides an intrinsic mechanism for spatial perception. (shrink)

I’m now looking at a soccer ball and a Nintendo Game Cube, and thus am having a perceptual experience of a sphere and a cube. My friend, blind from birth, (who’s helping me with the cleaning) is touching these items, and is thus having a perceptual experience of the same things. Not only are we perceiving the same items, but in doing so we apply the terms ‘sphere’ and ‘cube’, respectively, to them. Are we, in doing so, applying the same, (...) or different, perceptual concepts? (shrink)

Very encouraging results have been obtained from a new program that derives a dense three-dimensional evidence grid representation of a robot's surroundings from wide-angle stereoscopic images. The pro gram adds several spatial rays of evidence to a grid for each of about 2,500 local image features chosen per stereo pair. It was used to construct a 256x256x64 grid, representing 6 by 6 by 2 meters, from a hand- collected test set of twenty stereo image pairs of an office scene. (...) Fifty nine stereo pairs of an 8 by 8 meter laboratory were also processed. The positive (probably occupied) cells of the grids, viewed in perspec tive, resemble dollhouse scenes. Details as small as the curvature of chair armrests are discernible. The processing time, on a 100 MIPS Sparc 20, is less than five seconds per stereo pair, and total memory is under 16 megabytes. The results seem abundantly adequate for very reliable navigation of freely roaming mobile robots, and plausibly adequate for shape identification of objects bigger than 10 centimeters. The program is a first proof of concept, and awaits optimizations, enhancements, variations, extensions and applications. (shrink)

Gary Hatfield examines theories of spatial perception from the seventeenth to the nineteenth century and provides a detailed analysis of the works of Kant and Helmholtz, who adopted opposing stances on whether central questions about spatial perception were fully amenable to natural-scientific treatment. At stake were the proper understanding of the relationships among sensation, perception, and experience, and the proper methodological framework for investigating the mental activities of judgment, understanding, and reason issues which remain at (...) the core of philosophical psychology and cognitive science. (shrink)

An attempt is made to defend a general approach to the spatial content of perception, an approach according to which perception is imbued with spatial content in virtue of certain kinds of connections between perceiving organism's sensory input and its behavioral output. The most important aspect of the defense involves clearly distinguishing two kinds of perceptuo-behavioral skills—the formation of dispositions, and a capacity for emulation. The former, the formation of dispositions, is argued to by the central (...) pivot of spatial content. I provide a neural information processing interpretation of what these dispositions amount to, and describe how dispositions, so understood, are an obvious implementation of Gareth Evans' proposal on the topic. Furthermore, I describe what sorts of contribution are made by emulation mechanisms, and I also describe exactly how the emulation framework differs from similar but distinct notions with which it is often unhelpfully confused, such as sensorimotor contingencies and forward models. (shrink)

Ordinary cases of object seeing involve the visual perception of space and spatial location. But does seeing an object require such spatial perception? An empirical challenge to the idea that it does comes from reflection upon Bálint's syndrome, for some suppose that in Bálint's syndrome subjects can see objects without seeing space or spatial location. In this article, I question whether the empirical evidence available to us adequately supports this understanding of Bálint's syndrome, and explain (...) how the aforementioned empirical challenge can be resisted. (shrink)

Intentionalism is the view that the phenomenal character of a conscious experience is wholly determined by, or even reducible to, its representational content. In this essay I put forward a version of intentionalism that allows (though does not require) the reduction of phenomenal character to representational content. Unlike other reductionist theories, however, it does not require the acceptance of phenomenal externalism (the view that phenomenal character does not supervene on the internal state of the subject). According the view offered here, (...) phenomenal characters essentially represent subject-environment relations that are relevant to the possibilities for causal interaction between the subject and the environment; relations of the kind that J. J. Gibson dubbed affordances. I argue for this view chiefly through an examination of spatial perception, though other cases are also considered. The view assumes that a phenomenal character has an essential functional role; though it need not be assumed that a functional role is sufficient for a phenomenal character. (shrink)

