A Connectionist Theory of Phenomenal Experience

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. This hypothesis leads us to re-assess some common wisdom about consciousness, but, we will argue, in fruitful and ultimately plausible ways

Passive frame theory: A new synthesis.

Passive frame theory attempts to illuminate what consciousness is, in mechanistic and functional terms; it does not address the “implementation” level of analysis (how neurons instantiate conscious states), an enigma for various disciplines. However, in response to the commentaries, we discuss how our framework provides clues regarding this enigma. In the framework, consciousness is passive albeit essential. Without consciousness, there would not be adaptive skeletomotor action

Retrospective Prime Reliance: A Flexible Retrospective Mechanism for Semantic Priming in Visual Word Recognition

Recent evidences (Balota et al., 2008; Thomas et al., 2012) suggest that the cognitive system can retrospectively (i.e., after target presentation) increase its reliance on prime information when target-word recognition is made more difficult by experimental manipulations such as visual degradation. In fact, response time (RT) distributional analyses have shown that for clearly visible target-words the priming effect has the same size in all the portions of the RT distribution. In contrast, for degraded target-words, priming effects increase across the RT distribution, coherently with the idea of an increased reliance on prime information for degraded targets, which would be particularly beneficial for the most difficult responses (i.e., the slowest ones). The first study (with English-speaking participants), investigated the idea of retrospective prime reliance in the context of an important empirical conundrum within the word recognition literature, produced by the joint effects of stimulus visual quality (SQ), semantic priming and word frequency. The manipulation of these variables, in fact, has traditionally produced constraining results for models of priming (e.g., McNamara, 2005), as well as for visual word recognition models (e.g., Reynolds & Besner, 2004). In Experiment 1, all the three variables have been manipulated within a single speeded pronunciation task, where words and nonwords were randomly appearing as targets. The results indicated that the joint effect of SQ and word frequency on RTs were dependent upon prime relatedness. More specifically, additive effects of SQ and frequency were observed after related primes, while an overadditive interaction was observed after unrelated primes. Distributional analyses showed that this three-way interaction was mediated by slowest RTs and it was hypothesized that the pattern of effects reflects reliance on prime information. To test this hypothesis, in Experiment 2 related primes were eliminated from the list, to produce a context in which there was no reason to rely on prime information. Interactive effects of SQ and frequency found following unrelated primes in Experiment 1 reverted, in Experiment 2, to additive effects for the same unrelated prime conditions. Note that, in English, additive effects of SQ and frequency are found in standard speeded pronunciation tasks (i.e., with no primes), provided that words and nonwords are randomly intermixed in the target set (as was the case in Experiment 2). In a second study, the same experiments as in the first one were tested within a different priming paradigm, namely in zero-lag repetition priming (e.g., Ferguson et al., 2009) and within a different language (Italian). Although distributional analyses provided preliminary evidences that retrospective prime reliance is operative even in this context (Experiment 3), cross-linguistic differences were nonetheless observed. More specifically, in English SQ and frequency produce additive effects in a speeded pronunciation task, provided that nonword targets are intermixed with real words (O’Malley & Besner, 2008) and provided that primes (if present) are all unrelated (Experiment 2). This finding does not seem to be replicated in Italian, where the two variables still produced, in Experiment 4, an overadditive interaction despite the presence of nonwords in the target-set and despite the fact that only unrelated primes were presented (exactly as in Experiment 2). It was hypothesized the discrepancy might stem from the fact that, while in English the system needs to place a functional threshold at an earlier processing level in order to overcome the detrimental effect of visual degradation before lexical representations get activated (thus avoiding lexicalization errors), in a transparent language this might not be the case. It was thus argued that in Italian it is sufficient to increase the reliance on sublexical output, without qualitatively altering the activation-dynamics of the system. The third study explored the possibility that retrospective prime reliance entails episodic retrieval. In a first experiment, English-speaking participants first performed a lexical decision task where SQ and semantic priming were manipulated. After completing the lexical decision and a brief distracter-task, they also performed a recognition memory task on primes presented during the lexical decision. Results showed a trend towards better recognition of those primes that preceded degraded targets, as opposed to clearly visible ones. The result is coherent with the hypothesis that, for those primes that preceded degraded targets, episodic retrieval takes place even in lexical decision, thereby facilitating the recognition of these items in a subsequent memory task. In a second experiment (Italian participants), the effect of SQ in the memory task was not replicated, probably due to specific features of the materials used in the experiment. On the other hand, a strong lexicality effect was found in the memory performance: primes that preceded real words were recognized much better compared to those that preceded nonwords in the previous experimental phase. These results suggest that the interplay between primes and targets, and the cognitive operations required to process them in lexical decision may reflect into the memory traces left by these stimuli. In conclusion, retrospective prime reliance proved to be a useful theoretical tool to understand the joint effect of semantic priming, SQ, and frequency, thereby proposing a new perspective on this issue. Moreover, preliminary evidences suggest that a retrospective component might be involved even in a zero-lag repetition priming paradigm and that the mechanism beside retrospective reliance might entail the episodic retrieval of the prime’s representation. Most importantly, the results highlight the flexibility and the sensitivity of the reading system to the context (i.e., experimental task, characteristics of the stimuli)

