This paper examines Milner and Goodale’s hypothesis about the two visual streams and raises the questions of whether properties in egocentric space (commonly associated with the vision-for-action, or "dorsal," stream) can be part of the phenomenal content of perceptual experience, or only properties in allocentric space (commonly associated with the vision-for-perception, or "ventral," stream) can play this role, and how (if at all) properties in egocentric space differ from properties in allocentric space. These questions are reminiscent of (...) issues raised by Christopher Peacocke's "equal-sized trees" case: if you are looking at equal-sized trees on the side of a road, the trees will phenomenally look to you to be equally tall. But it is also true that a tree will take up more of the space in your visual field the closer it is to you. So, the equal-sized trees will also phenomenally look to you to have different heights. Your (visual) perceptual experience is not illusory. That is, the trees veridically look to you to have the same height, and they also veridically look to you to have different heights. Call the sort of issue raised here the "problem of dual looks." I provide a solution to the problem of dual looks that helps shed light on whether properties in egocentric space can be part of the phenomenal content of perceptual experience, and how (if at all) properties in egocentric space differ from properties in allocentric space. (shrink)

In visual information processing, two kinds of vision are distinguished: vision-for-perception related to the conscious identifi cation of objects, and vision-for-action that deals with visual control of movements. Neuroscience suggests that these two functions are performed by two separate brain neural systems - the ventral and dorsal pathways. Two experiments using behavioural measures were conducted with the objective of exploring any potential interaction between these two functions of vision. The aim was to combine in one (...) task methods allowing for the simultaneous capture of both perceptual global processing and affordance extraction and to check whether they infi uence each other. This aim was achieved by employing the paradigms of Navon and Tucker and Ellis. A compound fi gure was created made up of objects with handles that might or might not have orientation congruent between levels. The results revealed that while the affordance effect occurred every time, the Navon effect appeared only when subjects focused their attention on object elements responsible for inconsistence within compound fi gure. Most importantly, even when these two effects occurred at once, they had no effect on each other. Results from the study failed to confi rm the hypothesis about interaction and gives support to the view that vision-for-perception and vision-for-action tend to act as separate systems. (shrink)

In this book Gerald Vision argues for a new causal theory, one that engages provocatively with direct realism and makes no use of a now discredited subjectivism.

David Milner and Melvyn Goodale’s dissociation hypothesis is commonly taken to state that there are two functionally specialized cortical streams of visual processing originating in striate (V1) cortex: a dorsal, action-related “unconscious” stream and a ventral, perception-related “conscious” stream. As Milner and Goodale acknowledge, findings from blindsight studies suggest a more sophisticated picture that replaces the distinction between unconscious vision for action and conscious vision for perception with a tripartite division between unconscious vision for action, (...) conscious vision for perception, and unconscious vision for perception. The combination excluded by the tripartite division is the possibility of conscious vision for action. But are there good grounds for concluding that there is no conscious vision for action? There is now overwhelming evidence that illusions and perceived size can have a significant effect on action (Bruno & Franz, 2009; Dassonville & Bala, 2004; Franz & Gegenfurtner, 2008; McIntosh & Lashley, 2008). There is also suggestive evidence that any sophisticated visual behavior requires collaboration between the two visual streams at every stage of the process (Schenk & McIntosh, 2010). I nonetheless want to make a case for the tripartite division between unconscious vision for action, conscious vision for perception, and unconscious vision for perception. My aim here is not to refute the evidence showing that conscious vision can affect action but rather to argue (a) that we cannot gain cognitive access to action-guiding dorsal stream representations, and (b) that these representations do not correlate with phenomenal consciousness. This vindicates the semi-conservative view that the dissociation hypothesis is best understood as a tripartite division. (shrink)

Thompson provides an accessible review of the current scientific and philosophical discussions of colour vision and is vital reading for all cognitive scientists and philosophers whose interests touch upon this central area.Colour fascinates all of us, and scientists and philosophers have sought to understand the true nature of colour vision for many years. In recent times, investigations into colour vision have been one of the success stories of cognitive science, for each discipline within the field - neuroscience, (...) psychology, linguistics, computer science and artificial intelligence, and philosophy - has contributed significantly to our understanding of colour. Evan Thompson's book is a major contribution to this interdisciplinary project.Colour Vision provides an accessible review of the current scientific and philosophical discussions of colour vision. Thompson steers a course between the subjective and objective positions on colour, arguing for a relational account. This account develops a novel 'ecological' approach to colour vision in cognitive science and the philosophy of perception. It is vital reading for all cognitive scientists and philosophers whose interests touch upon this central area. (shrink)

According to an influential view, the detection of action possibilities and the selection of a plan for action are two segregated steps throughout the processing of visual information. This classical approach is committed with the assumption that two independent types of processing underlie visual perception: the semantic one, which is at the service of the identification of visually presented objects, and the pragmatic one which serves the execution of actions directed to specific parts of the same objects. However, as (...) our knowledge of vision has improved over the years, this established view has turned out to be only an approximation. This paper sets out the details of a non-modularist approach to visual perception of action possibilities and explains how to resist the lure of cognitive segregation. (shrink)

