The peripersonal space is an adaptive and flexible interface between the body and the environment that fulfills a dual-motor function: preparing the body for voluntary object-oriented actions to interact with incentive stimuli and preparing the body for defensive responses when facing potentially harmful stimuli. In this position article, we provide arguments for the sensorimotor rooting of the peripersonal space representation and highlight the variables that contribute to its flexible and adaptive characteristics. We also demonstrate that (...) class='Hi'>peripersonal space represents a mediation zone between the body and the environment contributing to not only the control of goal-directed actions but also the organization of social life. The whole of the data presented and discussed led us to the proposal of a new theoretical framework linking the peripersonal action space and the interpersonal social space and we highlight how this theoretical framework can account for social behaviors in populations with socio-emotional deficits. (shrink)

In this article, I link the empirical hypothesis that neural representations of sensory stimulation near the body involve a unique motor component to the idea that the perceptual field is structured by skillful bodily activity. The neurophenomenological view that emerges is illuminating in its own right, though it may also have practical consequences. I argue that recent experiments attempting to alter the scope of these near space sensorimotor representations are actually equivocal in what they show. I propose resolving this (...) ambiguity by treating these representations as responsive to the development or degeneration of know-how—which can be isolated as an appropriate object for scientific investigation. (shrink)

Philosophy of perception is guilty of focusing on the perception of far space, neglecting the possibility that the perception of the space immediately surrounding the body, which is known as peripersonal space, displays different properties. Peripersonal space is the space in which the world is literally at hand for interaction. It is also the space in which the world can become threatening and dangerous, requiring protective behaviours. Recent research in cognitive neuroscience has (...) yielded a vast array of discoveries on the multisensory and sensorimotor specificities of the processing of peripersonal space. Yet very little has been done on their philosophical implications. Here I will raise the following question: in what manner does the visual experience of a big rock close to my foot differ from the visual experience of the moon in the sky? (shrink)

In this chapter I focus on the relationship between embodied intersubjective interactions and the kind of spaces that shape and are shaped by such interactions. After clarifying some of the theoretical background involved in questions about social cognition, I review several empirical studies that suggest that social interactions and social relations can change our perceptions of the reachable space around us, as well as the more distant space beyond our immediate reach. These perceptions operate within the framework of (...) material culture and impact our experience of space as it is organized by cultural artifacts and practices. In this respect, the analysis provided by Material Engagement Theory helps us understand the role of material arrangements as they define affordances for action and interaction, correlated to transformations from individual body-schematic processes to intercorporeal processes in joint action. These same processes can be carried over into discussions of space and place as experienced on the larger stages of social-cultural activities. (shrink)

Philosophical considerations as well as several recent studies from neurophysiology, neuropsychology, and psychophysics converged in showing that the peripersonal space is structured in a body-centred manner and represented through integrated sensory inputs. Multisensory representations may deserve the function of coding peripersonal space for avoiding or interacting with objects. Neuropsychological evidence is reviewed for dynamic interactions between space representations and action execution, as revealed by the behavioural effects that the use of a tool, as a (...) physical extension of the reachable space, produces on visual–tactile extinction. In particular, tool-use transiently modifies action space representation in a functionally effective way. The possibility is discussed that the investigation of multisensory space representations for action provides an empirical way to consider in its specificity pre-reflexive self-consciousness by considering the intertwining of self-relatedness and object-directness of spatial experience shaped by multisensory and sensorimotor integrations. (shrink)

