Some cases of prosopagnosia involve a highly circumscribed loss of A-consciousness. When seen in this way they offer further support for the arguments made in Block's target article.

Block has attempted to reduce the confusion and controversy concerning the term “consciousness” by suggesting that there are two forms or types of consciousness, each of which has several characteristics or properties. This suggestion appears to further becloud the topic, however. Perhaps consciousness cannot be defined adequately and should not be considered as a topic that can be studied scientifically.

Blocks distinction between “phenomenal feel” consciousness and “thought/cognition” consciousness is a cultural construction. Consciousness (and its “subspecies”) is not a natural kind. Some crosscultural data are presented to support this.

It is argued that there is no fallacy in the reasoning in the example of the thirsty blindsight subject, on one reconstruction of that reasoning. Neither the case of orgasm nor the case of a visual versus an auditory experience as of something overheard shows that phenomenal content is not representational.

Two standard epistemological accounts are conflated in Dienes & Perner's account of knowledge, and this conflation requires the rejection of their four conditions of knowledge. Because their four metarepresentations applied to the explicit-implicit distinction are paired with these conditions, it follows by modus tollens that if the latter are inadequate, then so are the former. Quite simply, their account misses the link between true reasoning and knowledge.

If phenomenal consciousness is distinct from the computationally based access-consciousness that controls overt behavior, how can I tell which things (other than myself) enjoy phenomenal consciousness? And if phenomenal consciousness 'plays no role in controlling overt behavior, how do human bodies come to write target articles arguing for the existence of phenomenal consciousness?

Block's P-/A-consciousness distinction rules out P's involving a specific kind of cognitive access and commits him to a “strong” Pconsciousness. This not only confounds plausible research in the area but betrays an anosognosia about Wittgenstein's diagnosis about our philosophical “introspection” of mysterious inner processes.

I criticize Block's examples of P-consciousness and A-consciousness for being flawed and the notion of A-consciousness for not being a notion of consciousness at all. I argue that an empirically important distinction can be made between behavior that is supported by an underlying conscious experience and behavior that is brought about by nonconscious action-control mechanisms. This distinction is different from that made by Block.

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

Two studies are reported in which participants’ reports of altered states of consciousness were manipulated using priming methods. Study 1 used both subtle and blunt supraliminal priming methods, while Study 2 used a subliminal priming method. Across the two studies, two different methods for inducing ASC were used. In both studies a direct and an indirect measure of ASC was employed in order to separate the more nonconscious and spontaneous from the more conscious and directive reports of ASC. As predicted, (...) results indicated that the indirect measures of ASC were consistent with the ASC primes participants received. Implications and future research directions are discussed. (shrink)

A-consciousness may be regarded as the visibility of information that is the output of a process within a community of other processes. The most prominent function of “public” dissemination of information is giving access to it to processes whose relevance is not clear at the moment of dissemination. The function of P-consciousness may be outside the realm of cognition.

In response to the objection that his “access-consciousness” is not really consciousness but a matter of the availability of certain information for certain kinds of processing, Block will probably have to argue that consciousness in a more basic, familiar, traditional sense is an essential component of any instance of access-consciousness and thus justifies the name.

In common sense consciousness has a fairly determinate content – the (single) way an experience feels, the (single) line of thought being consciously followed. The determinacy of the object may be achieved by linking Block's two concepts, so that as long as we hold on to the determinacy of content we are unable to separate P and A.

Block contends that the concept of consciousness is a mongrel concept and that researchers go astray by conflating different notions of “consciousness.” This is certainly true. In fact, it is truer than Block acknowledges, because his own notion of P-consciousness runs together two, or arguably three, quite different and separable features of a sensory state.

The information processing that constitutes accessconsciousness is not sufficient to make a representational state conscious in any sense. Standard examples of computation without consciousness undermine A-consciousness, and Block's cases seem to derive their plausibility from a lurking phenomenal awareness. That is, people and other minded systems seem to have access-consciousness only insofar as the state accessed is a phenomenal one, or the state resulting from access is phenomenal, or both.

