The global workspace theory,the phenomenal concept strategy,and the distribution of consciousness

Peter Carruthers argues that the global workspace theory implies there are no facts of the matter about animal consciousness. The argument is easily extended to other cognitive theories of consciousness, posing a general problem for consciousness studies. But the argument proves too much, for it also implies that there are no facts of the matter about human consciousness. A key assumption is that scientific theories of consciousness must explain away the explanatory gap. I criticize this assumption and point to an alternative strategy for defending scientific theories of consciousness, one that better reflects the ongoing scientific practice. I argue there are introspectable inferential connections from phenomenal concepts to functional concepts that scientists can use to individuate the global workspace in terms of capacities that animals and humans share.     

A role for the anterior insular cortex in the global neuronal workspace model of consciousness

According to the global neuronal workspace model of consciousness, consciousness results from the global broadcast of information throughout the brain. The global neuronal workspace is mainly constituted by a fronto-parietal network. The anterior insular cortex is part of this global neuronal workspace, but the function of this region has not yet been defined within the global neuronal workspace model of consciousness. In this review, I hypothesize that the anterior insular cortex implements a cross-modal priority map, the function of which is to determine priorities for the processing of information and subsequent entrance in the global neuronal workspace.     

Identifying phenomenal consciousness

This paper examines the possibility of finding evidence that phenomenal consciousness is independent of access. The suggestion reviewed is that we should look for isomorphisms between phenomenal and neural activation spaces. It is argued that the fact that phenomenal spaces are mapped via verbal report is no problem for this methodology. The fact that activation and phenomenal space are mapped via different means does not mean that they cannot be identified. The paper finishes by examining how data addressing this theoretical question could be obtained.     

Hill on phenomenal consciousness

I argue that it is at least open to a proponent of type materialism for phenomenal consciousness to accept Hill’s representational theory of experiential awareness of perceptual qualia.     

The global workspace (GW) theory of consciousness and epilepsy

The global workspace (GW) theory proposes that conscious processing results from coherent neuronal activity between widely distributed brain regions, with fronto-parietal associative cortices as key elements. In this model, transition between conscious and non conscious states are predicted to be caused by abrupt non-linear massive changes of the level of coherence within this distributed neural space. Epileptic seizures offer a unique model to explore the validity of this central hypothesis. Seizures are often characterized by the occurrence of brutal alterations of consciousness (AOC) which are largely negatively impacting patients' lives. Recently, we have shown that these sudden AOC are contemporary to non-linear increases of neural synchrony within distant cortico-cortical and cortico-thalamic networks. We interpreted these results in the light of GW theory, and suggested that excessive synchrony could prevent this distributed network to reach the minimal level of differentiation and complexity necessary to the coding of conscious representations. These observations both confirm some predictions of the GW model, and further specify the physiological window of neural coherence (minimum and maximum) associated with conscious processing.     

Unitary and dual models of phenomenal consciousness

There is almost unanimous consensus among the theorists of consciousness that the phenomenal character of a mental state cannot exist without consciousness. We argue for a reappraisal of this consensus. We distinguish two models of phenomenal consciousness: unitary and dual. Unitary model takes the production of a phenomenal quality and it’s becoming conscious to be one and the same thing. The dual model, which we advocate in this paper, distinguishes the process in which the phenomenal quality is formed from the process that makes this quality conscious. We put forward a conceptual, methodological, neuropsychological and neural argument for the dual model. These arguments are independent but provide mutual support to each other. Together, they strongly support the dual model of phenomenal consciousness and the concomitant idea of unconscious mental qualities. The dual view is thus, we submit, a hypothesis worthy of further probing and development.     

Extending the global workspace theory to emotion: phenomenality without access

Recent accounts on the global workspace theory suggest that consciousness involves transient formations of functional connections in thalamo-cortico-cortical networks. The level of connectivity in these networks is argued to determine the state of consciousness. Emotions are suggested to play a role in shaping consciousness, but their involvement in the global workspace theory remains elusive. In the present study, the role of emotion in the neural workspace theory of consciousness was scrutinized by investigating, whether unconscious (masked) and conscious (unmasked) display of emotional compared to neutral facial expressions would differentially modulate EEG coherence. EEG coherence was measured by means of computing an average EEG coherence value between the frontal, parietal, and midline scalp sites. Objective awareness checks evidenced that conscious identification of the masked facial expressions was precluded. Analyses revealed reductions in EEG coherence in the lower frequency range for the masked as compared to unmasked neutral facial expressions. Crucially, a decline in EEG coherence was not observed for the emotional facial expressions. In other words, the level of EEG coherence did apparently vary as a function of awareness, but not when emotion was involved. The current finding suggests that EEG coherence is modulated by unconscious emotional processes, which extends common views on the global workspace architecture of consciousness.     

