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)

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.

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)

To see whether the mental and the neural have common attributes that could resolve some of the traditional dichotomies, we review neuroscientific data on the visual system. The results show that neuronal and perceptual function share a parallel and hierarchical architecture which is manifest not only in the anatomy and physiology of the visual system, but also in normal perception and in the deficits caused by lesions in different parts of the system. Based on the (...) description of parallel hierarchical levels of active information processing in the visual brain, we suggest a concept of dissociable levels of perception, advocating that the phenomenal perception and recognition is realized in the functional integrity of a network of reciprocal cortico-cortical connections. The properties shared by neuronal and perceptional functions provide a basis for a neuromental monism in which both functions are attributed a causal role. (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.

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)

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.

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.

Looking at a person’s expression is a good way of telling what she feels—what emotions she has. Why is that? Is it because we see her emotion, or is it because we infer her mental state from her expression? My claim is that there is a sense in which we do see the person’s emotion. I first argue that expressions are physical events that carry information about the emotions that produce them. I then examine evidence suggesting that specific brain areas (...) and structures are involved in the process that extracts such information and makes it available in the content of visual experience. I consider only what happens in early stages of visual processing and make no claim about the role of simulation and empathy. (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.

Various techniques have attempted to localize imagery. However, early findings using single cell recordings of human receptive fields during imagery tasks have had little impact. Reports by Marg and his coworkers (1968) found no evidence for imagery in human Area 17, 18, and 19. Single cells from humans suggest later imagery-related activity in hippocampus, amygdala, entorhinal cortex, and parahippocampal gyrus.

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.

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)

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)

Evidence from many different paradigms (e.g. change blindness, inattentional blindness, transsaccadic integration) indicate that observers are often very poor at reporting changes to their visual environment. Such evidence has been used to suggest that the spatio-temporal coherence needed to represent change can only occur in the presence of focused attention. In four experiments we use modified change blindness tasks to demonstrate (a) that sensitivity to change does occur in the absence of awareness, and (b) this sensitivity does not rely (...) on the redeploy- ment of attention. We discuss these results in relation to theories of scene percep- tion, and propose a reinterpretatio n of the role of attention in representing change. (shrink)

Pioneering molecular work on chelicerate visual system development in the horseshoe crab Limulus polyphemus surprised with the possibility that this process may not depend on the deeply conserved retinal determination function of Pax6 transcription factors. Genomic, transcriptomic, and developmental studies in spiders now reveal that the arthropod Pax6 homologs eyeless and twin of eyeless act as ancestral determinants of the ocular head segment in chelicerates, which clarifies deep gene regulatory and structural homologies and recommends more unified terminologies in (...) the comparison of arthropod visual systems. Following this phylotypic stage, chelicerate visual system development differs fundamentally from other arthropods during the compartmentalization of the ocular segment in that eye and optic neuropil primordia originate independently from each other. Comparative analyses of this phase identified further gene regulatory homologies but also major differences, most notably the possibly compensatory replacement of Pax6 by Pax2 in lateral eye specification. Also see the video abstract here: https://youtu.be/Hdfr3z5kEXU. (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.

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)

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)

Short-term memory, nonattentional task effects and nonspatial extraretinal representations in the visual system are signs of cognitive penetration. All of these have been found physiologically, arguing against the cognitive impenetrability of vision as a whole. Instead, parallel subcircuits in the brain, each subserving a different competency including sensory and cognitive (and in some cases motor) aspects, may have cognitively impenetrable components.

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.

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.

Pylyshyn claims that if a system is cognitively penetrable, its function depends in a semantically coherent way to the organism's goals and beliefs. He rejects evidence of attentional modulation observed in neurons within the visual system, claiming that any modulation seen is not logically related to goals and behavior. I present some of this evidence and claim that it is connected in exactly the way Pylyshyn requires and thus it refutes his main thesis.

Optic neuropathy refers to disease of the optic nerve and can result in loss of visual acuity and/or visual field defects. Combining findings from multiple fMRI modalities can offer valuable information for characterizing and managing optic neuropathies. In this article, we review a subset of resting-state functional magnetic resonance imaging (RS-fMRI) studies of optic neuropathies. We consider glaucoma, acute optic neuritis (ON), discuss traumatic optic neuropathy (TON), and explore consistency between findings from RS and visually driven fMRI studies. (...) Consistent with visually driven studies, glaucoma studies at rest also indicated reduced activation in the visual cortex and dorsal visual stream. RS-fMRI further reported varying levels of functional connectivity in the ventral stream depending on disease severity. ON patients show alterations within the visual cortex in both fMRI techniques. Particularly, higher-than-normal RS activity is observed in the acute phase and decreases as the disease progresses. A similar pattern is observed in the visual cortex of TON-like, open globe injury (OGI), patients. Additionally, visually driven and RS-fMRI studies of ON patients show recovery of brain activity in the visual cortex. RS-fMRI suggests recovery of signals in higher-tier visual areas MT and LOC as well. Finally, RS-fMRI has not yet been applied to TON, although reviewing OGI studies suggests that it is feasible. Future RS-fMRI studies of optic neuropathies could prioritize studying the fine scale RS activity of brain areas that visually driven studies have identified. We suggest that a more systematic longitudinal comparison of optic neuropathies with advanced fMRI would provide improved diagnostic and prognostic information. (shrink)

In 2015 the first mass migration and the first geopolitical and transnational crisis of the digital age began. This brought along the awakening of a new phase in slavery trade and trafficking of human beings (THB) at the European borders. In this article I introduce an ongoing field study I began in January 2016, in collaboration with experts from Spanish and European institutions, that so far has taken me to hotspots and borders, and to the accumulation of a vast multimedia (...) archive. This led to the creation of zonaautonomamilitarizada.eu, an immersive/360°, interactive and reactive audio-visual performative system conceptually rooted in military technologies, second-order cybernetics and mass media developments. (shrink)

Frost's article advocates for universal models of reading and critiques recent models that concentrate in what has been described as Although the challenge to develop models that can account for word recognition beyond Indo-European languages is welcomed, we argue that reading models should also be constrained by general principles of visual processing and object recognition.