Many philosophers doubt that one can provide any successful explanation of sensory qualities - of how things look, feel, or seem to a perceiving subject. To provide such an explanation, one would need to explain qualitative facts in non-qualitative terms. Attempts to construct such explanations have seemed, in principle, doomed. Austen Clark examines the strategy used in psychophysics, psychometrics, and sensory neurophysiology to explain qualitative facts. He argues that this strategy could succeed: its structure is sound, and (...) it can answer the various philosophical objections lodged against it. On this basis Professor Clark presents an analysis of senosry qualities that offers the possibility of explaining at least some qualia, and he sketches how this scheme might eventually reduce to neurophysiology. If he is correct, we are not doomed to an eternity of mere acquaintance with our qualia. (shrink)

Drawing on work in psychophysics, psychometrics, and sensory neurophysiology, Clark analyzes the character and defends the integrity of psychophysical explanations of qualitative facts, arguing that the structure of such explanations is sound and potentially successful.

The measurement of sensory intensity has had a long history, attracting the attention of investigators from many disciplines including physiology, psychology, physics, mathematics, philosophy, and even chemistry. While there has been a continuing doubt by some that sensation has the properties necessary for measurement, experiments designed to obtain estimates of sensory intensity have found that a general rule applies: Equal stimulus ratios produce equal sensory ratios. Theories concerning the basis for this simple psychophysical rule are discussed, with (...) emphasis given to the physical correlate theory, which considers judgments of subjective magnitudes to be based upon estimates of physical dimensions that vary regularly with changes in degree of stimulation. For the most thoroughly investigated sensory scales, brightness and loudness, the physical correlate is considered to be distance. Our “tacit knowledge” of the sensory effects of changing distance plays an essential role in matching motor activities to environmental conditions and in ensuring accurate perceptual evaluations through brightness and loudness constancies. In psychophysical experiments, subjects apparently use this same tacit knowledge when required to estimate relative subjective magnitudes. The evidence related to the physical correlate theory is summarized, and it is concluded that, while under appropriate conditions we demonstrate considerable skill in evaluating environmental relationships, we are quite unable to estimate the neurophysiological nature or quantity of sensory response. A psychophysics devoted to studying conditions required for accuracy and conditions producing errors in the perception of environmental relationships would seem to be more valuable than one devoted to subjective magnitudes. (shrink)

Neurophysiological investigations of the past two decades have consistently demonstrated a deficit in sensory gating associated with schizophrenia. Phillips & Silverstein interpret this impairment as being consistent with cognitive coordination dysfunction. However, the physiological mechanisms that underlie sensory gating have not been shown to involve gamma-band oscillations or NMDA-receptors, both of which are critical neural elements in the cognitive coordination model.

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.

This chapter examines the relations between psychology and neuroscience. There is a strong philosophical intuition that direct study of the brain can and will constrain the development of psychological theory. When this intuition is tested against case studies from the psychology of perception and memory, it turns out that psychology has led the way toward knowledge of neurophysiology. The chapter presents an abstract argument to show that psychology can and must lead the way in neuroscientific study of mental function. (...) The opposing intuition is based on mainly weak arguments about the fundamentality or objectivity of physics or physiology in relation to psychology. The chapter argues that psychological phenomena are methodologically prior to neurophysiological concepts and descriptions, that psychology provides the functional descriptions that guide the behavioral brain sciences, that psychological concepts are not reducible, but that neurophysiological data and concepts are nonetheless evidentially and explanatorily relevant for psychology. (shrink)

Talk of sensory qualities soon runs into puzzles, both about the nature of properties and about the status of mental predicates. Clark wishes to prepare the way for an eventual reduction of qualia-talk to neurophysiology, while postponing or taking an indirect approach to some of the large philosophical questions involved. Thus, for instance, rather than wading directly into the debate about what color is, he concentrates on the problem of why a particular stimulus looks colored to a particular (...) observer. (shrink)

Theories of binding have recently come into the focus of the consciousness debate. In this review, we discuss the potential relevance of temporal binding mechanisms for sensory awareness. Specifically, we suggest that neural synchrony with a precision in the millisecond range may be crucial for conscious processing, and may be involved in arousal, perceptual integration, attentional selection and working memory. Recent evidence from both animal and human studies demonstrates that specific changes in neuronal synchrony occur during all of these (...) processes and that they are distinguished by the emergence of fast oscillations with frequencies in the gamma-range. (shrink)