Despite the recognized importance of bodily movements in spatial audition, few studies have integrated action-based protocols with spatial hearing in the peripersonal space. Recent work shows that tactile feedback and active exploration allow participants to improve performance in auditory distance perception tasks. However, the role of the different aspects involved in the learning phase, such as voluntary control of movement, proprioceptive cues, and the possibility of self-correcting errors, is still unclear. We study the effect of guided reaching (...) exploration on perceptual learning of auditory distance in peripersonal space. We implemented a pretest-posttest experimental design in which blindfolded participants must reach for a sound source located in this region. They were divided into three groups that were differentiated by the intermediate training phase: Guided, an experimenter guides the participant’s arm to contact the sound source; Active, the participant freely explores the space until contacting the source; and Control, without tactile feedback. The effects of exploration feedback on auditory distance perception in the peripersonal space are heterogeneous. Both the Guided and Active groups change their performance. However, participants in the Guided group tended to overestimate distances more than those in the Active group. The response error of the Guided group corresponds to a generalized calibration criterion over the entire range of reachable distances. Whereas the Active group made different adjustments for proximal and distal positions. The results suggest that guided exploration can induce changes on the boundary of the auditory reachable space. We postulate that aspects of agency such as initiation, control, and monitoring of movement, assume different degrees of involvement in both guided and active tasks, reinforcing a non-binary approach to the question of activity-passivity in perceptual learning and supporting a complex view of the phenomena involved in action-based learning. (shrink)

In a recent paper, ‘Peripersonal perception in action’ (Synthese, 2018), Frédérique de Vignemont tackles the problem of defining what is peculiar to the visual perception of objects falling within the peripersonal space of the observer, i.e. the space immediately surrounding the body, and which is commonly described as the space in which action takes place. In this paper, I first discuss the proposal offered by de Vignemont about what characterizes peripersonal perception. Then, (...) I suggest an extension of this account that offers a meticulous description of the nature of the Content of Peripersonal Visual Experience - a topic never explicitly considered in the philosophical literature on vision - by discussing some peculiar features of it that, as recognized also by de Vignemont’s account, still need to be explained. In particular, I offer a philosophical examination of the specificity of peripersonal visual experience, in relation to its phenomenological dimension, its optical mechanisms and its neurophysiological underpinnings, in the light of our best theories from vision science, and in comparison to the visual experience of other visual spaces. (shrink)

Spatial, physical, and semantic magnitude dimensions can influence action decisions in human cognitive processing and interact with each other. For example, in the SNARC effect, semantic numerical magnitude facilitates left-hand or right-hand responding dependent on the small or large magnitude of number symbols. SNARC-like interactions of numerical magnitudes with the radial spatial dimension (depth) were postulated from early on. Usually, the SNARC effect in any direction is investigated using fronto-parallel computer monitors for presentation of stimuli. In such 2D setups, (...) however, the metaphorical and literal interpretation of the radial depth axis with seemingly close / far stimuli or responses are not distinct. Hence, it is difficult to draw clear conclusions with respect to the contribution of different spatial mappings to the SNARC effect. In order to disentangle the different mappings in a natural way, we studied parametrical interactions between semantic numerical magnitude, horizontal directional responses, and perceptual distance by means of stereoscopic depth in an immersive virtual reality (VR). Two VR experiments show horizontal SNARC effects across all spatial displacements in traditional latency measures and kinematic response parameters. No indications of a SNARC effect along the depth axis, as it would be predicted by a direct mapping account, were observed, but the results show a non-linear relationship between horizontal SNARC slopes and physical distance. Steepest SNARC slopes were observed for digits presented close to the hands. We conclude that spatial-numerical processing is susceptible to effector-based processes but relatively resilient to task-irrelevant variations of radial-spatial magnitudes. (shrink)

This article distinguishes three archetypal ways of articulating spatial cognition: (1) via metric representation of objective geometry, (2) via somatosensory constitution of the peripersonal environment, and (3) via pragmatic comprehension of the finalistic sense of action. The last one is documented by neuroscientific studies concerning mirror neurons. Bio-robotic experiments implementing mirror functions confirm the constitutive role of goal-oriented actions in spatial processes.

