This paper concerns local yet systematic problems of contrastive underdetermination of model choice in cognitive neuroscience debates about the so-called two visual systems hypothesis. The underdetermination problem is systematically generated by the way certain assumptions about the representationalist nature of computation are translated into experimental practice. The problem is that behavioural data underdetermine the choice between competing representational models. In this paper, I diagnose how these assumptions generate underdetermination problems in the choice between competing functional models of (...) perception–action. Using the tools of philosophy of science, I describe the type of underdetermination and sketch a possible cure. (shrink)

The purpose of this paper is to defend what I call the action-oriented coding theory (ACT) of spatially contentful visual experience. Integral to ACT is the view that conscious visual experience and visually guided action make use of a common subject-relative or 'egocentric' frame of reference. Proponents of the influential two visual systems hypothesis (TVSH), however, have maintained on empirical grounds that this view is false (Milner & Goodale, 1995/2006; Clark, 1999; 2001; Campbell, 2002; Jacob (...) & Jeannerod, 2003; Goodale & Milner, 2004). One main source of evidence for TVSH comes from behavioral studies of the comparative effects of size-contrast illusions on visual awareness and visuo- motor action. This paper shows that not only is the evidence from illusion studies inconclusive, there is a better, ACT-friendly interpretation of the evidence that avoids serious theoretical difficulties faced by TVSH. (shrink)

The two-visual-systems hypothesis proposed by Goodale and Milner is a radical one. If it were to be true, then our common sense such as we are acting on what we are perceiving should be completely abandoned. In this paper, I argue that the hypothesis over-generalizes what happens in simple tasks to what happens in complex tasks. By contrast, I demonstrate that what happens in complex tasks is compatible with our common sense. In a word, though what (...) we are acting on may come apart from what we are perceiving in some cases, that is not the whole story. (shrink)

This commentary on Jacob and Jeannerod’s Ways of Seeing evaluates the conclusions that the authors draw from the two visual systems hypothesis about the nature and phenomenology of visual experience.

What is the relationship between perception and action, between an organism and its environment, in explaining consciousness? These are issues at the heart of philosophy of mind and the cognitive sciences. This book explores the relationship between perception and action from a variety of interdisciplinary perspectives, ranging from theoretical discussion of concepts to findings from recent scientific studies. It incorporates contributions from leading philosophers, psychologists, neuroscientists, and an artificial intelligence theorist. The contributions take a range of positions with respect to (...) the view that perception is an achievement by an agent acting in a complex environment in which sensorimotor dynamics constitute an essential ingredient to perceptual experience. A key focus of the book is on the debate about action-oriented theories of visual perception versus the dual-visual systems hypothesis The former champions the role of sensorimotor dynamics in perceptual awareness while the latter favours a functional dichotomy between perception and action. At least on the surface, these two approaches are in conflict. Where one emphasizes the interdependence of action and perception, the other suggests that action and perception are functionally distinct. The dialogue between these two approaches brings out wider theoretical issues underlying the research paradigm of cognitive sciences and philosophy of mind. Exploring one of the major debates in the philosophy and psychology, this book is fascinating reading for all those in the cognitive sciences and philosophy of mind. (shrink)

This book is an interdisciplinary exploration of the relationship between perception and action, with a focus on the debate about the dual visual systems hypothesis, against action oriented theories of perception.

Perception, Action, and Consciousness: Sensorimotor Dynamics and Two Visual Systems is a state-of-the-art collection whose main goal is to explore, from an interdisciplinary perspective, the relationship between action and perception. A second goal of the volume is to investigate how perception and action interact specifically in the production of phenomenal awareness. In presenting and contrasting the major perspectives on the field, this volume marks a good sign of the progress being made on the nature of phenomenally conscious (...) class='Hi'>visual experience. By combining theoretical and empirical approaches it also contributes to the debate in key domains of the cognitive sciences .The book contains a useful editorial introduction written by the Editors and six sections further divided into fifteen chapters. In the first part of this review I briefly summarize the content of each section. Having offered an outline of the volume, I then turn my attention to the main theme of the collection, which is the dichotomy between action-oriented theories of perception and the two visual systems hypothesis and look at the dialectic underlying this debate. (shrink)

