A connectionist theory of phenomenal experience

When cognitive scientists apply computational theory to the problem of phenomenal consciousness, as many have been doing recently, there are two fundamentally distinct approaches available. Consciousness is to be explained either in terms of the nature of the representational vehicles the brain deploys or 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, although 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 that 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. 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 used in the dissociation studies--so critical, in fact, that it is 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 target article we develop and defend this connectionist vehicle theory of consciousness. It takes the form of the following simple empirical hypothesis: phenomenal experience consists of the explicit representation of information in neurally realized parallel distributed processing (PDP) networks. This hypothesis leads us to reassess some common wisdom about consciousness, but, we argue, in fruitful and ultimately plausible ways.     

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.     

内隐学习意识性研究的两种理论取向:二分与渐进

传统的内隐学习研究范式大多致力于意识与无意识加工的操作性分离。随着学习任务和测量手段的改进,越来越多的研究发现量化渐变比二元分离能更好地兼容实验数据。本文对认知领域中与二分和渐进两种取向相关的理论框架和实证研究进行介绍和评价,指出意识的二分与渐进假设是源自不同的概念定义层次的理论框架,即功能性概念和解释性概念,因而对现象学数据具有不同的解释效力。它们的共存提供了不同的研究视角,丰富了我们对内隐学习活动的认识。     

Investigating the Awareness of Remembering

ABSTRACT— There is a marked lack of consensus concerning the best way to learn how conscious experiences arise. In this article, we advocate for scientific approaches that attempt to bring together four types of phenomena and their corresponding theoretical accounts: behavioral acts, cognitive events, neural events, and subjective experience. We propose that the key challenge is to comprehensively specify the relationships among these four facets of the problem of understanding consciousness without excluding any facet. Although other perspectives on consciousness can also be informative, combining these four perspectives could lead to significant progress in explaining a conscious experience such as remembering. We summarize some relevant findings from cognitive neuroscience investigations of the conscious experience of memory retrieval and of memory behaviors that transpire in the absence of the awareness of remembering. These examples illustrate suitable scientific strategies for making progress in understanding consciousness by developing and testing theories that connect the behavioral expression of recall and recognition, the requisite cognitive transactions, the neural events that make remembering possible, and the awareness of remembering.     

Emotional consciousness: a neural model of how cognitive appraisal and somatic perception interact to produce qualitative experience

This paper proposes a theory of how conscious emotional experience is produced by the brain as the result of many interacting brain areas coordinated in working memory. These brain areas integrate perceptions of bodily states of an organism with cognitive appraisals of its current situation. Emotions are neural processes that represent the overall cognitive and somatic state of the organism. Conscious experience arises when neural representations achieve high activation as part of working memory. This theory explains numerous phenomena concerning emotional consciousness, including differentiation, integration, intensity, valence, and change.     

Defining consciousness in the context of incidental sequence learning: theoretical considerations and empirical implications

The notion that sequential regularities can be learned implicitly without ensuing conscious knowledge has sparked off a prolific research program within cognitive psychology. However, there is continuing dissent among researchers about the very existence of the phenomenon. This is, at least in part, due to a failure to ground research on implicit sequence learning in conceptual definitions of “consciousness” and “conscious sequence knowledge.” In this article the authors take up a definition of consciousness according to which conscious mental contents are characterized by their global availability to cognitive processes (e.g., Baars in: A cognitive theory of consciousness Cambridge University Press, 1988; in: In the theater of consciousness: the workspace of the mind Oxford University Press, 1997). It is argued that unlike recognition tests or generate tasks, verbal report is a sensitive and specific measure of conscious (i.e., globally available) sequence knowledge. Finally, it is shown that the choice between two commonly used measures of conscious sequence knowledge can profoundly affect the outcome of a sequence learning experiment.     

The modal breadth of consciousness

In this paper, I argue that the intentional structure of typical human conscious experience has “modal breadth”—that the contents of experience typically include alternate possibilities. I support this claim with analyses of conscious mental processes such as the perception of temporally extended events, persistent objects, and causality, and the experience of bodily agency. While modal breadth may not be strictly necessary for consciousness per se, it is essential to many cognitive processes that are pervasive and functionally important to normal human consciousness.     

Putting color back where it belongs

I disagree with Ross about the location of colors: They are in the brain, not in the external world. It is difficult to deny that there are colors in our conscious visual experience, and if we take the causal theory of perception seriously, we cannot identify these colors with the beginning of the causal chain in perception (external objects in the distal stimulus field), but we must search for them at the end of the causal chain (in the brain). Several lines of compelling evidence from cognitive neuroscience (e.g., synesthesia, dreaming, and achromatopsia) demonstrate unambiguously that color is in the brain. Furthermore, it seems that Ross has failed to consider one substantial version of subjectivism in his article. This monistic approach to color and consciousness appears to be the least implausible alternative when we try to understand what colors are and where they reside.     