This chapter examines a question at the intersection of the mind-body problem and the analysis of mental representation: the question of the direction of constraint between psychological fact and theory and neurophysiological or physical fact and theory. Does physiology constrain psychology? Are physiological facts more basic than psychological facts? Or do psychological theories, including representational analyses, guide and constrain physiology? Despite the antireductionist bent of functionalist positions, it has generally been assumed that physics or physiology are more basic than, and (...) hence contraining on, psychological fact and theory. Section 1 sketches the intuitions that would lead one to adopt such a view. The chapter then examines whether one-sided constraint has been and should be found in practice. It argues that philosophical analysis of psychological science shows that rigorous functional analyses can be carried out in advance of physiological knowledge. Indeed, in the investigation of sensory perception, ascription of psychological function leads the way in the individuation and investigation of neurophysiology. We shall look at several cases in visual perception (binocular single vision, stereopsis, and color vision), in which psychological results have provided a basis for physiological research. It is tempting to think that the psychological functions that enable physiological investigation would be Wrightian teleofunctions. It is, thus, natural to suppose that psychologists and neurophysiologists have proceeded with a conception of the purpose of a given neural structure, and have viewed neural anatomy and neural activity as the substrate for or instantiation of various properly psychological functions. For example, neuroscientists surely understand that the eye and visual system are for seeing, rather than for detecting an electric discharge in the vicinity of the retina (which sighted humans can do, via the subjective light produced by such discharges), and they guide their investigations of the eye, visual cortex, and intervening pathways accordingly. As a result, they will view rods and cones in the eye as photoreceptors, even though these structures will produce "output" (will respond with hyperpolarization) to other forms of energy. At the same time, there may be cases in which the functions that have guided research are in fact precisely determined input-output functions, whose teleofunctional status is absent or misdescribed. I will argue that in the case of trichromatic color matches, the psychological function involved is an input-output function, and that this result has implications for the description of color vision as a psychological capacity. (shrink)

BackgroundReconciling results obtained using different types of sensory measures is a challenge for autism sensory research. The present study used questionnaire, psychophysical, and neurophysiological measures to characterize autistic sensory processing in different measurement modalities.MethodsParticipants were 46 autistic and 21 typically developing 11- to 14-year-olds. Participants and their caregivers completed questionnaires regarding sensory experiences and behaviors. Auditory and somatosensory event-related potentials were recorded as part of a multisensory ERP task. Auditory detection, tactile static detection, and tactile spatial (...) resolution psychophysical thresholds were measured.ResultsSensory questionnaires strongly differentiated between autistic and typically developing individuals, while little evidence of group differences was observed in psychophysical thresholds. Crucially, the different types of measures appeared to be largely independent of one another. However, we unexpectedly found autistic participants with larger auditory Tb ERP amplitudes had reduced hearing acuity, even though all participants had hearing acuity in the non-clinical range.LimitationsThe autistic and typically developing groups were not matched on cognitive ability, although this limitation does not affect our main analyses regarding convergence of measures within autism.ConclusionOverall, based on these results, measures in different sensory modalities appear to capture distinct aspects of sensory processing in autism, with relatively limited convergence between questionnaires and laboratory-based tasks. Generally, this might reflect the reality that laboratory tasks are often carried out in controlled environments without background stimuli to compete for attention, a context which may not closely resemble the busier and more complex environments in which autistic people’s atypical sensory experiences commonly occur. Sensory questionnaires and more naturalistic laboratory tasks may be better suited to explore autistic people’s real-world sensory challenges. Further research is needed to replicate and investigate the drivers of the unexpected association we observed between auditory Tb ERP amplitudes and hearing acuity, which could represent an important confound for ERP researchers to consider in their studies. (shrink)

Evidence that led to the hypothesis of a backwards referral of conscious sensory experiences in time, and the experimental tests of its predictions, is summarized. Criticisms of the data and the conclusion by Churchland that this hypothesis is untenable are analysed and found to be based upon misconceptions and faulty evaluations of facts and theory. Subjective referral in time violates no neurophysiological principles or data and is compatible with the theory of "mental" and "physical" correspondence.

This dissertation examines representationalism about sensory phenomenology—the claim that for a sensory experience to have a particular phenomenal character is a matter of it having a particular representational content. I focus on a particular issue that is central to representationalism: whether reductive versions of the theory should be internalist or externalist. My primary goals are to demonstrate that externalist representationalism fails to provide a reductive explanation for phenomenal qualities, and to present a reductive internalist version of representationalism that (...) utilizes the empirical framework of psychophysics and neuroscience to develop a philosophical theory of content. The bulk of the project is an attempt to provide the outlines of what such an empirically-based representationalist theory would look like. In chapter 2, I argue that reductive externalist representationalism fails because it is vulnerable to the problem of bad structural correlation: the mismatch between the structure of phenomenal qualities and the structure of physical properties “tracked” by our sensory systems with which phenomenal qualities are identified. In chapter 3, I develop the outlines of a reductive internalist version of representationalism that characterizes phenomenal qualities as modes of presentation of sensory representations that can be reductively characterized in terms of a location in a psychophysically-defined quality space, which can in turn be given a neurophysiological interpretation. In addition, I argue that the neural mechanisms responsible for the representation of spatial locations and visual objects serve a referential role in sensory psychosemantics that grounds the intentionality of sensory states. In chapter 5 I provide a detailed account of the representation of spatial locations in sensory experience, and in chapter 6 I examine the “binding problem”, demonstrating how object-based sensory representations function to demonstratively pick out sensory individuals without explicitly representing any of their features. I describe the resulting view as methodological representationalism: an attempt to demonstrate how a particular philosophical theory of sensory phenomenology can be integrated into the empirical framework of cognitive science, and thereby provide an explanatory psychosemantic framework for sensory phenomenology that is valuable to both philosophers and cognitive scientists. (shrink)

