The search for neural correlates of consciousness (or NCCs) is arguably the cornerstone in the recent resurgence of the science of consciousness. The search poses many difficult empirical problems, but it seems to be tractable in principle, and some ingenious studies in recent years have led to considerable progress. A number of proposals have been put forward concerning the nature and location of neural correlates of consciousness. A few of these include.

This is the Stanford Encyclopedia of Philosophy entry on the contents of perception.

Consciousness is scientifically challenging to study because of its subjective aspect. This leads researchers to rely on report-based experimental paradigms in order to discover neural correlates of consciousness (NCCs). I argue that the reliance on reports has biased the search for NCCs, thus creating what I call 'methodological artefacts'. This paper has three main goals: first, describe the measurement problem in consciousness science and argue that this problem led to the emergence of methodological artefacts. Second, provide a critical assessment of (...) the NCCs put forward by the global neuronal workspace theory. Third, provide the means of dissociating genuine NCCs from methodological artefacts. (shrink)

In this paper we argue that awareness comes in degrees, and we propose a novel multi-factor account that spans both subjective experiences and perceptual representations. At the subjective level, we argue that conscious experiences can be degraded by being fragmented, less salient, too generic, or flash-like. At the representational level, we identify corresponding features of perceptual representations—their availability for working memory, intensity, precision, and stability—and argue that the mechanisms that affect these features are what ultimately modulate the degree of awareness. (...) We conclude the paper by demonstrating why the original interpretations of certain empirical findings that apparently pose problems for our account are, in fact, flawed. (shrink)

Do sensory measurements deserve the label of “measurement”? We argue that they do. They fit with an epistemological view of measurement held in current philosophy of science, and they face the same kinds of epistemological challenges as physical measurements do: the problem of coordination and the problem of standardization. These problems are addressed through the process of “epistemic iteration,” for all measurements. We also argue for distinguishing the problem of standardization from the problem of coordination. To exemplify our claims, we (...) draw on olfactory performance tests, especially studies linking olfactory decline to neurodegenerative disorders. (shrink)

Bas C. van Fraassen presents an original exploration of how we represent the world.

Do you dream in color? If you answer Yes, how can you be sure? Before you recount your vivid memory of a dream featuring all the colors of the rainbow, consider that in the 1950s researchers found that most people reported dreaming in black and white. In the 1960s, when most movies were in color and more people had color television sets, the vast majority of reported dreams contained color. The most likely explanation for this, according to the philosopher Eric (...) Schwitzgebel, is not that exposure to black-and-white media made people misremember their dreams. It is that we simply don't know whether or not we dream in color. In Perplexities of Consciousness, Schwitzgebel examines various aspects of inner life and argues that we know very little about our stream of conscious experience. Drawing broadly from historical and recent philosophy and psychology to examine such topics as visual perspective, and the unreliability of introspection, Schwitzgebel finds us singularly inept in our judgments about conscious experience. (shrink)

The source of endless speculation and public curiosity, our scientific quest for the origins of human consciousness has expanded along with the technical capabilities of science itself and remains one of the key topics able to fire public as much as academic interest. Yet many problematic issues, identified in this important new book, remain unresolved. Focusing on a series of methodological difficulties swirling around consciousness research, the contributors to this volume suggest that ‘consciousness’ is, in fact, not a wholly viable (...) scientific concept. Supporting this ‘eliminativist‘ stance are assessments of the current theories and methods of consciousness science in their own terms, as well as applications of good scientific practice criteria from the philosophy of science. For example, the work identifies the central problem of the misuse of qualitative difference and dissociation paradigms, often deployed to identify measures of consciousness. It also examines the difficulties that attend the wide range of experimental protocols used to operationalise consciousness—and the implications this has on the findings of integrative approaches across behavioural and neurophysiological research. The work also explores the significant mismatch between the common intuitions about the content of consciousness, that motivate much of the current science, and the actual properties of the neural processes underlying sensory and cognitive phenomena. Even as it makes the negative eliminativist case, the strong empirical grounding in this volume also allows positive characterisations to be made about the products of the current science of consciousness, facilitating a re-identification of target phenomena and valid research questions for the mind sciences.​. (shrink)

