We identify two aspects of the problem of maintaining perceptual stability despite an observer's eye movements. The first, visual direction constancy, is the (egocentric) stability of apparent positions of objects in the visual world relative to the perceiver. The second, visual position constancy, is the (exocentric) stability of positions of objects relative to each other. We analyze the constancy of visual direction despite saccadic eye movements.Three information sources have been proposed to enable the visual system to achieve stability: the structure (...) of the visual field, proprioceptive inflow, and a copy of neural efference or outflow to the extraocular muscles. None of these sources by itself provides adequate information to achieve visual direction constancy; present evidence indicates that all three are used.Our final question concerns how information processing operations result in a stable world. The three traditionally suggested means have been elimination, translation, or evaluation. All are rejected. From a review of the physiological and psychological evidence we conclude that no subtraction, compensation, or evaluation need take place. The problem for which these solutions were developed turns out to be a false one. We propose a “calibration” solution: correct spatiotopic positions are calculated anew for each fixation. Inflow, outflow, and retinal sources are used in this calculation: saccadic suppression of displacement bridges the errors between these sources and the actual extent of movement. (shrink)

The calibration solution to the stability of the world despite eye movements depends, according to Bridgeman et al., upon a combination of three factors which presumably all need to operate to achieve the goal of stability. Although the authors admit (sect. 4.3, para. 5) that the relative contributions of retinal and extraretinal factors will depend on the particular viewing situation, Figure 5 (sect. 4.3) makes it clear in its representation that the role of perceptual factors is relatively minor compared to (...) extraretinal ones. It is with this representation that this commentary wishes to take issue, believing that it occurs as a result of some assumptions about terminology that may be ambiguous, as well as some misconceptions about the circumstances in which there is a need for stability. (shrink)

With some help from the commentators, a few adjustments to the characterizations of A-consciousness and P-consciousness can avoid some trivial cases of one without the other. But it still seems that the case for the existence of P without A is stronger than that for A without P. If indeed there can be P without A, but not A without P, this would be a remarkable result that would need explanation.

Block's notion of P-consciousness catches too much in its net. He would do better to exclude all states that do not have a sensory component. I question what he says about my work with the “blind” monkey, Helen.

Block's cases of superblindsight, the pneumatic drill, and the Sperling experiments do not show that P-consciousness and Aconsciousness can come apart. On certain tendentious but not implausible construals of the concepts of P- and A-consciousness, they refer to the same psychological phenomenon.

Basically agreeing with Block regarding the need for a distinction between P- and A-consciousness, I characterize the problem somewhat diflerently, relating it more directly to the explanatory gap. I also speculate on the relation between the two forms of consciousness, arguing that some notion of access is essentially involved in phenomenal experience.

In Gray's conjecture, mismatches in the subicular comparator and matches have equal prominence in consciousness. In rival cognitive views novelty and difficulty especially elicit more conscious modes of cognition and higher levels of self-regulation. The mismatch between Gray's conjecture and these views is discussed.

Gray has expanded his account of schizophrenia to explain consciousness as well. His theory explains neither phenomenon adequately because he treats individual minds in isolation. The primary function of consciousness is to permit high level interactions with other conscious beings. The key symptoms of schizophrenia reflect a failure of this mechanism.

Gray takes an information-processing paradigm as his departure point, invoking a comparator as part of the system. He concludes that consciousness is to be found “in” the comparator but is unable to point to how the comparison takes place. Thus, the comparator turns out not to be an entity arising out of brain research per se, but out of the logic of the paradigm. In this way, Gray both reinvents dualism and remains trapped in the language game of his own (...) model – ending up dealing with the unknowable. (shrink)

To explore the mechanism of sensation correlations between EP component amplitude and signal detection indices were studied. The time of sensation coincided with the peak latency of those EP components that showed a correlation with both indices. The components presumably reflected information synthesis in projection cortical neurons. A mechanism providing the synthesis process is proposed.

