A familiar and enduring controversy surrounds the question of whether our phenomenal experience “overflows” availability to cognition: do we consciously see more than we can remember and report? Both sides to this debate have long sought to move beyond naïve appeals to introspection by providing empirical evidence for or against overflow. Recently, two notable studies—Bronfman, Brezis, Jacobson, and Usher and Vandenbroucke, Sligte, Fahrenfort, Ambroziak, and Lamme —have purported to provide compelling evidence in favor of overflow. Here I explain why the (...) data from both studies are wholly consistent with a “no overflow” interpretation. Importantly, when framed purely in representational or informational terms, this “no overflow” interpretation agrees with the interpretations respectively offered by both Bronfman et al. and Vandenbroucke et al.. The difference only emerges when additional assumptions are made concerning which representations correspond to elements in consc.. (shrink)

Dienes and Seth (2010) conclude that confidence ratings and post-decision wagering are two comparable and recommendable measures of conscious experience. In a recently submitted paper, we have however found that both methods are problematic and seem less suited to measure consciousness than a direct introspective measure. Here, we discuss the methodology and conclusions put forward by Dienes and Seth, and why we think the two experiments end up with so different recommendations.

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

Methodological problems of how awareness during learning should be measured have been extensively discussed and investigated in cognitive psychology. This review considers; 1)whether amnesics can perform implicit learning tasks at a similar level to normal controls, 2) whether differences in instructional orientations create dissociations in performance in tests of implicit and explicit knowledge, and 3) whether participants can retrospectively verbalise the learning outcomes. The paper concludes that; amnesics’ implicit learning abilities differ from the normal controls, instructions on implicit learning do (...) not guarantee the occurrence of implicit learning, and objective and subjective awareness measures used in the literature face inherent problems and so the awareness controversy remains unsettled. (shrink)

Studying consciousness requires contrasting conscious and unconscious perception. While many studies have reported unconscious perceptual effects, recent work has questioned whether such effects are genuinely unconscious, or whether they are due to weak conscious perception. Some philosophers and psychologists have reacted by denying that there is such a thing as unconscious perception, or by holding that unconscious perception has been previously overestimated. This article has two parts. In the first part, I argue that the most significant attack on unconscious perception (...) commits the criterion content fallacy: the fallacy of interpreting evidence that observers were conscious of something as evidence that they were conscious of the task-relevant features of the stimuli. In the second part, I contend that the criterion content fallacy is prevalent in consciousness research. For this reason, I hold that if unconscious perception exists, scientists studying consciousness could routinely underestimate it. I conclude with methodological recommendations for moving the debate forward. (shrink)

Local theories of consciousness state that one is conscious of a feature if it is adequately represented and processed in sensory brain areas, given some background conditions. We challenge the core prediction of local theories based on long-lasting postdictive effects demonstrating that features can be represented for hundreds of milliseconds in perceptual areas without being consciously perceived. Unlike previous empirical data aimed against local theories, localists cannot explain these effects away by conjecturing that subjects are phenomenally conscious of features that (...) they cannot report. We also discuss alternative explanations that localists could offer. (shrink)

What distinguishes conscious information processing from other kinds of information processing is its phenomenal aspect (PAC), the-what-it-is-like for an agent to experience something. The PAC supplies the agent with a sense of self, and informs the agent on how its self is affected by the agent’s own operations. The PAC originates from the activity that attention performs to detect the state of what I define “the self” (S). S is centered and develops on a hierarchy of innate and acquired values, (...) and is primarily expressed via the central and peripheral nervous systems; it maps the agent’s body and cognitive capacities, and its interactions with the environment. The detection of the state of S by attention modulates the energy level of the organ of attention (OA), i.e., the neural substrate that underpins attention. This modulation generates the PAC. The PAC can be qualified according to five dimensions: qualitative, quantitative, hedonic, temporal and spatial. Each dimension can be traced back to a specific feature of the modulation of the energy level of the OA. (shrink)