Semantic radical consistency and character transparency effects in Chinese: an ERP study

BACKGROUND: This event-related potential (ERP) study aims to investigate the representation and temporal dynamics of Chinese orthography-to-semantics mappings by simultaneously manipulating character transparency and semantic radical consistency. Character components, referred to as radicals, make up the building blocks used dur...postprin

Consciosusness in Cognitive Architectures. A Principled Analysis of RCS, Soar and ACT-R

This report analyses the aplicability of the principles of consciousness developed in the ASys project to three of the most relevant cognitive architectures. This is done in relation to their aplicability to build integrated control systems and studying their support for general mechanisms of real-time consciousness.\ud To analyse these architectures the ASys Framework is employed. This is a conceptual framework based on an extension for cognitive autonomous systems of the General Systems Theory (GST).\ud A general qualitative evaluation criteria for cognitive architectures is established based upon: a) requirements for a cognitive architecture, b) the theoretical framework based on the GST and c) core design principles for integrated cognitive conscious control systems

The role of previous experience in conscious perception

Which factors determine whether a stimulus is consciously perceived or unconsciously processed? Here, I investigate how previous experience on two different time scales – long term experience over the course of several days, and short term experience based on the previous trial – impact conscious perception. Regarding long term experience, I investigate how perceptual learning does not only change the capacity to process stimuli, but also the capacity to consciously perceive them. To this end, subjects are trained extensively to discriminate between masked stimuli, and concurrently rate their subjective experience. Both the ability to discriminate the stimuli as well as subjective awareness of the stimuli increase as a function of training. However, these two effects are not simple byproducts of each other. On the contrary, they display different time courses, with above chance discrimination performance emerging before subjective experience; importantly, the two learning effects also rely on different circuits in the brain: Moving the stimuli outside the trained receptive field size abolishes the learning effects on discrimination ability, but preserves the learning effects on subjective awareness. This indicates that the receptive fields serving subjective experience are larger than the ones serving objective performance, and that the channels through which they receive their information are arranged in parallel. Regarding short term experience, I investigate how memory based predictions arising from information acquired on the trial before affect visibility and the neural correlates of consciousness. To this end, I vary stimulus evidence as well as predictability and acquire electroencephalographic data. A comparison of the neural processes distinguishing consciously perceived from unperceived trials with and without predictions reveals that predictions speed up processing, thus shifting the neural correlates forward in time. Thus, the neural correlates of consciousness display a previously unappreciated flexibility in time and do not arise invariably late as had been predicted by some theorists. Admittedly, however, previous experience does not always stabilize perception. Instead, previous experience can have the reverse effect: Seeing the opposite of what was there, as in so-called repulsive aftereffects. Here, I investigate what determines the direction of previous experience using multistable stimuli. In a functional magnetic resonance imaging experiment, I find that a widespread network of frontal, parietal, and ventral occipital brain areas is involved in perceptual stabilization, whereas the reverse effect is only evident in extrastriate cortex. This areal separation possibly endows the brain with the flexibility to switch between exploiting already available information and emphasizing the new. Taken together, my data show that conscious perception and its neuronal correlates display a remarkable degree of flexibility and plasticity, which should be taken into account in future theories of consciousness

