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)

In this article, we present results from an interdisciplinary research project aimed at assessing consciousness in dreams. For this purpose, we compared lucid dreams with normal non-lucid dreams from REM sleep. Both lucid and non-lucid dreams are an important contrast condition for theories of waking consciousness, giving valuable insights into the structure of conscious experience and its neural correlates during sleep. However, the precise differences between lucid and non-lucid dreams remain poorly understood. The construction of the Lucidity and (...) Consciousness in Dreams scale was based on theoretical considerations and empirical observations. Exploratory factor analysis of the data from the first survey identified eight factors that were validated in a second survey using confirmatory factor analysis: INSIGHT, CONTROL, THOUGHT, REALISM, MEMORY, DISSOCIATION, NEGATIVE EMOTION, and POSITIVE EMOTION. While all factors are involved in dream consciousness, realism and negative emotion do not differentiate between lucid and non-lucid dreams, suggesting that lucid insight is separable from both bizarreness in dreams and a change in the subjectively experienced realism of the dream. (shrink)

When consciousness is examined using subjective ratings, the extent to which processing is conscious or unconscious is often estimated by calculating task performance at the subjective threshold or by calculating the correlation between accuracy and awareness. However, both these methods have certain limitations. In the present article, we propose describing task accuracy and awareness as functions of stimulus intensity as suggested by Koch and Preuschoff . The estimated lag between the curves describes how much stimulus intensity must increase for (...) awareness to change proportionally as much as accuracy and the slopes of the curves are used to assess how fast accuracy and awareness increases and whether awareness is dichotomous. The method is successfully employed to assess consciousness characteristics on data from four different awareness scales. (shrink)

In their comment on Sandberg, Timmermans, Overgaard, and Cleeremans , Dienes and Seth argue that increased sensitivity of the Perceptual Awareness Scale is a consequence of the scale being less exclusive rather than more exhaustive. According to Dienes and Seth, this is because PAS may measure some conscious content, though not necessarily relevant conscious content, “If one saw a square but was only aware of seeing a flash of something, then one has not consciously seen a square.” In this reply, (...) we claim that there is a difference between conscious visual experience, which may be partial, and the resulting conscious content, which is conceptual. Whereas PAS measures the first, confidence judgments and post-decision wagering measure the second. (shrink)

Memory researchers have discussed the relationship between consciousness and memory frequently in the last few decades. Beginning with research by Warrington and Weiskrantz (1968; 1970), memory has been shown to influence task performance even without awareness of retrieval. Data from amnesic patients show that a study episode influences task performance despite their lack of conscious memory for the study session. More recently, issues of intentionality, awareness, and the relationship between conscious and unconscious forms of memory have come to the (...) forefront. Conscious memory has sometimes been defined by intention to retrieve and sometimes by awareness of retrieval. This distinction has been debated as measurement methodologies have developed. In addition, the functional relationship between conscious and automatic forms of memory has implications for measurement of memory processes and the development of models of memory task performance. Several measurement techniques for conscious and automatic memory are reviewed. The current state of these issues is also discussed. (shrink)

This paper addresses what we consider to be the most pressing challenge for the emerging science of consciousness: the measurement problem of consciousness. That is, by what methods can we determine the presence of and properties of consciousness? Most methods are currently developed through evaluation of the presence of consciousness in humans and here we argue that there are particular problems in application of these methods to nonhuman cases—what we call the indicator validity problem and the (...) extrapolation problem. The first is a problem with the application of indicators developed using the differences between conscious and unconscious processing in humans to the identification of other conscious vs. nonconscious organisms or systems. The second is a problem in extrapolating any indicators developed in humans or other organisms to artificial systems. However, while pressing ethical concerns add urgency to the attribution of consciousness and its attendant moral status to nonhuman animals and intelligent machines, we cannot wait for certainty and we advocate the use of a precautionary principle to avoid causing unintentional harm. We also intend that the considerations and limitations discussed in this paper can be used to further analyze and refine the methods of consciousness science with the hope that one day we may be able to solve the measurement problem of consciousness. (shrink)