The most widely endorsed philosophical and scientific theories of consciousness assume that it contributes a single functional capacity to an organism’s information processing toolkit. However, conscious processes are a heterogeneous class of psychological phenomena supported by a variety of neurobiological mechanisms. This suggests a plurality of functional contributions of consciousness (FCCs), in the sense that conscious experience facilitates different functional capacities in different psychological domains. In this paper, I first develop a general methodological framework for isolating the psychological functions that (...) are associated with conscious experience. I then use this to show that the leading accounts—Global Workspace Theories, Higher Order Thought Theory and Information Integration Theory—all fail to acknowledge this functional pluralism, which limits their applicability as theories of consciousness. (shrink)

This study investigated the relationship between dream lucidity, i.e., a dreamer’s insight to the ongoing dream, and attention by considering lucidity as a trait. We examined the ways in which lucidity correlates with the orienting, alerting, and conflict components of the attentional network. A total of 77 participants rated the lucidity of their dreams over 7 consecutive days with the LuCiD scale and then completed the attentional network task. A negative correlation between trait lucidity and the conflict score of the (...) ANT was found for 49 participants whose responses were faster when an alerting signal was presented. This result suggested that, with a prerequisite that the presence of cues facilitates subsequent information processing, the greater a person’s trait lucidity, the more efficiently he or she is capable of resolving conflicts. (shrink)

Cerebral energy supply is insufficient to support continuous neuronal processing of the plethora of time-constant objects that we are aware of. As a result, the brain is forced to limit processing resources to cases of change. The neuronally generated world is thus temporally discontinuous. This parallels the fact that, in all relevant microscopic fundamental equations of nature, temporal change plays a dominant role. When a scientist calculates a “solution” to such an equation, integration over time is an essential step. The (...) present Hypothesis expresses that the step from neuronal activity to phenomenal content of consciousness is reflective of a “solution:” the main source of the incomprehensibility of consciousness is proposed to result from the introduction of phenomenal time-constant entities. These are “filled-in” via integration, even though neuronal data only exists for changes to these entities. In this way, a temporally continuous picture of the world phenomenally appears. Qualia are “initial conditions,” which are required for integration and cannot be deduced from present data. Phenomenal “identity” is related to qualia. Inattentive visual perception, which is only rarely investigated, offers insights into these relationships. Introspectively, unattended vision appears rich because percepts are cumulated over long time spans, whereas attentive perception relies purely on present neuronal signals. The present Hypothesis is that a brief neuronal activity can signify long-lasting and constant phenomenal content of consciousness. Experimental support is presented that comes from discrepancies between neuronal activity and perception: transient neuronal responses to sustained stimuli, “filling-in,” change blindness, identity vs. close resemblance. (shrink)

Within theoretical and empirical enquiries, many different meanings associated with consciousness have appeared, leaving the term itself quite vague. This makes formulating an abstract and unifying version of the concept of consciousness – the main aim of this article –into an urgent theoretical imperative. It is argued that consciousness, characterized as dually accessible (cognized from the inside and the outside), hierarchically referential (semantically ordered), bodily determined (embedded in the working structures of an organism or conscious system), and useful in action (...) (pragmatically functional), is a graded rather than an all-or-none phenomenon. A gradational approach, however, despite its explanatory advantages, can lead to some counterintuitive consequences and theoretical problems. In most such conceptions consciousness is extended globally (attached to primitive organisms or artificial systems), but also locally (connected to certain lower-level neuronal and bodily processes). For example, according to information integration theory (as introduced recently by Tononi and Koch, 2014), even such simple artificial systems as photodiodes possess miniscule amounts of consciousness. The major challenge for this article, then, is to establish reasonable, empirically justified constraints on how extended the range of a graded consciousness could be. It is argued that conscious systems are limited globally by the ability to individuate information (where individuated information is understood as evolutionarily embedded, socially altered, and private), whereas local limitations should be determined on the basis of a hypothesis about the action-oriented nature of the processes that select states of consciousness. Using these constraints, an abstract concept of consciousness is arrived at, hopefully contributing to a more unified state of play within consciousness studies itself. (shrink)