This chapter offers an indirect defence of the Evansian conception of egocentric space, by showing how it resolves a puzzle concerning the unity of egocentric spatial perception. The chapter outlines several common assumptions about egocentric perspectival structure and argues that a subject’s experience, both within and across her sensory modalities, may involve multiple structures of this kind. This raises the question of how perspectival unity is achieved, such that these perspectival structures form a complex whole, rather than merely disunified (...) set of individually, distinctively structured experiences. The shortcomings of variety of accounts are considered: switch accounts ; sensory accounts; transformation accounts; and ultimate accounts. These shortcomings are addressed by a further kind of account provided by the Evansian conception – an agentive account – according to which egocentrically structured experiences present the world in relation to parts of a single thing, the body as a dynamic unity. (shrink)

What representational state mediates between perception and action? Bence Nanay says pragmatic representations, which are outputs of perceptual systems. This commits him to the view that optic ataxics face difficulty in performing visually guided arm movements because the relevant perceptual systems output their pragmatic representations incorrectly. Here, I argue that it is not enough to say that pragmatic representations are output incorrectly; we also need to know why they are output that way. Given recent evidence that optic ataxia impairs (...) peripersonal space representation, I argue that pragmatic representations are output incorrectly because the organizing principle of the vision-for-action system is blocked by optic ataxia. I then show how this means that this principle, not pragmatic representations, is the representational state that mediates between perception and action, i.e. the principle, not pragmatic representations, is the immediate mental antecedent of action. (shrink)

Our understanding of body ownership largely relies on the Rubber Hand Illusion (RHI) paradigm where synchronous stroking of the real and fake hands leads to an illusion of ownership of RH provided its physical, anatomical, and spatial plausibility. Self-attribution of a fake hand also occurs during visuomotor synchrony, when the visual feedback of self-initiated movements follows the trajectory of the instantiated motor command. In both cases, the experience of ownership is established through bottom-up integration and top-down prediction of multisensory (proximodistal) (...) cues within the peripersonal space. It seems, however, that depending on whether the signals are externally or self-generated, top-down expectation signals are qualitatively different. On the one hand, in RHI, the sensory correlations are modulated by empirically induced priors about the internal model of the body. On the other hand, in mRHI, body ownership is actively shaped by processes allowing for continuous comparison between the actual and predicted sensory consequences of the actions. Ample research demonstrates that the differential processing of the predicted and the actual reafferent information is addressed by the central nervous system via an internal Forward Model (FM). Indeed, results from mRHI suggest that in action-contexts mechanism underlying body ownership could be similar to the FM. Crucially FMs integrate across all sensory input including not only proximodistal (visuomotor) but also purely distal sensory signals (visuoauditory). Thus if body ownership results from a consistency of FM, it would be affected by the (in)congruency of purely distal signals provided that they inform about the action-consequences relevant to the task. Here we explicitly address this question. To test our hypothesis, we devise an embodied VR-based task where action outcomes were signaled by distinct auditory cues. By manipulating the cues with respect to their spatial, temporal and semantic congruency, we show that purely distal feedback violating predictions about action outcomes compromises both body ownership and performance. These results demonstrate that body ownership is influenced by cues which not only pertain to the body itself but also those arising outside of the body, and suggest that in goal-oriented tasks body ownership might result from the consistency of forward models. (shrink)

Embodied cognitive theories predict that linguistic conceptual representations are grounded and continually represented in real world, sensorimotor experiences. However, there is an on-going debate on whether this also holds for abstract concepts. Grammar is the archetype of abstract knowledge, and therefore constitutes a test case against embodied theories of language representation. Former studies have largely focussed on lexical-level embodied representations. In the present study we take the grounding-by-modality idea a step further by using reaction time (RT) data from the linguistic (...) processing of nominal classifiers in Chinese. We take advantage of an independent body of research, which shows that attention in hand space is biased. Specifically, objects near the hand consistently yield shorter RTs as a function of readiness for action on graspable objects within reaching space, and the same biased attention inhibits attentional disengagement. We predicted that this attention bias would equally apply to the graspable object classifier but not to the big object classifier. Chinese speakers (N = 22) judged grammatical congruency of classifier-noun combinations in two conditions: graspable object classifier and big object classifier. We found that RTs for the graspable object classifier were significantly faster in congruent combinations, and significantly slower in incongruent combinations, than the big object classifier. There was no main effect on grammatical violations, but rather an interaction effect of classifier type. Thus, we demonstrate here grammatical category- specific effects pertaining to the semantic content and by extension the visual and tactile modality of acquisition underlying the acquisition of these categories. We conclude that abstract grammatical categories are subjected to the same mechanisms as general cognitive and neurophysiological processes and may therefore be grounded. (shrink)

