Research into the neural correlates of consciousness (NCC) aims to identify not just those brain areas that are NCC, but also those that are not. In the received method for ruling out a brain area from being an NCC, this is accomplished by showing a brain area’s content to be consistently absent from subjects’ reports about what they are experiencing. This paper points out how this same absence can be used to infer that the brain area’s content is cognitively inaccessible, (...) in which case we would expect its content to be absent from subjects’ reports whether its content is (phenomenally) conscious or not. If so, such reports cannot count as evidence against that brain area being an NCC, and the received method fails. An alternative method (one suggested in Block, 2007) is considered. (shrink)

abstract Postdiction effects are phenomena in which a stimulus influences the appearance of events taking place before it. In metacontrast masking, for instance, a masking stimulus can ren- der a target stimulus shown before the mask invisible. This and other postdiction effects have been considered incompatible with a simple explanation according to which (i) our perceptual experiences are delayed for only the time it takes for a distal stimulus to reach our sensory receptors and for our neural mechanisms to process (...) it, and (ii) the order in which the processing of stimuli is completed corresponds with the apparent temporal order of stimuli. As a result, the theories that account for more than a single postdiction effect reject at least one of these theses. This paper presents a new framework for the tim- ing of experiences—the non-linear latency difference view—in which the three most dis- cussed postdiction effects—apparent motion, the flash-lag effect, and metacontrast masking—can be accounted for while simultaneously holding theses (i) and (ii). This view is grounded in the local reentrant processes, which are known to have a crucial role in perception. Accordingly, the non-linear latency difference view is both more parsimonious and more empirically plausible than the competing theories, all of which remain largely silent about the neural implementation of the mechanisms they postulate. (shrink)

Mindfulness can be understood as the mental ability to focus on the direct and immediate perception or monitoring of the present moment with a state of open and nonjudgmental awareness. Descriptions of mindfulness and methods for cultivating it originated in eastern spiritual traditions. These suggest that mindfulness can be developed through meditation practice to increase positive qualities such as awareness, insight, wisdom, and compassion. In this article we focus on the relationships between mindfulness, with associated meditation practices, and the cognitive (...) neuroscience of attention and awareness. Mindful awareness is related to distributed attention, phenomenal consciousness, and momentary self-awareness, as characterized by recent findings in cognitive psychology and neuroscience as well as in influential consciousness models. Finally, we outline an integrated neurocognitive model of mindfulness, attention, and awareness, with a key role of prefrontal cortex. (shrink)

Relative blindsight is said to occur when different levels of subjective awareness are obtained at equality of objective performance. Using metacontrast masking, Lau and Passingham reported relative blindsight in normal observers at the shorter of two stimulus-onset asynchronies between target and mask. Experiment 1 replicated the critical asymmetry in subjective awareness at equality of objective performance. We argue that this asymmetry cannot be regarded as evidence for relative blindsight because the observers’ responses were based on different attributes of the stimuli (...) at the two SOAs. With an invariant criterion content , there was no asymmetry in subjective awareness across the two SOAs even though objective performance was the same. Experiment 3 examined the effect of criterion level on estimates of relative blindsight. Collectively, the present results question whether metacontrast masking is a suitable paradigm for establishing relative blindsight. Implications for theories of consciousness are discussed. (shrink)

One of the primordial functions of the brain is the acquisition of knowledge. The apparatus that it has evolved to do so is flexible enough to allow it to acquire knowledge about unambiguous conditions on the one hand, and about situations that are capable of two or more interpretations, each one of which has equal validity with the others. However, in the latter instance, we can only be conscious of one interpretation at any given moment. The study of ambiguity thus (...) gives us some insights into how activity at different stations of the brain can result in a micro-consciousness for an attribute, and also tell us something about interactions between different cerebral areas that result in several potential micro-conscious correlates, though only one predominates at any given time. Finally, the study of ambiguity also gives us insights into the neurological machinery that artists have tapped to create the ambiguity that is commonly a hallmark of great works of art. (shrink)

I give an account of the difference between "Holistic" and "Atomistic" views of conscious experience. On the Holistic view, we enjoy a unified "field" of awareness, whose parts are mere modifications of the whole, and therefore owe their existence to the whole. There is some tendency to saddle those who reject the Holistic field model with a (perhaps) implausible "building block" view. I distinguish a number of different theses about the parts of an experience that are suggested by the "building (...) block" metaphor, but which can be rejected by those who also reject the holistic field view. (shrink)