In their recent article, Kirsch and Hyland questioned the relation between psychological and associated neurophysiological phenomena in the introduction of complementarity into psychology. Mishkin's work on the neurophysiological basis of memory and perception provides an example of the extension of complementarity that I have proposed and that can serve as the basis for empirical testing of this extension. Mishkin's thesis that memory storage occurs at sensory stations in the cortex allows for the resolution of a fundamental problem in cognitive (...) psychology, namely the reciprocal dependence of perception and memory. Also, Mishkin's thesis allows that psychological phenomena do not depend on an objective world for their existence. (shrink)

Here, I outline the idea of a unified hypothesis of sensory perception, developed from the theoretical vibrational mechanism of olfaction, which can be applied across all sensory modalities. I propose that all sensory perception is based upon the detection of mechanical forces at a cellular level, and the subsequent mechanotransduction of the signal via the nervous system. Thus, I argue that the sensory modalities found in the animal kingdom may all be viewed as being mechanoreceptory, rather (...) than being discrete neurophysiological systems which evolved independently of each other. I go on to argue that this idea could potentially explain language evolution, with birdsong being an example of a more simple form of non-Saussurean language that employs ‘frequency-mimicking’ to produce a vocal signal which describes acoustic, chemical and electromagnetic vibrational frequencies detected within in the environment. I also give examples of how this hypothesis could potentially explain phenomena such as vocal mimicry in animals, as well as the human perception of musicality and the occurrence of synaesthesia; a condition found in humans, where the stimulation of one sensory modality results in the stimulation of another. For example, auditory stimuli are detected and are heard as an acoustic signal, as well as being perceived as colour by the visual system. (shrink)

What we perceive is the product of an intrinsic process and not part of external physical reality. This notion is consistent with the philosophical position of transcendental idealism but also agrees with physiological findings on the thalamocortical system. -Frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in thalamocortical networks, thereby transiently forming assemblies of coherent oscillations under constraints of sensory input and prefrontal attentional mechanisms. Perception and conscious experience may be (...) based on such assemblies and sensory input to thalamic nuclei plays merely a constraining role in their formation. In schizophrenia, the ability of sensory input to modulate self-organisation of thalamocortical activity may be generally reduced. If during arousal thalamocortical self-organisation is underconstrained by sensory input, then attentional mechanisms alone may determine the content of perception and hallucinations may arise. (shrink)

Researchers in post-war industrial laboratories such as Bell Labs and the Smith-Kettlewell Institute pioneered solutions to compensate for sensory loss through so-called sensory substitution systems, premised on an assumption of cortical and sensory plasticity. The article tracks early discussions of plasticity in psychology literature from William James, acknowledged by Wiener, but explicitly developed by Bach-y-Rita and his collaborators. After discussing the conceptual foundations of the principles of sensory substitution, two examples are discussed. First, ‘Project Felix’ was (...) an experiment in vibrotactile communication by means of ‘hearing gloves’ for the deaf at Norbert Wiener’s laboratory at Massachusetts Institute of Technology, demonstrated to Helen Keller in 1950. Second, the tactile-visual sensory substitution system for the blind pioneered by Paul Bach-y-Rita from 1968 onwards. Cumulatively, this article underlines the crucial yet occluded history of research on sensory impairments in the discovery of underlying neurophysiological processes of plasticity and the emergent discourse of neuroplastic subjectivity. (shrink)

In a previous paper it was suggested that specific concepts are needed in the psychological sciences and the basic mental triad was described as a useful tool to further our understanding of mentation. It was stated that the sensori-motor reflex principle cannot describe and explain mental phenomena, because the reflex is basically a mechanistic occurrence, while mental phenomena differ in essence from mechanisms. Since conditioned reflexes can be conceived as sensori-motor reflexes with another, non-mechanistic factor superimposed, similarities and contrasts between (...) reflexes and conditioned reflexes were taken as the material from which one can develop new thoughts about mentation. Reflex shutting of the eyelid, caused by direct contact between cornea and a small, invisible foreign body was compared with and contrasted to shutting the eye before a large, visible object thrusting toward the eye. It was shown that reflexes occur in response to a stimulus after the stimulus has been applied, while conditioned reflexes seem to anticipate the stimulus. This was taken as evidence that conditioned reflexes have a protensive character, have a relationship to the future, which sensori-motor reflexes lack. This difference in time relationship was developed into the statement that the difference between mechanisms and mental phenomena lies in their different relationship to the future. The need for specific concepts to describe mental phenomena stems from the inability of the reflex principle to deal with the protensive tendency of mental phenomena and to fill this need the concept of the basic mental triad was offered. This principle consists of three interdependent, interwoven phases: the triad connects with the past through condensation of some of the subject's past experience into a vaguely formed conglomerate; it connects with the future by projecting the condensed past into the future; the central phase of the triad is the act within the present instant, where a synthesis of past, present and future is accomplished. (shrink)