This paper explores whether consciousness can exist without attention. This is a hot topic in philosophy of mind and cognitive science due to the popularity of theories that hold attention to be necessary for consciousness. The discovery of a form of consciousness that exists without the influence of attention would require a change in the way that many global workspace theorists, for example, understand the role and function of consciousness. Against this understanding, at least three forms of consciousness have been (...) argued to exist without attention: perceptual gist, imagistic consciousness, and phenomenal consciousness. After first arguing that the evidence is inconclusive on the question of whether these forms of consciousness exist without attention, I here present a fourth form of consciousness that is likely to be more successful: conscious entrainment. I argue that conscious entrainment is a form of consciousness associated with skilled behavior in which attention is sometimes absent. (shrink)

Two debates loom large in current discussions on phenomenal consciousness. One debate concerns the relation between phenomenal character and representational content. Representationalism affirms, whereas “content separatism” denies, that phenomenal character is exhausted by representational content. Another debate concerns the relation between phenomenal consciousness and cognitive access. “Access separatism” affirms, whereas, e.g., the global workspace model denies, that there are phenomenally conscious states that are not cognitively accessed. I will argue that the two separatist views are related. Access separatism supports content (...) separatism by undermining the most prominent sort of arguments in favor of representationalism, namely ones that appeal to the phenomenology of perceptual experiences. (shrink)

This paper argues for a position of ‘dark pessimism’ towards introspective reports playing a strong justificatory role in consciousness science, based on the application of frameworks and concepts of measurement. I first show that treating introspective reports as measurements fits well within current discussions of the reliability of introspection, and argue that introspective reports must satisfy at least a minimal definition of measurement in order to play a justificatory role in consciousness science. I then show how treating introspective reports as (...) measurements makes it possible to identify the foundational methodological problems that underlie much of the current philosophical and scientific debate about the status of introspective evidence in studying consciousness. I argue that these problems prevent introspective reports from playing a strong justificatory role and resolving long-standing debates in consciousness science, both in contemporary work and in the future. (shrink)

This paper argues for a position of ‘dark pessimism’ towards introspective reports playing a strong justificatory role in consciousness science, based on the application of frameworks and concepts of measurement. I first show that treating introspective reports as measurements fits well within current discussions of the reliability of introspection, and argue that introspective reports must satisfy at least a minimal definition of measurement in order to play a justificatory role in consciousness science. I then show how treating introspective reports as (...) measurements makes it possible to identify the foundational methodological problems that underlie much of the current philosophical and scientific debate about the status of introspective evidence in studying consciousness. I argue that these problems prevent introspective reports from playing a strong justificatory role and resolving long-standing debates in consciousness science, both in contemporary work and in the future. (shrink)

The Hard Problem is surrounded by a vast literature, to which it is increasingly hard to contribute to in any meaningful way. Accordingly, the strategy here is not to offer any new metaphysical or ‘in principle’ arguments in favour of the success of materialism, but to assume a Type Q(uinian) approach and look to contemporary consciousness science to see how the concept of consciousness fares there, and what kind of explanations we can hope to offer of it. It is suggested (...) that while they will be materialist explanations, they will not be of the form that many scientists and philosophers would have us believe, but instead prompt a very different set of expectations and research projects. (shrink)

Does perceptual consciousness require cognitive access? Ned Block argues that it does not. Central to his case are visual memory experiments that employ post-stimulus cueing—in particular, Sperling's classic partial report studies, change-detection work by Lamme and colleagues, and a recent paper by Bronfman and colleagues that exploits our perception of ‘gist’ properties. We argue contra Block that these experiments do not support his claim. Our reinterpretations differ from previous critics' in challenging as well a longstanding and common view of visual (...) memory as involving declining capacity across a series of stores. We conclude by discussing the relation of probabilistic perceptual representations and phenomenal consciousness. (shrink)