The essay deals with the mechanism of interpretation for legal metaphorical expressions. Firstly, it points out the perspective the cognitive approach induced about legal metaphors; then it suggests that this perspective gains in plausibility when a new bilateral model of language understanding is endorsed. A possible sketch of the meaning-making procedure for legal metaphors, compatible with this new model, is then proposed, and illustrated with some examples built on concepts belonging to the Italian Civil Code. The insights the bilateral model (...) of understanding provides are compared with the practice followed by legal communities for dealing with the metaphorical expressions they coin and use. (shrink)

Usually, the B-theory of time is taken to involve the claim that time does not, in reality, pass; after all, on the B-theory, nothing really becomes present and then more and more past, times do not come into existence successively, and which facts obtain does not change. For this reason, many B-theorists have recently tried to explain away one or more aspect(s) of experience that they and their opponents take to constitute an experience of time as passing. In this paper, (...) I examine three prominent proposals of this kind and argue that, though intriguing, the proposals undermine, to some extent, the assumption that there is an element of experience that B-theorists need to take to be illusory. (shrink)

I argue that Manzotti and Pepperell’s presentation of the New Mind not only obfuscates pertinent differences between externalist views of various strengths, but also, and most problematically, conflates a distinction that cannot, without consequences, be conflated. We can talk about the contents of the mind and/or about the vehicles of those contents. But we should not conflate the two. Conflation of contents and vehicles comes with a price. In Manzotti and Pepperell’s case, it undermines claims they make about the implications (...) of the New Mind. (shrink)

In my dissertation I critically survey existing theories of time consciousness, and draw on recent work in neuroscience and philosophy to develop an original theory. My view depends on a novel account of temporal perception based on the notion of temporal qualities, which are mental properties that are instantiated whenever we detect change in the environment. When we become aware of these temporal qualities in an appropriate way, our conscious experience will feature the distinct temporal phenomenology that is associated with (...) the passing of time. The temporal qualities model of perception makes two predictions about the mechanisms of time perception; one that time perception is modality specific and the other that it can occur without awareness. My argument for this view partially depends on a number of psychophysical experiments that I designed and implemented myself and which investigate subjective time distortions caused by looming visual stimuli. These results show that the mechanisms of conscious experience of time are distinct from the mechanisms of time perception, as my theory of temporal qualities predicts. (shrink)

Quality Space Theory is a holistic model of qualitative states. On this view, individual mental qualities are defined by their locations in a space of relations, which reflects a similar space of relations among perceptible properties. This paper offers an extension of Quality Space Theory to temporal perception. Unconscious segmentation of events, the involvement of early sensory areas, and asymmetries of dominance in multi-modal perception of time are presented as evidence for the view.

In apparent motion experiments, participants are presented with what is in fact a succession of two brief stationary stimuli at two different locations, but they report an impression of movement. Philosophers have recently debated whether apparent motion provides evidence in favour of a particular account of the nature of temporal experience. I argue that the existing discussion in this area is premised on a mistaken view of the phenomenology of apparent motion and, as a result, the space of possible philosophical (...) positions has not yet been fully explored. In particular, I argue that the existence of apparent motion is compatible with an account of the nature of temporal experience that involves a version of direct realism. In doing so, I also argue against two other claims often made about apparent motion, viz. that apparent motion is the psychological phenomenon that underlies motion experience in the cinema, and that apparent motion is subjectively indistinguishable from real motion. (shrink)

This paper outlines some key issues that arise when agency and temporality are considered jointly, from the perspective of psychology, cognitive neuroscience, phenomenology, and action theory. I address the difference between time simpliciter and time as represented as it figures in phenomena like intentional binding, goal-oriented action plans, emulation systems, and ‘temporal agency’. An examination of Husserl’s account of time consciousness highlights difficulties in generalizing his account to include a substantive notion of agency, a weakness inherited by explanatory projects like (...) neurophenomenology. I conclude by sketching a project analogous to the projects in neurophenomenology, based on Thompson’s naïve action theory. (shrink)

