Block () highlights two experimental studies of neglect patients which, he contends, provide ‘dramatic evidence’ for unconscious seeing. In Block's hands this is the highly non-trivial thesis that seeing of the same fundamental kind as ordinary conscious seeing can occur outside of phenomenal consciousness. Block's case for it provides an excellent opportunity to consider a large body of research on clinical syndromes widely held to evidence unconscious perception. I begin by considering in detail the two studies of neglect to which (...) Block appeals. I show why their interpretation as evidence of unconscious seeing faces a series of local difficulties. I then explain how, even bracketing these issues, a long-standing but overlooked problem concerning our criterion for consciousness problematizes the appeal to both studies. I explain why this problem is especially pressing for Block given his view that phenomenal consciousness overflows access consciousness. I further show that it is epidemic—not only affecting all report-based studies of unconscious seeing in neglect, but also analogous studies of the condition most often alleged to show unconscious seeing, namely blindsight. (shrink)

Theories of consciousness can be separated into those that see it as cognitive in nature, or as an aspect of cognitive functioning, and those that see consciousness as importantly distinct from any kind of cognitive functioning. One version of the former kind of theory is the higher-order-thought theory of consciousness. This family of theories posits a fundamental role for cognitive states, higher-order thought-like intentional states, in the explanation of conscious experience. These states are higher-order in that they represent the subject (...) herself as being in various world-directed first-order states and thus constitute a kind of cognitive access to one's own mental life. This distinctive cognitive access is postulated to account for what it is like for one to have a conscious experience. One important challenge to this approach is Block's case for phenomenological overflow (Block, 2007, 2011, 2012). The basic argument is that, overall, the balance of evidence favors the identification of phenomenal consciousness with first-order non-cognitive states rather than our cognitive access to those states. Emerging clearly from the ensuing debate is that Block's argument is meant to establish that phenomenology overflows working memory. This is important because, unlike other theories, the higher-order thought theory can allow that our conscious experience overflows working memory. In addition, it can account for the subjective impression that there is overflow even if there isn't. (shrink)

Tyler Burge presents an original study of the most primitive ways in which individuals represent the physical world. By reflecting on the science of perception and related psychological and biological sciences, he gives an account of constitutive conditions for perceiving the physical world, and thus aims to locate origins of representational mind.

One of the most important issues concerning the foundations ofconscious perception centerson thequestion of whether perceptual consciousness is rich or sparse. The overflow argument uses a form of ‘iconic memory’ toarguethatperceptual consciousnessisricher (i.e.,has a higher capacity) than cognitive access: when observing a complex scene we are conscious of more than we can report or think about. Recently, the overflow argumenthas been challenged both empirically and conceptually. This paper reviews the controversy, arguing that proponents of sparse perception are committed to the (...) postulation of (i) a peculiar kind of generic conscious representation that has no independent rationale and (ii) an unmotivated form of unconscious representation that in some cases conflicts with what we know about unconscious representation. (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.

Conscious experience is one of the most difficult and thorny problems in psychological science. Its study has been neglected for many years, either because it was thought to be too difficult, or because the relevant evidence was thought to be poor. Bernard Baars suggests a way to specify empirical constraints on a theory of consciousness by contrasting well-established conscious phenomena - such as stimulus representations known to be attended, perceptual, and informative - with closely comparable unconscious ones - such as (...) stimulus representations known to be preperceptual, unattended, or habituated. Adducing data to show that consciousness is associated with a kind of global workplace in the nervous system, and that several brain structures are known to behave in accordance with his theory, Baars helps to clarify many difficult problems. (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)

Consciousness is a mongrel concept: there are a number of very different "consciousnesses." Phenomenal consciousness is experience; the phenomenally conscious aspect of a state is what it is like to be in that state. The mark of access-consciousness, by contrast, is availability for use in reasoning and rationally guiding speech and action. These concepts are often partly or totally conflated, with bad results. This target article uses as an example a form of reasoning about a function of "consciousness" based on (...) the phenomenon of blindsight. Some information about stimuli in the blind field is represented in the brains of blindsight patients, as shown by their correct "guesses," but they cannot harness this information in the service of action, and this is said to show that a function of phenomenal consciousness is somehow to enable information represented in the brain to guide action. But stimuli in the blind field are BOTH access-unconscious and phenomenally unconscious. The fallacy is: an obvious function of the machinery of access-consciousness is illicitly transferred to phenomenal consciousness. (shrink)