Continuous sedation at the end of life is a practice that has attracted a great deal of attention. An increasing number of guidelines on the proposed correct performance of the practice have been drafted. All of the guidelines stress the importance of using sedation in proportion to the severity of the patient’s symptoms, thus to reduce the patient’s consciousness no more than is absolutely necessary. As different patients can have different experiences of suffering, the amount of suffering should, ideally, (...) be assessed subjectively; that is, via communication with the patient. Continuously sedated patients are often unable to communicate, however, making subjective methods of pain assessment unusable. For these patients, the degree of consciousness is the sole available measure. It therefore seems important to adequately measure how deeply the patient is sedated, thereby allowing sedation to be increased when it is too light and decreased when it is too heavy. This is in accordance with the idea that reducing consciousness is not an ethically neutral act.Although consciousness measuring techniques are a hot topic in anesthesiology, almost no research exists on the use of such techniques in the context of continuous sedation at the end of life. This article aims to review existing techniques to measure consciousness and to evaluate their applicability, efficiency, and invasiveness for patients who are continuously sedated until death.Techniques commonly used to assess the depth of sedation in continuously sedated patients are basic clinical assessment and sedation scales, as they are often considered reliable and noninvasive. These techniques might not be very reliable, however, since it is known that some patients are nonresponsive and yet aware. Moreover, sedation scales require stimulation of the patient (for example prodding, shaking, or providing painful stimuli), and can thus be considered invasive of one’s bodily integrity or dignity. Other techniques, such as EEG (electroencephalography) derivatives, may score better on reliability and invasiveness. Yet these have so far never been compared to sedation scale scores for patients receiving continuous sedation at the end of life.Therefore, we conclude that, for both clinical and ethical reasons, research into the efficiency and applicability of other techniques, such as derivatives of EEG, are urgently needed. (shrink)

Consciousness is now a hot topic in both philosophy and the cognitive sciences, yet there is much controversy over how to measure it. First, it is not clear whether biased subjective reports should be taken as adequate for measuring consciousness, or if more objective measures are required. Ways to benefit from the advantages of both these measures in the form of ‘Type 2’ metacognitive measures are under development, but face criticism. Research into neurophysiological measures of consciousness (...) is potentially very valuable, but often hindered by its dependence on behavioural measures that are themselves controversial. Newer informational measures are theoretically interesting, but as yet not easily applicable, while other measures of consciousness are designed for application in clinical cases . Although much optimism accompanies research into measures of consciousness, the controversies and methodological problems reviewed here suggest that making progress in this area may be more difficult than is often acknowledged. (shrink)

There are two versions of the putative connection between consciousness and the measurement problem of quantum mechanics : consciousness as the cause of state vector reduction, and state vector reduction as the physical basis of consciousness. In this article, these controversial ideas are neither accepted uncritically, nor rejected from the outset in the name of some prejudice about objective knowledge. Instead, their origin is sought in our most cherished (but disputable) beliefs about the place of mind and (...) consciousness in the world. It is first pointed out that these common beliefs about mind and consciousness arise from reification of situated first-person experience. Then, situatedness is shown to be a constitutive part of any exhaustive treatment of quantum measurements. It turns out that the alleged connection between consciousness and the measurement problem is a symptom of (i) the ineliminability of our being situated from the end-product of science, and (ii) our difficulty to express correctly this being situated. (shrink)

Consciousness can be measured in various ways, but different measures often yield different conclusions about the extent to which awareness relates to performance. Here, we compare five different subjective measures of awareness in the context of an artificial grammar learning task. Participants expressed their subjective awareness of rules using one of five different scales: confidence ratings , post-decision wagering , feeling of warmth , rule awareness , and continuous scale . All scales were equally sensitive to conscious knowledge. PDW, (...) however, was affected by risk aversion, and both RAS and SDS applied different minimal criteria for rule awareness. CR seems to capture the largest range of consciousness, but failed to indicate unconscious knowledge with the guessing criterion. We close by discussing the theoretical implications of scale sensitivity and propose that CR’s unique features enable a finer assessment of subjective states of awareness. (shrink)

This chapter discusses the main types of so-called ’subjective measures of consciousness’ used in current-day science of consciousness. After explaining the key worry about such measures, namely the problem of an ever-present response bias, I discuss the question of whether subjective measures of consciousness are introspective. I show that there is no clear answer to this question, as proponents of subjective measures do not employ a worked-out notion of subjective access. In turn, this makes the problem of (...) response bias less tractable than it might otherwise be. (shrink)

Sandberg et al. show that the Perceptual Awareness Scale scale is sensitive compared to confidence ratings and wagering in detecting accurate perception. They go on to argue that the PAS scale is hence a sensitive measure of conscious perception compared to confidence ratings, a claim disputed here. The fact that some visual content is conscious does not entail that the visual content relevant to making a discrimination is conscious. For example, if one saw a square but was only aware of (...) seeing a flash of something, then one has not consciously seen a square. When PAS and confidence ratings come in conflict, we suggest that it is confidence ratings that more reliably indicate the conscious status of contents allowing discrimination. (shrink)

It is shown that (a) the conscious observer plays no essential part in the measurement process, and (b) environmental perturbations of whatever kind fail to account for the evolution of systems into “mixtures” or “dynamically decoupled” systems.

