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)

Philosophers have usually approached the concept of timing of experiences by addressing the question how the experiences of temporal phenomena can be explained. As a result, the issue of timing has been addressed in two different ways. The first, similar to the questions posed in sciences, concerns the relationship between the experienced time of events and the objective time of events. The second approach is more specific to philosophers’ debates, and concerns the phenomenology of experiences: how is the apparent temporal (...) structure of experiences constituted? In regard to both questions, this article shows why and how philosophers’ views differ from those held by most scientists. To conclude, I present a combination of views that is not only compatible with that of scientists, but also addresses the problems that engage philosophers. (shrink)

What is attention? On one influential position, attention constitutively is the selection of some stimulus for coupling with a response. Wayne Wu has proposed a master argument for this position that relies on the claim that cognitive science commits to an empirical sufficient condition (ESC), according to which, if a subject S perceptually selects (or response-couples) X to guide performance of some experimental task T, she therein attends to X. In this paper I show that this claim about cognitive science (...) is false. Cognitive science allows for inattentive selection-for-task, or inattentive response-coupling. This means that Wu’s account is without independent support. (shrink)

Is perceptual processing in dedicated sensory areas sufficient for conscious perception? Localists say ‘Yes—given some background conditions.’ Prefrontalists say ‘No: conscious perceptual experience requires the involvement of prefrontal structures.’ I review the evidence for prefrontalism. I start by presenting correlational evidence. In doing so, I answer the ‘report argument’, according to which the apparent involvement of the prefrontal cortex in consciousness stems from the requirement for reports. I then review causal evidence for prefrontalism and answer the ‘lesion argument’, which purports (...) to show that prefrontalism is wrong because lesions to the prefrontal cortex do not abolish consciousness. I conclude that multiple sources of evidence converge toward the view that the prefrontal cortex plays a significant role in consciousness. (shrink)

Despite the consensus promoted by the evidence-based medicine framework, many authors continue to express doubts about the superiority of randomized controlled trials. This paper evaluates four objections targeting the legitimacy, feasibility, and extrapolation problems linked to the experimental practice of random allocation. I argue that random allocation is a methodologically sound and feasible practice contributing to the internal validity of controlled experiments dealing with heterogeneous populations. I emphasize, however, that random allocation is solely designed to ensure the validity of causal (...) inferences at the level of groups. By itself, random allocation cannot enhance test precision, doesn’t contribute to external validity, and limits the applicability of causal claims to individuals. (shrink)

A central debate in philosophy and neuroscience pertains to whether PFC activity plays an essential role in the neural basis of consciousness. Neuroimaging and electrophysiology studies have revealed that the contents of conscious perceptual experience can be successfully decoded from PFC activity, but these findings might be confounded by post- perceptual cognitive processes, such as thinking, reasoning, and decision-making, that are not necessary for con- sciousness. To clarify the involvement of the PFC in consciousness, we present a synthesis of research (...) that has used intracranial electrical stimulation (iES) for the causal modulation of neural activity in the human PFC. This research provides compelling evidence that iES of only certain prefrontal regions (i.e., orbitofrontal cortex and anterior cingu- late cortex) reliably perturbs conscious experience. Conversely, stimulation of anterolateral prefrontal sites, often con- sidered crucial in higher-order and global workspace theories of consciousness, seldom elicits any reportable alterations in consciousness. Furthermore, the wide variety of iES-elicited effects in the PFC (e.g., emotions, thoughts, and olfactory and visual hallucinations) exhibits no clear relation to the immediate environment. Therefore, there is no evidence for the kinds of alterations in ongoing perceptual experience that would be predicted by higher-order or global workspace theories. Nevertheless, effects in the orbitofrontal and anterior cingulate cortices suggest a specific role for these PFC subregions in supporting emotional aspects of conscious experience. Overall, this evidence presents a challenge for higher-order and global workspace theories, which commonly point to the PFC as the basis for con- scious perception based on correlative and possibly confounded information. (shrink)

The role of consciousness in the production of actions has received much attention from philosophy and neuroscience. Wegner claims that what he calls the conscious will plays no role in the causal production of human actions, and that it is just an illusion. I will argue that Wegner’s claim is mistaken, because his defense of the alleged illusion rests on how he conceives of what the Readiness Potential represents in a key experiment—Libet’s experiment—and this conception is mistaken. Therefore, Wegner has (...) not offered a convincing reason to believe that humans are deluded about the way they produce their actions. (shrink)

Whether the prefrontal cortex is part of the neural substrates of consciousness is currently debated. Against prefrontal theories of consciousness, many have argued that neural activity in the prefrontal cortex does not correlate with consciousness but with subjective reports. We defend prefrontal theories of consciousness against this argument. We surmise that the requirement for reports is not a satisfying explanation of the difference in neural activity between conscious and unconscious trials, and that prefrontal theories of consciousness come out of this (...) debate unscathed. (shrink)

As for most measurement procedures in the course of their development, measures of consciousness face the problem of coordination, i.e., the problem of knowing whether a measurement procedure actually measures what it is intended to measure. I focus on the case of the Perceptual Awareness Scale to illustrate how ignoring this problem leads to ambiguous interpretations of subjective reports in consciousness science. In turn, I show that empirical results based on this measurement procedure might be systematically misinterpreted.

