The representation of visual scenes

The visual world exists all around us, yet this information must be gleaned through a succession of eye fixations in which high visual acuity is limited to the small foveal region of each retina. In spite of these physiological constraints, we experience a richly detailed and continuous visual world. Research on transsaccadic memory, perception, picture memory and imagination of scenes will be reviewed. Converging evidence suggests that the representation of visual scenes is much more schematic and abstract than our immediate experience would indicate. The visual system may have evolved to maximize comprehension of discrete views at the expense of representing unnecessary detail, but through the action of attention it allows the viewer to access detail when the need arises. This capability helps to maintain the 'illusion' of seeing a rich and detailed visual world at every glance.     

Action in perception? Empirical and philosophical arguments against the enactive approach to perception

This paper focuses on the epistemic conditions of visual perception, ie it concentrates on the question of what kind of knowledge is required for us in order to be able to see colours and shapes as spatial properties of things. According to contemporary theories of sensory perception that follow the tradition of George Berkeley, like Alva Noe's so-called enactive approach to perception, this type of visual perception requires a certain kind of implicit practical knowledge, namely implicit sensorimotor knowledge of the way sensory stimulation varies as the perceiver moves. Two objections are presented against this central claim of the enactive approach. First, empirical evidence from psychological research on children's cognitive and motor development suggests that visual content is entirely independent of sensorimotor knowledge. Second, the enactive approach gets involved in the characteristic problems of classical sense--datum theories by introducing the extremely problematic claim that the recognition of appearances is the epistemic starting point for the perception of things and their properties.     

Close to me: multisensory space representations for action and pre-reflexive consciousness of oneself-in-the-world

Philosophical considerations as well as several recent studies from neurophysiology, neuropsychology, and psychophysics converged in showing that the peripersonal space (i.e. closely surrounding the body-parts) 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.     

Consciousness from the Viewpoint of the Structural-functional Relationships of the Brain

The brain of vertebrates consists of brainstem and spinal cord conducting reflexes, compound movements, and innate behaviour, and the cerebral neocortex generating sensorimotor function and association function. These five major functions are assisted by four regulatory systems: limbic system, basal ganglia, cerebellum and sleep-wakefulness brainstem centres. Consciousness contains three different levels, i.e., wakefulness, awareness and self-consciousness. Wakefulness is a fundamental brain function regulated by the brainstem wakefulness centres. Awareness represents integration of diverse sensory signals, largely in the neocortex, for the perception of what is going on in the external world. Consciousness in humans is directed to the self so that an individual is aware of what is going on in his or her internal world, i.e., the mind, and seems to be inherent to the association cortex, in particular the frontal lobe. Freud's id emerges from the hypothalamus and limbic system, whereas the ego involves both the sensorimotor and association cortices. The super-ego is likely to be embodied in part of the association cortex. When movement and thought are conceived as a control system function, instruction for control corresponds to the will which initiates these actions and which represents a positive aspect of consciousness. Though consciousness is related to brain structures in these ways, a crucial question remains as to how we subjectively experience will, affect or self-consciousness as a consequence of neuronal activities in the brain structures.     

Colour Discrimination And Monitoring Theories of Consciousness

According to the monitoring theory of consciousness, a mental state is conscious in virtue of being represented in the right way by a monitoring state. David Rosenthal, William Lycan, and Uriah Kriegel have developed three different influential versions of this theory. In order to explain colour experiences, each of these authors combines his version of the monitoring theory of consciousness with a specific account of colour representation. Even though Rosenthal, Lycan, and Kriegel disagree on the specifics, they all hold that colours are represented by a single type of mental state. The main goal of this paper is to show that a more complex account of colour representation is needed for the monitoring theory of consciousness to do justice to the phenomenology of colour experiences. In particular, I will argue that the fine-grained character of colour experience—that is, the fact that perceivers can become conscious of small differences between colours—requires that colour representation be construed in terms of two different types of mental states, namely sensory states that represent appearance properties and colour representations that represent physical colours.     