Vision has been the primary focus of naturalistic philosophical research concerning perception and perceptual experience. Guided by visual experience and vision science, many philosophers have focused upon theoretical issues dealing with the perception of objects. Recently, however, hearing researchers have discussed auditory objects. I present the case for object perception in vision, and argue that an analog of object perception occurs in auditory perception. I propose a notion of an auditory object that (...) is stronger than just that of an intentional object of audition, but that does not identify auditory objects with the ordinary material objects we see. (shrink)

It seems almost a truism to say that colour is a sensation; and yet Young, by honestly recognizing this elementary truth, established the first consistent theory of colour. So far as I know, Thomas Young was the first who, starting from the well-known fact that there are three primary colours, sought for the explanation of this fact, not in the nature of light, but in the constitution of man. (James Clerk Maxwell, p. 267.)It is doubtless scientific to disregard certain aspects (...) when we work; but to urge that therefore such aspects are not fact, and that what we use without them is an independent real thing-this is barbarous metaphysics. (F. H. Bradley, p. 15.). (shrink)

Object perception deploys a suite of perceptual capacities that constrains attention, guides reidentification, subserves recognition, and anchors demonstrative thought. Objects for perception—perceptual objects—are the targets of such capacities. Characterizing perceptual objects for multisensory perception faces two puzzles. First is the diversity of objects across sensory modalities. Second is the unity of multisensory perceptual objects. This paper resolves the puzzles. Objects for perception are structured mereologically complex individuals. Perceptual objects are items that bear perceptible features and have (...) perceptible parts arranged to form a unified whole. This circumscribes the targets of object perception where neutral talk concerning intentional objects and objects of perception cannot. Nonetheless, it is more permissive than identifying perceptual objects with material bodies, which excludes too much and leans too heavily on vision. The account thus is tailored to capture the role of objects in perception beyond vision: tactual, auditory, and olfactory objects are individuals with differing structures. Its flexibility also enables the account to accommodate shared objects for multisensory perception: multisensory perceptual objects are mereologically complex individuals with hybrid structure. For instance, one can bimodally perceive a common whole with parts accessible to one but not both modalities. Each sense provides a partial perspective on a complex whole that is perceptible through the coordinated use of multiple senses. Understanding perceptual objects as structured mereologically complex individuals thus provides a theoretically useful notion of an object for multisensory perception that resolves the puzzles of diversity and of unity. (shrink)

Cognitive and affective penetration of perception refers to the influence that higher mental states such as beliefs and emotions have on perceptual systems. Psychological and neuroscientific studies appear to show that these states modulate the visual system at the visuomotor, attentional, and late levels of processing. However, empirical evidence showing that similar consequences occur in early stages of visual processing seems to be scarce. In this paper, I argue that psychological evidence does not seem to be either sufficient or (...) necessary to argue in favour of or against the cognitive penetration of perception in either late or early vision. In order to do that we need to have recourse to brain imaging techniques. Thus, I introduce a neuroscientific study and argue that it seems to provide well-grounded evidence for the cognitive penetration of early vision in face perception. I also examine and reject alternative explanations to my conclusion. (shrink)

Future technological developmentsconcerning food, agriculture, and theenvironment face a gulf of social legitimationfrom a skeptical public and media, in the wakeof the crises of BSE, GM food, and foot andmouth disease in the UK (House of Lords, 2000). Keyethical issues were ignored by the bioindustry,regulators, and the Government, leaving alegacy of distrust. The paper examinesagricultural biotechnology in terms of a socialcontract, whose conditions would have to be fulfilled togain acceptance of novel applications. Variouscurrent and future GM applications areevaluated against these (...) conditions. Successwould depend critically on how far a sharedvision can be found with the public. Tore-establish trust, significant changes areidentified in the planning and pursuit ofbiotechnology. (shrink)

Because moral perception plays an essential role in guiding morally responsible behaviour, agents have a responsibility to develop their capacities in this area. There are several strategies agents can (and should) pursue in order to improve their skills at moral perception. I appeal to insights derived from the work of feminist epistomologists and philosophers of science to argue that feminist approaches to multiculturalism are particularly valuable tools for improving moral perception.

This article considers photography’s role as a visual technology and the consequent effects of expanded frames of knowledge. At the very moment human vision and memory were called into profound doubt, photography provided a mechanical, prosthetic extension to perceptual experience. However, as a technology, it contains the potential for both revelation and control. In this article, photography is considered as a technique that: expands human perception; inscribes its own mechanical operations into new visual forms, therefore enframing and encoding (...) visible knowledge; and can be harnessed as a disciplinary instrument and technique of power. As a consequence, photography’s revealing of hitherto invisible dimensions of reality unfolds within a history of revelation, spectacle and power. (shrink)

In _Action in Perception _Alva No develops and presents a sensorimotor account of vision and of visual consciousness. According to such an account seeing (and indeed perceiving more generally) is analysed as a kind of skilful bodily activity. Such a view is consistent with the emerging emphasis, in both philosophy and cognitive science, on the critical role of embodiment in the construction of intelligent agency. I shall argue, however, that the full sensorimotor model faces three important challenges. The (...) first is to negotiate a path between two prima facie unsatisfactory readings of the central claim that conscious perceptual experience is constituted by knowledge of patterns of sensorimotor dependence. The second is to convince us that the sensorimotor contribution, in such cases, is actually constitutive of perceptual experience rather than merely causally implicated in the origination of such experience.² And the third is to respond to the important challenge raised by what I will dub 'sensorimotor summarizing' models of the relation between conscious experience and richly detailed sensorimotor routines. According to such models³ conscious perceptual experience only rather indirectly reflects the rich detail of our actual sensorimotor engagements, which are instead lightly sampled as a coarse guide, optimized for planning and reasoning, and geared and filtered according to current needs and purposes. (shrink)

Problems of Vision is divided into three parts. The first part argues for the “insight at [the] core” of the causal theory of perception.