Perceptual illusions have often served as an important tool in the study of perceptual experience. In this paper I argue that a recently discovered set of visual illusions sheds new light on the nature of time consciousness. I suggest the study of these silencing illusions as a tool kit for any philosopher interested in the experience of time and show how to better understand time consciousness by combining detailed empirical investigations with a detailed philosophical analysis. In addition, and more specifically, (...) I argue against an initially plausible range of views that assume a close match between the temporal content of visual experience and the temporal layout of experience itself. Against such a widely held structural matching thesis I argue that which temporal changes we are experiencing bears no close relation to how our experience itself is changing over time. Explanations of the silencing illusions that are compatible with the structural matching thesis fail. (shrink)

In a second there is also time enough, we might add. In his dichotomizing fervor, Bogen fails to realize that our argument is neutral with respect to the number of consciousnesses that inhabit the normal or the split-brain skull. Should there be two, for instance, we would point out that within the neural network that subserves each, no privileged locus should be postulated. (Midline location is not the issue--it was only a minor issue for Descartes, in fact.).

This is a bibliography of books and articles on consciousness in philosophy, cognitive science, and neuroscience over the last 30 years. There are three main sections, devoted to monographs, edited collections of papers, and articles. The first two of these sections are each divided into three subsections containing books in each of the main areas of research. The third section is divided into 12 subsections, with 10 subject headings for philosophical articles along with two additional subsections for articles in cognitive (...) science and neuroscience. Of course the division is somewhat arbitrary, but I hope that it makes the bibliography easier to use. This bibliography has first been compiled by Thomas Metzinger and David Chalmers to appear in print in two philosophical anthologies on conscious experience . From 1995 onwards it has been continuously updated by Thomas Metzinger, and now is freely available as a PDF-, RTF-, or HTML-file. This bibliography mainly attempts to cover the Anglo-Saxon and German debates, in a non-annotated, fully formatted way that makes it easy to "cut and paste" from the original file. To a certain degree this bibliography also contains items in other languages than English and German - all submissions in other languages are welcome. Last update of current version: July 13th, 2001. (shrink)

The law of prior entry was one of E.B. Titchener’s seven fundamental laws of attention. According to Titchener : “the object of attention comes to consciousness more quickly than the objects which we are not attending to.” Although researchers have been studying prior entry for more than a century now, progress in understanding the effect has been hindered by the many methodological confounds present in early research. As a consequence, it is unclear whether the behavioral effects reported in the majority (...) of published studies in this area should be attributed to attention, decisional response biases, and/or, in the case of exogenous spatial cuing studies of the prior-entry effect, to sensory facilitation effects instead. In this article, the literature on the prior-entry effect is reviewed, the confounds present in previous research highlighted, current consensus summarized, and some of the key questions for future research outlined. In particular, recent research has now provided compelling psychophysical and electrophysiological evidence to support the claim that attending to a sensory modality, spatial location, or stimulus feature/attribute can all give rise to a relative speeding-up of the time of arrival of attended, as compared to relatively less attended stimuli. Prior-entry effects have now been demonstrated following both the endogenous and exogenous orienting of attention, though prior-entry effects tend to be smaller in magnitude when assessed by means of participants’ performance on SJ tasks than when assessed by means of their performance on TOJ tasks. (shrink)

Drawing on the findings of neuroscience, this text proposes and defends the hypothesis that the various modalities of sensation share a generic form that the author, Austen Clark, calls feature-placing.

O'Brien & Opie's (O&O's) theory demands a view of unconscious processing that is incompatible with virtually all current PDP models of neural activity. Relative to the alternatives, the theory is closer to an AI than a parallel distributed processing (PDP) perspective, and its treatment of phenomenology is ad hoc. It raises at least one important question: Could features of network relaxation be the “switch” that turns an unconscious into a conscious network?

Evidence for motion extrapolation at motion offset is scarce. In contrast, there is abundant evidence that subjects mentally extrapolate the future trajectory of weak motion signals at motion offset. Further, pointing movements overshoot at motion offset. We believe that mental and sensorimotor extrapolation is sufficient to solve the problem of perceptual latencies. Both present the advantage of being much more flexible than motion extrapolation.