What it is like to see: A sensorimotor theory of perceptual experience

The paper proposes a way of bridging the gapbetween physical processes in the brain and the 'felt'aspect of sensory experience. The approach is based onthe idea that experience is not generated by brainprocesses themselves, but rather is constituted by theway these brain processes enable a particular form of'give-and-take' between the perceiver and theenvironment. From this starting-point we are able tocharacterize the phenomenological differences betweenthe different sensory modalities in a more principledway than has been done in the past. We are also ableto approach the issues of visual awareness andconsciousness in a satisfactory way. Finally weconsider a number of testable empirical consequences,one of which is the striking prediction of thephenomenon of 'change blindness'.     

The ontology of neglect

As shown by neuroscientific evidence, neglect may occur without elementary sensorimotor impairments. The deficit is to be found at a higher, more abstract level of representation, which prevents the patient not only from seeing, but from conceiving the contralesional space. By analysing a series of neuropsychological results, in this paper we suggest a crucial role of time for the construction of a world: on this basis, we try to explain how it is possible that half the ontology gets lost. The analysis of the ontological implication of neglect will allow us to shed light on manifestations of the pathology apparently disconnected.     

Baby steps: investigating the development of perceptual–motor couplings in infancy

There are cells in our motor cortex that fire both when we perform and when we observe similar actions. It has been suggested that these perceptual‐motor couplings in the brain develop through associative learning during correlated sensorimotor experience. Although studies with adult participants have provided support for this hypothesis, there is no direct evidence that associative learning also underlies the initial formation of perceptual–motor couplings in the developing brain. With the present study we addressed this question by manipulating infants’ opportunities to associate the visual and motor representation of a novel action, and by investigating how this influenced their sensorimotor cortex activation when they observed this action performed by others. Pre‐walking 7–9‐month‐old infants performed stepping movements on an infant treadmill while they either observed their own real‐time leg movements (Contingent group) or the previously recorded leg movements of another infant (Non‐contingent control group). Infants in a second control group did not perform any steps and only received visual experience with the stepping actions. Before and after the training period we measured infants’ sensorimotor alpha suppression, as an index of sensorimotor cortex activation, while they watched videos of other infants’ stepping actions. While we did not find greater sensorimotor alpha suppression following training in the Contingent group as a whole, we nevertheless found that the strength of the visuomotor contingency experienced during training predicted the amount of sensorimotor alpha suppression at post‐test in this group. We did not find any effects of motor experience alone. These results suggest that the development of perceptual–motor couplings in the infant brain is likely to be supported by associative learning during correlated visuomotor experience.     

Sensory features of mental images in the framework of human actions

What determines the sensory impression of a self-generated motor image? Motor imagery is a process in which subjects imagine executing a body movement with a strong kinesthetic and/or visual component from a first-person perspective. Both sensory modalities can be combined flexibly to form a motor image. 90 participants of varying ages had to freely generate motor images from a large set of movements. They were asked to rate their kinesthetic as well as their visual impression, the perceived vividness, and their personal experience with the imagined movement. Data were subjected to correlational analyses, linear regressions, and representation similarity analyses. Results showed that both action characteristics and experience drove the sensory impression of motor images with a strong individual component. We conclude that imagining actions that impose varying demands can be considered as reexperiencing actions by using one’s own sensorimotor representations that represent not only individual experience but also action demands.     

Shared representations in body perception

The ability to understand events that happen to other people is a characteristic feature of the human mind. Here, we investigate whether the links between mental representation of one's own body and the bodies of other people could form the basis of human social representations. We studied interpersonal body representation (IBR) in a series of behavioural cueing experiments. Subjects responded to tactile events on their own body after a visual event was presented in either the corresponding anatomical location on a model's body, or in a non-corresponding location. We found that reactions were faster when the visual cue was in register with the tactile stimulation. This effect was absent when identical visual events were presented on a non-body control stimulus, suggesting a body specific mechanism for interpersonal registration of purely sensory events. Similar interpersonal systems have been demonstrated previously for the coding of action and emotion, but we believe that our results provide the first behavioural evidence for interpersonal body representation at the purely sensory level. We show that a sensory processing mechanism specific for bodies is automatically activated when viewing another person. Interpersonal body representation may be an important precursor to empathy and theory of mind. In our social world, we understand the percepts of others by registering them against the representations used to perceive our own body, and this mechanism involves an interpersonal somatotopic map.     

Egocentric Spatial Representation in Action and Perception*

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.     