According to higher-order theories of consciousness, a mental state is conscious only when represented by another mental state. Higher-order theories must predict there to be some brain areas (or networks of areas) such that, because they produce (the right kind of) higher-order states, the disabling of them brings about deficits in consciousness. It is commonly thought that the prefrontal cortex produces these kinds of higher-order states. In this paper, I first argue that this is likely correct, meaning that, if some (...) higher-order theory is true, prefrontal lesions should produce dramatic deficits in visual consciousness. I then survey prefrontal lesion data, looking for evidence of such deficits. I argue that no such deficits are to be found, and that this presents a compelling case against higher-order theories. (shrink)

Here, we argue that any neurobiological theory based on an experience/function division cannot be empirically confirmed or falsified and is thus outside the scope of science. A ‘perfect experiment’ illustrates this point, highlighting the unbreachable boundaries of the scientific study of consciousness. We describe a more nuanced notion of cognitive access that captures personal experience without positing the existence of inaccessible conscious states. Finally, we discuss the criteria necessary for forming and testing a falsifiable theory of consciousness.

Perceptual conscious experiences result from non-conscious processes that precede them. We document a new characteristic of the cognitive system: the speed with which visual meaningful stimuli are prioritized to consciousness over competing noise in visual masking paradigms. In ten experiments (N = 399) we find that an individual's non-conscious visual prioritization speed (NVPS) is ubiquitous across a wide variety of stimuli, and generalizes across visual masks, suppression tasks, and time. We also find that variation in NVPS is unique, in that (...) it cannot be explained by variation in general speed, perceptual decision thresholds, short-term visual memory, or three networks of attention (alerting, orienting and executive). Finally, we find that NVPS is correlated with subjective measures of sensitivity, as they are measured by the Highly Sensitive Person scale. We conclude by discussing the implications of variance in NVPS for understanding individual variance in behavior and the neural substrates of consciousness. (shrink)

Concepts of space and time are widely developed in physics. However, there is a considerable lack of biologically plausible theoretical frameworks that can demonstrate how space and time dimensions are implemented in the activity of the most complex life-system – the brain with a mind. Brain activity is organized both temporally and spatially, thus representing space-time in the brain. Critical analysis of recent research on the space-time organization of the brain’s activity pointed to the existence of so-called operational space-time in (...) the brain. This space-time is limited to the execution of brain operations of differing complexity. During each such brain operation a particular short-term spatio-temporal pattern of integrated activity of different brain areas emerges within related operational space-time. At the same time, to have a fully functional human brain one needs to have a subjective mental experience. Current research on the subjective mental experience offers detailed analysis of space-time organization of the mind. According to this research, subjective mental experience (subjective virtual world) has definitive spatial and temporal properties similar to many physical phenomena. Based on systematic review of the propositions and tenets of brain and mind space-time descriptions, our aim in this review essay is to explore the relations between the two. To be precise, we would like to discuss the hypothesis that via the brain operational space-time the mind subjective space-time is connected to otherwise distant physical space-time reality. (shrink)

Fechner remains virtually unknown for his psychological research on the unconscious. However, he was one of the most prominent theorists of unconscious cognition of the 19th century, in the context of the rise of scientific investigations on the unconscious in German psychology. In line with the models previously developed by Leibniz and Herbart, Fechner proposes an explanative system of unconscious phenomena based on a modular conception of the mind and on the idea of a functional dissociation between representational and attentional (...) activity. For Fechner, the unconscious is a state of consciousness resulting from the isolation of representational activity from the rest of psychical life. Unconscious mental phenomena are unattended mental states that behave autonomously while remaining able to act on consciousness. This paper aims to revisit Fechner’s contribution to the history of the unconscious, but also the theoretical significance of the Fechnerian unconscious vis-à-vis current research on the cognitive unconscious. (shrink)