In this paper we focus on the modularity of visual functions in the human visual cortex, that is, the specific problems that the visual system must solve in order to achieve recognition of objects and visual space. The computational theory of early visual functions is briefly reviewed and is then used as a basis for suggesting computational constraints on the higher-level visual computations. The remainder of the paper presents neurological evidence for the existence of (...) two visual systems in man, one specialized for spatial vision and the other for object vision. We show further clinical evidence for the computational hypothesis that these two systems consist of several visual modules, some of which can be isolated on the basis of specific visual deficts which occur after lesions to selected areas in the visually responsive brain. We will provide examples of visual modules which solve information processing tasks that are mediated by specific anatomic areas. We will show that the clinical data from behavioral studies of monkeys (Ungerleider and Mishkin 1984) supports the distinction between two visual systems in monkeys, the 'what' system, involved in object vision, and the 'where' system, involved in spatial vision. (shrink)

Argues for a category of “cognitive feelings”, which are representationally significant, but are not part of the content of the states they accompany. The feeling of pastness in episodic memory, of familiarity (missing in Capgras syndrome), and of motivation (that accompanies desire) are examples. The feeling of presence that accompanies normal visual states is due to such a cognitive feeling; the “two visual systems” are partially responsible for this feeling.

The two contrasting theoretical approaches to visual perception, the constructivist and the ecological, are briefly presented and illustrated through their analyses of space and size perception. Earlier calls for their reconciliation and unification are reviewed. Neurophysiological, neuropsychological, and psychophysical evidence for the existence of two quite distinct visual systems, the ventral and the dorsal, is presented. These two perceptual systems differ in their functions; the ventral system's central function is that of identification, while the dorsal system (...) is mainly engaged in the visual control of motor behavior. The strong parallels between the ecological approach and the functioning of the dorsal system, and between the constructivist approach and the functioning of the ventral system are noted. It is also shown that the experimental paradigms used by the proponents of these two approaches match the functions of the respective visual systems. A dual-process approach to visual perception emerges from this analysis, with the ecological-dorsal process transpiring mainly without conscious awareness, while the constructivist-ventral process is normally conscious. Some implications of this dual-process approach to visual-perceptual phenomena are presented, with emphasis on space perception. Key Words: constructivist; dual-process approach; ecological; size perception; space perception; two visual systems; visual perception theories. (shrink)

Molyneux’s question famously asks about whether a newly sighted subject might immediately recognize, by sight alone, shapes that were already familiar to her from a tactile point of view. This paper addresses three crucial points concerning this puzzle. First, the presence of two different questions: the classic one concerning visual recognition and another one concerning vision-for-action. Second, the explicit distinction, reported in the literature, between ocular and cortical blindness. Third, the importance of making reference to our best neuroscientific account (...) on vision, ‘the two visual systems model’, in order to better address Molyneux’s problem. Then, by offering a new, deeper analysis of the relation between, and, this paper suggests that the subjects of Molyneux’s two different questions show the same visual impairment as brain-damaged subjects with different lesions of the visual cortex. In particular, the subject of the first question shows the same impairment in visual recognition as a visual agnosic subject, while the subject of the second question shows the same visual impairment in visuomotor processing as an optic ataxic subject. These impairments still hold even if ocular processing is restored. Therefore, I suggest the following. For the first classic question, the required experimental setting cannot be properly reached. By contrast, concerning the second question, based on the interpretation we select, either the answer is negative, or, as with the first question, the experimental setting cannot be properly reached. This proposal constitutes, with the other approaches offered in the literature, a further attempt to tackle the enormous complexity of Molyneux’s puzzle. (shrink)

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

The parallel drawn by Norman between the dorsal and ventral systems and direct and indirect approaches is based on two misrepresentations of the direct approach – that it is concerned only with the unconscious control of action, and that it cannot explain learning. We propose a way of understanding the visual system differences from within the direct approach.

Perception of (and during) events is a necessary feature of any perceptual theory. Norman's dual-process approach cannot account for the perception of events without substantial interactions between the dorsal and ventral systems. These interactions, as outlined by Norman, are highly problematical. The necessity for interactions between the two systems makes the distinction useless.