The manifest image is teeming with activity. Objects are booming and buzzing by, changing their locations and properties, vivid perceptions are replaced, and we seem to be inexorably slipping into the future. Time—or at least our experience in time— seems a very turbulent sort of thing. By contrast, time in the scientist image seems very still. The fundamental laws of physics don’t differentiate between past and future, nor do they pick out a present moment that flows. Except for a minus (...) sign in the relativistic metric, there are few differences between the temporal and spatial coordinates in natural science. We seem to have, to echo another debate, an “explanatory gap” between time as we find it in experience and as we find it in science. Reconciling these two images of the world is the principal goal of philosophy of time. (shrink)

Although information-processing theories cannot provide a full explanatory account of P-consciousness, there is less conflation and confusion in cognitive psychology than Block suspects. Some of the reasoning that Block criticises can be interpreted plausibly in the light of a folk psychological view of the relation between P-consciousness and A-consciousness.

An extended examination of Libet's works led to a comprehensive reinterpretation of his results. According to this reinterpretation, the Minimum Train Duration of electrical brain stimulation should be considered as the time needed to create a brain stimulus efficient for producing conscious sensation and not as a basis for inferring the latency for conscious sensation of peripheral origin. Latency for conscious sensation with brain stimulation may occurafterthe Minimum Train Duration. Backward masking with cortical stimuli suggests a 125-300 ms minimum value (...) for the latency for conscious sensation of threshold skin stimuli. Backward enhancement is not suitable for inferring this latency. For determining temporal relations between stimuli that correspond to subjects' reports, theendof cerebral Minimum Train Duration should be used as reference, rather than its onset. Results of coupling peripheral and cortical stimuli are explained by a latency after the cortical Minimum Train Duration, having roughly the same duration as the latency for supraliminal skin stimuli. Results of coupling peripheral stimuli and stimuli to medial lemniscus (LM) are explained by a shorter LM latency and/or a longer peripheral latency. This interpretation suggests a 230 ms minimum value for the latency for conscious sensation of somatosensory near-threshold stimuli. The backward referral hypothesis, as formulated by Libet, should not be retained. Long readiness potentials preceding spontaneous conscious or nonconscious movements suggest that both kinds of movement are nonconsciously initiated. The validity of Libet's measures of W and M moments (Libet et al., 1983a) is questionable due to problems involving latencies, training, and introspective distinction of W and M. Veto of intended actions may be initially nonconscious but dependent on conscious awareness. (shrink)

The question is, How does the brain make its mind? In Cognition, computation and consciousness [Ito et al. (Eds) (1997) Oxford & New York: Oxford University Press], a variety of noted theoreticians from the fields of cognitive psychology, computer science, and philosophy postulate answer-blueprints rather than full-blown explanatory solutions to this most nettlesome question. Coming to the problem from quite different starting points and perspectives, they nevertheless succeed in reaching consensus on the idea that the contingencies of the brain's evolution (...) have resulted in an organ that generates its mind by a complex process of information exchange among its constituents. Put in the vernacular, the brain produces its mind by having its parts, especially those most recently evolved, talk to each other. In this essay I take a critical look at proposals of several celebrated (neuro)scientists and philosophers in their specific areas of expertise. The underlying theme of brain component communication suggests the image of conversations in the cortex. From such cortical conversations arise selves (the mind/brain's I) and their stories and projects. This in turn suggests the idea that the brain is a stage where a Pirandello-like play is continually rehearsed. (shrink)

One of the interesting and occasionally controversial aspects of Dennett’s career is his direct involvement in the scientific process. This article describes some of Dennett’s participation on one particular project conducted at MIT, the building of the humanoid robot named Cog. One of the intentions of this project, not to date fully realized, was to test Dennett’s multiple drafts theory of consciousness. I describe Dennett’s involvement and impact on Cog from the perspective of a graduate student. I also describe the (...) problem of coordinating distributed intelligent systems, drawing examples from robot intelligence, human intelligence, and the Cog project itself. (shrink)

