This paper argues for an explanation of the mechanistic (computational) basis of consciousness that is based on the distinction between localist (symbolic) representation and distributed representation, the ideas of which have been put forth in the connectionist literature. A model is developed to substantiate and test this approach. The paper also explores the issue of the functional roles of consciousness, in relation to the proposed mechanistic explanation of consciousness. The model, embodying the representational difference, is able to account for the functional role of consciousness, in the form of the synergy between the conscious and the unconscious. The fit between the model and various cognitive phenomena and data (documented in the psychological literatures) is discussed to accentuate the plausibility of the model and its explanation of consciousness. Comparisons with existing models of consciousness are made in the end.

Cleeremans: The search for the computational correlates of consciousness

Research on consciousness is currently enjoying a spectacular revival of interest in the cognitive sciences. From an empirical point of view, the NCC program --- the search for the "Neural Correlates of Consciousness" --- holds the promise of establishing correlations between physiological and phenomenal states in a way that directly resembles G. T. Fechners (1860) so-called "inner psychophysics". Should the NCC program be entirely successful, we would thus be able to predict phenomenal states based on physiological states. we would be able to predict phenomenal states based on physiological states. In this paper, we explore some of the conceptual and methodological difficulties of this approach. In both neurobiology and psychology, there are serious measurement problems that stand in the way of correlation research, even after the "hard problem" has been set aside. Thus, even if one had identified certain internal functional states as indicators of phenomenal states, the ...

This paper aims to explore mechanistic and teleological explanations of consciousness. In terms of mechanistic explanations, it critiques various existing views, especially those embodied by existing computational cognitive models. In this regard, the paper argues in favor of the explanation based on the distinction between localist (symbolic) representation and distributed representation (as formulated in the connectionist literature), which reduces the phenomenological dierence to a mechanistic dierence. Furthermore, to establish a teleological explanation of consciousness, the paper discusses the issue of the functional role of consciousness on the basis of the afore-mentioned mechanistic explanation. A proposal based on synergistic interaction between the conscious and the unconscious is advanced that encompasses various existing views concerning the functional roles of consciousness. This two-step deepening explanation has some empirical support, in the form of a cognitive model...

Theories of access consciousness address how it is that some mental states but not others are available for evaluation, choice behavior, and verbal report. Farah, O'Reilly, and Vecera (1994) argue that quality of representation is critical; Dehaene, Sergent, and Changeux (2003) argue that the ability to communicate representations is critical. We present a probabilistic information transmission or PIT model that suggests both of these conditions are essential for access consciousness.

In the physical sciences a rigorous theory is a hierarchy of descriptions in which causal relationships between many general types of entity at a phenomenological level can be derived from causal relationships between smaller numbers of simpler entities at more detailed levels. The hierarchy of descriptions resembles the modular hierarchy created in electronic systems in order to be able to modify a complex functionality without excessive side effects. Such a hierarchy would make it possible to establish a rigorous scientific theory of consciousness. The causal relationships implicit in definitions of access consciousness and phenomenal consciousness are made explicit, and the corresponding causal relationships at the more detailed levels of perception, memory, and skill learning described. Extension of these causal relationships to physiological and neural levels is discussed. The general capability of a range of current consciousness models to support a modular hierarchy which could generate these causal relationships is reviewed, and the specific capabilities of two models with good general capabilities are compared in some detail.

Attractor networks, which map an input space to a discrete output space, are useful for pattern completion---cleaning up noisy or missing input features. However, designing a net to have a given set of attractors is notoriously tricky; training procedures are CPU intensive and often produce spurious attractors and ill-conditioned attractor basins. These difficulties occur because each connection in the network participates in the encoding of multiple attractors. We describe an alternative formulation of attractor networks in which the encoding of knowledge is local, not distributed. Although localist attractor networks have similar dynamics to their distributed counterparts, they are much easier to work with and interpret. We propose a statistical formulation of localist attractor net dynamics, which yields a convergence proof and a mathematical interpretation of model parameters. We present simulation experiments that explore the behavior of localist attractor networks, show...

The radical plasticity thesis — 2 In this chapter, I sketch a conceptual framework which takes it as a starting point that conscious and unconscious cognition are rooted in the same set of interacting learning mechanisms and representational systems. On this view, the extent to which a representation is conscious depends in a graded manner on properties such as its stability in time or its strength. Crucially, these properties are accrued as a result of learning, which is in turn viewed as a mandatory process that always accompanies information processing. From this perspective, consciousness is best characterized as involving (1) a graded continuum defined over “quality of representation”, such that availability to consciousness and to cognitive control correlates with quality, and (2) the implication of systems of metarepresentations. A first implication of these ideas is that the main function of consciousness is to make flexible, adaptive control over behavior possible. A second, much more speculative implication, is that we learn to be conscious. This I call the “radical

This paper aims at evaluating existing computational (mechanistic) models of cognition in relation to the study of consciousness, on the basis of psychological and philosophical theories and data. It rst critiques various mechanistic explanations of consciousness, especially existing computational cognitive models. It then explores the issue of the functional roles of consciousness and examines various views in this regard, in relation to the mechanistic explanation of consciousness. In these examinations, the paper argues in favor of the explanation based on the distinction between localist (symbolic) representation and distributed representation (the ideas of which have been put forth in the connectionist literature). Serving as a basis for the discussions, a model of the conscious/unconscious interaction, utilizing the representational dierence explanation of consciousness, is briey described. The paper also advances a proposal regarding the synergistic interaction between the co...

`Forty--two! ' yelled Loonquawl. `Is that all you've got to show for seven and a half million years ' work?' `I checked it very thoroughly, ' said the computer, `and that quite definitely is the answer. I think the problem, to be quite honest with you, is that you've never actually known what the question is.' `But it was the Great Question! The Ultimate Question of Life, the Universe and Everything, ' howled Loonquawl. `Yes, ' said Deep Thought with the air of one who suffers fools gladly, `but what actually is it?' A slow stupefied silence crept over the men as they stared at the computer and then at each other. `Well, you know, it's just Eveything... Everything... ' offered Phouchg weakly. `Exactly! ' said Deep Thought. `So once you do know what the question actually is, you'll know what the answer means.'