Theorists are converging from quite different quarters on a version of the global neuronal workspace model of consciousness, but there are residual confusions to be dissolved. In particular, theorists must resist the temptation to see global accessibility as the cause of consciousness (as if consciousness were some other, further condition); rather, it is consciousness. A useful metaphor for keeping this elusive idea in focus is that consciousness is rather like fame in the brain. It is not a privileged medium of (...) representation, or an added property some states have; it is the very mutual accessibility that gives some informational states the powers that come with a subject's consciousness of that information. Like fame, consciousness is not a momentary condition, or a purely dispositional state, but rather a matter of actual influence over time. Theorists who take on the task of accounting for the aftermath that is critical for consciousness often appear to be leaving out the Subject of consciousness, when in fact they are providing an analysis of the Subject, a necessary component in any serious theory of consciousness. (shrink)

Little, Brown, 1992 Review by Glenn Branch on Jul 5th 1999 Volume: 3, Number: 27.

A breathtaking look at the new science that can track consciousness deep in the brain How does our brain generate a conscious thought? And why does so much of our knowledge remain unconscious? Thanks to clever psychological and brain-imaging experiments, scientists are closer to cracking this mystery than ever before. In this lively book, Stanislas Dehaene describes the pioneering work his lab and the labs of other cognitive neuroscientists worldwide have accomplished in defining, testing, and explaining the brain events behind (...) a conscious state. We can now pin down the neurons that fire when a person reports becoming aware of a piece of information and understand the crucial role unconscious computations play in how we make decisions. The emerging theory enables a test of consciousness in animals, babies, and those with severe brain injuries. A joyous exploration of the mind and its thrilling complexities, Consciousness and the Brain will excite anyone interested in cutting-edge science and technology and the vast philosophical, personal, and ethical implications of finally quantifying consciousness. (shrink)

This paper proposes a new argument in favour of the claim that phenomenal consciousness overflows – that is, has a far higher capacity than – cognitive access. It shows that opponents of overflow implicate a necessary role for visual imagery in the change detection paradigm. However, empirical evidence suggests that there is no correlation between visual imagery abilities and performance in this paradigm. Since the use of imagery is not implicated in the performance strategy of subjects, we find a new (...) argument for consciousness without access. (shrink)

The question of whether our conscious experience is rich or sparse remains an enduring controversy in philosophy. The “overflow” account argues that perceptual consciousness is far richer than cognitive access: when perceiving a complex scene, subjects see more than they can report. This paper draws on aphantasia to propose a new argument in favor of overflow. First, it shows that opponents of overflow explain subjects’ performance in a change detection paradigm by appealing to a type of “internal imagery.” Second, it (...) provides empirical evidence to demonstrate that aphantasics are incapable of generating this imagery. However, aphantasics perform equally well in this task; and so the no-overflow account fails to explain their performance. This means that proponents of this view are committed to an unsupported view of perception. (shrink)

Often when there is no attention to an object, there is no conscious perception of it either, leading some to conclude that conscious perception is an attentional phenomenon. There is a well-known perceptual phenomenon—visuo-spatial crowding, in which objects are too closely packed for attention to single out one of them. This article argues that there is a variant of crowding—what I call ‘‘identity-crowding’’—in which one can consciously see a thing despite failure of attention to it. This conclusion, together with new (...) evidence that attention to an object occurs in unconscious perception, suggests there may be a double dissociation between conscious perception of an object and attention to that object, constraining the extent to which consciousness can be constitutively attentional. The argument appeals to a comparison between the minimal resolution (or ‘‘grain’’) of object-attention and object-seeing. (shrink)

This article challenges Block's ‘overflow argument’ for the conclusion that phenomenal consciousness and access-consciousness are distinct. It shows that the data can be explained just as well in terms of a distinction between contents that are made globally accessible through bottom–up sensory stimulation and those that are sustained and made available in working memory through top-down attention.

Can we consciously see more items at once than can be held in visual working memory? This question has elud- ed resolution because the ultimate evidence is subjects’ reports in which phenomenal consciousness is filtered through working memory. However, a new technique makes use of the fact that unattended ‘ensemble prop- erties’ can be detected ‘for free’ without decreasing working memory capacity.