Event-related potential studies have attempted to discover the processes that underlie conscious visual perception by contrasting ERPs produced by stimuli that are consciously perceived with those that are not. Variability of the proposed ERP correlates of consciousness is considerable: the earliest proposed ERP correlate of consciousness coincides with sensory processes and the last one marks postperceptual processes. A negative difference wave called visual awareness negativity , typically observed around 200 ms after stimulus onset in occipitotemporal sites, gains strong support for (...) reflecting the processes that correlate with, and possibly enable, aware visual perception. Research suggests that the early parts of conscious processing can proceed independently of top-down attention, although top-down attention may modulate visual processing even before consciousness. Evidence implies that the contents of consciousness are provided by interactions in the ventral stream, but indispensable contributions from dorsal regions influence already low-level visual responses. (shrink)

This article summarizes a variety of current as well as previous research in support of a new theory of consciousness. Evidence has been steadily accumulating that information about a stimulus complex is distributed to many neuronal populations dispersed throughout the brain and is represented by the departure from randomness of the temporal pattern of neural discharges within these large ensembles. Zero phase lag synchronization occurs between discharges of neurons in different brain regions and is enhanced by presentation of stimuli. This (...) evidence further suggests that spatiotemporal patterns of coherence, which have been identified by spatial principal component analysis, may encode a multidimensional representation of a present or past event. How such distributed information is integrated into a holistic percept constitutes the binding problem. How a percept defined by a spatial distribution of nonrandomness can be subjectively experienced constitutes the problem of consciousness. Explanations based on a discrete connectionistic network cannot be reconciled with the relevant facts. Evidence is presented herein of invariant features of brain electrical activity found to change reversibly with loss and return of consciousness in a study of 176 patients anesthetized during surgical procedures. A review of relevant research areas, as well as the anesthesia data, leads to a postulation that consciousness is a property of quantumlike processes, within a brain field resonating within a core of structures, which may be the neural substrate of consciousness. This core includes regions of the prefrontal cortex, the frontal cortex, the pre- and paracentral cortex, thalamus, limbic system, and basal ganglia. (shrink)

Amidst the many brain events evoked by a visual stimulus, which are specifically associated with conscious perception, and which merely reflect non-conscious processing? Several recent neuroimaging studies have contrasted conscious and non-conscious visual processing, but their results appear inconsistent. Some support a correlation of conscious perception with early occipital events, others with late parieto-frontal activity. Here we attempt to make sense of those dissenting results. On the basis of a minimal neuro-computational model, the global neuronal workspace hypothesis, we propose a (...) taxonomy which distinguishes between vigilance and access to conscious report, as well as between subliminal, preconscious and conscious processing. We suggest that these distinctions map onto different neural mechanisms, and that conscious perception is systematically associated with a sudden surge of parieto-frontal activity causing top-down amplification. (shrink)

One of the greatest challenges of consciousness research is to understand the relationship between consciousness and its implementing substrate. Current research into the neural correlates of consciousness regards the biological brain as being this substrate, but largely fails to clarify the nature of the brain-consciousness connection. A popular approach within this research is to construe brain-consciousness correlations in causal terms: the neural correlates of consciousness are the causes of states of consciousness. After introducing the notion of the neural correlate of (...) consciousness, we argue (see Against Causal Accounts of NCCs) that this causal strategy is misguided. It implicitly involves an undesirable dualism of matter and mind and should thus be avoided. A non-causal account of the brain-mind correlations is to be preferred. We favor the theory of the identity of mind and brain, according to which states of phenomenal consciousness are identical with their neural correlates. Research into the neural correlates of consciousness and the theory of identity (in the philosophy of mind) are two major research paradigms that hitherto have had very little mutual contact. We aim to demonstrate that they can enrich each other. This is the task of the third part of the paper in which we show that the identity theory must work with a suitably defined concept of type. Surprisingly, neither philosophers nor neuroscientists have taken much care in defining this central concept; more often than not, the term is used only implicitly and vaguely. We attempt to open a debate on this subject and remedy this unhappy state of affairs, proposing a tentative hierarchical classification of phenomenal and neurophysiological types, spanning multiple levels of varying degrees of generality. The fourth part of the paper compares the theory of identity with other prominent conceptions of the mind-body connection. We conclude by stressing that scientists working on consciousness should engage more with metaphysical issues concerning the relation of brain processes and states of consciousness. Without this, the ultimate goals of consciousness research can hardly be fulfilled. (shrink)