Peripheral vision has different functional priorities for mammals than foveal vision. One of its roles is to monitor the environment while central vision is focused on the current task. Becoming distracted too easily would be counterproductive in this perspective, so the brain should react to behaviourally relevant changes. Gist processing is good for this purpose, and it is therefore not surprising that evidence from both functional brain imaging and behavioural research suggests a tendency to generalize and blend (...) information in the periphery. This may be caused by the balance of perceptual influence in the periphery between bottom-up and top-down processing channels. Here, we investigated this interaction behaviourally using a peripheral numerosity discrimination task with top-down and bottom-up manipulations. Participants compared numerosity between the left and right peripheries of a screen. Each periphery was divided into a centre and a surrounding area, only one of which was a task relevant target region. Our top-down task modulation was the instruction which area to attend – centre or surround. We varied the signal strength by altering the stimuli durations i.e., the amount of information presented/processed. We found that numerosity perceived in target regions was affected by contextual information in neighbouring areas. This effect appeared as soon as stimulus duration allowed the task to be reliably performed and persisted even at the longest duration. We compared the pattern of results with an ideal-observer model and found a qualitative difference in the way centre and surround areas interacted perceptually in the periphery. When participants reported on the central area, the irrelevant surround would affect the response as a weighted combination – consistent with the idea of a receptive field focused in the target area to which irrelevant surround stimulation leaks in. When participants report on surround, we can best describe the response with a model in which occasionally the attention switches from task relevant surround to task irrelevant centre – consistent with a selection model of two competing streams of information. Overall our results show that the influence of spatial context in the periphery is mandatory but task dependent. (shrink)

According to the cognitive penetrability hypothesis, our beliefs, desires, and possibly our emotions literally affect how we see the world. This book elucidates the nature of the cognitive penetrability and impenetrability hypotheses, assesses their plausibility, and explores their philosophical consequences. It connects the topic's multiple strands (the psychological findings, computationalist background, epistemological consequences of cognitive architecture, and recent philosophical developments) at a time when the outcome of many philosophical debates depends on knowing whether and how cognitive states can influence (...) class='Hi'>perception. All sixteen chapters were written especially for the book. The first chapters provide methodological and conceptual clarification of the topic and give an account of the relations between penetrability, encapsulation, modularity, and cross-modal interactions in perception. Assessments of psychological and neuroscientific evidence for cognitive penetration are given by several chapters. Most of the contributions analyse the impact of cognitive penetrability and impenetrability on specific philosophical topics: high-level perceptual contents, the epistemological consequences of penetration, nonconceptual content, the phenomenology of late perception, metacognitive feelings, and action. The book includes a comprehensive introduction which explains the history of the debate, its key technical concepts (informational encapsulation, early and late vision, the perception-cognition distinction, hard-wired perceptual processing, perceptual learning, theory-ladenness), and the debate's relevance to current topics in the philosophy of mind and perception, epistemology, and philosophy of psychology. (shrink)

The detection of a human’s intended behavior is one of the most important skills that a social robot should have in order to become acceptable as a part of human society, because humans are used to understand the actions of other humans in a goal-directed manner and they will expect the social robot to behave similarly. A breakthrough in this area can advance several research branches related to social intelligence such as learning by imitation and mutual adaptation. To achieve this (...) goal the robot needs to integrate all possible evidence of intention and neglect the unintended behavior, and a complete solution should use low-level signal processing and high-level reasoning. This work explores the low-level signal processing part of the solution by proposing an interactive adaptive perception scheme that uses four important features of human behavior to amplify the signals originating from intended behavior with respect to signals originating from unintended behavior and other noise sources such as instrumental noise. This work follows the vision that intelligence is not only a function of a centralized sophisticated artificial brain, but can be presented in different forms in the entire robot including its perception and motion systems (the mind is not contained in the brain, but distributed in every cell in the body). A simple example of using the proposed scheme was implemented and the results of two experiments with it are also presented. (shrink)

If a man born blind were to gain his sight in later life would he be able to identify the objects he saw around him? Would he recognise a cube and a globe on the basis of his earlier tactile experiences alone? This was William Molyneux's famous question to John Locke and it was much discussed by English and French empiricists in the eighteenth century as part of the controversy over innatism and abstract ideas. Dr Morgan examines the whole history (...) of this debate: Locke's own (negative) answer to the question, the contributions of Berkeley, Condillac, Diderot and Voltaire and the factual accounts of early cataract operations and modern laboratory studies. He shows how this debate is involved in the development and eventual separation of philosophy and experimental psychology after the eighteenth century and considers why the original question is effectively still unanswered. This is one problem-area with its intricate cluster of connected conceptual and technical difficulties which suggests the need for some reunion or at least collaboration between the two subjects. (shrink)