From the late thirteenth to the early seventeenth century, the process of visual imaging was understood in the Latin West as an essentially subjective act initiated by the eye and completed by the brain. The crystalline lens took center stage in this act, its role determined by its peculiar physical and sensitive capacities. As a physical body, on the one hand, it was disposed to accept the physical impressions of light and color radiating to it from external objects. As a (...) sensitive body, on the other hand, it was enabled by the visual spirit flowing to it from the brain to feel those impressions visually. Acting as a sentient selector of visual information, the lens transformed the brute physical impressions of light and color into visual impressions. These, in turn, gave rise to perceptual “depictions” that were passed back along the stream of visual spirits to the brain. Known in Scholastic parlance as “intentional species,” these depictions served as virtual representations of their generating objects. As such, they provided the wherewithal not only for perception, but also for conception and cognition. (shrink)

1. The spatial perception requirementCassam surveys arguments for what he calls the ‘Spatial Perception Requirement’ . This is the following principle: " SPR: In order to perceive that something is the case and thereby to know that it is the case one must be capable of spatial perception. " A couple of preliminary glosses. By ‘spatial perception’ Cassam means either perception of location, or perception of specifically spatial properties of (...) an object, such as its size and shape. Second, Cassam takes it that there is something basic about cases in which one's perceiving that something is the case depends on perception of an object. That is, he takes it that there is something basic about such cases as that in which, for example, you perceive that the door is open by perceiving the door.On this second point, it is not quite obvious that one could not perceive that things are thus and so if one could not perceive material objects. Cannot someone lost in fog, for example, perceive that it is foggy, even if they cannot see a thing because of the fog? Moreover, suppose we have someone who cannot perceive that things are thus and so. This person has only a series of sensations. Is it obvious that this person could not come to have knowledge of their world by reasoning about the probable causes of those sensations? These points seem to me to have some interest, but I will not pursue them here. I will assume we are considering cases in which propositional knowledge is grounded in perception that such and such is the case, and that this in turn depends on perception of objects.One sort of argument you might give for SPR runs as follows. Perception of an object demands that you have perceptually differentiated the object from its …. (shrink)

It has been well documented, and fairly well known, that concomitant with an increase in chronological age is a corresponding increase in sensory impairment. As most people realize, our hearing suffers as we get older; hence, the increased need for hearing aids. The first portion of the present paper is how the change in age apparently affects auditory judgments of sound source position. A summary of the literature evaluating the changes in the perception of sound source location and the (...) perception of sound source motion as a function of chronological age is presented. The review is limited to empirical studies with behavioral findings involving humans. It is the view of the author that we have an immensely limited understanding of how chronological age affects perception of space when based on sound. In the latter part of the paper, discussion is given to how auditory spatial perception is traditionally conducted in the laboratory. Theoretically, beneficial reasons exist for conducting research in the manner it has been. Nonetheless, from an ecological perspective, the vast majority of previous research can be considered unnatural and greatly lacking in ecological validity. Suggestions for an alternative and more ecologically valid approach to the investigation of auditory spatial perception are proposed. It is believed an ecological approach to auditory spatial perception will enhance our understanding of the extent to which individuals perceive sound source location and how those perceptual judgments change with an increase in chronological age. (shrink)

Marr (1982) may have been one of the rst vision researchers to insist that in modeling vision it is important to separate the location of visual features from their type. He argued that in early stages of visual processing there must be “place tokens” that enable subsequent stages of the visual system to treat locations independent of what specic feature type was at that location. Thus, in certain respects a collinear array of diverse features could still be perceived as a (...) line, and under certain conditions could function as such in perceptual phenomena like the Poggendorf illusion. (shrink)

This chapter provides an overview of the phenomenology of size perception and the use of instructions to tease apart phenomenal and cognitive aspects. It develops his own recent proposals concerning the geometry of visual space. The chapter proposes that visual space is contracted along the lines of sight. This contraction would explain the apparent convergence of railway tracks, but without invoking a “proximal mode” experience. Parallel railway tracks receding into the distance project converging lines onto the retinas. A true (...) proximal mode representation would show these lines converging as if in a vertical plane. But we experience them as converging while also receding in depth along the ground. The chapter suggests that this calls for a third geometry of visual space, intermediate between a linear perspective projection and full phenomenal constancy. The chapter attributes reports of full constancy to cognitive factors. size perception, visual space, geometry, lines of sight, proximal mode, phenomenal constancy. (shrink)