Basically agreeing with Block regarding the need for a distinction between P- and A-consciousness, I characterize the problem somewhat diflerently, relating it more directly to the explanatory gap. I also speculate on the relation between the two forms of consciousness, arguing that some notion of access is essentially involved in phenomenal experience.

Block's cases of superblindsight, the pneumatic drill, and the Sperling experiments do not show that P-consciousness and Aconsciousness can come apart. On certain tendentious but not implausible construals of the concepts of P- and A-consciousness, they refer to the same psychological phenomenon.

This study renews the classical concept of subliminal perception by investigating the impact of subliminal flicker from fluorescent lighting on affect and cognitive performance. It was predicted that low compared to high frequency lighting would evoke larger changes in affective states and also impair cognitive performance. Subjects reported high rather than low frequency lighting to be more pleasant, which, in turn, enhanced their problem solving performance. This suggests that sensory processing can take place outside of conscious awareness resulting in conscious (...) emotional consequences; indicating a role of affect in subliminal/implicit perception, and that positive affect may facilitate cognitive task performance. (shrink)

Previous research has demonstrated electroencephalogram (EEG) changes in response to low-odor concentrations, resulting in near-chance detection. Such findings have been taken as evidence for olfaction without awareness. We replicated and extended previous work by examining EEG responses to water-water control, 0.0001, 0.001, 0.01, and 1 ppm isoamyl acetate (IAA) in water paired with water only. Detection was above chance (>50%) for .001 and above, and alpha decreased only to those concentrations, suggesting that EEG changes corresponded to IAA awareness. However, when (...) correct trial EEGs were compared to incorrect trial EEGs during .001 ppm, right posterior/central alpha decreased during incorrect trials and alpha decreased more globally (including frontal sites) during correct trials. These data may not reflect awareness or unawareness per se. Instead, results are discussed regarding activation of perceptual systems in the posterior region during incorrect trials and the activation of frontal action systems during a subset of correct trials. (shrink)

This commentary offers two criticisms of Block's account of phenomenal consciousness and a brief sketch of a rival account. The negative points are that monitoring consciousness also involves the possession of certain states and that phenomenal consciousness inevitably involves some sort of monitoring. My positive suggestion is that “phenomenal consciousness” may refer to our ability to monitor the rich but preconceptual states that retain perceptual information for complex processing.

Research by Raz and his associates has repeatedly found that suggestions for hypnotic agnosia, administered to highly hypnotizable subjects, reduce or even eliminate Stroop interference. The present paper sought unsuccessfully to extend these findings to negative priming in the Stroop task. Nevertheless, the reduction of Stroop interference has broad theoretical implications, both for our understanding of automaticity and for the prospect of de-automatizing cognition in meditation and other altered states of consciousness.

One can share Block's aim of distinguishing “phenomenal” experience from cognitive function and agree with much in his views, yet hold that the inclusion of representational content within phenomenal content, if only in certain spatial cases, obscures this distinction. It may also exclude some modular theories, although it is interestingly suggestive of what may be the limits of the phenomenal penetration of the representational mind.

Three experiments examined the role of response criteria in a masked semantic priming paradigm using an exclusion task. Experiment 1 used on-line prime-report and exclusion instructions in which participants were told to avoid completing a word stem with a word related to a prime flashed for 0, 38 or 212 ms. Semantic priming was significant in the items analysis, but was moderated by peoples’ ability to report the prime in the participant analysis. Prime-report thresholds in Experiment 2 were made more (...) liberal by instructing participants to guess on every trial. Prime-report increased from Experiment 1 as exclusion failures were eliminated. Experiment 3 clarified the relationship between awareness and prime identification using an on-line measure of confidence and different liberal prime report instructions. The current findings suggest that the ability to act upon and report information in a masked prime is determined by a variable response criterion, which can be manipulated as an independent variable. (shrink)

Block's notion of P-consciousness catches too much in its net. He would do better to exclude all states that do not have a sensory component. I question what he says about my work with the “blind” monkey, Helen.