서비스 로봇이나 자율주행자동차처럼 현실의 공간에서 작동하는 기계가 임무를 성공적으로 수행하기 위하여 갖추어야 할 조건은 그것이 처한 환경의 상태를 파악하는 능력, 곧 지각의 능력이다. 이 논문은 이런 기계 지각, 특히 인간을 대행하도록 의도된 기계의 지각이 충족해야 할 조건들을 검토한다. 이러한 시도는 오늘의 사회가 집단적으로 추진하고 있는 공학 프로젝트에서 기술의 지향점을 환기시키면서 그것을 향한 실천을 구체화하는 논의라는 의미를 지닌다. 공학윤리의 원칙에 명시된 최우선의 가치를 고려할 때, 인간을 대행할 인공물은 우리가 아는 범위에서 가장 안전한 방식으로 구성되어야 하고, 이를 위하여 기계 시각을 비롯한 인공물의 (...) 지각은 일차적으로 그것이 대행할 인간의 지각을 닮은 결과를 산출하도록 설계, 제작되어야 한다. 인간의 지각은 자연의 역사가 부여한 여러 흥미로운 속성들을 가지고 있다. 특히 이 논문은 지각의 대상을 개념적 범주들을 적용해 판별하는 방식, 지각에 나타나는 다양한 항등성의 측면들, 인간의 지각에 나타나는 행지주의적 특성에 주목한다. 이 세 요소는 자율주행자동차를 비롯하여 이 논문이 고려한 적용의 영역들에서 모두 뚜렷한 유관성을 드러낸다. 이로부터, 이런 똑똑한 인공물을 설계, 제작하는 과정에서 인간 지각의 이러한 속성들이 실현되거나 아니면 적어도 실질적인 손실 없이 대체되는지를 살펴야 한다는 당위가 도출된다. (shrink)

The main causes of suicide and how suicide could and should be prevented are ongoing controversies in the scientific literature as well as in public media. In the bill on public health from 2008, the Swedish Parliament adopted an overarching “Vision Zero for Suicide” and nine strategies for suicide prevention. However, how the VZ should be interpreted in healthcare is unclear. The VZ has been criticized both from a philosophical perspective and against the background of clinical experience and alleged (...) empirical claims regarding the consequences of regulating suicide prevention. This study is part of a larger research project in medical ethics with the overarching aim to explore whether the VZ is ethically justifiable. The aim is to enrich the normative discussion by investigating empirically how the VZ is perceived in healthcare. Interviews based on a semi-structured interview guide were performed with 12 Swedish psychiatrists. The interviews were analysed with descriptive qualitative content analysis aiming for identifying perceptions of the Vision Zero for Suicide as well as arguments for and against it. Though most of the participants mentioned at least some potential benefit of the Vision Zero for Suicide, the overall impression was a predominant skepticism. Some participants focused on why they consider the VZ to be unachievable, while others focused more on its potential consequences and normative implications. The VZ was perceived to be impossible to realize, nonconstructive or potentially counterproductive, and undesirable because of potential conflicts with other values and interests of patients as well as the general public. There were also important notions of the VZ having negative consequences for the working conditions of psychiatrists in Sweden, in increasing their work-related anxiety and thwarting the patient-physician relationship. (shrink)

Mental capacities for perceiving, remembering, thinking, and planning involve the processing of structured mental representations. A compositional semantics of such representations would explain how the content of any given representation is determined by the contents of its constituents and their mode of combination. While many have argued that semantic theories of mental representations would have broad value for understanding the mind, there have been few attempts to develop such theories in a systematic and empirically constrained way. This paper contributes to (...) that end by developing a semantics for a ‘fragment’ of our mental representational system: the visual system’s representations of the bounding contours of objects. At least three distinct kinds of composition are involved in such representations: ‘concatenation’, ‘feature composition’, and ‘contour composition’. I sketch the constraints on and semantics of each of these. This account has three principal payoffs. First, it models a working framework for compositionally ascribing structure and content to perceptual representations, while highlighting core kinds of evidence that bear on such ascriptions. Second, it shows how a compositional semantics of perception can be compatible with holistic, or Gestalt, phenomena, which are often taken to show that the whole percept is ‘other than the sum of its parts’. Finally, the account illuminates the format of a key type of perceptual representation, bringing out the ways in which contour representations exhibit domain-specific form of the sort that is typical of structured icons such as diagrams and maps, in contrast to typical discursive representations of logic and language. (shrink)

Sensory substitution presents the philosopher of cognitive science with a particularly interesting case. Using prosthetics to map visual stimuli onto other modalities, such as touch or audition, otherwise blind individuals may develop perceptual capacities and behaviours commonly associated with sight. Experienced users can distinguish ‘visually’ presented objects and will even jerk back from a looming surface. Whether perception with sensory substitution devices should be classed as a type of vision, some other modality, or a new sense remains a (...) matter of debate, however. In the following, I review arguments commonly used to rebut the visual interpretation and, drawing on recent experimental studies and phenomenological self-reports, construct a novel case for treating sensory substitution as a visual process. (shrink)