Binding and the phenomenal unity of consciousness.

The binding problem is frequently discussed in consciousness research. However, it is by no means clear what the problem is supposed to be and how exactly it relates to consciousness. In the present paper the nature of the binding problem is clarified by distinguishing between different formulations of the problem. Some of them make no mention of consciousness, whereas others are directly related to aspects of phenomenal experience. Certain formulations of the binding problem are closely connected to the classical philosophical problem of the unity of consciousness and the currently fashionable search for the neural correlates of consciousness. Nonetheless, only a part of the current empirical research on binding is directly relevant to the study of consciousness. The main message of the present paper is that the science of consciousness needs to establish a clear theoretical view of the relation between binding and consciousness and to encourage further empirical work that builds on such a theoretical foundation.     

A cognitive architecture that combines internal simulation with a global workspace

This paper proposes a brain-inspired cognitive architecture that incorporates approximations to the concepts of consciousness, imagination, and emotion. To emulate the empirically established cognitive efficacy of conscious as opposed to non-conscious information processing in the mammalian brain, the architecture adopts a model of information flow from global workspace theory. Cognitive functions such as anticipation and planning are realised through internal simulation of interaction with the environment. Action selection, in both actual and internally simulated interaction with the environment, is mediated by affect. An implementation of the architecture is described which is based on weightless neurons and is used to control a simulated robot.     

Phenomenal and access consciousness in olfaction

Contemporary literature on consciousness, with some exceptions, rarely considers the olfactory system. In this article the characteristics of olfactory consciousness, viewed from the standpoint of the phenomenal (P)/access (A) distinction, are examined relative to the major senses. The review details several qualitative differences in both olfactory P consciousness (shifts in the felt location, universal synesthesia-like and affect-rich experiences, and misperceptions) and A consciousness (recovery from habituation, capacity for conscious processing, access to semantic and episodic memory, learning, attention, and in the serial-unitary nature of olfactory percepts). The basis for these differences is argued to arise from the functions that the olfactory system performs and from the unique neural architecture needed to instantiate them. These data suggest, at a minimum, that P and A consciousness are uniquely configured in olfaction and an argument can be made that the P and A distinction may not hold for this sensory system.     

Applying global workspace theory to the frame problem

The subject of this article is the frame problem, as conceived by certain cognitive scientists and philosophers of mind, notably Fodor for whom it stands as a fundamental obstacle to progress in cognitive science. The challenge is to explain the capacity of so-called informationally unencapsulated cognitive processes to deal effectively with information from potentially any cognitive domain without the burden of having to explicitly sift the relevant from the irrelevant. The paper advocates a global workspace architecture, with its ability to manage massively parallel resources in the context of a serial thread of computation, as an answer to this challenge. Analogical reasoning is given particular attention, since it exemplifies informational unencapsulation in its most extreme form. Because global workspace theory also purports to account for the distinction between conscious and unconscious information processing, the paper advances the tentative conclusion that consciousness may go hand-in-hand with a solution to the frame problem in the biological brain.     

Perceptual consciousness overflows cognitive access

One of the most important issues concerning the foundations of conscious perception centers on the question of whether perceptual consciousness is rich or sparse. The overflow argument uses a form of 'iconic memory' to argue that perceptual consciousness is richer (i.e., has a higher capacity) than cognitive access: when observing a complex scene we are conscious of more than we can report or think about. Recently, the overflow argument has been challenged both empirically and conceptually. This paper reviews the controversy, arguing that proponents of sparse perception are committed to the postulation of (i) a peculiar kind of generic conscious representation that has no independent rationale and (ii) an unmotivated form of unconscious representation that in some cases conflicts with what we know about unconscious representation.     

A dyadic model of consciousness

The proposed model for consciousness, called a dyadic model, is based upon reexamination of traditional thought structures in the light of modern experimental evidence from a number of scientific fields. It is an evolutionary cosmological model using energy and information as fundamental concepts. It proposes that the antecedent attributes of anthropic consciousness find their roots in the field of zero point quantum potential which gave rise to the Big Bang. In this model consciousness has both a fundamental aspect and an evolutionary aspect in the same sense that quantized energy manifests fundamentally as wave/particles and is observed in more complex form as molecular matter. Physical existence evolved through natural process into ever more complex organizations of matter; so also must anthropic consciousness have evolved from more fundamental antecedent characteristics. The dyadic model proposes a scenario for this evolution that corresponds to the appearance of the universe we seem to inhabit.     