How does the brain generate our experience of being in control over our actions and their effects? Here, we argue that the perception of events as self-caused emerges from a comparison between anticipated and actual action-effects: if the representation of an event that follows an action is activated before the action, the event is experienced as caused by one’s own action, whereas in the case of a mismatch it will be attributed to an external cause rather than to the self. (...) In a subliminal priming paradigm we show that participants overestimated how much control they had over objectively uncontrollable stimuli, which appeared after free- or forced-choice actions, when a masked prime activated a representation of the stimuli immediately before each action. This prime-induced control-illusion was independent from whether primes were consciously perceived. Results indicate that the conscious experience of control is modulated by unconscious anticipations of action-effects. (shrink)

• An adequate conceptual framework is still needed to account for phenomena that (i) have a first-person, subjective-experiential or phenomenal character; (ii) are (usually) reportable and describable (in humans); and (iii) are neurobiologically realized.2 • The conscious subject plays an unavoidable epistemological role in characterizing the explanadum of consciousness through first-person descriptive reports. The experimentalist is then able to link first-person data and third-person data. Yet the generation of first-person data raises difficult epistemological issues about the relation of second-order awareness (...) or meta-awareness to first-order experience (e.g. (shrink)

The belief that conscious will is merely "an illusion created by the brain" appears to be gaining in popularity among cognitive neuroscientists. Its main adherents usually refer to the classic, but controversial 'Libet-experiments', as the empirical evidence that vindicates this illusion-claim. However, based on recent work that provides other interpretations of the Libet-experiments, we argue that the illusion-claim is not only empirically invalid, but also theoretically incoherent, as it is rooted in a category mistake; namely, the presupposition that neuronal activity (...) causes conscious will. We show that the illusion-claim is based on the behaviorist 'input-output' paradigm, and discuss the notions of 'self-organization' and 'self-steering' to provide an alternative perspective on the causal efficacy of conscious will. In the final sections, a tentative theoretical picture is sketched of conscious will as an instance of self-steered self-organization. We conclude that the subjective experience of conscious will is not a misguided one, but rather that the mechanisms supporting conscious will are considerably more complex than mainstream cognitive neuroscience currently acknowledges. (shrink)

Intentional action involves both a series of neural events in the motor areas of the brain, and also a distinctive conscious experience that ''I'' am the author of the action. This paper investigates some possible ways in which these neural and phenomenal events may be related. Recent models of motor prediction are relevant to the conscious experience of action as well as to its neural control. Such models depend critically on matching the actual consequences of a movement against its internally (...) predicted effects. However, it remains unclear whether our conscious experience of action depends on a precise matching process, or a retrospective inference that ''I'' must have been responsible for a particular event. We report an experiment in which normal subjects judged the perceived time of either intentional actions, involuntary movements, or subsequent effects (auditory tones) of these. We found that the subject's intention to produce the auditory tone produced an intentional binding between the perceived times of the subject's action and the tone. However, if the intention was interrupted by an imposed involuntary movement, followed by the identical tone, no such binding occurred. The phenomenology of intentional action requires an appropriate predictive link between intentions and effects, rather than a retrospective inference that ''I'' caused the effect. (shrink)

Scientific concepts are defined by metaphors. These metaphors determine what atten- tion is and what count as adequate explanations of the phenomenon. The authors analyze these metaphors within 3 types of attention theories: (a) --cause-- theories, in which attention is presumed to modulate information processing (e.g., attention as a spotlight; attention as a limited resource); (b) --effect-- theories, in which attention is considered to be a by-product of information processing (e.g., the competition meta- phor); and (c) hybrid theories that combine (...) cause and effect aspects (e.g., biased- competition models). The present analysis reveals the crucial role of metaphors in cognitive psychology, neuroscience, and the efforts of scientists to find a resolution to the classic problem of cause versus effect interpretations. (shrink)