Even today, film restoration is a challenge, because it involves multidisciplinary competences: from analogue film inspection and conservation to digitisation and image enhancement. In this context, thanks to the high manageability of digital files, the film restoration workflow often follows a digitisation step, which presents many approximations and issues that are often ignored. In this work, we propose an alternative approach to the issues commonly encountered in film restoration aiming at restoring the original colour appearance, through models of human colour (...) perception. (shrink)

Computational theories of vision typically rely on the analysis of two aspects of human visual function: (1) object and shape recognition (2) co-calibration of sensory measurements. Both these approaches are usually based on an inverse-optics model, where visual perception is viewed as a process of inference from a 2D retinal projection to a 3D percept within a Euclidean space schema. This paradigm has had great success in certain areas of vision science, but has been relatively less successful (...) in understanding perceptual representation, namely, the nature of the perceptual encoding. One of the drawbacks of inverse-optics approaches has been the difficulty in defining the constraints needed to make the inference computationally tractable (e.g. regularity assumptions, Bayesian priors, etc.). These constraints, thought to be learned assumptions about the nature of the physical and optical structures of the external world, have to be incorporated into any workable computational model in the inverse-optics paradigm. But inference models that employ an inverse optics plus structural assumptions approach inevitably result in a na. (shrink)

There is a certain excitement in vision science concerning the idea of applying the tools of bayesian decision theory to explain our perceptual capacities. Bayesian models are thought to be needed to explain how the inverse problem of perception is solved, and to rescue a certain constructivist and Kantian way of understanding the perceptual process. Anticlimactically, I argue both that bayesian outlooks do not constitute good solutions to the inverse problem, and that they are not constructivist in nature. (...) In explaining how visual systems derive a single percept from underdetermined stimulation, orthodox versions of bayesian accounts encounter a problem. The problem shows that such accounts need to be grounded in Natural Scene Statistics (NSS), an approach that takes seriously the Gibsonian insight that studying perception involves studying the statistical regularities of the environment in which we are situated. Additionally, I argue that bayesian frameworks postulate structures that hardly rescue a constructivist way of understanding perception. Except for percepts, the posits of bayesian theory are not representational in nature. bayesian perceptual inferences are not genuine inferences. They are biased processes that operate over nonrepresentational states. (shrink)

Common everyday materials such as textiles, foodstuffs, soil or skin can have complex, mutable and varied appearances. Under typical viewing conditions, most observers can visually recognize materials effortlessly, and determine many of their properties without touching them. Visual material perception raises many fascinating questions for vision researchers, neuroscientists and philosophers, yet has received little attention compared to the perception of color or shape. Here we discuss some of the challenges that material perception raises and argue that (...) further philosophical thought should be directed to how we see materials. (shrink)

Correspondence should be addressed to David A. Leopold [email protected] the viewing of certain patterns, widely known as ambiguous or puzzle figures, perception lapses into a sequence of spontaneous alternations, switching every few seconds between two or more visual interpretations of the stimulus. Although their nature and origin remain topics of debate, these stochastic switches are generally thought to be the automatic and inevitable consequence of viewing a pattern without a unique solution. We report here that in humans such perceptual (...) alternations can be slowed, and even brought to a standstill, if the visual stimulus is periodically removed from view. We also show, with a visual illusion, that this stabilizing effect hinges on perceptual disappearance rather than on actual removal of the stimulus. These findings indicate that uninterrupted subjective perception of an ambiguous pattern is required for the initiation of the brain-state changes underlying multistable vision.Visual perception involves coordination between sensory sampling of the world and active interpretation of the sensory data. Human perception of objects and scenes is normally stable and robust, but it falters when one is presented with patterns that are inherently ambiguous or contradictory. Under such conditions, vision lapses into a chain of continually alternating percepts, whereby a viable visual interpretation dominates for a few seconds and is then replaced by a rival interpretation. This multistable vision, or 'multistability', is thought to result from destabilization of fundamental visual mechanisms, and has offered valuable insights into how sensory patterns are actively organized and interpreted in the brain1, 2. Despite a great deal of recent research and interest in multistable perception, however, its neurophysiological underpinnings remain poorly understood. Physiological studies have suggested that disambiguation of ambiguous patterns. (shrink)

PurposeCodes of ethics are important instruments in journalism, as they promote transparency and self-regulation of media, in addition to monitoring the quality of information. The purpose of this paper is to analyse the perceptions that Spanish journalists have of the effectiveness of codes of ethics and to evaluate the different personal and professional variables which condition this vision.Design/methodology/approachThe methodology used in the present study is based on quantitative content analysis using the survey technique. This technique makes it possible to (...) obtain empirical data on various key aspects of the profession that are determining factors in ascertaining Spanish journalists’ views of one of the instruments of accountability that is external to the media: general ethical codes.FindingsThe results show that Spanish journalists are largely confident in the effectiveness of ethical codes in their profession. Likewise, it was seen that variables such as age, professional experience or the media with which they work influence the perceptions that professionals have of such instruments.Originality/valueIf understanding journalism as a profession whose mission is to guarantee the citizens their right to information, then it is essential to be familiar with the tools provided by the profession itself to be accountable to the public regarding this professional mission. Hence the importance of instruments of accountability and the perceptions of the professionals themselves regarding their effectiveness. (shrink)