Autoscopic phenomena are complex experiences that include the visual illusory reduplication of one’s own body. From a phenomenological point of view, we can distinguish three conditions: autoscopic hallucinations, heautoscopy, and out-of-body experiences. The dysfunctional pattern involves multisensory disintegration of personal and extrapersonal space perception. The etiology, generally either neurological or psychiatric, is different. Also, the hallucination of Self and own body image is present during dreams and differs according to sleep stage. Specifically, the representation of the Self in REM dreams (...) is frequently similar to the perception of Self in wakefulness, whereas in NREM dreams, a greater polymorphism of Self and own body representation is observed. The parallels between autoscopic phenomena in pathological cases and the Self-hallucination in dreams will be discussed to further the understanding of the particular states of self awareness, especially the complex integration of different memory sources in Self and body representation. (shrink)

Local theories of consciousness state that one is conscious of a feature if it is adequately represented and processed in sensory brain areas, given some background conditions. We challenge the core prediction of local theories based on long-lasting postdictive effects demonstrating that features can be represented for hundreds of milliseconds in perceptual areas without being consciously perceived. Unlike previous empirical data aimed against local theories, localists cannot explain these effects away by conjecturing that subjects are phenomenally conscious of features that (...) they cannot report. We also discuss alternative explanations that localists could offer. (shrink)

The present paper was written as a contribution to ongoing methodological debates within the NCC project. We focus on the neural correlates of conscious perceptual episodes. Our claim is that the NCC notion, as applied to conscious perceptual episodes, needs to be reconceptualized. It mixes together the processing related to the perceived contents and the neural substrate of consciousness proper, i.e. mechanisms making the perceptual contents conscious. We thus propose that the perceptual NCC be divided into two constitutive subnotions. The (...) main theoretical idea that emerges as a consequence of this reconceptualization is that the neural correlate of a perceptual episode is formed in the neural interaction between content-processing and consciousness-conferring mechanisms. The paper elaborates this distinction, marshals some initial arguments in its favour, and tests it against some of the most debated theories of consciousness. (shrink)

As anthropology becomes more interested in consciousness and its numerous states, and with a slowly increasing appeal to neuroscience for insights and explanations of consciousness, there is an understandable interest in the components of consciousness and how they combine into alternative states in different sociocultural settings. One of those components should be the complexity of information processing producing the knowing aspect of consciousness. The author introduces an approach to this aspect in the form of conceptual systems theory, a neo-Piagetian model (...) of cognitive development, which has been used to good effect to explain information processing in social situations but heretofore neglected by anthropologists. The neuroanthropological underpinnings of CST are discussed, as is the range of potential applications to ethnological and ethnographic problems. (shrink)

We pose a foundational problem for those who claim that subjects are ontologically irreducible, but causally reducible (weak emergence). This problem is neuroscience’s notorious binding problem, which concerns how distributed neural areas produce unified mental objects (such as perceptions) and the unified subject that experiences them. Synchrony, synapses and other mechanisms cannot explain this. We argue that this problem seriously threatens popular claims that mental causality is reducible to neural causality. Weak emergence additionally raises evolutionary worries about how we’ve survived (...) the perils of nature. Our emergent subject hypothesis (ESH) avoids these shortcomings. Here, a singular, unified subject acts back on the neurons it emerges from and binds sensory features into unified mental objects. Serving as the mind’s controlling center, this subject is ontologically and causally irreducible (strong emergence). ESH draws on recent experimental evidence, including the motivation of a possible correlate (or “seat”) of the subject, which enhances its testability. (shrink)

Recent findings indicate that complex cognitive functions are organized at a global level in the brain and rely on large-scale information processing requiring functional integration of multiple disparate neural assemblies. The critical question of the integration of distributed brain activities is whether the essential integrative role can be attributed to a specific structure in the brain or whether this ability is inherent to the cognitive network as a whole. The results of the present study show that mean values of the (...) running correlation function in frontal-temporal EEG pairs with one electrode in the anterior cingulate cortex are significantly higher than the same values in other frontal-temporal pairs. These findings indicate a particular role of the ACC in large-scale communication, which could reflect its unique integrative functions in cognitive processing. (shrink)