Content externalism and phenomenal character: a new worry about privileged access

Some philosophers argue that the thesis of content externalism, according to which the contents of a subject’s thoughts are in part individuated by environmental factors, threatens the standard idea that a subject can know the contents of her thoughts without empirical investigation. It is typically assumed, however, that this thesis does not threaten another common idea about privileged access: that a subject can know the phenomenal character of her experience–its “what it’s like” aspect–without empirical investigation. That is, even if content externalism is true and does imply that a subject cannot know without empirical investigation the contents of some of her thoughts (e.g., her thoughts about water), surely she can know without empirical investigation what it’s like for her to be having whatever experience she is having. I argue that if content externalism threatens privileged access to content (I do not discuss whether it does), then it also threatens privileged access to phenomenal character. My argument does not involve claiming that phenomenal character is itself externally individuated. Rather, it depends on two other claims: (1) that introspective access to phenomenal character is conceptual; and (2) that standard arguments for content externalism suggest that some phenomenal concepts are externally individuated.     

Towards a cognitive neuroscience of consciousness: basic evidence and a workspace framework

This introductory chapter attempts to clarify the philosophical, empirical, and theoretical bases on which a cognitive neuroscience approach to consciousness can be founded. We isolate three major empirical observations that any theory of consciousness should incorporate, namely (1) a considerable amount of processing is possible without consciousness, (2) attention is a prerequisite of consciousness, and (3) consciousness is required for some specific cognitive tasks, including those that require durable information maintenance, novel combinations of operations, or the spontaneous generation of intentional behavior. We then propose a theoretical framework that synthesizes those facts: the hypothesis of a global neuronal workspace. This framework postulates that, at any given time, many modular cerebral networks are active in parallel and process information in an unconscious manner. An information becomes conscious, however, if the neural population that represents it is mobilized by top-down attentional amplification into a brain-scale state of coherent activity that involves many neurons distributed throughout the brain. The long-distance connectivity of these 'workspace neurons' can, when they are active for a minimal duration, make the information available to a variety of processes including perceptual categorization, long-term memorization, evaluation, and intentional action. We postulate that this global availability of information through the workspace is what we subjectively experience as a conscious state. A complete theory of consciousness should explain why some cognitive and cerebral representations can be permanently or temporarily inaccessible to consciousness, what is the range of possible conscious contents, how they map onto specific cerebral circuits, and whether a generic neuronal mechanism underlies all of them. We confront the workspace model with those issues and identify novel experimental predictions. Neurophysiological, anatomical, and brain-imaging data strongly argue for a major role of prefrontal cortex, anterior cingulate, and the areas that connect to them, in creating the postulated brain-scale workspace.     

A general model of primitive consciousness

We present a simple model of consciousness as it may exist in animals and can exist in man-made artifacts. The minimum unit of consciousness is a brain/body in interaction with a world. No parts of that system are themselves, conscious. Emphasis is placed on structures that could have evolved from earlier structures by small steps each of which conferred advantage to its possessors. The model is functional, so it becomes possible to build such conscious systems. Indeed, we show why conscious systems should be built as well as how humans should interact with them.     

Where experiences are: Dualist, physicalist, enactive and reflexive accounts of phenomenal consciousness

Dualists believe that experiences have neither location nor extension, while reductive and ‘non-reductive’ physicalists (biological naturalists) believe that experiences are really in the brain, producing an apparent impasse in current theories of mind. Enactive and reflexive models of perception try to resolve this impasse with a form of “externalism” that challenges the assumption that experiences must either be nowhere or in the brain. However, they are externalist in very different ways. Insofar as they locate experiences anywhere, enactive models locate conscious phenomenology in the dynamic interaction of organisms with the external world, and in some versions, they reduce conscious phenomenology to such interactions, in the hope that this will resolve the hard problem of consciousness. The reflexive model accepts that experiences of the world result from dynamic organism–environment interactions, but argues that such interactions are preconscious. While the resulting phenomenal world is a consequence of such interactions, it cannot be reduced to them. The reflexive model is externalist in its claim that this external phenomenal world, which we normally think of as the “physical world,” is literally outside the brain. Furthermore, there are no added conscious experiences of the external world inside the brain. In the present paper I present the case for the enactive and reflexive alternatives to more classical views and evaluate their consequences. I argue that, in closing the gap between the phenomenal world and what we normally think of as the physical world, the reflexive model resolves one facet of the hard problem of consciousness. Conversely, while enactive models have useful things to say about percept formation and representation, they fail to address the hard problem of consciousness.