简论里贝特的意识理论

里贝特是人类意识和自由意志的实验研究领域的一个卓越的、先驱性的神经科学家。里贝特的意识研究工作涉及如下四个方面：（1）关于意识研究的认识论原则;（2）对意识现象本性的界定;（3）意识机制的时控理论;（4）对自由意志的阐释和有意识的心智场理论。里贝特的意识研究独树一帜,其时控理论具有坚实可信的实验证据,它从时间维度揭示了有意识的主观体验以及无意识的心智功能与神经活动之间的时间机制。     

In and out of consciousness: Sustained electrophysiological activity reflects individual differences in perceptual awareness

Although significant advances in our understanding of the cognitive and neural processes involved in conscious awareness have occurred in recent years, the precise mechanisms that support consciousness remain elusive. Examining the neural correlates associated with the moment a stimulus enters or exits conscious awareness is one way to potentially identify the neural mechanisms that give rise to consciousness. In the present study, we recorded neural activity using electroencephalography (EEG) while participants observed a bilateral shape-from-motion (SFM) display. While the display is in motion, the observer perceives an object that is immediately segregated from a noisy background. After the motion stops, the observer's experience of the object remains momentarily in awareness, before it eventually fades out of consciousness back into the noisy background. Consistent with subjective reports of perceptual experience, we observed a prominent sustained posterior contralateral negativity known as the contralateral delay activity (CDA). This activity was sustained only in conditions associated with sustained awareness. Interestingly, the amplitude of the CDA was correlated with individual differences in visual awareness, suggesting that this activity plays a significant role in the maintenance of objects in consciousness. The CDA is typically associated with visual short-term memory (VSTM), suggesting that conscious visual awareness may be mediated by the same neural and cognitive mechanisms that support VSTM. Our results demonstrate that the CDA may reflect the contents of conscious awareness, and therefore can provide a measure to track when information moves in and out of consciousness.     

冲突适应独立于意识：来自行为和ERP的证据

尽管已有研究发现诸如抑制控制和任务转换等认知控制功能独立于意识, 但是对冲突适应是否需要意识的参与目前还存在激烈的争论。为了进一步探讨此问题, 本研究记录了18名被试在完成箭头偏对比掩蔽任务(meta-contrast masking task)时的行为和脑电数据。结果显示, 在有意识和无意识条件下在反应时和额中N2和中顶P3波幅上均表现出了显著的冲突适应效应。这不仅表明冲突控制独立于意识, 而且也表明先前无意识经验对人类信息加工系统的适应性调节作用。本研究对认识认知控制和意识的本质具有重要意义, 也为建构认知控制与意识关系的理论提供了启示。     

The development of conscious control in childhood

Developmental data suggest that the growth of executive function in childhood can be understood in terms of the development of consciousness. According to the "levels of consciousness" (LOC) model, there are age-related increases in the highest degree of self-reflection or LOC that children are able to muster in response to situational demands. These increases in LOC with age have consequences for the quality of experience, the potential for recall, the complexity of children's explicit knowledge structures, and the possibility of the conscious control of thought, emotion, and action. The hierarchical LOCs identified by this analysis are also useful for understanding the complex structure of conscious experience in adults, and they provide a metric for measuring the level at which consciousness is operating in specific situations.     

Consciousness, accessibility, and the mesh between psychology and neuroscience

How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We see the problem in stark form if we ask how we can tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: Find the neural natural kinds that are the basis of phenomenal consciousness in clear cases--when subjects are completely confident and we have no reason to doubt their authority--and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: Do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is "Yes," then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is "Yes"? The suggested methodology requires an answer to the question it was supposed to answer! This target article argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. I argue that we can find a neural realizer of this overflow if we assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified (other things being equal) by the explanations it allows.     

A starting point for consciousness research: Reply to Thomas Schmidt

Anesthesia research has focused on showing learning in the absence of awareness for good practical reasons. Crucially, continued learning during otherwise clinically adequate anesthesia may affect patients’ well-being on recovery. Theoretically, preserved perceptual priming during anesthesia offers a useful starting point for consciousness research by determining the limits of memory function during minimal (if not absent) consciousness. The big question for consciousness research is not to demonstrate absolutely unconscious processing, but rather to map out the cognitive and neurobiological processes that enable conscious experience itself.     

无意识信息引发的认知控制及其神经机制

对无意识信息引发的认知控制的研究是揭示意识的功能与局限的重要方法和步骤.在无意识认知控制研究中主要采用模式掩蔽和偏对比掩蔽创设无意识条件,使用客观测量方法对意识状态进行测量.作者从无意识抑制控制、无意识冲突控制和无意识错误加工三个方面回顾了近年对无意识认知控制及其神经机制的研究.已有研究从行为和认知神经研究两个方面强有力地证明了无意识认知控制的存在,揭示了其神经机制.这些研究拓展了人们对意识信息广度和深度的认识,也为未来进一步揭示意识的起源等问题奠定了一定的基础.未来的研究可以从无意识认知控制和有意识认知控制的相互转化等方面进行进一步研究.     