A “fallacy” is something like the sense-datum fallacy, involving a logically invalid argument. A “conflation” is something like Block's conflation of the (alleged) raw feel of an experience with what it is like to have the experience. Trivially, a self is conscious of something only if it accesses it. Substantive issues concern the nature of the conscious self and the nature of access.

Should we distinguish between access and phenomenal consciousness? Block says yes and that various pathologies of consciousness support and clarify the distinction. The commentary charge that the distinction is neither supported nor clarified by the clinical data. It recommends an alternative reading of the data and urges Block to clarify the distinction.

Our perception of external features comprises, among others, functional and phenomenological levels. At the functional level, the perceiver’s mind processes external features according to its own causal- functional organization. At the phenomenological level, the perceiver has consciousness of external features. The question of this paper is: How do the functional and the phenomenological levels of perception relate to each other? The answer I propose is that functional states of specifically perceptual attention constitute the necessary basis for the arising of consciousness (...) in a perceiver. -/- Widely studied within cognitive psychology, perceptual attention is still awaiting a thoroughgoing philosophical treatment. The paper presents and draws upon Anne Treisman’s feature-integration theory of attention (cf. A. Treisman & G. Gelade, “A Feature-Integration Theory of Attention,” Cognitive Psychology, 12, 1980. Pp. 97-136). According to this theory, attentional mechanisms are responsible for the binding of perceptual features into coherent and stable objects of perception. By itself, I will claim, the theory of feature integration does not allow a straightforward reduction of consciousness to the functional processing underlying it. However, on the basis of Treisman’s theory we can produce a methodological argument for endorsing the non-reductivist thesis that attentional states constitute the necessary basis for the arising of consciousness in a perceiver. The paper closes by presenting this argument, according to which the thesis is implied by a unified account of the common representational natures of attentional and conscious states. (shrink)

Although not the main point of his target article, Block defends the view that perception and awareness of perception could be functions of different brain systems. I will argue that the available data do not support this view, and that Block's defense of the view rests on problematic eonstruals of the “executive system” and of the components of information-processing models.

Propositions as to the nature of consciousness, based on disorders of perception that result from brain damage, and taking insufficient account of the numerous ways in which normal subjects may deviate from that “usual” sequence of events (input → subjective awareness → output) risk increasing rather than diminishing any existing confusion about the function of consciousness.

The implicit-explicit distinction is applied to knowledge representations. Knowledge is taken to be an attitude towards a proposition which is true. The proposition itself predicates a property to some entity. A number of ways in which knowledge can be implicit or explicit emerge. If a higher aspect is known explicitly then each lower one must also be known explicitly. This partial hierarchy reduces the number of ways in which knowledge can be explicit. In the most important type of implicit knowledge, (...) representations merely reflect the property of objects or events without predicating them of any particular entity The dearest cases of explicit knowledge of a fact are representations of one's own attitude of knowing that fact. These distinctions are discussed in their relationship to similar distinctions such as procedural-declarative, conscious unconscious, verbalizable-nonverbalizable, direct-indirect tests, and automatic voluntary control. This is followed by an outline of how these distinctions can be used to integrate and relate the often divergent uses of the implicit-explicit distinction in different research areas. We illustrate this for visual perception, memory, cognitive development, and artificial grammar learning. (shrink)

The differences Block attempts to capture with his putative distinction between P-consciousness and A-consciousness are more directly and perspicuously handled in terms of differences in richness of content and degree of influence. Block's critiques, based on his misbegotten distinction, evaporate on closer inspection.

To demonstrate that a fallacy is committed, Block needs to convince us of two things: first, that the concept of phenomenal consciousness is distinct from that of access consciousness, and second, that it picks out a different property from that of access consciousness. I raise doubt about both of these claims, suggesting that the concept of a phenomenal property is the concept of a property to which we have a special sort of access.