In this book, Michael Madary examines visual experience, drawing on both phenomenological and empirical methods of investigation. He finds that these two approaches—careful, philosophical description of experience and the science of vision—independently converge on the same result: Visual perception is an ongoing process of anticipation and fulfillment. Madary first makes the case for the descriptive premise, arguing that the phenomenology of vision is best described as on ongoing process of anticipation and fulfillment. He discusses visual experience as (...) being perspectival, temporal, and indeterminate; considers the possibility of surprise when appearances do not change as we expect; and considers the content of visual anticipation. Madary then makes the case for the empirical premise, showing that there are strong empirical reasons to model vision using the general form of anticipation and fulfillment. He presents a range of evidence from perceptual psychology and neuroscience, and reinterprets evidence for the two-visual-systems hypothesis. Finally, he considers the relationship between visual perception and social cognition. An appendix discusses Husserlian phenomenology as it relates to the argument of the book. Madary argues that the fact that there is a convergence of historically distinct methodologies itself is an argument that supports his findings. With Visual Phenomenology, he creates an exchange between the humanities and the sciences that takes both methods of investigation seriously. (shrink)

Milner and Goodale's Two Visual Systems Hypothesis is regarded as common ground in recent discussions of visual consciousness. A central part of TVSH is a functional model of vision and action. In this paper, I provide a brief overview of these current discussions and argue that there is ambiguity between a strong and a weak version of PAM. I argue that, given a standard way of individuating computational mechanisms, the available evidence cannot be used to distinguish (...) between these versions. This not only has consequences for philosophical theories of the role of visual consciousness but also for the role of experimental evidence in model testing in cognitive neuroscience. (shrink)

Neuroanatomy and neurophysiology are insufficient to specify function. Modeling is essential to elucidate function, but psychophysics is also required. An example is the cognitive and sensorimotor branches of the visual system: anatomy shows direct cross talk between the branches. Psychophysics in normal humans shows links from cognitive to sensorimotor, but the reverse link is excluded by visual illusions affecting the cognitive system but not the sensorimotor system.

According to the two visual systems model, the visual processing of objects divides into semantic and pragmatic processing. We provide various criteria for this distinction. Further, we argue that both the semantic and pragmatic processing of visual information about objects should be divided into low-level processing and high-level processing. Finally, we re-evaluate the contribution of the human parietal lobe to the concious visual perception of spatial relations among objects.

In this paper I present a psychofunctionalist argument for conceptualism, the thesis that conscious visual experience is a conceptual state rather than a nonconceptual state. The argument draws on the holistic character of functionalist accounts of mind, together with the “Two Visual Systems Hypothesis” notably defended by Melvyn Goodale and David Milner.

Norman's reconciliation of the two theories of perception is challenged because it directly leads to the nature-nurture dichotomy in the development of the two visual systems. In contrast, the proposition of a separate development of the two visual systems may be better understood as involving different types of information that follow a distinct temporal sequence.

Norman's aim to reconcile two longstanding and seemingly opposed philosophies of perception, the constructivist and the ecological, by casting them as approaches to complementary subsystems within the visual brain is laudable. Unfortunately, Norman overreaches in attempting to equate direct perception with dorsal/unconscious visual processing and indirect perception with ventral/conscious visual processing. Even a cursory review suggests that the functional and neural segregation of direct and indirect perception is not as clear as the target article would suggest.

Berkeley and Helmholtz proposed different indirect mechanisms for size perception: Berkeley, that size was conditioned to various cues, independently of perceived distance; Helmholtz, that it was unconsciously calculated from angular size and perceived distance. The geometrical approach cannot explain size-distance paradoxes (e.g., moon illusion). The dorsal/ventral solution is dubious for close displays and untestable for far displays.