Towards a pluralistic neurobiological understanding of consciousness

Theories of consciousness are often based on the assumption that a single, unified neurobiological account will explain different types of conscious awareness. However, recent findings show that, even within a single modality such as conscious visual perception, the anatomical location, timing, and information flow of neural activity related to conscious awareness vary depending on both external and internal factors. This suggests that the search for generic neural correlates of consciousness may not be fruitful. I argue that consciousness science requires a more pluralistic approach and propose a new framework: joint determinant theory (JDT). This theory may be capable of accommodating different brain circuit mechanisms for conscious contents as varied as percepts, wills, memories, emotions, and thoughts, as well as their integrated experience.     

Singularity and consciousness: A neuropsychological contribution

In common sense experience based on introspection, consciousness is singular. There is only one ‘me’ and that is the one that is conscious. This means that ‘singularity’ is a defining aspect of ‘consciousness’. However, the three main theories of consciousness, Integrated Information, Global Workspace and Recurrent Processing theory, are generally not very clear on this issue. These theories have traditionally relied heavily on neuropsychological observations and have interpreted various disorders, such as anosognosia, neglect and split-brain as impairments in conscious awareness without any reference to ‘the singularity’. In this review, we will re-examine the theoretical implications of these impairments in conscious awareness and propose a new way how to conceptualize consciousness of singularity. We will argue that the subjective feeling of singularity can coexist with several disunified conscious experiences. Singularity awareness may only come into existence due to environmental response constraints. That is, perceptual, language, memory, attentional and motor processes may largely proceed unintegrated in parallel, whereas a sense of unity only arises when organisms need to respond coherently constrained by the affordances of the environment. Next, we examine from this perspective psychiatric disorders and psycho-active drugs. Finally, we present a first attempt to test this hypothesis with a resting state imaging experiment in a split-brain patient. The results suggest that there is substantial coherence of activation across the two hemispheres. These data show that a complete lesioning of the corpus callosum does not, in general, alter the resting state networks of the brain. Thus, we propose that we have separate systems in the brain that generate distributed conscious. The sense of singularity, the experience of a ‘Me-ness’, emerges in the interaction between the world and response-planning systems, and this leads to coherent activation in the different functional networks across the cortex.     

Anosognosia and the Unity of Consciousness

There are researchers in cognitive science whouse clinical and experimental evidence to drawsome rather skeptical conclusions about acentral feature of our conscious experience,its unity. They maintain that the examinationof clinical phenomena reveals that humanconsciousness has a much more fragmentarycharacter than the one we normally attribute toit. In the article, these claims are questionedby examining some of the clinical studies onthe deficit of anosognosia. I try to show thatthese studies support a moderate sense of theunity of reflexive consciousness.     

The nature of primary consciousness. A new synthesis

While the philosophical puzzles about “life” that once confounded biology have all been solved by science, much of the “mystery of consciousness” remains unsolved due to multiple “explanatory gaps” between the brain and conscious experience. One reason for this impasse is that diverse brain architectures both within and across species can create consciousness, thus making any single neurobiological feature insufficient to explain it. We propose instead that an array of general biological features that are found in all living things, combined with a suite of special neurobiological features unique to animals with consciousness, evolved to create subjective experience. Combining philosophical, neurobiological and evolutionary approaches to consciousness, we review our theory of neurobiological naturalism that we argue closes the “explanatory gaps” between the brain and subjective experience and naturalizes the “experiential gaps” between subjectivity and third-person observation of the brain.     

Dynamics of mental activity

Motivated by neuronal modeling, our development of the mathematical foundations of consciousness in [W. Miranker, G. Zuckerman, Mathematical Foundations of Consciousness, J. Appl. Logic (2009)] (M-Z) was characterized by an axiomatic theory for consciousness operators that acted on the collection of all sets. Consciousness itself was modeled as emanating from the action of such operators on the labeled decoration of a graph, the latter set theoretic construct given the characterization of experience. Since mental activity (conscious and unconscious) is a time dependent process, we herein develop a discrete time dependent version of the theory. Specification of the relevant mental dynamics illuminates and expands the development of the mathematical framework in (M-Z) upon which our study of consciousness rests. This framework is an abstraction of neural net modeling.We review the Aczel theory for decorating labeled graphs, in particular that theory's application to the (M-Z) foundations. The relevant neuronal modeling concepts and terminology are also reviewed. A number of examples are presented. Then an extension of our considerations from graphs to multigraphs is made, since the latter represent a more accurate model of neuronal circuit connectivity. The dynamics are crafted for non-well-founded constructs by development of a hierarchy of systems, starting with the McCulloch–Pitts neuronal voltage input–output relations and building to a dynamics for the cognitive notions of memes and themata; these latter corresponding to aspects of decorations of labeled graphs associated with neural networks. We conclude with a summary and discussion of the semantics of the cognitive features of our development: memes, themata, qualia, consciousness operators, awareness field.