One necessary condition on any adequate account of perception is clarity regarding whether unconscious perception exists. The issue is complicated, and the debate is growing in both philosophy and science. In this paper we consider the case for unconscious perception, offering three primary achievements. First, we offer a discussion of the underspecified notion of central coordinating agency, a notion that is critical for arguments that purportedly perceptual states are not attributable to the individual, and thus not genuinely (...) perceptual. We develop an explication of what it is for a representational state to be available to central coordinating agency for guidance of behavior. Second, drawing on this explication, we place a more careful understanding of the attributability of a state to the individual in the context of a range of empirical work on vision-for-action, saccades, and skilled typing. The results place pressure on the skeptic about unconscious perception. Third, reflecting upon broader philosophical themes running through debates about unconscious perception, we highlight how our discussion places pressure on the view that perception is a manifest kind, rather than a natural kind. In doing so, we resist the tempting complaint that the debate about unconscious perception is merely verbal. (shrink)

Reid maintained that the perceptions that we obtain from the senses of smell, taste, hearing, and touch are ‘suggested’ by corresponding sensations. However, he made an exception for the sense of vision. According to Reid, our perceptions of the real figure, position, and magnitude of bodies are suggested by their visible appearances, which are not sensations but objects of perception in their own right. These visible appearances have figure, position, and magnitude, as well as ‘colour,’ and the standard (...) view among Reid scholars has been that Reid maintained that our perceptions of visible figure, position, and magnitude are also not suggested by any sensation. They are instead suggested by the material impression on the retina. Gideon Yaffe challenges the standard interpretation. According to Yaffe, Reid believed that our perceptions of visible figure are suggested by corresponding sensations, by sensations of colour. We defend the standard interpretation of Reid. According to Reid, there is no “local sign” in our sensations of colour. The same colour sensation can be associated with different positions on the visual field, and different colour sensations can be associated to the same position on the visual field. According to Reid, we only have evidence for a correlation between the image on the retina and the perception of visible figure. (shrink)

A single case study of a patient, D.M., with a lesion in the region of the right occipito-temporal gyrus is presented. D.M. had well-preserved language and general cognitive abilities. Colour discrimination, contrast sensitivity, gross depth perception, spatial localization, and motion appreciation were within normal limits.On the evaluation of perceptual abilities, he failed to identify two-dimensional shapes from stereoscopic vision, motion, and texture although in all cases he was able to identify the rough area subtended by the shape. These (...) findings are considered in relation to the current anatomical-physiological functional models of vision and it is suggested that D.M. 's deficits provide evidence for the existence in man of a functional pathway involved in the computation of texture and fine aspects of shape, which is distinct from the pathways involved in motion and stereopsis processing on one hand and colour and coarse aspects of form on the other hand. (shrink)

Action is a means of acquiring perceptual information about the environment. Turning around, for example, alters your spatial relations to surrounding objects and, hence, which of their properties you visually perceive. Moving your hand over an object’s surface enables you to feel its shape, temperature, and texture. Sniffing and walking around a room enables you to track down the source of an unpleasant smell. Active or passive movements of the body can also generate useful sources of perceptual information (Gibson 1966, (...) 1979). The pattern of optic flow in the retinal image produced by forward locomotion, for example, contains information about the direction in which you are heading, while motion parallax is a “cue” used by the visual system to estimate the relative distances of objects in your field of view. In these uncontroversial ways and others, perception is instrumentally dependent on action. According to an explanatory framework that Susan Hurley (1998) dubs the “Input-Output Picture”, the dependence of perception on action is purely instrumental: "Movement can alter sensory inputs and so result in different perceptions… changes in output are merely a means to changes in input, on which perception depends directly" (1998: 342). -/- The action-based theories of perception, reviewed in this entry, challenge the Input-Output Picture. They maintain that perception can also depend in a noninstrumental or constitutive way on action (or, more generally, on capacities for object-directed motor control). This position has taken many different forms in the history of philosophy and psychology. Most action-based theories of perception in the last 300 years, however, have looked to action in order to explain how vision, in particular, acquires either all or some of its spatial representational content. Accordingly, these are the theories on which we shall focus here. -/- We begin in Section 1 by discussing George Berkeley’s Towards a New Theory of Vision (1709), the historical locus classicus of action-based theories of perception, and one of the most influential texts on vision ever written. Berkeley argues that the basic or “proper” deliverance of vision is not an arrangement of voluminous objects in three-dimensional space, but rather a two-dimensional manifold of light and color. We then turn to a discussion of Lotze, Helmholtz, and the local sign doctrine. The “local signs” were felt cues for the mind to know what sort of spatial content to imbue visual experience with. For Lotze, these cues were “inflowing” kinaesthetic feelings that result from actually moving the eyes, while, for Helmholtz, they were “outflowing” motor commands sent to move the eyes. -/- In Section 2, we discuss sensorimotor contingency theories, which became prominent in the 20thcentury. These views maintain that an ability to predict the sensory consequences of self-initiated actions is necessary for perception. Among the motivations for this family of theories is the problem of visual direction constancy—why do objects appear to be stationary even though the locations on the retina to which they reflect light change with every eye movement?—as well as experiments on adaptation to optical rearrangement devices (ORDs) and sensory substitution. -/- Section 3 examines two other important 20th century theories. According to what we shall call the motor component theory, efference copies generated in the oculomotor system and/or proprioceptive feedback from eye-movements are used together with incoming sensory inputs to determine the spatial attributes of perceived objects. Efferent readiness theories, by contrast, look to the particular ways in which perceptual states prepare the observer to move and act in relation to the environment. The modest readiness theory, as we shall call it, claims that the way an object’s spatial attributes are represented in visual experience can be modulated by one or another form of covert action planning. The bold readiness theory argues for the stronger claim that perception just is covert readiness for action. -/- In Section 4, we move to the disposition theory, most influentially articulated by Gareth Evans (1982, 1985), but more recently defended by Rick Grush (2000, 2007). Evans’ theory is, at its core, very similar to the bold efferent readiness theory. There are some notable differences, though. Evans’ account is more finely articulated in some philosophical respects. It also does not posit a reduction of perception to behavioral dispositions, but rather posits that certain complicated relations between perceptual input and behavioral provide spatial content. Grush proposes a very specific theory that is like Evans’ in that it does not posit a reduction, but unlike Evans’ view, does not put behavioral dispositions and sensory input on an undifferentiated footing. (shrink)