Little is known about distance processing in patients with posterior brain damage. Although many investigators have claimed that distance estimates are normal or abnormal in some of these patients, many of these observations were made informally and the examiners often asked for relative, and not absolute, distance estimates. The present investigation served two purposes. First, we wanted to contrast the use of distance information in peripersonal space for perceptual report as opposed to visuomotor control in our visual form (...) agnosic patient, DF. Second, we wanted to see to what extent her abilities to process distance cues were dependent on binocular vision, in light of Milner et al.'s (1991) observations of preserved stereopsis in DF, and Dijkerman et al.'s (1996) and Marotta et al.'s (1997) observations that her visual guidance of grasping may be particularly dependent on binocular vision of the target. We hypothesized that DF's visuomotor responses would show normal sensitivity to target distance, while her perceptual estimates would not. In the first experiment, we required DF and two age- and sex-matched control subjects to reach out and grasp black cubes placed at varying distances, or to estimate the distance of the cubes from the hand starting position without making a reaching movement. In the second experiment, we required DF and two age-matched control subjects to point as rapidly and accurately as possible to small LED targets which differed in spatial location, under binocular and monocular conditions. The results showed that, relative to the control subjects, DF's grasping movements produced normal peak velocity-distance scaling-when she reached for blocks which varied in depth or pointed to LED targets which were presented at different distances in depth. In contrast, in the cube experiment, her verbal estimates of object distance were poorly scaled, although they improved slightly under the binocular conditions. The results are discussed in terms of current theories of processing streams in extrastriate visual cortex and the distinction between categorical and coordinate spatial processing. (shrink)

I argue that conscious visual experience consists in a direct and noninferential grasp of the way one’s current perceptual contact with the environment poises one to pursue various intentional plans, goals and projects. I show that such a view of visual consciousness is supported by current work in cognitive neuroscience, affords a compelling account of colour perception, and suggests a way to bridge the ‘explanatory gap’ between consciousness and the language of the natural sciences. In chapter 1, I examine the (...) reasoning that leads to the appearance of an explanatory gap between the phenomenal and the physical in more detail, and set out the constraints on a solution that our discussion of the problem has imposed. I then sketch the two rival takes on the relationship between perception and action mentioned above – adjudicating between these two theories is the task of the next two chapters, and is a recurring theme throughout. Chapter 2 moves on to discuss some recent work in the neuropsychology of vision and what it might suggest about the functional role of conscious vision, and the first half of chapter 3 considers two puzzle cases concerning colour perception. Each of these discussions turns out to constitute a source of support for the actionspace view that visual perception consists in a grasp of the practical consequences of sensation, and the second half of chapter 3 sets out this view and responds to an initial range of questions and objections it might face. Chapter 4 illustrates our view via a discussion of colour perception, and chapter 5 discusses the type of grasp of practical consequences that is necessary for perceptual sensitivity to issue in conscious experience. By chapter 6, we are in a position to see how the action-space approach can help close the explanatory gap for phenomenal consciousness, and our final chapter sets out how I think this should be done. I conclude with a brief discussion of further questions and prospects for the action-space approach. (shrink)

INTRODUCTION The philosophy of action and the philosophy of space and time may well seem to be unconnected areas. I will argue that in each of these areas ...