A MAJOR PHILOSOPHICAL INTERPRETER of Kant and critic of Herbart and Hegel, Hermann Lotze ( 1817-1881) is known to historians of psychology primarily for his theory of spatial perception.' As Professor of Philosophy at Gottingen University from 1845 to 1880, he published his theory of the physiological mechanism for spatial consciousness no less than six times.2 Standard accounts present his local sign theory as an associationistic, empiricistic, or empiristic view.3 Yet they also mention its influence among nativists (...) such as Lotze's own student Carl Stumpf. Certainly there is an historical irony here which deserves explanation. This paper will describe Lotze's theory, indicate its origins in the work of scientists such as E. H. Weber and Johannes Muiller and philosophers such as Jakob Friedrich Fries and Johann Friedrich Herbart, and trace its transformation at the hands of psycholo- gists of various theoretical persuasions.4 The intent is not to argue for Lotze's personal influence so much as to illustrate how one fertile idea in the history of science can serve as the catalyst for a much broader conceptual development. (shrink)

It seems plausible that visual experiences of darkness have perceptual phenomenal content that clearly differentiates them from absences of visual experiences. I argue, relying on psychological results concerning auditory attention, that the analogous claim is true about auditory experiences of silence. More specifically, I propose that experiences of silence present empty spatial directions like ‘right’ or ‘left’, and so have egocentric spatial content. Furthermore, I claim that such content is genuinely auditory and phenomenal in the sense that one (...) can, in principle, recognize that one is experiencing silence. This position is far from obvious, as the majority of theories concerning silence perception do not ascribe perceptual phenomenal content to experiences of silence. (shrink)

Review of Gary Hatfield, The Natural and the Normative: Theories of Spatial Perception from Kant to Helmholtz. MIT Press, 1990.

Recent research put forward the hypothesis that eye movements are integrated in memory representations and are reactivated when later recalled. However, “looking back to nothing” during recall might be a consequence of spatial memory retrieval. Here, we aimed at distinguishing between the effect of spatial and oculomotor information on perceptual memory. Participants’ task was to judge whether a morph looked rather like the first or second previously presented face. Crucially, faces and morphs were presented in a way that (...) the morph reactivated oculomotor and/or spatial information associated with one of the previously encoded faces. Perceptual face memory was largely influenced by these manipulations. We considered a simple computational model with an excellent match that expresses these biases as a linear combination of recency, saccade, and location. Surprisingly, saccades did not play a role. The results suggest that spatial and temporal rather than oculomotor information biases perceptual face memory. (shrink)

Neuropsychological findings used to motivate the "two visual systems" hypothesis have been taken to endanger a pair of widely accepted claims about spatial representation in conscious visual experience. The first is the claim that visual experience represents 3-D space around the perceiver using an egocentric frame of reference. The second is the claim that there is a constitutive link between the spatial contents of visual experience and the perceiver's bodily actions. In this paper, I review and assess three (...) main sources of evidence for the two visual systems hypothesis. I argue that the best interpretation of the evidence is in fact consistent with both claims. I conclude with some brief remarks on the relation between visual consciousness and rational agency. (shrink)

Covert spatial attention alters the way things look. There is strong empirical evidence showing that objects situated at attended locations are described as appearing bigger, closer, if striped, stripier than qualitatively indiscernible counterparts whose locations are unattended. These results cannot be easily explained in terms of which properties of objects are perceived. Nor do they appear to be cases of visual illusions. Ned Block has argued that these results are best accounted for by invoking what he calls ‘mental paint’. (...) In this paper I argue, instead, in favour of an account of these phenomena in terms of the perceptual experience of affordances concerning saccadic eye movement. As part of the argument I draw connections with the empirical literature on the way in which performance efficiency also alters visual appearance. (shrink)

Despite the large interest in the human ability to perceive space present in neuroscience, cognitive science and psychology, as well as philosophy of mind, the issues regarding egocentric space representation received relatively less attention. In this paper I take up a unique phenomenon related to this faculty: the “spatial purport” of perceptual experiences. The notion was proposed by Rick Grush to describe the subjective, qualitative aspects of egocentric representations of spatial properties and relations. Although Grush offered an explanation (...) of the mechanism giving rise to appearance of spatial purport, his model had considerable shortcomings. In the paper I thoroughly analyze both the notion of spatial purport and Grush’s explanation of the mechanism at its core in order to develop his theory using the insights provided by the predictive processing theory of mind, and more particularly by the active inference framework. The extended account I offer, named Predictive and Hierarchical Skill Theory, explains phenomena that escaped Grush’s model and furthers the research on egocentric space representation from the perspective of both neuroscience and philosophy of mind. (shrink)