Pain is an important focus for consciousness research because it is an avenue for exploring somatic awareness, emotion, and the genesis of subjectivity. In principle, pain is awareness of tissue trauma, but pain can occur in the absence of identifiable injury, and sometimes substantive tissue injury produces no pain. The purpose of this paper is to help bridge pain research and consciousness studies. It reviews the basic sensory neurophysiology associated with tissue injury, including transduction, transmission, modulation, and central (...) representation. In addition, it highlights the central mechanisms for the emotional aspects of pain, demonstrating the physiological link between tissue trauma and mechanisms of emotional arousal. Finally, we discuss several current issues in the field of pain research that bear on central issues in consciousness studies, such as sickness and sense of self. (shrink)

Pain is an important focus for consciousness research because it is an avenue for exploring somatic awareness, emotion, and the genesis of subjectivity. In principle, pain is awareness of tissue trauma, but pain can occur in the absence of identifiable injury, and sometimes substantive tissue injury produces no pain. The purpose of this paper is to help bridge pain research and consciousness studies. It reviews the basic sensory neurophysiology associated with tissue injury, including transduction, transmission, modulation, and central (...) representation. In addition, it highlights the central mechanisms for the emotional aspects of pain, demonstrating the physiological link between tissue trauma and mechanisms of emotional arousal. Finally, we discuss several current issues in the field of pain research that bear on central issues in consciousness studies, such as sickness and sense of self. (shrink)

In this target article we question the assumption that perception is divided into separate domains of vision, hearing, touch, taste, and smell. We review implications of this assumption for theories of perception and for our understanding of ambient energy arrays (e.g., the optic and acoustic arrays) that are available to perceptual systems. We analyze three hypotheses about relations between ambient arrays and physical reality: (1) that there is an ambiguous relation between ambient energy arrays and physical reality, (2) that there (...) is a unique relation between individual energy arrays and physical reality, and (3) that there is a redundant but unambiguous relation, within or across arrays, between energy arrays and physical reality. This is followed by a review of the physics of motion, focusing on the existence and status of referents for physical motion. Our review indicates that it is not possible, in principle, for there to be a unique relation between physical motion and the structure of individual energy arrays. We argue that physical motion relative to different referents is specified only in the global array, which consists of higher-order relations across different forms of energy. The existence of specificity in the global array is consistent with the idea of direct perception, and so poses a challenge to traditional, inference-based theories of perception and cognition. However, it also presents a challenge to much of the ecological approach to perception and action, which has accepted the assumption of separate senses. (shrink)

Different explanations of color vision favor different philosophical positions: Computational vision is more compatible with objectivism (the color is in the object), psychophysics and neurophysiology with subjectivism (the color is in the head). Comparative research suggests that an explanation of color must be both experientialist (unlike objectivism) and ecological (unlike subjectivism). Computational vision's emphasis on optimally prespecified features of the environment (i.e., distal properties, independent of the sensory-motor capacities of the animal) is unsatisfactory. Conceiving of visual perception instead (...) as the visual guidance of activity in an environment that is determined largely by that very activity suggests new directions for research. (shrink)

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of (...) acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The out- side world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the gov- erning laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Sev- eral lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual “filling in,” visual stability despite eye movements, change blindness, sensory substitution, and color perception. (shrink)

Descartes held the following view of declarative memory: to remember is to reconstruct an idea that you intellectually recognize as a reconstruction. Descartes countenanced two overarching varieties of declarative memory. To have an intellectual memory is to intellectually reconstruct a universal idea that you recognize as a reconstruction, and to have a sensory memory is to neurophysiologically reconstruct a particular idea that you recognize as a reconstruction. Sensory remembering is thus a capacity of neither ghosts nor machines, but (...) only of human beings qua mind-body unions. This interpretation unifies Descartes’s various remarks (and conspicuous silences) about remembering, from the 1628 Rules for the Direction of the Mind through the suppressed-in-1633 Treatise of Man to the 1649 Passions of the Soul. It also rebuts a prevailing thesis in the current secondary literature—that Cartesian critters can remember—while incorporating the textual evidence for that thesis—Descartes’s detailed descriptions of the corporeal mechanisms that construct sensory memories. (shrink)

An historical review of the concepts of self-consciousness is presented, highlighting the important role of the body (particularly, body perception but also body action) and the social other in the construction of self-consciousness. More precisely, body perception, especially intermodal sensory perception including kinesthetic perception, is involved in the construction of a sense of self allowing self-nonself differentiation. Furthermore, the social other, through very early social and emotional interactions, provides meaning to the infant’s perception and contributes to the development of (...) his/her symbolization capacities. This is a necessary condition for body image representation and awareness of a permanent self in a time-space continuum (invariant over time and space). Self-image recognition impairments in the mirror are also discussed regarding a comprehensive developmental theory of self-consciousness. Then, a neuropsychological and neurophysiological approach to self-consciousness reviews the role of complex brain activation/integration pathways and the mirror neuron system in self-consciousness. Finally, this article offers new perspectives on self-consciousness evaluation using the mirror as an experimental paradigm to study self- and other- image and body recognition. (shrink)