In this chapter, we discuss a selection of current views of the neural correlates of consciousness (NCC). We focus on the different predictions they make, in particular with respect to the role of prefrontal cortex (PFC) during visual experiences, which is an area of critical interest and some source of contention. Our discussion of these views focuses on the level of functional anatomy, rather than at the neuronal circuitry level. We take this approach because we currently understand more about experimental (...) evidence at this coarse level and because these results are appropriate for arbitrating between current theoretical frameworks. We discuss the Two-Visual-Systems Hypothesis (Milner & Goodale 1995; 2006), Local Recurrency (Lamme 2010; Lamme 2006), Higher Order (Lau 2008; Lau & Rosenthal 2011) and Global Workspace theories (Baars 1997; Baars 2005; Dehaene & Naccache 2001; Dehaene 2014). Despite the apparent stark differences between conscious and unconscious perceptual processing, available evidence suggests that their neural substrates must be largely shared. This indicates that the difference in neural activity between conscious and unconscious perceptual processing is likely to be subtle and highly specialized. We argue that current experimental evidence about the involvement of specific activity in prefrontal cortex supports the higher order neural theory of consciousness. In consequence, imaging techniques that focus only on marked differences between conscious and unconscious level of activity are likely to be insensitive to the relevant neural activity patterns that underlie conscious experiences. Finally, it follows from the evidence we discuss that the functional advantages of conscious over unconscious perceptual processing may be more limited than commonly thought. (shrink)

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)

According to the global neuronal workspace model of consciousness, consciousness results from the global broadcast of information throughout the brain. The global neuronal workspace is mainly constituted by a fronto-parietal network. The anterior insular cortex is part of this global neuronal workspace, but the function of this region has not yet been defined within the global neuronal workspace model of consciousness. In this review, I hypothesize that the anterior insular cortex implements a cross-modal priority map, the function of which is (...) to determine priorities for the processing of information and subsequent entrance in the global neuronal workspace. (shrink)

The Oxford Handbook of the Philosophy of Consciousness provides the most comprehensive overview of current philosophical research on consciousness. Featuring contributions from some of the most prominent experts in the field, it explores the wide range of types of consciousness there may be, the many psychological phenomena with which consciousness interacts, and the various views concerning the ultimate relationship between consciousness and physical reality. It is an essential and authoritative resource for anyone working in philosophy of mind or interested in (...) states of consciousness. (shrink)

Consistent with numerous electrophysiological studies, we recently reported that conscious perception is associated with a widely distributed modulation of the P3 component . We also showed that correct objective performance in the absence of subjective awareness is associated with a spatially more restricted modulation of the P3. The relatively late occurrence of the P3 along with lack of control for post-perceptual processes suggests that this component might reflect processes related to stimulus evaluation or confidence rather than to visual awareness or (...) objective performance. The main aim of the current study was to test this hypothesis. While EEG was recorded, participants performed a forced-choice localization task and reported their subjective perception of the target on a 3-level scale that also indexed their confidence. The results showed that our previous findings are replicated when confidence is controlled for. (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)

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)

Can conscious awareness be ascertained from physiological responses alone? We evaluate a novel learning-based procedure permitting detection of conscious awareness without reliance on language comprehension or behavioural responses. The method exploits a situation whereby only consciously detected violations of an expectation alter skin conductance responses . Thirty participants listened to sequences of piano notes that, without their being told, predicted a pleasant fanfare or an aversive noise according to an abstract rule. Stimuli were presented without distraction , or while distracted (...) by a visual task to remove awareness of the rule . A test phase included occasional violations of the rule. Only participants attending the sounds reported awareness of violations and only they showed significantly greater SCR for noise occurring in violation, vs. accordance, with the rule. Our results establish theoretically significant dissociations between conscious and unconscious processing and furnish new opportunities for clinical assessment of residual consciousness in patient populations. (shrink)

6 and 14 recently proposed taxonomies that distinguish between four processing states, based on bottom-up stimulus strength and top-down attentional amplification. The aim of the present study was to empirically test these processing states using the priming paradigm. Our results showed that attention and stimulus strength significantly modulated priming effects: either receiving top-down attention or possessing sufficient bottom-up strength was a prerequisite for a stimulus to elicit priming. When both top-down attention and sufficient bottom-up strength were present, the priming effect (...) was boosted. The origins of the observed priming effects also varied between different processing states. We can conclude that our empirical study using the priming paradigm confirmed the presence of four processing states, which displayed a differential pattern of response priming effects and differential origins of the response priming effects. (shrink)