Introspective and phenomenological methods are once again being used to support the use of subjective reports, rather than objective behavioural measures, to investigate and measure consciousness. Objective measures are often seen as useful ways of investigating the range of capacities subjects have in responding to phenomena, but are fraught with the interpretive problems of how to link behavioural capacities with consciousness. Instead, gathering subjective reports is seen as a more direct way of assessing the contents of consciousness. This article explores (...) three different ways of gathering subjective reports that have been discussed in recent literature on consciousness, including immediate retrospection (Schwitzgebel [2007]) and two types of introspective training (Overgaard et al. [2004]; Schwitzgebel [2008]). Although not an exhaustive survey of the range of introspective methods now used, the discussion below highlights a range of general methodological problems with introspective methods, many identified up to a century ago. It is argued that none of the methodological problems established in earlier criticisms of the use of subjective reports have been dealt with, yet are still valid criticisms. Given that this is not the first time proponents of introspective, subjective measures of conscious have failed to answer these criticisms, this raises the question of whether the goal of providing a measure of consciousness is a methodological muddle worth pursuing. (shrink)

This book presents the concept of “complementary science” which contributes to scientific knowledge through historical and philosophical investigations. It emphasizes the fact that many simple items of knowledge that we take for granted were actually spectacular achievements obtained only after a great deal of innovative thinking, painstaking experiments, bold conjectures, and serious controversies. Each chapter in the book consists of two parts: a narrative part that states the philosophical puzzle and gives a problem-centred narrative on the historical attempts to solve (...) the puzzle; and the analysis part which provides in-depth analyses of certain scientific, historical, and philosophical aspects of the story. (shrink)

In a recent article, [Sergent, C. & Dehaene, S. . Is consciousness a gradual phenomenon? Evidence for an all-or-none bifurcation during the attentional blink, Psychological Science, 15, 720–729] claim to give experimental support to the thesis that there is a clear transition between conscious and unconscious perception. This idea is opposed to theoretical arguments that we should think of conscious perception as a continuum of clarity, with e.g., fringe conscious states [Mangan, B. . Sensation’s ghost—the non-sensory “fringe” of consciousness, Psyche, (...) 7, 18]. In the experimental study described in this article, we find support for this opposite notion that we should have a parsimonious account of conscious perception. Our reported finding relates to the hypothesis that there is more than one perceptual threshold [Merikle, P.M., Smilek, D. & Eastwood, J.D. . Perception without awareness: perspectives from cognitive psychology, Cognition, 79, 115–134], but goes further to argue that there are different “levels” of conscious perception. (shrink)

What is the best way of assessing the extent to which people are aware of a stimulus? Here, using a masked visual identification task, we compared three measures of subjective awareness: The Perceptual Awareness Scale , through which participants are asked to rate the clarity of their visual experience; confidence ratings , through which participants express their confidence in their identification decisions, and Post-decision wagering , in which participants place a monetary wager on their decisions. We conducted detailed explorations of (...) the relationships between awareness and identification performance, looking to determine which scale best correlates with performance, and whether we can detect performance in the absence of awareness and how the scales differ from each other in terms of revealing such unconscious processing. Based on these findings we discuss whether perceptual awareness should be considered graded or dichotomous. Results showed that PAS showed a much stronger performance-awareness correlation than either CR or PDW, particularly for low stimulus intensities. In general, all scales indicated above-chance performance when participants claimed not to have seen anything. However, such above-chance performance only showed when we also observed a correlation between awareness and performance. Thus PAS seems to be the most exhaustive measure of awareness, and we find support for above-chance performance in the absence of subjective awareness, but such unconscious knowledge only contributes to performance when we observe conscious knowledge as well. Similarities and differences between scales are discussed in the light of consciousness theories and response strategies. (shrink)

Subliminal perception (SP) is today considered a well-supported theory stating that perception can occur without conscious awareness and have a significant impact on later behaviour and thought. In this article, we first present and discuss different approaches to the study of SP. In doing this, we claim that most approaches are based on a dichotomic measure of awareness. Drawing upon recent advances and discussions in the study of introspection and phenomenological psychology, we argue for both the possibility and necessity of (...) using an elaborated measure of subjective states. In the second part of the article, we present findings where these considerations are implemented in an empirical study. The results and implications are discussed in detail, both with reference to SP, and in relation to the more general problem of using elaborate introspective reports as data in relation to studies of cognition. (shrink)