Sensory feedback, which can be presented in different modalities - single and combined, aids task performance in human-robot interaction (HRI). However, combining feedback modalities does not always lead to optimal performance. Indeed, it is not known how feedback modalities affect operator performance under stress. Furthermore, there is limited information on how feedback affects neural processes differently for males and females and under stress. This is a critical gap in the literature, particularly in the domain of surgical robotics, where surgeons (...) are under challenging socio-technical environments that burden them physiologically. In the present study, we posited operator performance as the summation of task performance and neurophysiological cost of maintaining that performance. In a within-subject design, we used functional near-infrared spectroscopy (fNIRS) to assess cerebral activations of 12 participants who underwent a 3D manipulation task within a virtual environment with concurrent feedback (visual and visual + haptic) in the presence and absence of a cognitive stressor. Cognitive stress was induced with the serial-7 subtraction test. We found that while task performance was higher with visual than visual + haptic feedback, it degraded under stress. The two feedback modalities were found to be associated with varying neural activities and neural efficiencies, and these were stress- and gender-dependent. Our findings engender further investigation into effectiveness of feedback modalities on males and females under stressful conditions in HRI. (shrink)

In sensory neuroscience, the neural and perceptual levels of investigation are commonly related through a reductive research strategy based in psycho-neural isomorphisms. Davida Teller’s “linking propositions” are a particularly vivid illustration of this epistemology in the context of vision science. For Teller, linking propositions guide the core epistemological practices of vision science by expressing the criteria for acceptable explanations of perceptual phenomena by neural processes and by articulating heuristics for discovering neural properties on grounds of perceptual ones, and vice (...) versa. Furthermore, linking propositions create a uniform discourse in which ontological identity statements can be formulated on the basis of structural terms applicable to both the neurophysiological and perceptual domains.I argue that the epistemic practices of current color vision science are better understood through Machamer-style mechanisms than isomorphism-based linking propositions. For Machamer, activity types of mechanisms are central for both explanation and the discovery of entities and their properties. The activity type of color cancellation is fundamental to the opponent process paradigm of color vision precisely in this manner. The descriptive inadequacy of linking propositions for clarifying vision scientific research is particularly damaging because activity types have a unifying role for the structural facts of color perception. As a form of local reductionism, Teller’s proffered epistemology aims to create a uniform domain for neuroscience and perceptual psychology but on the basis of a non-unified, disparate set of structural identity statements. By bringing attention to the unifying role of activity types, Machamer mechanisms allow also for critical epistemological explorations of ontological reductions on grounds of the fit between activity types of higher-level and lower-level sciences. They offer a Machamer-ontological-critical or MOCing framework, for short, against local reductionism. (shrink)

Neuroplasticity, the capacity of the brain to induce changes in response to environmental stimuli, entails a continuous rearrangement of the neural network through a complex interaction between genetics and environment. Within this process, the plastic brain uses its internal representations to predict future conditions and proactively proceed to actions. It can be said that plasticity demands a rethinking of the concept of determinism as the process of coming-to-be is directly related to modifications produced by experience. Pure determinism and complete randomness (...) are the two ends of a spectrum of positions relevant to the debate of the existence of free will. However, none conceptually supports free decision-making. How brain activity and the conscious experience of volition are related to one another has been a matter of significant research, with a plethora of findings indicating that early brain signals precede the self-reported time of the decision to act. The meaning of these findings, however, has been debated at both a theoretical and empirical level and the controversy is still ongoing. Consciousness is intertwined with free will along the dimension of time as it would otherwise be purposeless, taking place right at the next moment. Electrical activity of the brain is a measure of neurophysiological function and contributes to the understanding of processes that underlie high-order cognitive functions. A multidisciplinary approach in the study of free will could be designed in a way that philosophical concepts are connected to neural correlates by psychologically functionalizing them in terms of cognitive abilities. Such abilities are at the margins of conscious and nonconscious sensory information and are closely linked to brain processes of executive functions like attentional control and working memory. (shrink)

Evidence from neurophysiological and psychological studies is coming together to shed light on how we represent and recognize objects. This review describes evidence supporting two major hypotheses: the first is that objects are represented in a mosaic-like form in which objects are encoded by combinations of complex, reusable features, rather than two-dimensional templates, or three-dimensional models. The second hypothesis is that transform-invariant representations of objects are learnt through experience, and that this learning is affected by the temporal sequence in which (...) different views of the objects are seen, as well as by their physical appearance. (shrink)