Continuities of Consciousness, Life-Worlds, and Numinous Experience: Cognitive-Phenomenological Foundations for an Empirical Neo-Shamanism

Numinous experience—as the felt sense of the sacred—evokes feelings of allone unity, communality, humility, and healing. Its schematization in the absolutes of traditional religion can also be seen as all-encompassing symbolic unifications of an otherwise fragmented human life-world—as more analytically depicted in the life-world phenomenologies of Husserl and Heidegger. In both feeling and concept the numinous would be the semantic amplification of the more concrete organism-surround nonduality of non symbolic organisms—as reflected in a primary consciousness shared across Uexkuell’s sentient animal umwelten and Gibson’s “envelopes of flow.” H usserl’s phenomenology of passive synthesis and James on pure experience can be understood as intuiting the implicit forms underlying such a primary transspecies consciousness, as both differentiated into these concrete lifeworlds, to the level of the inferably sentient protozoa, and abstractly amplified as the human numinous. The latter, with its original social template in an ethically responsible shamanism, becomes similarly responsible in the contemporary context of a human caused global climate crisis for the care and conservation of that Spirit it both develops as such and accurately intuits as a universal is-like shared with all sentient beings

Can Science Explain Consciousness?

For diverse reasons, the problem of phenomenal consciousness is persistently challenging. Mental terms are characteristically ambiguous, researchers have philosophical biases, secondary qualities are excluded from objective description, and philosophers love to argue. Adhering to a regime of efficient causes and third-person descriptions, science as it has been defined has no place for subjectivity or teleology. A solution to the “hard problem” of consciousness will require a radical approach: to take the point of view of the cognitive system itself. To facilitate this approach, a concept of agency is introduced along with a different understanding of intentionality. Following this approach reveals that the autopoietic cognitive system constructs phenomenality through acts of fiat, which underlie perceptual completion effects and “filling in”—and, by implication, phenomenology in general. It creates phenomenality much as we create meaning in language, through the use of symbols that it assigns meaning in the context of an embodied evolutionary history that is the source of valuation upon which meaning depends. Phenomenality is a virtual representation to itself by an executive agent (the conscious self) tasked with monitoring the state of the organism and its environment, planning future action, and coordinating various sub- agencies. Consciousness is not epiphenomenal, but serves a function for higher organisms that is distinct from that of unconscious processing. While a strictly scientific solution to the hard problem is not possible for a science that excludes the subjectivity it seeks to explain, there is hope to at least psychologically bridge the explanatory gulf between mind and matter, and perhaps hope for a broader definition of science

Homing in on consciousness in the nervous system: An action-based synthesis

Abstract: The primary function of consciousness in the nervous system remains mysterious. Passive frame theory, a synthesis of empirically supported hypotheses from diverse fields of investigation, reveals that consciousness serves as a frame that constrains and directs skeletal muscle output, thereby yielding adaptive behavior. How consciousness achieves this is more counterintuitive, “low level, ” and passive than the kinds of functions that theorists have attributed to consciousness. From this unique, action-based perspective, consciousness is in the service of the somatic nervous system. The framework begins to isolate the neuroanatomical, cognitive-mechanistic, and representational processes associated with consciousness.