Visual Feeling of Presence

Everyday visual experience constantly confronts us with things we can interact with in the real world. We literally feel the outside presence of physical objects in our environment via visual perceptual experience. The visual feeling of presence is a crucial feature of vision that is largely unexplored in the philosophy of perception, and poorly debated in vision neuroscience. The aim of this article is to investigate the feeling of presence. I suggest that visual feeling of presence depends on the visual representation of a very particular spatial relation with the object we interact with: the visual representation of absolute egocentric depth, which is due to stereoscopic vision.     

The liabilities of mobility: a selection pressure for the transition to consciousness in animal evolution

The issue of the biological origin of consciousness is linked to that of its function. One source of evidence in this regard is the contrast between the types of information that are and are not included within its compass. Consciousness presents us with a stable arena for our actions-the world-but excludes awareness of the multiple sensory and sensorimotor transformations through which the image of that world is extracted from the confounding influence of self-produced motion of multiple receptor arrays mounted on multijointed and swivelling body parts. Likewise excluded are the complex orchestrations of thousands of muscle movements routinely involved in the pursuit of our goals. This suggests that consciousness arose as a solution to problems in the logistics of decision making in mobile animals with centralized brains, and has correspondingly ancient roots.     

Understanding ‘sensorimotor understanding’

Sensorimotor theories understand perception to be a process of active, exploratory engagement with the environment, mediated by the possession and exercise of a certain body of knowledge concerning sensorimotor dependencies. This paper aims to characterise that exercise, and to show that it places constraints upon the content of sensorimotor knowledge itself. Sensorimotor mastery is exercised when it is put to use in the service of intentional action-planning and selection, and this rules out certain standard readings of sensorimotor contingency knowledge. Rather than holding between movements and sensory inputs or appearances, sensorimotor contingencies concern the suite of ways in which an object can be revealed through exploration. Sensorimotor knowledge is thus directed through experience to the world itself.     

身体表征的分离:二分解释模型及其证据

身体表征是一种内部结构,它具有追踪身体状态并对其进行编码的功能。这种结构可以对身体进行错误的表征,并可以从身体中分离出来。来自海豹肢症与躯体失认症等方面的病例,证实部分身体畸形与脑损伤患者的身体表征存在分离;来自橡胶手错觉与全身错觉的实验证据,验证了健康个体身体表征分离的事实。基于上述证据,以身体图式和身体意象为二分维度的模型解释了身体表征的分离。未来的研究可以从神经心理学实验和虚拟现实技术着手,对身体表征的分离进行深入探究。     

Touchant-touché: the role of self-touch in the representation of body structure

The "body image" is a putative mental representation of one's own body, including structural and geometric details, as well as the more familiar visual and affective aspects. Very little research has investigated how we learn the structure of our own body, with most researchers emphasising the canonical visual representation of the body when we look at ourselves in a mirror. Here, we used non-visual self-touch in healthy participants to investigate the possibility that primary sensorimotor experience may influence cognitive representations of one's own body structure. Participants used the fingers of one hand (the 'active' hand), to touch the fingers of the other (the 'passive' hand). A conflict between the experience of the active and passive hand was introduced by experimenter interleaving their fingers with the fingers of the participant's passive hand. This led to the active hand experiencing that it touched more fingers than the passive hand felt it was being touched by. The effects on representation of body structure were assessed using an implicit measure based on Kinsbourne and Warrington's 'in-between task'. We found an underestimation of the number of fingers in the central part of the hand specifically linked to the experience of self-touch. This pattern of results corresponds to the experience of the passive hand, but not the active hand. Nevertheless, comparable reorganisation of fingers within the hand representation was found for both active and passive hands. We show that primary sensorimotor experience can modify the representation of body structure. This modification is driven by the passive experience of being touched, rather than by the active experience of touching. We believe this is the first experimental study of effects of self-touch on the mental representation of the body.     

Seeing Empty Space

Abstract: In this paper I offer an account of a particular variety of perception of absence, namely, visual perception of empty space. In so doing, I aim to make explicit the role that seeing empty space has, implicitly, in Mike Martin's account of the visual field. I suggest we should make sense of the claim that vision has a field—in Martin'ss sense—in terms of our being aware of its limitations or boundaries. I argue that the limits of the visual field are our own sensory limitations, and that we are aware of them as such. Seeing empty space, I argue, involves a structural feature of experience that constitutes our awareness of our visual sensory limitations, and thus, in virtue of which vision has a field.