Assessing Consciousness Theory: A Systematic Scoping Review of 25 Years of Empirical Evidence for Neuroscientific Theories of Consciousness A Thesis Presented to The Division of Philosophy, Religion, Psychology, and Linguistics Reed College In Partial Fulfillment of the Requirements for the Degree Bachelor of Arts Cole Dembski May 2020 Approved for the Division (Psychology) Michael Pitts Acknowledgments Many, many thanks to Michael Pitts, for providing guidance and encouragement throughout the process of putting together this thesis – and for accompanying me as I found, for the first time, an area of study that genuinely excited me. Boundless gratitude and love for my family, without whom I would never have had the extraordinary opportunity to come to Reed and who have supported me throughout my academic experience here. And, of course, to all those I have been fortunate enough to have in my life over the last four years: I cannot express the love and appreciation I have for you – thank you. Table of Contents A Science of Consciousness .............................................................................................. 1 The Problem of Consciousness ....................................................................................... 1 The Explanatory Gap .................................................................................................. 3 The Problems .............................................................................................................. 3 Approaching the Problems .......................................................................................... 5 The Meta-Problem ...................................................................................................... 6 Overarching Issues in the Field ...................................................................................... 7 A Mature Science ........................................................................................................ 8 A Clear Terminology ................................................................................................ 10 Challenges in Consciousness Science........................................................................... 12 Basic Difficulties....................................................................................................... 13 Biased and Conflicting Measures ............................................................................. 14 Levels of Description and the Matching Problem .................................................... 15 The Modern Science of Consciousness ........................................................................ 16 Theoretical Directions ............................................................................................... 17 Theories of Consciousness .............................................................................................. 19 Approaches to Theorizing Consciousness .................................................................... 19 Neurobiological Naturalism ...................................................................................... 19 Illusionism ................................................................................................................. 20 Higher-Order Approaches ......................................................................................... 21 Global Neuronal Workspace Theory ............................................................................ 22 Global Workspace Theory ........................................................................................ 22 Pyramidal Neurons and Global Availability ............................................................. 24 Feedback Systems, Top-Down Attention, and Accessing the Global Workspace ... 24 Sustained Contents in the Global Workspace ........................................................... 25 Integrated Information Theory ...................................................................................... 25 The Dynamic Core Hypothesis ................................................................................. 25 The Structure of IIT .................................................................................................. 27 Information in IIT ..................................................................................................... 29 The Axioms ............................................................................................................... 29 The Postulates ........................................................................................................... 30 Causal Power, Complexes, and Integrated Information ........................................... 32 Attention Schema Theory ............................................................................................. 35 The Body Schema ..................................................................................................... 36 The Process of Attention ........................................................................................... 38 Monitoring Attention ................................................................................................ 38 The Attention Schema ............................................................................................... 39 Between-Theory Compatibility .................................................................................... 40 Methods ............................................................................................................................ 43 Protocol ......................................................................................................................... 43 Eligibility Criteria ......................................................................................................... 43 Information Sources ...................................................................................................... 44 Search Method .............................................................................................................. 45 Selection of Sources of Evidence ................................................................................. 47 Data Charting Process ................................................................................................... 48 Results .............................................................................................................................. 49 Neural Network Properties ........................................................................................... 49 Integration & Modularity .......................................................................................... 50 Dynamic Activity and Complexity ........................................................................... 52 Brain Regions and Markers of Consciousness ............................................................. 54 Early Posterior Activity ............................................................................................ 54 The Ventral and Dorsal Visual Streams .................................................................... 55 Late Frontal Activity ................................................................................................. 56 Core Networks .......................................................................................................... 58 Mechanisms of Perception ............................................................................................ 59 Basic Processes of Visual Perception ....................................................................... 59 Visual Short-Term Memory ...................................................................................... 61 Multisensory Perception ........................................................................................... 62 Attention ....................................................................................................................... 63 Role of Attention in Modulating the Contents of Awareness ................................... 63 Attention and Consciousness .................................................................................... 65 Effects of Awareness .................................................................................................... 67 Visual and Temporal Binding ................................................................................... 67 Content Maintenance and Manipulation ................................................................... 68 Attentional Control ................................................................................................... 70 Sensory Integration ................................................................................................... 72 Phenomenology ............................................................................................................ 75 Illusory Perception .................................................................................................... 75 Attention, Expectations, and Predictive Processing.................................................. 77 Qualia Space ............................................................................................................. 78 Discussion......................................................................................................................... 81 Assessing the Theories.................................................................................................. 82 Integrated