Neurophysiological studies in humans employing magneto- and electro- encephalography increasingly suggest that oscillatory rhythmic activity of the brain may be a core mechanism for binding sensory information across space, time, and object features to generate a unified perceptual representation. To distinguish whether oscillatory activity is causally related to binding processes or whether, on the contrary, it is a mere epiphenomenon, one possibility is to employ neuromodulatory techniques such as transcranial alternating current stimulation. tACS has seen a rising interest due (...) to its ability to modulate brain oscillations in a frequency-dependent manner. In the present review, we critically summarize current tACS evidence for a causal role of oscillatory activity in spatial, temporal, and feature binding in the context of visual perception. For temporal binding, the emerging picture supports a causal link with the power and the frequency of occipital alpha rhythms ; however, there is no consistent evidence on the causal role of the phase of occipital tACS. For feature binding, the only study available showed a modulation by occipital alpha tACS. The majority of studies that successfully modulated oscillatory activity and behavioral performance in spatial binding targeted parietal areas, with the main rhythms causally linked being the theta and beta frequency bands. On the other hand, spatio-temporal binding has been directly modulated by parieto-occipital gamma and alpha tACS, suggesting a potential role of cross-frequency coupling when binding across space and time. Nonetheless, negative or partial results have also been observed, suggesting methodological limitations that should be addressed in future research. Overall, the emerging picture seems to support a causal role of brain oscillations in binding processes and, consequently, a certain degree of plasticity for shaping binding mechanisms in visual perception, which, if proved to have long lasting effects, can find applications in different clinical populations. (shrink)

From the neurophysiological perspective, thinking in dreaming and the quality of dream thought have been considered hallucinatory, bizarre, illogical, improbable, or even impossible. This empirical phenomenological research concentrates on testing whether dream thought can be defined as rational in the sense of an intervening mental process between sensory perception and the creation of meaning, leading to a conclusion or to taking action. From 10 individual dream journals of male participants aged 22–59 years and female participants aged 25–49 years, we (...) delimited four dreams per journal and randomly selected five thought units from each dream for scoring. The units provided a base for testing a hypothesis that the thought processes of dream construction are rational. The results support the hypothesis and demonstrate that eight fundamental rational thought processes can be applied to the dreaming process. (shrink)

C. L. Hardin has argued that the colour opponency of the vision system leads to chromatic subjectivism: chromatic sensory states reduce to neurophysiological states. Much of the force of Hardin's argument derives from a critique of chromatic objectivism. On this view chromatic sensory states are held to reduce to an external property. While I agree with Hardin's critique of objectivism it is far from clear that the problems which beset objectivism do not apply to the subjectivist position as (...) well. I develop a critique of subjectivism that parallels Hardin's antiobjectivist argument. (shrink)

Western science claims to provide unique, objective information about the world. This is supported by the observation that peoples across cultures will agree upon a common description of the physical world. Further, the use of scientific instruments and mathematics is claimed to enable the objectification of science. In this work, carried out by reviewing the scientific literature, the above claims are disputed systematically by evaluating the definition of physical reality and the scientific method, showing that empiricism relies ultimately upon the (...) human senses for the evaluation of scientific theories and that measuring instruments cannot replace the human sensory system. Nativist and constructivist theories of human sensory development are reviewed, and it is shown that nativist claims of core conceptual knowledge cannot be supported by the findings in the literature, which shows that perception does not simply arise from a process of maturation. Instead, sensory function requires a long process of learning through interactions with the environment. To more rigorously define physical reality and systematically evaluate the stability of perception, and thus the basis of empiricism, the development of the method of dimension analysis is reviewed. It is shown that this methodology, relied upon for the mathematical analysis of physical quantities, is itself based upon empiricism, and that all of physical reality can be described in terms of the three fundamental dimensions of mass, length and time. Hereafter the sensory modalities that inform us about these three dimensions are systematically evaluated. The following careful analysis of neuronal plasticity in these modalities shows that all the relevant senses acquire from the environment the capacity to apprehend physical reality. It is concluded that physical reality is acquired rather than given innately, and leads to the position that science cannot provide unique results. Rather, those it can provide are sufficient for a particular environmental setting. (shrink)

What is it like to dream? On an orthodox view, dreams involve misleading sensations and false beliefs. I argue, on philosophical, psychological, and neurophysiological grounds, that orthodoxy about dreaming should be rejected in favor of an imagination model of dreaming. I am thus in partial agreement with Colin McGinn, who has argued that we do not have misleading sensory experiences while dreaming, and partially in agreement with Ernest Sosa, who has argued that we do not form false beliefs while (...) dreaming. Rather, on my view, dreams involve mental imagery and propositional imagination. I defend the imagination model of dreaming from objections. (shrink)