In this chapter, we discuss a selection of current views of the neural correlates of consciousness (NCC). We focus on the different predictions they make, in particular with respect to the role of prefrontal cortex (PFC) during visual experiences, which is an area of critical interest and some source of contention. Our discussion of these views focuses on the level of functional anatomy, rather than at the neuronal circuitry level. We take this approach because we currently understand more about (...) experimental evidence at this coarse level and because these results are appropriate for arbitrating between current theoretical frameworks. We discuss the Two-Visual-Systems Hypothesis (Milner & Goodale 1995; 2006), Local Recurrency (Lamme 2010; Lamme 2006), Higher Order (Lau 2008; Lau & Rosenthal 2011) and Global Workspace theories (Baars 1997; Baars 2005; Dehaene & Naccache 2001; Dehaene 2014). Despite the apparent stark differences between conscious and unconscious perceptual processing, available evidence suggests that their neural substrates must be largely shared. This indicates that the difference in neural activity between conscious and unconscious perceptual processing is likely to be subtle and highly specialized. We argue that current experimental evidence about the involvement of specific activity in prefrontal cortex supports the higher order neural theory of consciousness. In consequence, imaging techniques that focus only on marked differences between conscious and unconscious level of activity are likely to be insensitive to the relevant neural activity patterns that underlie conscious experiences. Finally, it follows from the evidence we discuss that the functional advantages of conscious over unconscious perceptual processing may be more limited than commonly thought. (shrink)

Statistical learning enables humans to involuntarily process and utilize different kinds of patterns from the environment. However, the cognitive mechanisms underlying the simultaneous acquisition of multiple regularities from different perceptual modalities remain unclear. A novel multidimensional serial reaction time task was developed to test 40 participants’ ability to learn simple first‐order and complex second‐order relations between uni‐modal visual and cross‐modal audio‐visual stimuli. Using the difference in reaction times between sequenced and random stimuli as the index of domain‐general statistical (...) learning, a significant difference and dissociation of learning occurred between the initial and final learning phases. Furthermore, we used a negative and positive occurrence‐frequency‐and‐reaction‐time correlation to indicate implicit and explicit learning, respectively, and found that learning simple uni‐modal patterns involved an implicit‐to‐explicit segue, while acquiring complex cross‐modal patterns required an explicit‐to‐implicit segue, resulting in a X‐shape crossing of regularity learning. Thus, we propose an X‐way hypothesis to elucidate the dynamic interplay between the implicit and explicit systems at two distinct stages when acquiring various regularities in a multidimensional probability space. (shrink)

It is natural to assume that the fine-grained and highly accurate spatial information present in visual experience is often used to guide our bodily actions. Yet this assumption has been challenged by proponents of the Two Visual Systems Hypothesis , according to which visuomotor programming is the responsibility of a “zombie” processing stream whose sources of bottom-up spatial information are entirely non-conscious . In many formulations of TVSH, the role of conscious vision in action is limited (...) to “recognizing objects, selecting targets for action, and determining what kinds of action, broadly speaking, to perform” . Our aim in this study is to show that the available evidence not only fails to support this dichotomous view but actually reveals a significant role for conscious vision in motor programming, especially for actions that require deliberate attention. (shrink)

Among the exciting prospects raised by advocates of predictive processing [PP] is the offer of a systematic description of our neural activity suitable for drawing explanatory bridges to the structure of conscious experience. Yet the gulf to cross seems wide. For, as critics of PP have argued, our visual experience certainly doesn’t seem probabilistic.While Clark proposes a means to make PP compatible with the experience of a determinate world, I argue that we should not rush to do so. Two (...) notions of determinacy are conflated in the claim that perception is determinate: ‘univocality’ and ‘full detail’. The former, as Clark argues, is only to be expected in any PP agent that models its world for the purpose of acting on it. But as Husserl argued, and as perceptual psychology has borne out, we significantly overestimate the degree of detail with which we perceive a univocal world.This second form of indeterminacy is due not to the probabilistic nature of PP’s model, but rather to its hierarchical structure, with increasingly coarse-grained representations as we move further from the sensory periphery. A PP system may, or may not, deliver a univocal hypothesis at each of these levels. An action-oriented PP system would only be expected to do so only at the level needed for successful action guidance. A naïve reporter’s overestimation of the degree of determinate detail in their visual experience can thereby be accounted for with a more gradual version of the ‘refrigerator light’ effect: we experience determinate details just to the degree that they’re needed – immediately as they’re needed. (shrink)