Proponents of the higher‐order (HO) theory of consciousness (e.g., Lau and Rosenthal) have recently appealed to brain lesion evidence to support their thesis that mental states are conscious when and only when represented by other mental states. This article argues that this evidence fails to support HO theory, doing this by first determining what kinds of conscious deficit should result when HO state‐producing areas are damaged, then arguing that these kinds of deficit do not occur in the studies to which (...) HO theorists appeal. The article also develops an apparatus that can be used to evaluate whether other lesion evidence confirms or disconfirms HO theory. (shrink)

According to Milner and Goodale’s dual visual systems (DVS) theory, a division obtains between visual consciousness and motor action, in that the visual system producing conscious vision (the ventral stream) is distinct from the one guiding action (the dorsal stream). That there would be this division is often taken (by Andy Clark and others) to undermine the folk view on how consciousness and action relate. However, even if this division obtains, this leaves open the possibility that con- scious ventral information (...) is often transmitted to the uncon- scious dorsal stream and then used to guide action, a possibility seeming to preserve a significant role for consciousness in action. This article assesses this possibility. In course of doing so, we will review those arguments recently having been made against the DVS view on how visual consciousness and action relate (ones due to, e.g., Briscoe and Schwenkler, or Schenk and McIntosh). What we will find is that, if we properly analyze the data upon which these arguments are based, we are still left with the impression that the DVS view is largely correct; i.e., it is only rarely that visual experience guides action. (shrink)

Common sense suggests that visual consciousness is essential to skilled motor action, but Andy Clark—inspired by Milner and Goodale's dual visual systems theory—has appealed to a wide range of experimental dissociations to argue that such an assumption is false. Critics of Clark's argument contend that the content driving motor action is actually within subjects' experience, just not easily discovered. In this article, I argue that even if such content exists, it cannot be guiding motor action, since a review of current (...) visual neuroscience indicates that the visual brain areas producing conscious representations are distinct from those driving motor action. (shrink)

Local Recurrency Theory (LR) holds that recurrent loops of neural activity localized to the visual cortex are necessary and sufficient for visual consciousness (if certain background conditions obtain). LR’s popularity has recently waned in favor of theories holding that higher-level types of processing are necessary for consciousness (for example, the Global Neuronal Workspace Theory and Higher-order Theory). This has been in part because of empirical evidence thought to disconfirm LR. However, these competing theories now face challenges of their own, often (...) coming in the form of evidence showing that higher-level brain areas (that is, in the prefrontal cortex) are probably not essential for consciousness. Given growing challenges to LR's competitors, it would be timely to re-assess the prospects for LR. This article carries out such an investigation, first laying out the theory precisely, then going on to survey the evidence presented against it. What will be found is that none of the evidence necessarily undermines LR, but instead just fosters its theoretical enrichment. The overall conclusion: LR remains among our most promising neuroscientific theories of visual consciousness. (shrink)

Any attempt at consciousness assessment in organoids requires careful consideration of the theory of consciousness that researchers will rely on when performing this task. In cognitive neuroscience and the clinic, there are tools and theories used to detect and measure consciousness, typically in human beings, but none of them is neither fully consensual nor fit for the biological characteristics of organoids. I discuss the existing attempt relying on the Integrated Information Theory and its models and tools. Then, I revive the (...) distinction between global theories of consciousness and local theories of consciousness as a thought-provoking one for those engaged in the difficult task of adapting models of consciousness to the biological reality of brain organoids. The “microconsciousness theory” of Semir Zeki is taken as an exploratory path and illustration of a theory defending that minimal networks can support a form of consciousness. I suggest that the skepticism prevailing in the neuroscience community regarding the possibility of organoid consciousness relies on some assumptions related to a globalist account of consciousness and that other accounts are worth exploring at this stage. (shrink)

In spite of enormous recent interest in the neurobiology of the self, we currently have no global models of the brain that explain how its anatomical structure, connectivity, and physiological functioning create a unified self. In this article I present a triadic neurohierarchical model of the self that proposes that the self can be understood as the product of three hierarchical anatomical systems: The interoself system, the integrative self system, and the exterosensorimotor system. An analysis of these three systems and (...) their functional features indicates that the neural hierarchy possesses features of both non-nested and nested hierarchies that are necessary for the creation of a unified consciousness and self. These functional properties also make the central nervous system a biologically unique entity unlike anything else in nature. (shrink)