This paper offers a review of research on demonstratives from an interdisciplinary perspective. In particular, we consider the role of demonstratives in current research on language universals, language evolution, language acquisition, multimodal communication, signed language, language and perception, language in interaction, spatial imagery, and discourse processing. Traditionally, demonstratives are analyzed as a particular class of spatial deictics. Yet, a number of recent studies have argued that space is largely irrelevant to deixis and that demonstratives are primarily used for social (...) and interactive purposes. Synthesizing findings in the literature, we conclude that demonstratives are a very special class of linguistic items that are foundational to both spatial and social aspects of language and cognition. (shrink)

Manipulation of physical models such as tangrams and tiles is a popular approach to teaching early mathematics concepts. This pedagogical approach is extended by new computational media, where mathematical entities such as equations and vectors can be virtually manipulated. The cognitive and neural mechanisms supporting such manipulation-based learning—particularly how actions generate new internal structures that support problem-solving—are not understood. We develop a model of the way manipulations generate internal traces embedding actions, and how these action-traces recombine during problem-solving. This (...) model is based on a study of two groups of sixth-grade students solving area problems. Before problem-solving, one group manipulated a tangram, the other group answered a descriptive test. Eye-movement trajectories during problem-solving were different between the groups. A second study showed that this difference required the tangram's geometrical structure, just manipulation was not enough. We propose a theoretical model accounting for these results, and discuss its implications. (shrink)

Peripersonal space (PPS) is frequently defined as a plastic, pragmatic and goal-directed multisensory buffer that connects the brain-body with its immediate environment. While such characterisations indicate that peripersonal spatiality is profoundly embodied and enactive, comparatively few attempts have aimed to systematically synthesise PPS literature with compatible phenomenological accounts of lived space provided by Heidegger and Merleau-Ponty. Moreover, in traditional cognitive neuroscience, neurophysiological activity is thought to map onto discrete ‘cognitive correlates’. In contemporary 4E approaches to cognition, (...) however, phenomenology-derived notions such as ‘pre-reflective cognition’ and ‘motor-intentionality’ frequently appear, yet their neural correlates may be comparatively difficult to pin down. Pre-reflectively, agents seemingly do not thematise spatial properties as operationalised in key experimental paradigms (e.g., spatial rotation tasks) but are instead inherently spatially embedded within the world. To refine this distinction, I survey how tools co-determine this distinctly spatial ‘world-embeddedness’ using a neurophenomenological methodology (Varela, _Journal of Consciousness Studies, 3_(4), 330–349, 1996 ). Specifically, I conduct two neurophenomenological analyses of tool-perception and tool-use, examining both how distance modulates affordance-perception and how tool-use remaps bodily space via the withdrawal of tools from intentional-objects into co-constituting motor-intentionality itself. I conclude by briefly distinguishing this interpretation of spatial cognition from cognitivist frameworks. Thereafter, I briefly highlight the temporal scaffolding underlying PPS while conceptually grounding my account within Embodied Simulation Theory (Gallese, _Reti, Saperi, Linguaggi_, (1), 31–46, 2018 ). What is at stake is thus both an explicitly embodied-enactive account of bodily space that is qualitative and situational instead of quantitative and positional, as well as a viable, interdisciplinary strategy for unifying pre-reflective cognition with neurophysiological data. (shrink)

I defend the view that we should not overintellectualize the mind. Nonhuman animals can occupy islands of practical rationality: they can have contextbound reasons for action even though they lack full conceptual abilities. Holism and the possibility of mistake are required for such reasons to be the agent's reasons, but these requirements can be met in the absence of inferential promiscuity. Empirical work with animals is used to illustrate the possibility that reasons for action could be bound to (...) symbolic or social contexts, and connections are made to simulationist accounts of cognitive skills. (shrink)