What are the factors that contribute to (or inhibit) diachronic sound change? While acoustically motivated sound changes are well documented, research on the articulatory and audiovisual-perceptual aspects of sound change is limited. This paper investigates the interaction of articulatory variation and audiovisual speech perception in the Northern Cities Vowel Shift (NCVS), a pattern of sound change observed in the Great Lakes region of the United States. We focus specifically on the maintenance of the contrast between the vowels /ɑ/ and /ɔ/, (...) both of which are fronted as a result of the NCVS. We present results from two experiments designed to test how the NCVS is produced and perceived. In the first experiment, we present data from an articulatory and acoustic analysis of the production of fronted /ɑ/ and /ɔ/. We find that some speakers distinguish /ɔ/ from /ɑ/ with a combination of both tongue position and lip rounding, while others do so using either tongue position or lip rounding alone. For speakers who distinguish /ɔ/ from /ɑ/ along only one articulatory dimension, /ɑ/ and /ɔ/ are acoustically more similar than for speakers who produce multiple articulatory distinctions. While all three groups of speakers maintain some degree of acoustic contrast between the vowels, the question is raised as to whether these articulatory strategies differ in their perceptibility. In the perception experiment, we test the hypothesis that visual speech cues play a role in maintaining contrast between the two sounds. The results of this experiment suggest that articulatory configurations in which /ɔ/ is produced with unround lips are perceptually weaker than those in which /ɔ/ is produced with rounding, even though these configurations result in acoustically similar output. We argue that these findings have implications for theories of sound change and variation in at least two respects: 1) visual cues can shape phonological systems through misperception-based sound change, and 2) phonological systems may be optimized not only for auditory but also for visual perceptibility. (shrink)

David Milner and Melvyn Goodale, and the many psychologists and philosophers who have been influenced by their work, claim that ‘the visual system that gives us our visual experience of the world is not the same system that guides our movements in the world’. The arguments that have been offered for this surprising claim place considerable weight on two sources of evidence — visual form agnosia and the reaching behaviour of normal subjects when picking up objects that (...) induce visual illusions. The present article shows that, if we are careful to consider the possibility that a demonstrative gesture can contribute content to a conscious experience, then neither source of evidence is compelling. (shrink)

By hypothesis, awareness is involved in the modulation of feedback from semantics to the lexical level in the visual word recognition system. When subjects are aware of the fact that there are many related prime–target pairs in a semantic priming experiment, this knowledge is used to configure the system to feed activation back from semantics to the lexical level so as to facilitate processing. When subjects are unaware of this fact, the default set is maintained in which activation (...) is not fed back from semantics to the lexical level so as to conserve limited resources. Qualitative differences in the pattern of data from two lexical decision experiments that employ masked priming are consistent with this hypothesis. Semantic context and stimulus quality interact when the prime is processed with awareness whereas these same two factors produce additive effects on RT when the prime is unlikely to have been processed with awareness. These experiments thus illustrate one way in which awareness affects the dynamics of visual word recognition. (shrink)

In Section I, I clarify turning point issues in the Phillips and Block debate about whether there is unconscious perception. These include questions about whether uptake of certain visual information is an individual or person level accomplishment, as required for genuine unconscious _perceiving_. Section II takes up a recent reorientation proposed in Block ( 2017 ) towards the question of whether there is unconscious perceiving, where we are to look for the pervasive role of unconscious perceiving in, perhaps especially, (...) the online control of everyday reaching and grasping. I point out that while this may well be a helpfully different approach to explore, it does not evade the central questions and challenges familiar from the prior debate between Phillips and Block. Section III reviews an approach summarized in Dehaene ( 2014 ), drawing from a range of measures of neural activity. Dehaene provides evidence of quite rich non-conscious perceptual system responses, some arguably individual or person level. But in a fairly thin or fragile way, absent taking up, in higher level assessment, the information encoded in initial visual response. Or that is the interpretation I argue for, in relating the Dehaene account to the Phillips and Block debate, in a way that illuminates the Phillips and Block discussions. An Appendix provides an overview of debates in the literature about the Goodale and Milner Two Visual Systems Hypothesis, that Block ( 2017 ) makes central appeal to. (shrink)

I aim to give a new account of picture perception: of the way our visual system functions when we see something in a picture. My argument relies on the functional distinction between the ventral and dorsal visual subsystems. I propose that it is constitutive of picture perception that our ventral subsystem attributes properties to the scene, whereas our dorsal subsystem attributes properties to the surface. Keywords: picture perception; dorsal subsystem;.