Representation and content in some (actual) theories of perception -- Representation in perception and cognition : task analysis, psychological functions, and rule instantiation -- Perception as unconscious inference -- Representation and constraints : the inverse problem and the structure of visual space -- On perceptual constancy -- Getting objects for free (or not) : the philosophy and psychology of object perception -- Color perception and neural encoding : does metameric matching entail a loss of information? -- Objectivity and subjectivity revisited (...) : color as a psychobiological property -- Sense data and the mind body problem -- The reality of qualia -- The sensory core and the medieval foundations of early modern perceptual theory -- Postscript (2008) on Ibn al-Haytham's (Alhacen's) theory of vision -- Attention in early scientific psychology -- Psychology, philosophy, and cognitive science : reflections on the history and philosophy of experimental psychology -- What can the mind tell us about the brain? : psychology, neurophysiology, and constraint -- Introspective evidence in psychology. (shrink)

The source of endless speculation and public curiosity, our scientific quest for the origins of human consciousness has expanded along with the technical capabilities of science itself and remains one of the key topics able to fire public as much as academic interest. Yet many problematic issues, identified in this important new book, remain unresolved. Focusing on a series of methodological difficulties swirling around consciousness research, the contributors to this volume suggest that ‘consciousness’ is, in fact, not a wholly viable (...) scientific concept. Supporting this ‘eliminativist‘ stance are assessments of the current theories and methods of consciousness science in their own terms, as well as applications of good scientific practice criteria from the philosophy of science. For example, the work identifies the central problem of the misuse of qualitative difference and dissociation paradigms, often deployed to identify measures of consciousness. It also examines the difficulties that attend the wide range of experimental protocols used to operationalise consciousness—and the implications this has on the findings of integrative approaches across behavioural and neurophysiological research. The work also explores the significant mismatch between the common intuitions about the content of consciousness, that motivate much of the current science, and the actual properties of the neural processes underlying sensory and cognitive phenomena. Even as it makes the negative eliminativist case, the strong empirical grounding in this volume also allows positive characterisations to be made about the products of the current science of consciousness, facilitating a re-identification of target phenomena and valid research questions for the mind sciences.​. (shrink)

In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis—the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive (...) activation model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that contemporary versions of models based on the idea of interactive activation continue to provide a basis for efforts to achieve a fuller understanding of the process of perception. (shrink)

Phenomenal consciousness or the subjective experience of feeling sensory stimuli is fundamental to human existence. Because of the ubiquity of their subjective experiences, humans seem to readily accept the anthropomorphic extension of these mental states to other animals. Humans will typically extrapolate feelings of pain to animals if they respond physiologically and behaviourally to noxious stimuli. The alternative view that fish instead respond to noxious stimuli reflexly and with a limited behavioural repertoire is defended within the context of our (...) current understanding of the neuroanatomy and neurophysiology of mental states. Consequently, a set of fundamental properties of neural tissue necessary for feeling pain or experiencing affective states in vertebrates is proposed. While mammals and birds possess the prerequisite neural architecture for phenomenal consciousness, it is concluded that fish lack these essential characteristics and hence do not feel pain. (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)

C. L. Hardin has argued that the colour opponency of the vision system leads to chromatic subjectivism: chromatic sensory states reduce to neurophysiological states. Much of the force of Hardin's argument derives from a critique of chromatic objectivism. On this view chromatic sensory states are held to reduce to an external property. While I agree with Hardin's critique of objectivism it is far from clear that the problems which beset objectivism do not apply to the subjectivist position as (...) well. I develop a critique of subjectivism that parallels Hardin's anti-objectivist argument. (shrink)

This chapter addresses the notion of embodied simulation (ES), trying to show that a new understanding of intersubjectivity can benefit from a bottom‐up study and characterization of the nonpropositional and non meta‐representational aspects of social cognition. The chapter introduces some recent developments of ES in relation to language, proposing that ES instantiates a form of paradigmatic knowledge. For decades the main goal of the neurophysiological investigation of the cortical motor system was uniquely focused on the study of elementary physical features (...) of movement such as force, direction, and amplitude. A further element of novelty about the cognitive properties of the cortical motor system concerns its role in perception, since one can now know that many motor neurons are endowed with sensory properties. Mirror neurons (MNs) boosted a renewed interest in simulation theories and also suggested an embodied approach to simulation. (shrink)

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

The author presents a biogenetic structural theory of the body image in human beings. The theory accounts for both the universal principles and the variance in body image cross‐culturally. All humans develop a neurocognitive model of their body which combines information about the body obtained via both the internal and external sensory systems. Their experience of themselves is mediated in part by this model. The initial model of the body is "hard‐wired" and already present and active in the cognitively (...) and perceptually competent pre‐ and perinatal human being, and develops as a consequence of both genetically imposed and socioculturally influenced processes of growth. The role of behavior in this process is shown to be the control of perception such that the body image experienced in perception approximates that anticipated by the cognized self. The theory accounts for the use of the body‐assymbol and the distortion of the body image for communicative purposes. The neurophysiology of imagery is reviewed and suggestions are made for possible clinical methods that might be used to effect therapeutic changes in pathological body imagery. (shrink)