The present study investigated how multisensory integration in peripersonal space is modulated by limb posture and limb congruency . This was done separately for the upper limbs and the lower limbs . The crossmodal congruency task was used to measure peripersonal space integration for the hands and the feet. It was found that the peripersonal space representation for the hands but not for the feet is dynamically updated based on both limb posture and limb (...) congruency. Together these findings show how dynamic cues from vision, proprioception, and touch are integrated in peripersonal limb space and highlight fundamental differences in the way in which peripersonal space is represented for the upper and lower extremity. (shrink)

I defend the view that we should not overintellectualize the mind. Nonhuman animals can occupy islands of practical rationality: they can have context‐bound reasons for action even though they lack full conceptual abilities. Holism and the possibility of mistake are required for such reasons to be the agent's reasons, but these requirements can be met in the absence of inferential promiscuity. Empirical work with animals is used to illustrate the possibility that reasons for action could be bound to (...) symbolic or social contexts, and connections are made to simulationist accounts of cognitive skills. (shrink)

What is space? And why are questions of space important to social theory? Society, Action and Space is the first English translation of a book which has been widely recognized in Europe as a major contribution to the interface between geography and social theory. Benno Werlen focuses on the issues which are at the heart of the most important debates in human and social geography today. One of the most significant recent developments in social analysis has (...) been the increasing interchange among geographers, sociologists, anthropologists and social philosophers concerning "the spatial." This debate involves the work of Giddens, Foucault, Bourdieu, Lefebvre, Harvey, Gregory, Soja, and many others. From these new developments a whole series of new forms and empirical work, as well as theoretical innovations, have come into being. Spatial considerations are no longer confined to the realm of geography, but are now seen as fundamental to all forms of social theorizing, especially under conditions of late modernity and globalization. Society, Action and Space links discussions in the philosophy of social science with theories of action which have direct relevance to concepts of space. Benno Werlen provides a discussion of Popper's critical rationalism, and connects it to ideas drawn from phenomenology. This epistemological debate is linked with the sociological action theories of Pareto, Weber, Parsons, and Schutz. The book closes with an evaluation of how "the spatial" can be systematically integrated into action theory. Ambitious, original, and persuasive in its arguments, it raises exciting new implications for the study of space and social theory. (shrink)

What is space? It isn't a question that most of us normally stop to ask. Space is the venue of physics; it's where things exist, where they move and take shape. Yet over the past few decades, physicists have discovered a phenomenon that operates outside the confines of space and time. The phenomenon-the ability of one particle to affect another instantly across the vastness of space-appears to be almost magical. Einstein grappled with this oddity and couldn't (...) quite resolve it, describing it as "spooky action at a distance." But this strange occurrence has direct connections to black holes, particle collisions, and even the workings of gravity. If space isn't what we thought it was, then what is it?In Spooky Action at a Distance, George Musser sets out to answer that question, offering a provocative exploration of nonlocality and a celebration of the scientists who are trying to understand it. Musser guides us on an epic journey of scientific discovery into the lives of experimental physicists observing particles acting in tandem, astronomers discovering galaxies that look statistically identical, and cosmologists hoping to unravel the paradoxes surrounding the big bang. Their conclusions challenge our understanding not only of space and time but of the origins of the universe-and their insights are spurring profound technological innovation and suggesting a new grand unified theory of physics. (shrink)

The sense of touch provides us knowledge of two kinds of events. Tactile sensation (T) makes us aware of events on or just below the skin; haptic perception (H) gives us knowledge of things outside the body with which we are in contact. This paper argues that T and H are distinct experiences, and not (as some have argued) different aspects of the same touch-experience. In other words, T ≠ H. Moreover, H does not supervene on T. Secondly: In T, (...) we are aware of immanent, phenomenal qualities; in H, we come to know of transcendent qualities in things that exist independently of ourselves. Finally: T is non-spatial; it is indexed by parts of the body, but not by position in space. H, by contrast, is spatial. This brings to mind Kant’s contention that things are presented as existing objectively when they are represented spatially. (shrink)