Philosophers have lately seized upon Sperling's partial report technique and subsequent work on iconic memory in support of controversial claims about perceptual experience, in particular that phenomenology overflows cognitive access. Drawing on mounting evidence concerning postdictive perception, I offer an interpretation of Sperling's data in terms of cue-sensitive experience which fails to support any such claims. Arguments for overflow based on change-detection paradigms (e.g. Landman et al., 2003; Sligte et al., 2008) cannot be blocked in this way. However, such paradigms (...) are fundamentally different from Sperling's and, for rather different reasons, equally fail to establish controversial claims about perceptual experience. (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)

I propose a new argument showing that conscious vision sometimes depends constitutively on conscious attention. I criticise traditional arguments for this constitutive connection, on the basis that they fail adequately to dissociate evidence about visual consciousness from evidence about attention. On the same basis, I criticise Ned Block's recent counterargument that conscious vision is independent of one sort of attention (‘cognitive access'). Block appears to achieve the dissociation only because he underestimates the indeterminacy of visual consciousness. I then appeal to (...) empirical work on the interaction between visual indeterminacy and attention, to argue for the constitutive connection. (shrink)

A familiar and enduring controversy surrounds the question of whether our phenomenal experience “overflows” availability to cognition: do we consciously see more than we can remember and report? Both sides to this debate have long sought to move beyond naïve appeals to introspection by providing empirical evidence for or against overflow. Recently, two notable studies—Bronfman, Brezis, Jacobson, and Usher and Vandenbroucke, Sligte, Fahrenfort, Ambroziak, and Lamme —have purported to provide compelling evidence in favor of overflow. Here I explain why the (...) data from both studies are wholly consistent with a “no overflow” interpretation. Importantly, when framed purely in representational or informational terms, this “no overflow” interpretation agrees with the interpretations respectively offered by both Bronfman et al. and Vandenbroucke et al.. The difference only emerges when additional assumptions are made concerning which representations correspond to elements in consc.. (shrink)

The distinction between access consciousness and phenomenal consciousness is a subject of intensive debate. According to one view, visual experience overflows the capacity of the attentional and working memory system: We see more than we can report. According to the opposed view, this perceived richness is an illusion—we are aware only of information that we can subsequently report. This debate remains unresolved because of the inevitable reliance on report, which is limited in capacity. To bypass this limitation, this study utilized (...) color diversity—a unique summary statistic—which is sensitive to detailed visual information. Participants were shown a Sperling-like array of colored letters, one row of which was precued. After reporting a letter from the cued row, participants estimated the color diversity of the noncued rows. Results showed that people could estimate the color diversity of the noncued array without a cost to letter report, which suggests that color diversity is registered automatically, outside focal attention, and without consuming additional working memory resources. (shrink)

Introspectively we experience a phenomenally rich world. In stark contrast, many studies show that we can only report on the few items that we happen to attend to. So what happens to the unattended objects? Are these consciously processed as our first person perspective would have us believe, or are they – in fact – entirely unconscious? Here, we attempt to resolve this question by investigating the perceptual characteristics of visual sensory memory. Sensory memory is a fleeting, high-capacity form of (...) memory that precedes attentional selection and working memory. We found that memory capacity benefits from figural information induced by the Kanizsa illusion. Importantly, this benefit was larger for sensory memory than for working memory and depended critically on the illusion, not on the stimulus configuration. This shows that pre-attentive sensory memory contains representations that have a genuinely perceptual nature, suggesting that non-attended representations are phenomenally experienced rather than unconscious. (shrink)

Orthodox interpretations of Sperling‘s partial report paradigm support the idea that there is substantially more in our streams of consciousness than we can attend to or recall. I propose an alternative, postdictive interpretation which fails to support any such conclusion. This account is defended at greater length in my ‗Perception and iconic memory‘. Here I focus on the role ascribed to attention by the rival interpretations. I argue that orthodox accounts fail to assign a plausible role to attention. In contrast, (...) I suggest a novel way in which heterodox, postdictive account can assign attention a plausible role. We should therefore prefer such accounts over their orthodox rivals. Consequently, Sperling‘s paradigm fails to probe the true extent of conscious awareness unfettered by limitations on attention or memory. (shrink)