This paper considers how best an eliminativist might argue for the radical falsity of commonsense psychology. I will be arguing that Paul Churchland’s “official” arguments for eliminative materialism (in, e.g., Churchland 1981) are unsatisfactory, although much of the paper will be developing themes that are clearly present in Churchland’s writings. The eliminativist needs to argue that the representations that feed into action are fundamentally different from those invoked by propositional attitude psychology. The “springs of action” are representations of features that (...) are much more finely grained than those encoded within the vocabulary that we employ to specify the content of propositional attitudes. The eliminativist’s most promising strategy is to argue that, whatever we might think about why we behave the way we do, careful experimental work will show that we are in fact acting in virtue of representations of properties and microfeatures that fall completely outside the ambit of propositional attitude psychology. The paper considers a number of examples of how this eliminativist strategy might be developed, ranging from the implications of the two visual systems hypothesis to research in social psychology into the role that situational factors play in controlling action. (shrink)

Irvin Rock's hypothesis that certain stages of perceptual processing resemble problem solving in cognition is contrasted to some recent work in computer vision (Marr, Ullman) which tries to reduce intelligence in perception to computational organization. The focal example is subjective contours which Marr thought could be handled by computational modules without descending control, and which Rock thinks are the outcome of intelligent processing.

According to what I’ll call the ‘two visual systems account’ (TWO-SYSTEMS), the visual system is divided into two independent sub- systems, a ventral system implementing ‘vision for perception’ and a dorsal system implementing ‘vision for action’ (Milner and Goodale, 2006). TWO-SYSTEMS is widely discussed in philosophy due to the counter-intuitive role that it posits for conscious experience in the control of actions. However, recent evidence undermines the model’s core tenets: it no longer appears that (...) the ventral and dorsal streams constitute isolated processing systems, and there is now evidence for the involvement of both streams in conscious experience and online motor control. I articulate a new ‘direct dorsal control account’ (DORSAL-CONTROL), show that it is immune to three empirical challenges facing TWO-SYSTEMS, and show that it nonetheless has similarly significant implications for the perceiving mind. -/- Section 1 articulates TWO-SYSTEMS and its philosophical implications. Section 2 describes three empirical challenges to TWO-SYSTEMS. Section 3 articulates DORSAL-CONTROL and shows that it is immune to the three challenges. Section 4 articulates DORSAL-CONTROL’s philosophical implications. (shrink)

Context: Neurophenomenology is a relatively new field, with scope for novel and informative approaches to empirical questions about what structural parallels there are between neural activity and phenomenal experience. Problem: The overall aim is to present a method for examining possible correlations of neurodynamic and phenodynamic structures within the structurally-coupled work of Alexander Technique practitioners with their pupils. Method: This paper includes the development of an enkinaesthetic explanatory framework, an overview of the salient aspects of the Alexander Technique, and the (...) presentation of an elicitation interview technique as part of a neurophenomenological method. It will propose a way of testing the hypothesis that if, in the effective practice of Alexander Technique, there is a union between the nervous systems of teacher and pupil, it should be visible neurologically and affective phenomenologically, and thus it should be possible to investigate both its neural and phenomenal signatures. Results: The proposed means of testing the hypothesis is to use the elicitation interview technique alongside neural monitoring during the teaching of the Alexander Technique in four paired sets of subjects. Constructivist content: At the heart of this paper is the claim that all activity is co-activity. I make no assumption of an ontological primacy of mental or physical, or explanatory primacy of any methodology. Implications: This has important ramifications for somatic education and therapies, for establishing frameworks of co-engagement and care in health-care situations, and for understanding empathy. (shrink)

Although seeing is commonly experienced as a unitary activity, the scientific description of vision resists such an intuitive account. Both psychologists and neuroscientists are in agreement with the idea that the elaboration of visual information is distributed across several different routes provided with different functions. Importantly, these routes can be mapped onto well-identified anatomical subdivision of the visual system. Crucially, although originally based on the assumption that different visual information are elaborated via different neural channels, such a (...) model is nowadays used as a tool for indicating a common neural basis between action and perception. The present review is aimed at providing a description of how the modular model of visual system has developed from a model where action and perception are considered as segregate to a model where action and perception are considered ass two labels of the same concept. (shrink)

The following analysis shows how developments in epistemic logic can play a nontrivial role in cognitive neuroscience. We argue that the striking correspondence between two modes of identification, as distinguished in the epistemic context, and two cognitive systems distinguished by neuroscientific investigation of the visual system (the "where" and "what" systems) is not coincidental, and that it can play a clarificatory role at the most fundamental levels of neuroscientific theory.