The question about the potential for consciousness of artificial systems has often been addressed using thought experiments, which are often problematic in the philosophy of mind. A more promising approach is to use real experiments to gather data about the correlates of consciousness in humans, and develop this data into theories that make predictions about human and artificial consciousness. A key issue with an experimental approach is that consciousness can only be measured using behavior, which places fundamental limits on our (...) ability to identify the correlates of consciousness. This paper formalizes these limits as a distinction between type I and type II potential correlates of consciousness (PCCs). Since it is not possible to decide empirically whether type I PCCs are necessary for consciousness, it is indeterminable whether a machine that lacks neurons or hemoglobin, for example, is potentially conscious. A number of responses have been put forward to this problem, including suspension of judgment, liberal and conservative attribution of the potential for consciousness and a psychometric scale that models our judgment about the relationship between type I PCCs and consciousness. (shrink)

Does phenomenal consciousness overflow access consciousness? Some researchers have claimed that it does, relying on interpretations of various psychological experiments such as Sperling's or Landman's, and crucially using alleged subjective reports from participants to argue in favor of these interpretations. However, systematic empirical investigations of participants' subjective reports are scarce. To fill this gap, we reproduced Sperling's and Landman's experiments, and carefully collected reports made by subjects about their own experiences, using questionnaires and interviews. We found that participants' subjective reports (...) do not support the overflow thesis, but rather suggest alternative interpretations of the experiments. (shrink)

Although our subjective impression is of a richly detailed visual world, numerous empirical results suggest that the amount of visual information observers can perceive and remember at any given moment is limited. How can our subjective impressions be reconciled with these objective observations? Here, we answer this question by arguing that, although we see more than the handful of objects, claimed by prominent models of visual attention and working memory, we still see far less than we think we do. Taken (...) together, we argue that these considerations resolve the apparent conflict between our subjective impressions and empirical data on visual capacity, while also illuminating the nature of the representations underlying perceptual experience. (shrink)

If we were to connect two individuals’ brains together, how would this affect the individuals’ conscious experiences? In particular, it is possible for two people to share any of their conscious experiences; to simultaneously enjoy some token experiences while remaining distinct subjects? The case of the Hogan twins—craniopagus conjoined twins whose brains are connected at the thalamus—seems to show that this can happen. I argue that while practical empirical methods cannot tell us directly whether or not the twins share conscious (...) experiences, considerations about the locality of content processing in the brain entails that they most likely do so. (shrink)

Temporal experiences, according to retentionalism, essentially have temporally extended contents: contents which represent distinct events at distinct temporal locations, and some of their temporal relations. This means, retentionalists insist, that temporal experiences themselves needn’t be extended in time: only their contents are. The paper reviews an experiment by Moutoussis and Zeki, which demonstrates a colour-motion visual asynchrony (§2): information about motion seems to be processed more slowly than information about colour, so that the former is delayed relative to the latter. (...) This, the paper argues, raises an important difficulty for retentionalism and its account of the temporal ontology of experiences: it suggests that a central background assumption about neural processing presupposed by retentionalism is false, at least in cases of visual asynchrony. The paper then explores the general significance of this result for retentionalism (§3). (shrink)

It is commonly assumed that where consciousness is present, it is a single stream. This notion is bolstered by functions attributed to consciousness, particularly providing multi-faceted experience of a perceptual scene and contributing to the production of coherent behavior, which supposedly require consciousness to be unitary. It is believed that were the unitary structure of consciousness to break down, such that multiple streams of consciousness are present, these functions would be compromised. The split-brain syndrome is widely regarded as evidence for (...) this claim. However, the split-brain syndrome is an atypical structure of human consciousness. As such, conclusions based on the split-brain syndrome regarding the structure and functions of consciousness may be limited in generalizability. There may be cases where multiple consciousness is neither maladaptive nor anomalous but is the naturally evolved configuration, and thus may not compromise the capacity of consciousness to subserve multi-faceted experience and coherent behavior. This paper speculates on the different forms multiple consciousness may take, and demonstrates how they may be able to implement the aforementioned functions of consciousness. In doing so, the paper demonstrates that the commitment a unitary model of consciousness may be due more to anatomical constraints than functional ones. (shrink)