Perception is a first-person internal sensation induced within the nervous system at the time of arrival of sensory stimuli from objects in the environment. Lack of access to the first-person properties has limited viewing perception as an emergent property and it is currently being studied using third-person observed findings from various levels. One feasible approach to understand its mechanism is to build a hypothesis for the specific conditions and required circuit features of the nodal points where the mechanistic (...) operation of perception take place for one type of sensation in one species and to verify it for the presence of comparable circuit properties for perceiving a different sensation in a different species. The present work explains visual perception in mammalian nervous system from a first-person frame of reference and provides explanations for the homogeneity of perception of visual stimuli above flicker fusion frequency, the perception of objects at locations different from their actual position, the smooth pursuit and saccadic eye movements, the perception of object borders, and perception of pressure phosphenes. Using results from temporal resolution studies and the known details of visual cortical circuitry, explanations are provided for (a) the perception of rapidly changing visual stimuli, (b) how the perception of objects occurs in the correct orientation even though, according to the third-person view, activity from the visual stimulus reaches the cortices in an inverted manner and (c) the functional significance of well-conserved columnar organization of the visual cortex. A comparable circuitry detected in a different nervous system in a remote species-the olfactory circuitry of the fruit fly Drosophila melanogaster-provides an opportunity to explore circuit functions using genetic manipulations, which, along with high-resolution microscopic techniques and lipid membrane interaction studies, will be able to verify the structure-function details of the presented mechanism of perception. (shrink)

Colour vision plays a foundational explanatory role in the philosophy of colour, and serves as perennial quarry in the wider philosophy of perception. I present two contributions to our understanding of this notion. The first is to develop a constitutive approach to characterizing colour vision. This approach seeks to comprehend the nature of colour vision qua psychological kind, as contrasted with traditional experiential approaches, which prioritize descriptions of our ordinary visual experience of colour. The second contribution (...) is to argue that colour vision does not constitutively involve the ability to see colours, in a natural and categorically committed sense. I argue that two subjects exactly alike in respect of their constitutive colour vision abilities could differ in respect of whether or not they have categorical perception of colour. The argument is supported by thought experiment and dissociations observed in cognitive neuropsychology. The argument also bears connections to recent neo-Whorfian accounts of colour categorization. _1._ Introduction _2._ Colour Vision, Experience, and Natures _3._ The Central Argument _3.1._ Colour constancy and discrimination _3.2._ Dissociating colour vision and categorical perception for colour _4._ Whorf and the View from Cognitive Neuropsychology _5._ Conclusion. (shrink)

Traditionally, vision science and information/data visualization have interacted by using knowledge of human vision to help design effective displays. It is argued here, however, that this interaction can also go in the opposite direction: the investigation of successful visualizations can lead to the discovery of interesting new issues and phenomena in visual perception. Various studies are reviewed showing how this has been done for two areas of visualization, namely, graphical representations and interaction, which lend themselves to work (...) on visual processing and the control of visual operations, respectively. The results of these studies have provided new insights into aspects of vision such as grouping, attentional selection and the sequencing of visual operations. More generally yet, such results support the view that the perception of visualizations can be a useful domain for exploring the nature of visual cognition, inspiring new kinds of questions as well as casting new light on the limits to which information can be conveyed visually. (shrink)

This paper considers the implications of David Marr's computational theory of vision for the issues of individualism and methodological solipsism. A recent argument that the theory is nonindividualistic is shown to be similar to Gibson's arguments for "direct perception." The paper argues that a complete analysis of Marr's theory must take into account Marr's rejection of Gibson's approach, and that such an analysis shows Marr's theory to be consistent with methodological solipsism as a research strategy.

