Role In Conscious Experience Research Articles

The reach of reactivation: Effects of consciously triggered versus unconsciously triggered reactivation of associative memory

Consolidating memories for long-term storage depends on reactivation. Reactivation occurs both consciously, during wakefulness, and unconsciously, during wakefulness and sleep. While considerable work has examined conscious awake and unconscious sleep reactivation, in this study, we directly compare the consequences of conscious and unconscious reactivation during wakefulness. Forty-one participants learned associations consisting of adjective-object-position triads. Objects were clustered into distinct semantic groups (e.g., fruits, vehicles) such that we could examine consequences of reactivation on semantically related memories. After an intensive learning protocol, we systematically reactivated some of the triads by presenting the adjective as a cue. Reactivation was done so that it was consciously experienced for some triads, and only unconsciously processed for others. Memory for spatial positions, the most distal part of the association, was affected by reactivation in a consciousness-dependent and memory-strength-dependent manner. Conscious reactivation resulted in weakening of semantically related memories that were strong initially, resonating with prior findings of retrieval-induced forgetting. Unconscious reactivation, on the other hand, selectively benefited weak reactivated memories, as previously shown for reactivation during sleep. Semantically linked memories were not impaired, but rather were integrated with the reactivated memory. These results taken together demonstrate that conscious and unconscious reactivation have qualitatively different consequences. Results support a consciousness-dependent inhibition account, whereby unconscious reactivation entails less inhibition than conscious reactivation, thus allowing more liberal spread of activation. Findings set the stage for additional exploration into the role of conscious experience in memory storage and structuring.

Neural synchrony in cortical networks: history, concept and current status.

Following the discovery of context-dependent synchronization of oscillatory neuronal responses in the visual system, the role of neural synchrony in cortical networks has been expanded to provide a general mechanism for the coordination of distributed neural activity patterns. In the current paper, we present an update of the status of this hypothesis through summarizing recent results from our laboratory that suggest important new insights regarding the mechanisms, function and relevance of this phenomenon. In the first part, we present recent results derived from animal experiments and mathematical simulations that provide novel explanations and mechanisms for zero and nero-zero phase lag synchronization. In the second part, we shall discuss the role of neural synchrony for expectancy during perceptual organization and its role in conscious experience. This will be followed by evidence that indicates that in addition to supporting conscious cognition, neural synchrony is abnormal in major brain disorders, such as schizophrenia and autism spectrum disorders. We conclude this paper with suggestions for further research as well as with critical issues that need to be addressed in future studies.

One brain, two selves

Having a sense of self is an explicit and high-level functional specialization of the human brain. The anatomical localization of self-awareness and the brain mechanisms involved in consciousness were investigated by functional neuroimaging different emotional mental states of core consciousness in patients with Multiple Personality Disorder (i.e., Dissociative Identity Disorder (DID)). We demonstrate specific changes in localized brain activity consistent with their ability to generate at least two distinct mental states of self-awareness, each with its own access to autobiographical trauma-related memory. Our findings reveal the existence of different regional cerebral blood flow patterns for different senses of self. We present evidence for the medial prefrontal cortex (MPFC) and the posterior associative cortices to have an integral role in conscious experience.

Subjective rating scales: science or art?

Subjective rating scales are widely used in almost every aspect of ergonomics research and practice for the assessment of workload, fatigue, usability, annoyance and comfort, and lesser known qualities such as urgency and presence, but are they truly scientific? This paper raises some of the key issues as a basis for debate. First, it is argued that all empirical observations, including those conventionally labelled as ‘objective’, are unavoidably subjective. Shared meaning between observers, or intersubjectivity, is the key criterion of scientific probity. The practical steps that can be taken to increase intersubjective agreement are discussed and the well-known sources of error and bias in human judgement reviewed. The role of conscious experience as a mechanism for appraising the environment and guiding behaviour has important implications for the interpretation of subjective reports. The view that psychometric measures do not conform to the requirements of truly ‘scientific’ measurement is discussed. Human judgement of subjective attributes is essentially ordinal and, unlike physical measures, can be matched to interval scales only with difficulty, but ordinal measures can be used successfully both to develop and test substantive theories using multivariate statistical techniques. Constructs such as fatigue are best understood as latent or inferred variables defined by a set of manifest or directly observed indicator variables. Both construct validity and predictive validity are viewed from this perspective and this helps to clarify several problems including the dissociation between measures of different aspects of a given construct, the question of whether physical (e.g. physiological) measures should be preferred to subjective measures and whether a single measure of constructs which are essentially multidimensional having both subjective and physical components is desirable. Finally, the fitness of subjective ratings to different purposes within the broad field of ergonomics research is discussed. For testing of competing hypotheses concerning the mechanisms underlying human performance, precise quantitative predictions are rarely needed. The same is frequently true of comparative evaluation of competing designs. In setting design standards, however, something approaching the level of measurement required for precise quantitative prediction is required, but this is difficult to achieve in practice. Although it may be possible to establish standards within restricted contexts, general standards for broadly conceived constructs such as workload are impractical owing to the requirement for representative sampling of tasks, work environments and personnel.

Perception and Reason

This volume presents an original view of the role of conscious experience in the acquisition of knowledge. It argues that experiences must provide reasons for beliefs if there are to be any beliefs about the mind-independent world at all

Experience and Reason in Perception

The question I am interested in is this. What exactly is the role of conscious experience in the acquisition of knowledge on the basis of perception? The problem here, as I see it, is to solve simultaneously for the nature of this experience, and its role in acquiring and sustaining the relevant beliefs, in such a way as to vindicate what I regard as an undeniable datum, that perception is a basic source of knowledge about the mind-independent world, in a sense of ‘basic’ which is also to be elucidated. I shall sketch the way in which I think that this should be done. In section I, I argue that perceptual experiences must provide reasons for empirical beliefs. In section II, I explain how they do so. My thesis is that a correct account of the sense in which perceptual experiences are experiences of mind-independent things is itself an account of the way in which they provide peculiarly basic reasons for beliefs about the world around the perceiver.