The visual attention (VA) span is defined as the amount of distinct visual elements which can be processed in parallel in a multi-element array. Both recent empirical data and theoretical accounts suggest that a VA span deficit might contribute to developmental dyslexia, independently of a phonological disorder. In this study, this hypothesis was assessed in two large samples of French and British dyslexic children whose performance was compared to that of chronological-age matched control children. Results of the (...) French study show that the VA span capacities account for a substantial amount of unique variance in reading, as do phonological skills. The British study replicates this finding and further reveals that the contribution of the VA span to reading performance remains even after controlling IQ, verbal fluency, vocabulary and single letter identification skills, in addition to phoneme awareness. In both studies, most dyslexic children exhibit a selective phonological or VA span disorder. Overall, these findings support a multi-factorial view of developmental dyslexia. In many cases, developmental reading disorders do not seem to be due to phonological disorders. We propose that a VA span deficit is a likely alternative underlying cognitive deficit in dyslexia. (shrink)

Many philosophers sympathetic with a Humean understanding of laws of nature have thought that, in the final analysis, the fundamental laws will include not only the traditional dynamical equations, but also two additional principles: the Past Hypothesis and the Statistical Postulate. The former says that the universe began in a particular very-low-entropy macrostate M(0), and the latter posits a uniform probability distribution over the microstates compatible with M(0). Such a view is arguably vindicated by the orthodox Humean Best System (...) Account (BSA). However, I argue here that recent developments of the BSA render the Past Hypothesis otiose. In particular, the trend among Humeans toward a more pragmatic view of laws — according to which the best system is the one that is maximally effective at helping creatures like us amplify our information about the world — does not support the idea that the Past Hypothesis is a law of nature. (shrink)

The behavioral immune system (BIS) includes perceptual mechanisms for detecting cues of contamination. Former studies have indicated that moisture has a disgusting property. Therefore, moisture could be a target for detecting contamination cues by the BIS. We conducted two experiments to examine the psychophysical basis of moisture perception and clarify the relationship between the perception of moisture and the BIS. We assumed that the number of high luminance areas in a visual image provided optical information that would enable the (...) visual perception of moisture. In two experiments, we presented eight images of dough that contained different amounts of moisture as experimental stimuli. The amount of moisture shown in the images was increased in eight steps, from 28.6% to 42.9% of the total weight of the dough. In Experiment 1, the images were randomly presented on a computer display, and the participants (n = 22) were asked to rank the images in the order of the visually perceived moisture content. In Experiment 2, the participants (n = 15) completed pairwise comparisons based on the perceived moistness of the images. Furthermore, to examine the BIS responses, the participants rated the strength of disgust evoked by the stimuli, their motivation to avoid touching the stimuli, and the estimated magnitude of the risk of contamination by physical contact with the stimuli. The results indicated that the moisture content and the numbers of high luminance areas in the images accurately predicted the perception of moisture, suggesting that the detection of visual moisture was highly accurate, and the optical information served as an essential perceptual cue for detecting moisture. On the other hand, the BIS responses peaked in response to stimuli having approximately 33% to 39% moisture content. These results show that objects containing a moderate amount of moisture could be the target of visually detecting pathogens by the BIS. (shrink)

The Visual World Paradigm (VWP) presents listeners with a challenging problem: They must integrate two disparate signals, the spoken language and the visual context, in support of action (e.g., complex movements of the eyes across a scene). We present Impulse Processing, a dynamical systems approach to incremental eye movements in the visual world that suggests a framework for integrating language, vision, and action generally. Our approach assumes that impulses driven by the language and the visual (...) context impinge minutely on a dynamical landscape of attractors corresponding to the potential eye-movement behaviors of the system. We test three unique predictions of our approach in an empirical study in the VWP, and describe an implementation in an artificial neural network. We discuss the Impulse Processing framework in relation to other models of the VWP. (shrink)