We question the usefulness of Pylyshyn's dichotomy between cognitively penetrable and cognitively impenetrable mechanisms as the basis for his distinction between cognition and early vision. This dichotomy is comparable to others that have been proposed in psychology prompting disputes that by their very nature could not be resolved. This fate is inevitable for Pylyshyn's thesis because of its reliance on internal representations and their interpretation. What is more fruitful in relation to this issue is not a difficult dichotomy, but (...) a different look at perception such as proposed by Gibson (1979). (shrink)

Vision consists of four essays: “Seeing distance,” “Size,” “Perceptual inference,” and “A Gibsonian alternative?” The continuous thread is the Berkeleian treatment of the perception of spatial properties, particularly in connection with what is and is not “immediately perceived.” The first two essays are closely connected with specific Berkeleian arguments and modern responses to them. The second two essays deal more generally with modern discussions by psychologists of whether visual perception is “direct” or “indirect.” The claims on the (...) cover that the book is “unique in its blend of philosophical and historical perspectives on contemporary issues in vision studies” and that it is “clearly written” and suitable “for an interdisciplinary readership in philosophy of mind, philosophy of science, cognitive psychology and history of science” are all entirely justified. (shrink)

More than one third of the human brain is devoted to the processes of seeing - vision is after all the main way in which we gather information about the world. But human vision is a dynamic process during which the eyes continually sample the environment. Where most books on vision consider it as a passive activity, this book is unique in focusing on vision as an 'active' process. It goes beyond most accounts of vision (...) where the focus is on seeing, to provide an integrated account of seeing AND looking. The book starts by pointing out the weaknesses in our traditional approaches to vision and the reason we need this new approach. It then gives a thorough description of basic details of the visual and oculomotor systems necessary to understand active vision. The book goes on to show how this approach can give a new perspective on visual attention, and how the approach has progressed in the areas of visual orienting, reading, visual search, scene perception and neuropsychology. Finally, the book summarises progress by showing how this approach sheds new light on the old problem of how we maintain perception of a stable visual world. Written by two leading vision scientists, this book will be valuable for vision researchers and psychology students, from undergraduate level upwards. (shrink)

b>. Computational models of colour vision assume that the biological function of colour vision is to detect surface reflectance. Some philosophers invoke these models as a basis for 'externalism' about perceptual content (content is distal) and 'objectivism' about colour (colour is surface reflectance). In an earlier article (Thompson et al. 1992), I criticized the 'computational objectivist' position on the basis of comparative colour vision: There are fundmental differences among the colour vision of animals and these differences (...) do not converge on the detection of any single type of environmental property. David R. Hilbert (1992) has recently defended computational objectivism against my 'comparative argument;' his arguments are based on the externalist approach to perceptual content originally developed by Mohan Matthen (1988) and on the computationally inspired theory of the evolutionary basis for trichromacy developed by Roger N. Shepard (1990). The present article provides a reply to Hilbert with extensive criticism of both Matthen's and Shepard's theories. I argue that the biological function of colour vision is not to detect surface reflectance, but to provide a set of perceptual categories that can apply to objects in a stable way in a variety of conditions. Comparative research indicates that both the perceptual categories and the distal stimuli will differ according to the animal and its visual ecology; therefore externalism and objectivism must be rejected. (shrink)

I elaborate on Pylyshyn's definition of the cognitive impenetrability (CI) of early vision, and draw on the role of concepts in perceptual processing, which links the problem of the CI or cognitive penetrability (CP) of early vision with the problem of the nonconceptual content (NCC) of perception. I explain, first, the sense in which the content of early vision is CI and I argue that if some content is CI, it is conceptually encapsulated, that is, it (...) is NCC. Then, I examine the definitions of NCC and argue that they lead to the view that the NCC of perception is retrieved in a stage of visual processing that is CI. Thus, the CI of a state and content is a sufficient and necessary condition for the state and its content to be purely NCC, the CI?≡?NCC thesis. Since early vision is CI, the purely NCC of perception is formed in early vision. I defend the CI?≡?NCC thesis by arguing against objections raised against both the sufficient and the necessary part of the thesis. (shrink)

In this thesis, I both analyze the phenomenology of vision from a geometrical point of view, and also develop certain connections between that geometrical analysis and the mind body problem. In order to motivate the need for such an analysis, I first show, by means of a refutation of direct realism, that visual space is never identical with any of the physical objects being indirectly "seen" by constituting color arrangements in it. It thus follows that the geometry of visual (...) space may be quite different from the Euclidean geometry of physical space, and I proceed to analyze that geometry. ;I argue that topologically, visual space is two dimensional, inasmuch as regions of it are capable of being bounded by a line, such as the borders around the various objects constituted in it. An apparent paradox arises here though, inasmuch as we posess phenomenal depth perception, which is particularly striking during binocular vision, and thus the question arises as to how the binocular depth cue of retinal disparity is registered phenomenally in a two dimensional space. I resolve this apparent paradox by arguing that the internal metric struture of this space can be apprehended phenomenally, and can serve as such a phenomenal depth cue. It is shown that holistically, this metric structure is elliptical, since for example marginal distortions in wide-angle photography are not present in visual space, and it is also noted that there is a tendency towards size constancy in visual perception. It is shown from these geometrical considerations that visual space posseses a variable curvature, with that curvature being determined by the physical depths of objects constituted in the space. ;Finally, I investigate what bearing the preceding geometrical conclusions have on the question of how events in visual space may be causally determined by neural events in the brain. The classical isomorphic theory of Gestalt psychology is then reinterpreted in light of my analysis of the geometry of visual space. (shrink)