A growing body of evidence in cognitive psychology and neuroscience suggests a deep interconnection between sensory-motor and language systems in the brain. Based on recent neurophysiological findings on the anatomo-functional organization of the fronto-parietal network, we present a computational model showing that language processing may have reused or co-developed organizing principles, functionality, and learning mechanisms typical of premotor circuit. The proposed model combines principles of Hebbian topological self-organization and prediction learning. Trained on sequences of either motor or linguistic units, (...) the network develops independent neuronal chains, formed by dedicated nodes encoding only context-specific stimuli. Moreover, neurons responding to the same stimulus or class of stimuli tend to cluster together to form topologically connected areas similar to those observed in the brain cortex. Simulations support a unitary explanatory framework reconciling neurophysiological motor data with established behavioral evidence on lexical acquisition, access, and recall. (shrink)

There is a long-lasting quest of demarcating a minimally representational behavior. Based on neurophysiologically-informed behavioral studies, we argue in detail that one of the simplest cases of organismic behavior based on low-resolution spatial vision–the visually-guided obstacle avoidance in the cubozoan medusaTripedalia cystophora–implies already a minimal form of representation. We further argue that the characteristics and properties of this form of constancy-employing structural representation distinguish it substantially from putative representational states associated with mere sensory indicators, and we reply to some (...) possible objections from the liberal representationalists camp by defending and qualitatively demarcating the minimal nature of our case. Finally, we briefly discuss the implications of our thesis within a naturalistic framework. (shrink)

The comorbidity of chronic pain and opioid addiction is a serious problem that has been growing with the practice of prescribing opioids for chronic pain. Neuroimaging research has shown that chronic pain and opioid dependence both affect brain structure and function, but this is the first study to evaluate the neurophysiological alterations in patients with comorbid chronic pain and addiction. Eighteen participants with chronic low back pain and opioid addiction were compared with eighteen age- and sex-matched healthy individuals in a (...) pain-induction fMRI task. Unified structural equation modeling (SEM) with Lagrange multiplier (LM) testing yielded a network model of pain processing for patient and control groups based on 19 a priori defined regions. Tests of differences between groups on specific regression parameters were determined on a path-by-path basis using z-tests corrected for the number of comparisons. Patients with the chronic pain and addiction comorbidity had increased connection strengths; many of these connections were interhemispheric and spanned regions involved in sensory, affective, and cognitive processes. The affected regions included those that are commonly altered in chronic pain or addiction alone, indicating that this comorbidity manifests with neurological symptoms of both disorders. Understanding the neural mechanisms involved in the comorbidity is crucial to finding a comprehensive treatment, rather than treating the symptoms individually. (shrink)

In this paper I examine the meaning of physical touch as it occurs in the nurse–patient interaction. There are two aspects of the nurse–patient relationship that are found in most nurse–patient interactions which together have profound implications for nurses as practitioners and as individual human persons. The first is the clinical intimacy of the nurse–patient relationship where nurses touch, rub, smooth, clean, dress and otherwise physically interact with patients. The other is the existential crisis, the possibility of loss, suffering and (...) death that lurks at the horizon of most, if not all, healthcare encounters. Edmund Husserl, Merleau‐Ponty and more recently Robert Sokolowski argue that tactile sensations and resultant perceptions are fundamental to all sensory perception. Further, they argue that tactile sensation is fundamental for the ongoing constitution of ‘my’ self as a person and for the development and exercise of human intersubjectivity. If tactile interaction is crucial to the development of our very selves as persons and a significant aspect of our interaction with patients includes direct or observed tactile sensations and if further these sensations occur around the context of existential crises for our patients, then nurse's very selves as persons are being challenged by these interactions. Here, then I examine the philosophical argument for the role of tactile sensations in our human development and briefly look at contemporary neurophysiologic research that supports this philosophical account. I then suggest ways such physical intimacy can lead to a strengthening or weakening of the person of the nurse and the nursing interaction and end with some thoughts about ways to support nurses in these activities. (shrink)

Kammerer and Frankish (this issue) suggest we evaluate introspection of mental states to examine consciousness, but in cephalopods we can only judge internal actions by behaviour output. We can look for mental states — perceptions, beliefs, and intentions — where the tight input–action linkage that is true for reflexes, instincts, and well-learned actions is discontinuous. Here the animal is internally evaluating the sensory input from previous information and making a decision before acting. Perceptions: the octopus motion parallax head bob (...) and wound tending. Beliefs: the cuttlefish delay of gratification. Intentions: use of previous information for future strategies in octopus win-switch foraging and carrying a coconut for future shelter. Intentions are also used in skin displays, their widespread directional lateralization, the octopus 'passing cloud' to startle an immobile prey, the cuttlefish eyespot dot production to repel only visual predators, and the cuttlefish males' deceptive use of the female skin display. These examples allow us to assume in what situations introspection might be used but tell us little about the process of these actions. However, the quantitative variation, laterality, and combination of different displays suggest that cephalopod sexual skin displays are a special case of linkage of internal evaluation to external output that needs further behavioural and neurophysiological assessment. (shrink)