UC Merced

The primary and overarching goal of this dissertation is to disambiguate consciousness through a combined approach of physiological experimentation and philosophical investigation. I start with a behavioral experiment in Chapter 2 on inattentional deafness that lays the groundwork for a follow-up EEG paradigm. Both experiments were conducted using a 2 × 2 design that manipulated perceptual and/or cognitive load while measuring auditory awareness. Our behavioral results aligned with load theory. We found that high perceptual load reliably led to failures in sound detection, while effects of cognitive load were more nuanced. In Chapter 3, I extended this paradigm to explore the neural correlates of consciousness (NCCs) via EEG analysis, with a central focus on how task relevance and the act of reporting may be conflated with perceptual awareness. The neurophysiological results of the experiment included both event related potentials (ERPs) and oscillatory activity. For ERPs, I found a centroparietal N2 and P300, as well as a frontocentral P1–N1–P2–N2 sequence. Aligning with previous literature, the P300 component emerged only in task-relevant (report) conditions. A frontocentral N2 was observed across all conditions, however, it was also modulated by task relevance (reporting). Oscillatory activity results revealed modulations in the alpha, beta, and theta frequency bands. No ERPs were revealed when comparing the no report conditions, however, an atypical frequency band was found in the overlapping theta/alpha range (7-8.5 Hz). Based on these findings, I propose a graded model of consciousness that bridges empirical data and theoretical perspectives. In this, I emphasize a pluralistic and pragmatic approach to consciousness, in which all theories hold a relatively truthful perspective, and the “right” theory depends on the specific context. Furthermore, in Chapter 4, I challenge the idea of a separation between access and phenomenal consciousness, framing consciousness instead as a temporally extended, relational process. In the final chapter, this perspective is expanded into a classification space for potentially conscious systems across existence. Working from the common definition of consciousness as “subjective experience,” I employ subjectivity and information processing as the two core dimensions of our classification space. Awareness, as I define it, is a fundamental presence and the essence of consciousness. This underlying awareness is unveiled and expressed through the unique architecture of a subjective information processing system. Overall, our work draws from philosophy, neuroscience, evolutionary biology, and dynamical systems theory to offer a pluralistic and integrative account of consciousness.