If successive, brief visual images are exposed for recognition or for psychophysical ratings, various effects and phenomena of fast dynamics of conscious perception such as mutual masking, metacontrast, proactive enhancement of contrast, proactive speed-up of the latency of subjective visual experience, the Fröhlich Effect, the Tandem Effect, attentional facilitation by visuospatial precuing, and some others have been found. The theory proposed to deal with these phenomena proceeds from the assumption that two types of brain processes are necessary in order to (...) consciously recognize visual stimuli: fast, specific processes of encoding that allocate and reactivate the stimulus representation which is based on the activity of selected cortical neurons and relatively slower processes of facilitation of the activity of this specific representation that are mediated by the excitatory modulation of the EPSPs of those selected cortical neurons by the ascending input from nonspecific thalamus. Theperceptual retouchconstruct is proposed in order to characterize and analyze the interaction of and . The neurophysiological characteristics of this bifunctional system of afference help to put forward several predictions that are found to be consistent with the empirical regularities of the above-described perceptual-attentional phenomena. These data form a body of converging evidence that is consistent with the predictions of the perceptual retouch approach. (shrink)

Abstract Connectionist views in psychology and neuroscience give the impression that there is no one place in the brain into which all information funnels. If these impression are accurate, then we will have great difficulty picking out a point in neuronal or psychological time at which phenomena become conscious. If so, pointing to one place in which we are conscious of a particular event and expecting a psychophysical correlation between qualitative and neural events seems hopeless. In response to this worry, (...) I argue that ERP research can bridge the psychology and neuroscience such that we can identify when qualitative experiences occur relative to other cognitive events. I present data suggesting that accessing an early implicit priming system gives rise to a qualitatively different kind of ERP wave than does accessing a later episodic memory system. These results illustrate how it is possible to parse psychological events finely enough in (neuro?)psychological investigations in order to determine when particular psychological events occur in the head. So, if we could align consciousness with some psychological event, then we should be able to articulate when that event occurs in the processing stream (relative to other events) as long as that event can be correlated with some ERP waveform. (shrink)

Trevena and Miller provide further evidence that readiness potentials occur in the brain prior to the time that participants claim to have initiated a voluntary movement, a contention originally forwarded by Libet, Gleason, Wright, and Pearl . In their examination of this issue, though, aspects of their data lead them to question whether their measurement of the initiation of a voluntary movement was accurate. The current article addresses this concern by providing a direct analysis of biases in this task. This (...) was done by asking participants to make subjective timing decisions regarding a stimulus that could be measured objectively. Our findings suggest that their timing task was indeed biased such that participants' tend to report events as happening approximately 70 ms later than they actually happened. Implications for the original Libet et al. claims are discussed. (shrink)

When cognitive scientists apply computational theory to the problem of phenomenal consciousness, as many of them have been doing recently, there are two fundamentally distinct approaches available. Either consciousness is to be explained in terms of the nature of the representational vehicles the brain deploys; or it is to be explained in terms of the computational processes defined over these vehicles. We call versions of these two approaches _vehicle_ and _process_ theories of consciousness, respectively. However, while there may be space (...) for vehicle theories of consciousness in cognitive science, they are relatively rare. This is because of the influence exerted, on the one hand, by a large body of research which purports to show that the explicit representation of information in the brain and conscious experience are _dissociable_, and on the other, by the _classical_ computational theory of mind – the theory that takes human cognition to be a species of symbol manipulation. But two recent developments in cognitive science combine to suggest that a reappraisal of this situation is in order. First, a number of theorists have recently been highly critical of the experimental methodologies employed in the dissociation studies – so critical, in fact, it’s no longer reasonable to assume that the dissociability of conscious experience and explicit representation has been adequately demonstrated. Second, classicism, as a theory of human cognition, is no longer as dominant in cognitive science as it once was. It now has a lively competitor in the form of _connectionism; _and connectionism, unlike classicism, does have the computational resources to support a robust vehicle theory of consciousness. In this paper we develop and defend this connectionist vehicle theory of consciousness. It takes the form of the following simple empirical hypothesis: _phenomenal experience consists in the explicit_ _representation of information in neurally realized PDP networks_.. (shrink)