This collection of essays brings together research on sense modalities in general and spatial perception in particular in a systematic and interdisciplinary way. It updates a long-standing philosophical fascination with this topic by incorporating theoretical and empirical research from cognitive science, neuroscience, and psychology. The book is divided thematically to cover a wide range of established and emerging issues. Part I covers notions of objectivity and subjectivity in spatial perception and thinking. Part II focuses on the (...) canonical distal senses, such as vision and audition. Part III concerns the chemical senses, including olfaction and gustation. Part IV discusses bodily awareness, peripersonal space, and touch. Finally, the volume concludes with Part V, on multimodality. Spatial Senses is an important contribution to the scholarly literature on the philosophy of perception that takes into account important advances in the sciences. (shrink)

From the outside, our senses are spatially integrated in our body in manifestly different ways. This paper starts from the suggestion that the philosophical formulation of the problem of spatial perception, as it flows from the modern opposition of mind and world, is partly responsible for the fact that philosophers have often explicitly disregarded the spatial nature of the senses themselves. An indirect consequence is that much philosophical work focuses on how the senses can – or cannot (...) – perceive the same spatial features of objects in the same way, while disregarding the massive differences in performance among the senses. This paper explores the ways in which the spatial integration of our senses determines what each of our senses excels in, and hence what they contribute to our spatial relation to a physical environment. By juxtaposing descriptive analyses of a variety of selected cases, the paper gives priority to how various aspects of the world appear to us in order to obtain insight into the meaning of spatiality for different senses. (shrink)

From the outside, our senses are spatially integrated in our body in manifestly different ways. This paper starts from the suggestion that the philosophical formulation of the problem of spatial perception, as it flows from the modern opposition of mind and world, is partly responsible for the fact that philosophers have often explicitly disregarded the spatial nature of the senses themselves. An indirect consequence is that much philosophical work focuses on how the senses can – or cannot (...) – perceive the same spatial features of objects in the same way, while disregarding the massive differences in performance among the senses. This paper explores the ways in which the spatial integration of our senses determines what each of our senses excels in, and hence what they contribute to our spatial relation to a physical environment. By juxtaposing descriptive analyses of a variety of selected cases, the paper gives priority to how various aspects of the world appear to us in order to obtain insight into the meaning of spatiality for different senses. (shrink)

En este ensayo exploro cierta veta reduccionista del enfoque enactivo de Noë. Primero argumento que su concepción de nuestro encuentro perceptual con las propiedades intrínsecas de los objetos requiere una metafísica relacional revisionista para ser exitosa. Luego argumento que la propuesta de Noë sobre el rol de la percepción para el pensamiento espacial exige una concepción revisionista de nuestros conceptos espaciales cotidianos. Finalmente, sugiero que a la base de estas formas de revisionismo está una comprensión reduccionista de la egocentricidad perceptual (...) que debe abandonarse si queremos una concepción más substantiva de la percepción y su rol explicativo en el pensamiento. (shrink)

Summary Music has been primarily conceived as a temporal art. However, over the last two centuries or so, researchers across different disciplines including musicology, psychology, and philosophy, have been intrigued by the spatial nature of music and sounds, using spatial concepts to define music. This paper aims to demonstrate that an understanding of music perception from a temporal perspective inherently implies a certain spatial dimension. To do this, first, I briefly examine some key arguments that lead (...) to conceiving sound perception in temporal terms. At the same time, I highlight some of the limitations of a purely temporal account of sound perception which necessitate the incorporation of spatial considerations into the conceptualization of sound perception. Consequently, I move on to consider prominent spatial accounts of musical sounds that have been elaborated by psychologists, musicologists, and music composers. In conclusion, I discuss some of the challenges arising from the analogy between music and space, whether conceived in perceptual or cognitive terms. (shrink)

This paper investigates Hume's theory of the perception of spatial magnitude or size as developed in the _Treatise<D>, as well as its relation to his concepts of space and geometry. The central focus of the discussion is Hume's espousal of the 'composite' hypothesis, which holds that perceptions of spatial magnitude are composed of indivisible sensible points, such that the total magnitude of a visible figure is a derived by-product of its component parts. Overall, it will be argued (...) that a straightforward reading of this hypothesis fails to do full justice to the complexity of Hume's theory of spatial perception and geometry, and that a more adequate treatment must also admit an important role for the more direct process of spatial magnitude perception which he dubs 'intuition'. (shrink)