This book explores how we can measure consciousness. It clarifies what consciousness is, how it can be generated from a physical system, and how it can be measured. It also shows how conscious states can be expressed mathematically and how precise predictions can be made using data from neurophysiological studies.

A wide range of problems of the relationship between consciousness and matter are discussed. Particular attention is paid to the analysis of the structure and properties of consciousness in the framework of information evolution. The role of specific (non-computational) properties of consciousness in the procedure of classical and quantum measurements is analyzed. In particular, the issue of "cloning" of consciousness (the possibility of copying its properties onto a new material carrier) is discussed in detail. We hope (...) that the generalized principle of complementarity formulated by us will open up new ways for studying the problems of consciousness within the framework of the fundamental physical picture of the world. (shrink)

Delirium has conventionally been considered a disorder of consciousness, but this remains a relatively unexamined precept. First, a review of the role of consciousness disruption in delirium is revised from an historical and diagnostic perspective. Second, consciousness measurement in routine assessment of delirium is considered. Conscious levels, comprising alertness and arousal, are most commonly used but are not representative of the multidimensionality of consciousness. Third, a justification for the exploration of phenomenal consciousness is presented. Three (...) candidate dimensions of phenomenal consciousness are identified as the pre-reflective state, phenomenal experience, and reflective thought. Finally, the clinical implications of a deeper understanding of delirium through measurement of phenomenal consciousness is considered. (shrink)

Dienes and Seth (2010) conclude that confidence ratings and post-decision wagering are two comparable and recommendable measures of conscious experience. In a recently submitted paper, we have however found that both methods are problematic and seem less suited to measure consciousness than a direct introspective measure. Here, we discuss the methodology and conclusions put forward by Dienes and Seth, and why we think the two experiments end up with so different recommendations.

It is possible to reveal and to examine the collective and social fields of consciousness experimentally. An account is given of planned experiments based on quantitative calculations, which indicate that the effects of individual and collective fields of consciousness on matter may elicit directly observable physical results. Moreover, it is shown that collective coherent consciousness fields may enhance the physical effects of consciousness at a significant rate. The predicted results have a significance in our picture of (...) our consciousness, in self-assertion and dynamising of consciousness, the expansion of collective fields of consciousness, and thus the raising of the level of consciousness for humanity. (shrink)

A recent report by Persaud et al. [Persaud, N., McLeod, P. & Cowey, A. . Post-decision wagering objectively measures awareness. Nature Neuroscience 10, 257–261] addresses a fundamental issue in consciousness science: the experimental measurement of conscious content. The authors propose a novel technique, ‘post-decision wagering’, in which subjects place bets on the correctness of decisions or discriminations. In this note, I critique the authors’ claim that their method “measures awareness directly”.

The accurate measurement of the level of consciousness of a creature remains a major scientific challenge, nevertheless a number of new accounts that attempt to address this problem have been proposed recently. In this paper we analyze the principles of these new measures of consciousness along with other classical approaches focusing on their applicability to Machine Consciousness (MC). Furthermore, we propose a set of requirements of what we think a suitable measure for MC should be, discussing the (...) associated theoretical and practical issues. Using the proposed requirements as a framework for the design of an integrative measure of consciousness, we explore the possibility of designing such a measure in the context of current state of the art in consciousness studies. (shrink)

Three experiments investigated response times for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember–know decision was preceded by an old/new decision or was made without a preceding old/new decision . The finding of faster RTs for R responses was also found when remember–know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful (...) than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test. (shrink)

Interpreting empirical measures of integration and differentiation as indices of cortical performance and memory consolidation during wakefulness rather than consciousness per se is inconsistent with the literature. Recent studies show that these theory-inspired measures can dissociate from such processes and reliably index the brain's capacity for experience. We consider this as a positive trend in consciousness research.

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)

States of sensory absorption may offer a means to disentangle perception from report. Interestingly, such states lead to an antagonistic relationship between perceptual and cognitive-access networks, suggesting that perceptual awareness does not depend on a read-out by high order cognitive-access mechanisms. Rather, it may emerge internally, through a cooperative coding dynamics, whereby each neuron simultaneously represents and reads-out the perceptual awareness state.