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

Subliminal primes are assumed to produce weaker and short-lived effects on subsequent behavior compared to clearly visible primes. However, this difference in priming effect may be due to differences in signal strength, rather than level of awareness. In the present study we manipulated prime discriminability by using metacontrast masks and pseudomasks, while keeping the prime strength equal. This manipulation resulted in large differences in discriminability of the primes. However, both immediate response priming and long-term response priming was equal for the (...) poorly discriminable and well discriminable primes, and equal for groups that differed markedly in terms of how well they could discriminate the primes. Our findings imply that discriminability of information is independent of both the immediate and long-term effects that information can have on behavior. (shrink)

In this Letter to the Editor, we seize the opportunity to respond to the recent comments by Anzulewicz and Wierzchoń, and further clarify and extend the scope of our original paper. We re‐emphasize that conscious experiences come in degrees, and that there are several factors that determine this degree. Endorsing the suggestions of Anzulewicz and Wierzchoń, we discuss that besides low‐level attentional mechanisms, high‐level attentional and non‐attentional mechanisms might also modulate the quality of conscious experiences.

In this paper we argue that awareness comes in degrees, and we propose a novel multi-factor account that spans both subjective experiences and perceptual representations. At the subjective level, we argue that conscious experiences can be degraded by being fragmented, less salient, too generic, or flash-like. At the representational level, we identify corresponding features of perceptual representations—their availability for working memory, intensity, precision, and stability—and argue that the mechanisms that affect these features are what ultimately modulate the degree of awareness. (...) We conclude the paper by demonstrating why the original interpretations of certain empirical findings that apparently pose problems for our account are, in fact, flawed. (shrink)

Is attention both necessary and sufficient for consciousness? Call this central question of this treatise, “Q.” We commonly have the experience of consciously paying attention to something, but is it possible to be conscious of something you are not attending to, or to attend to something of which you are not conscious? Where might we find examples of these? This treatise is a quest to find an answer to Q in two parts. Part I reviews the foundations upon which the (...) discourse on Q is built. Different inputs to Q produce different answers. After consideration of the many ways “attention” and “consciousness” have been defined, I settle upon phenomenal consciousness and Executive Attention (defined as a suite of strategies for structuring cognition for further processing implemented by the executive of working memory) as the most interesting inputs to Q, and the ones on which Part II focuses. Attention without consciousness seems relatively easy to establish empirically, but consciousness without attention is much harder. The putative candidates all seem to have major problems, but I build a strong abductive case for the hitherto ignored case of foveal phenomenal overflow. We consciously see far more detail in our foveal fields than we can Executively Attend, although there is a serious obstacle to our ever confirming that empirically—identifying conscious content relies on Executive Attentional report. Triangulating the capacity limitations of attention, consciousness, and working memory strengthens this case for consciousness without attention, and suggests that cognition must work something like my “Witches’ Hat Model,” on which content can become conscious outside of Executive Attention or working memory. I conclude with some reflections on the implications of my arguments for the discourse on Q, and for other discourses such as the ontologies of attention and consciousness, theories of consciousness, some other cognitive concepts, and ethical considerations in humans, animals, and machines. A conclusive answer to Q continues to elude us. It may perhaps be an ultimately insoluble conundrum. But it is the very essence of humanity to seek an answer, and in so doing, to improve our understanding of our own nature: “The proper study of mankind is man.”1. (shrink)

When visual attention is directed away from a stimulus, neural processing is weak and strength and precision of sensory data decreases. From a computational perspective, in such situations observers should give more weight to prior expectations in order to behave optimally during a discrimination task. Here we test a signal detection theoretic model that counter-intuitively predicts subjects will do just the opposite in a discrimination task with two stimuli, one attended and one unattended: when subjects are probed to discriminate the (...) unattended stimulus, they rely less on prior information about the probed stimulus’ identity. The model is in part inspired by recent findings that attention reduces trial-by-trial variability of the neuronal population response and that they use a common criterion for attended and unattended trials. In five different visual discrimination experiments, when attention was directed away from the target stimulus, subjects did not adjust their response bias in reaction to a change in stimulus presentation frequency despite being fully informed and despite the presence of performance feedback and monetary and social incentives. This indicates that subjects did not rely more on the priors under conditions of inattention as would be predicted by a Bayes-optimal observer model. These results inform and constrain future models of Bayesian inference in the human brain. (shrink)