Consciousness in experimental subjects is typically inferred from reports and other forms of voluntary behaviour. A wealth of everyday experience confirms that healthy subjects do not ordinarily behave in these ways unless they are conscious. Investigation of consciousness in vegetative state patients has been based on the search for neural evidence that such broad functional capacities are preserved in some vegetative state patients. We call this the standard approach. To date, the results of the standard approach have suggested that some (...) vegetative state patients might indeed be conscious, although they fall short of being demonstrative. The fact that some vegetative state patients show evidence of consciousness according to the standard approach is remarkable, for the standard approach to consciousness is rather conservative, and leaves open the pressing question of how to ascertain whether patients who fail such tests are conscious or not. We argue for a cluster-based ‘natural kind’ methodology that is adequate to that task, both as a replacement for the approach that currently informs research into the presence or absence of consciousness in vegetative state patients and as a methodology for the science of consciousness more generally. 1. Introduction2. The Vegetative State3. The Standard Approach4. The Natural Kind Methodology5. Is Consciousness a Special Case? 5.1 Is consciousness a natural kind?5.2 A special obstacle?6. Conclusion. (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)

How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We can see the problem in stark form if we ask how we could tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: find the neural natural kinds that are the basis of phenomenal consciousness in clear cases when subjects are completely confident and we have no reason to doubt their (...) authority, and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is ‘Yes’, then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is ‘Yes’? The suggested methodology requires an answer to the question it was supposed to answer! The paper argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. The paper argues that we can find a neural realizer of this overflow if assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified by the explanations it allows. (shrink)

What is Computational Intelligence (CI) and what are its relations with Artificial Intelligence (AI)? A brief survey of the scope of CI journals and books with ``computational intelligence'' in their title shows that at present it is an umbrella for three core technologies (neural, fuzzy and evolutionary), their applications, and selected fashionable pattern recognition methods. At present CI has no comprehensive foundations and is more a bag of tricks than a solid branch of science. The change of focus from methods (...) to challenging problems is advocated, with CI defined as a part of computer and engineering sciences devoted to solution of non-algoritmizable problems. In this view AI is a part of CI focused on problems related to higher cognitive functions, while the rest of the CI community works on problems related to perception and control, or lower cognitive functions. Grand challenges on both sides of this spectrum are addressed. (shrink)

In Section I, I clarify turning point issues in the Phillips and Block debate about whether there is unconscious perception. These include questions about whether uptake of certain visual information is an individual or person level accomplishment, as required for genuine unconscious _perceiving_. Section II takes up a recent reorientation proposed in Block ( 2017 ) towards the question of whether there is unconscious perceiving, where we are to look for the pervasive role of unconscious perceiving in, perhaps especially, the (...) online control of everyday reaching and grasping. I point out that while this may well be a helpfully different approach to explore, it does not evade the central questions and challenges familiar from the prior debate between Phillips and Block. Section III reviews an approach summarized in Dehaene ( 2014 ), drawing from a range of measures of neural activity. Dehaene provides evidence of quite rich non-conscious perceptual system responses, some arguably individual or person level. But in a fairly thin or fragile way, absent taking up, in higher level assessment, the information encoded in initial visual response. Or that is the interpretation I argue for, in relating the Dehaene account to the Phillips and Block debate, in a way that illuminates the Phillips and Block discussions. An Appendix provides an overview of debates in the literature about the Goodale and Milner Two Visual Systems Hypothesis, that Block ( 2017 ) makes central appeal to. (shrink)

Apparent motion is an illusion in which two sequentially presented and spatially separated stimuli give rise to the experience of one moving stimulus. This phenomenon has been deployed in various philosophical arguments for and against various theories of consciousness, time consciousness and the ontology of time. Nevertheless, philosophers have continued working within a framework that does not reflect the current understanding of apparent motion. The main objectives of this paper are to expose the shortcomings of the explanations provided for apparent (...) motion and to offer an alternative explanation for the phenomenon. (shrink)

This article examines what is known about the cognitive science of working memory, and brings the findings to bear in evaluating philosophical accounts of central cognitive processes of thinking and reasoning. It is argued that central cognition is sensory based, depending on the activation and deployment of sensory images of various sorts. Contrary to a broad spectrum of philosophical opinion, the central mind does not contain any workspace within which goals, decisions, intentions, or non-sensory judgments can be active.Introduction: philosophers’ commitmentsMost (...) philosophers believe that our so-called “personal-level” propositional attitudes—our personal judgments, beliefs, goals, values, decisions, and intentions—are consciously accessible. Many will also allow, of course, that some of the processing that takes place within our perceptual faculties is inaccessible to us; and many will grant the possibility of unconscious attitudes, as well as processes of inference and decision mak. (shrink)

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)

The Hard Problem is surrounded by a vast literature, to which it is increasingly hard to contribute to in any meaningful way. Accordingly, the strategy here is not to offer any new metaphysical or ‘in principle’ arguments in favour of the success of materialism, but to assume a Type Q(uinian) approach and look to contemporary consciousness science to see how the concept of consciousness fares there, and what kind of explanations we can hope to offer of it. It is suggested (...) that while they will be materialist explanations, they will not be of the form that many scientists and philosophers would have us believe, but instead prompt a very different set of expectations and research projects. (shrink)