A new constructivist approach to modeling in economics and theory of consciousness is proposed. The state of elementary object is defined as a set of its measurable consumer properties. A proprietor's refusal or consent for the offered transaction is considered as a result of elementary economic measurement. Elementary (indivisible) technology, in which the object's consumer values are variable, in this case can be formalized as a generalized economic measurement. The algebra of such measurements has been constructed. It has been (...) shown that in the general case the quantummechanical formalism of the theory of selective measurements is required for description of such conditions. The economic analogs of the elementary slit experiments in physics have been created. The proposed approach can be also used for consciousness modeling. (shrink)

We live in a world in which we are socially, politically, economically, and environmentally connected with other people. Online communication has facilitated people coming together from different parts of the world. In terms of social justice movements, people have come together to share ideas about how they perceive social inequality and how to address it, which is what academics call critical consciousness. While scholars have explored critical consciousness in the American context, whether it operates on a global scale (...) is under-explored. To address this question, we administered the Critical Consciousness Scale (a validated survey) with students from the United States, Iran, and Ukraine. Our findings demonstrate that critical consciousness maintains its factor structure across the entire sample, meaning that students from these three countries share some notions of critical consciousness. However, when comparing national groups, we find that critical consciousness is defined differently by students in different countries. In a practical sense, these findings mean that some aspects of critical consciousness are shared, but there are important differences in how it is perceived and how its components relate to one another. By attempting to understand critical consciousness internationally, this study serves as a cautionary narrative for international solidarity movements organized around the goal of social justice. (shrink)

A structural analogy is pointed out between a check hermeneutically developed phenomenological description, based on Husserl, of the process of perceptual cognition on the one hand and quantum mechanical measurement on the other hand. In Husserl's analytic phase of the cognition process, the 'intentionality-structure' of the subject/object union prior to predication of a local object is an entangled symmetry-making state, and this entanglement is broken in the synthetic phase when the particular local object is constituted under the influence of an (...) iota ('inner horizon') and the 'facticity' of the local world ('outer horizon'). Replacing 'perceptual cognition' by 'measurement' and 'subject' by 'expert subject using a measuring device' the analogy of a formal quantum structure is extended to the conscious structure of all empirical cognition. This is laid out in three theses: about perception, about classical measurement, and about quantum measurement. The results point to the need for research into the quantum structure of the physical embodiment of human cognition. (shrink)

There has been an upsurge of interest lately in developing Wigner’s hypothesis that conscious observation causes collapse by exploring dynamical collapse models in which some purportedly quantifiable aspect of consciousness resist superposition. Kremnizer–Ranchin, Chalmers–McQueen and Okon–Sebastián have explored the idea that collapse may be associated with a numerical measure of consciousness. More recently, Chalmers–McQueen have argued that any single measure is inadequate because it will allow superpositions of distinct states of equal consciousness measure to persist. They suggest (...) a satisfactory model needs to associate collapse with a set of measures quantifying aspects of consciousness, such as the “Q-shapes” defined by Tononi et al. in their “integrated information theory” of consciousness. I argue here that Chalmers–McQueen’s argument against associating a single measure with collapse requires a precise symmetry between brain states associated with different experiences and thus does not apply to the only case where we have strong intuitions, namely human observers. In defence of Chalmers–McQueen’s stance, it might be argued that idealized artificial information processing networks could display such symmetries. However, I argue that the most natural form of any theory that postulates a map from network states to mind states is one that assigns identical mind states to isomorphic network states. This suggests that, if such a map exists, no familiar components of mind states, such as viewing different colours, or experiencing pleasure or pain, are likely to be related by symmetries. (shrink)

Ever since the early days of quantum mechanics it has been suggested that consciousness could be linked to the collapse of the wave function. However, no detailed account of such an interplay is usually provided. In this paper we present an objective collapse model where the collapse operator depends on integrated information, which has been argued to measure consciousness. By doing so, we construct an empirically adequate scheme in which superpositions of conscious states are dynamically suppressed. Unlike other (...) proposals in which “consciousness causes the collapse of the wave function,” our model is fully consistent with a materialistic view of the world and does not require the postulation of entities suspicious of laying outside of the quantum realm. (shrink)

The hard problem of consciousness is to explain the experience of qualia. But everything gets easier once we realise that what has to be explained is not how qualia can exist as objective entities but rather why the conscious subject should believe that they exist. This essay lays out a programme for doing this. It makes radical proposals as to how the “qualia illusion” is created, and why sustaining this illusion is biologically adaptive.

This article addresses two issues: the distinction between objective and subjective measures and the directness of such measures. It is argued that the distinction is unambiguous only when based on a methodological criterion rather than a semantic one. Different senses of directness are discussed: metaphysical, methodological, semantic, and causal.