The essay is a study of phenomenal specificity. By ‘phenomenal’ here we mean conscious awareness, which needs to be cashed out in detail throughout the study. Intuitively, one dimension of phenomenology is along with specificity. For example it seems appropriate to say that one’s conscious awareness in the middle of the visual field is in some sense more specific than the awareness in the periphery under normal circumstances. However, it is difficult to characterise the nature of phenomenal specificity in an (...) accurate way. This essay seeks to do just that. In the introduction, I set up the discussion by invoking a threefold Campbellian framework. Chapter 1 introduces a key notion of the analogue, its roots in sciences, and its applications in philosophy. Chapter 2 focuses on the major case study – the Sperling iconic memory paradigm – and explains how the relevant notion of the analogue can be used to explain phenomenal specificity involved in the Sperling case. Chapter 3 discusses functions of attention, as it is a crucial element in the Sperling case. Chapter 4 extends the project by explaining how visual demonstratives fit into the present picture. Finally chapter 5 discusses several directions for future researches. This essay is not an attempt to discuss all the issues concerning the Sperling case, but to provide a new angle in seeing the issue: most people agree that visual phenomenology is in some sense specific, but there are not enough attempts to model phenomenal specificity explicitly. On this occasion we use a notion of the analogue and related ideas to understand phenomenal specificity and how it applies to certain empirical cases. (shrink)

Visual phenomenology is highly elusive. One attempt to operationalize or to measure it is to use ‘cognitive accessibility’ to track its degrees. However, if Ned Block is right about the overflow phenomenon, then this way of operationalizing visual phenomenology is bound to fail. This thesis does not directly challenge Block’s view; rather it motivates a notion of cognitive accessibility different from Block’s one, and argues that given this notion, degrees of visual phenomenology can be tracked by degrees of cognitive accessibility. (...) Block points out that in the psychology literature, ‘cognitive accessibility’ is often regarded as either all or nothing. However, the notion motivated in the thesis captures the important fact that accessibility comes in degrees (consider the visual field from fovea the periphery). Different legitimate notions of accessibility might be adopted for different purposes. The notion of accessibility motivated here is weaker than Block’s ‘identification’ (2007) but is stronger than Tye’s ‘demonstration’ (2007). The moral drawn from the discussion of Block can be applied to the debate between Dretske and Tye on the speckled-hen style examples. Dretske’s view is even stronger than Block’s, but his arguments from various figures he provides do not support his conclusion since he does not have right ideas about fixation and attention. Tye’s picture is more plausible but his notion of accessibility is so weak that he reaches the excessive conclusion that accessibility overflows phenomenology. Three ramifications might be considered in the final part of the thesis. The first is the relation between this debate and the one concerning higher-order/same-order theories of consciousness. The second is about John McDowell’s early proposal about demonstrative concepts in visual experiences. The third is the relation between the interpretation of the Sperling case proposed here and McDowell new view of experiential contents, i.e., his story about how we carve out conceptual contents out of intuitional contents without falling pray to the Myth of the Given. (shrink)

In this article, I argue that consciousness is a unique way of processing information, in that: it produces information, rather than purely transmitting it; the information it produces is meaningful for us; the meaning it has is always individuated. This uniqueness allows us to process information on the basis of our personal needs and ever-changing interactions with the environment, and consequently to act autonomously. Three main basic cognitive processes contribute to realize this unique way of information processing: the self, attention (...) and working memory. The self, which is primarily expressed via the central and peripheral nervous systems, maps our body, the environment, and our relations with the environment. It is the primary means by which the complexity inherent to our composite structure is reduced into the “single voice” of a unique individual. It provides a reference system that (albeit evolving) is sufficiently stable to define the variations that will be used as the raw material for the construction of conscious information. Attention allows for the selection of those variations in the state of the self that are most relevant in the given situation. Attention originates and is deployed from a single locus inside our body, which represents the center of the self, around which all our conscious experiences are organized. Whatever is focused by attention appears in our consciousness as possessing a spatial quality defined by this center and the direction toward which attention is focused. In addition, attention determines two other features of conscious experience: periodicity and phenomenal quality. Self and attention are necessary but not sufficient for conscious information to be produced. Complex forms of conscious experiences, such as the various modes of givenness of conscious experience and the stream of consciousness, need a working memory mechanism to assemble the basic pieces of information selected by attention. (shrink)