The study of continuous group actions is ubiquitous in mathematics, and perhaps the most general kinds of actions for which we can hope to prove theorems in just ZFC are those where a Polish group acts on a Polish space.For this general class we can find works such as [29] that build on ideas from ergodic theory and examine actions of locally compact groups in both the measure theoretic and topological contexts. On the other hand a text in model (...) theory, such as [12], will typically consider issues bearing on the actions by the symmetric group of all permutations of the integers. More generally [1] shows that the orbit equivalence relations induced by closed subgroups of the infinite symmetric group can be reduced to the isomorphism relation on corresponding classes of countable models.This paper considers a third category formed by the continuous actions of separable Banach spaces on Polish spaces. These examples cannot be subsumed under the two earlier headings, and it is known from [10] that theBorel cardinalitiesof the quotient spaces that arise from such actions are incomparable with the equivalence relations induced by the symmetric group or any locally compact Polish group action.One of the first things to be addressed concerns the complexity of these equivalence relations. This question forappears in [1]. (shrink)

Grammatical categories represent implicit knowledge, and it is not known if such abstract linguistic knowledge can be continuously grounded in real-life experiences, nor is it known what types of mental states can be simulated. A former study showed that attention bias in peripersonal space affects reaction times in grammatical congruency judgments of nominal classifiers, suggesting that simulated semantics may include reenactment of attention. In this study, we contrasted a Chinese nominal classifier used with nouns denoting pinch grip objects (...) with a classifier for nouns with big object referents in a pupil dilation experiment. Twenty Chinese native speakers read grammatical and ungrammatical classifier-noun combinations and made grammaticality judgment while their pupillary responses were measured. It was found that their pupils dilated significantly more to the pinch grip classifier than to the big object classifier, indicating attention simulation in PPS. Pupil dilations were also significantly larger with congruent trials on the whole than in incongruent trials, but crucially, congruency and classifier semantics were independent of each other. No such effects were found in controls. (shrink)

To generate coherent behaviour, the brain needs to attend selectively to the many objects that are present in the environment, but this poses several questions. How does the brain know which objects 'belong together'? How does the information from different senses get combined? How does this help to plan and carry out actions? The subject of attentional mechanisms has a long history in cognitive psychology, as it is the key to making sense of the visual world. However, new developments in (...) cognitive neuroscience, and greater understanding of how attention and action are integrated, have transformed the field. This book is the first to bring together leading researchers to discuss the convergence of experimental findings in the following areas: Visual selective attention Attention and perceptual integration Spatial representation and attention Visual attention and action Control of attention Attention, Space, and Action provides a unique combination of perspectives that will appeal to students and researchers from psychology, neuropsychology, neurophysiology, and neuroanatomy. (shrink)

Research into peripersonal space has yielded exciting discoveries across many fields, from anthropology to cognitive neuroscience. Bringing these perspectives together for the first time, The World at Our Fingertips presents a fresh, accessible dialogue, challenging entrenched ideas about the way people see and understand the world around them.

Schwinger's action principle is formulated for the quantum system which corresponds to the classical system described by the LagrangianL c( $\dot x$ , x)=(M/2)gij(x) $\dot x$ i $\dot x$ j−v(x). It is sufficient for the purpose of deriving the laws of quantum mechanics to consider onlyc-number variations of coordinates and time. The Euler-Lagrange equation, the canonical commutation relations, and the canonical equations of motion are derived from this principle in a consistent manner. Further, it is shown that an arbitrary (...) point transformation leaves the forms of the fundamental equations invariant. The judicious choice of the quantal Lagrangian is essential in our formulation. A quantum mechanical analog of Noether's theorem, which relates the invariance of the quantal action with a conservation law, is established. The ambiguities in the quantal Lagrangian are also discussed and it is pointed out that the requirement of invariance is not sufficient to determine uniquely the quantal Lagrangian and the Hamiltonian. (shrink)