The overflow debate concerns this following question: does conscious iconic memory have a higher capacity than attention does? In recent years, Ned Block has been invoking empirical works to support the positive answer to this question. The view is called the “rich view” or the “Overflow view”. One central thread of this discussion concerns the nature of iconic memory: for example how rich they are and whether they are conscious. The first section discusses a potential misunderstanding of “visible persistence” in (...) this literature. The second section discusses varieties of attention relevant to this debate. The final section discusses the most prominent alternative interpretation of the Sperling paradigm—the postdiction interpretation—and explains how it can be made compatible with a weaker version of the rich or overflow view. (shrink)

Emotional states of consciousness, or what are typically called emotional feelings, are traditionally viewed as being innately programed in subcortical areas of the brain, and are often treated as different from cognitive states of consciousness, such as those related to the perception of external stimuli. We argue that conscious experiences, regardless of their content, arise from one system in the brain. On this view, what differs in emotional and non-emotional states is the kind of inputs that are processed by a (...) general cortical network of cognition, a network essential for conscious experiences. Although subcortical circuits are not directly responsible for conscious feelings, they provide non-conscious inputs that coalesce with other kinds of neural signals in the cognitive assembly of conscious emotional experiences. In building the case for this proposal, we defend a modified version of what is known as the higher-order theory of consciousness. (shrink)

Is consciousness independent of the general-purpose information processes known as ‘cognitive access’? The dominantmethodology for supporting this independence hypothesis appeals to partial report experiments as evidence for perceptual consciousness in the absence of cognitive access. Using a standard model of evidential support, and reviewing recent elaborations of the partial report paradigm, this article argues that the paradigm has the wrong structure to support the independence hypothesis. Like reports in general, a subject’s partial report is evidence that she is conscious of (...) information only where that information is cognitively accessed. So partial report experiments could dissociate consciousness from cognitive access only if there were uncontroversial evidence forconsciousness which did not imply reportability. There is no such evidence. An alternative, broadly Marrian methodology for supporting the independence hypothesis is suggested, and some challenges to it outlined. This methodology does not require experimental evidence for consciousness in the absence of cognitive access. Instead it focuses on a function of perceptual consciousness when a stimulus is cognitively accessed. If the processes best suited to implement this function exclude cognitive access, the independence hypothesis will be supported. One relevant function of consciousness may be reflected in reason-based psychological explanations of a subject’s behaviour. (shrink)

Science and philosophy still lack an overarching theory of consciousness. We suggest that a further step toward it requires going beyond the view of the brain as input-output machine and focusing on its intrinsic activity, which may express itself in two distinct modalities, i.e. aware and unaware. We specifically investigate the predisposition of the brain to evaluate and to model the world. These intrinsic activities of the brain retain a deep relation with consciousness. In fact the ability of the brain (...) to evaluate and model the world can develop in two modalities, implicit or explicit, that correspond to what we usually refer to as the unconscious and consciousness, and both are multilevel configurations of the brain along a continuous and dynamic line. Starting from an empirical understanding of the brain as intrinsically active and plastic, we here distinguish between higher cognitive functions and basic phenomenal consciousness, suggesting that the latter might characterize the brain’s intrinsic activity as such, even if at a very basic level. We proceed to explore possible impacts of the notion of intrinsic cerebral phenomenality on our understanding of consciousness and its disorders, particularly on the diagnosis and management of patients with disorders of consciousness. (shrink)