Legally blind participants were able to identify a visual stimulus attribute in the absence of consciously identifying its presence. Specifically, participants—with their corrective lenses removed—correctly guessed the hour-hand position above chance on a clockface shown on a computer screen. This occurred both when presented in a 1-clockface display , as well as when shown a display containing 4 clockfaces , in which only 1 face contained a hand. Even more striking, hand identification accuracy in the 4-clockface condition was comparable whether (...) the clockface containing the hand was or was not correctly identified. That legally blind individuals are capable of identifying stimulus attributes without conscious awareness provides an additional vehicle for exploring implicit perception. Consistent with previous research, the visualsystem can apparently cope with degraded visual input through information available through a secondary pathway via the superior colliculi. (shrink)

Two experiments examine the effects of unreportable hints on anagram solving performance and on solvers' subjective experience of insight. In Experiment 1, after seeing a hint presented too briefly to identify, participants solved anagrams preceded by the solution fastest and solved anagrams preceded by unrelated hints slowest. Participants' “warmth” ratings for solution hints were more insight-like than those for unrelated hints. In Experiment 2 a hint, or no hint, was presented at one of three different exposure durations . Participants benefited (...) from solution-relevant hints that were either unreportable or reportable, but showed a cost only for unrelated hints that were reportable. Participants' ratings of their insight experiences showed that unreportable solution and semantically related hints produced more insight-like experiences than did unrelated hints. The results suggest that unreportable processing of solution-related information is important for the insight experience. (shrink)

Two experiments examine the effects of unreportable hints on anagram solving performance and on solvers' subjective experience of insight. In Experiment 1, after seeing a hint presented too briefly to identify, participants solved anagrams preceded by the solution fastest and solved anagrams preceded by unrelated hints slowest. Participants' “warmth” ratings for solution hints were more insight-like than those for unrelated hints. In Experiment 2 a hint, or no hint, was presented at one of three different exposure durations. Participants benefited from (...) solution-relevant hints that were either unreportable or reportable, but showed a cost only for unrelated hints that were reportable. Participants' ratings of their insight experiences showed that unreportable solution and semantically related hints produced more insight-like experiences than did unrelated hints. The results suggest that unreportable processing of solution-related information is important for the insight experience. (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)

With some help from the commentators, a few adjustments to the characterizations of A-consciousness and P-consciousness can avoid some trivial cases of one without the other. But it still seems that the case for the existence of P without A is stronger than that for A without P. If indeed there can be P without A, but not A without P, this would be a remarkable result that would need explanation.

Additional experiments show that P-consciousness and A consciousness can be empirically dissociated for the theoretically so phisticated observer. Phenomenal consciousness can have several degrees that are indirectly measurable.

Block seems to propose untested answers to empirical questions. Whether consciousness is a “mongrel problem,” rather than a single core fact with many facets, is an empirical issue. Likewise, the intimate relationship between personal consciousness and global access functions cannot be decided pretheoretically. This point is demonstrated by the reader's private experience of foveal versus parafoveal vision, and for conscious versus unconscious representation of the many meanings of common words.

Although information-processing theories cannot provide a full explanatory account of P-consciousness, there is less conflation and confusion in cognitive psychology than Block suspects. Some of the reasoning that Block criticises can be interpreted plausibly in the light of a folk psychological view of the relation between P-consciousness and A-consciousness.

Block's distinction between phenomenal and access consciousness is accepted, and it is agreed that one may be found without the other, but his account of the distinction is challenged. Phenomenal consciousness is perceptual consciousness, and it is a matter of gaining information of a detailed, nonverbal sort about the subject's body and environment. Access consciousness is good, old-fashioned introspection.

This is a bibliography of books and articles on consciousness in philosophy, cognitive science, and neuroscience over the last 30 years. There are three main sections, devoted to monographs, edited collections of papers, and articles. The first two of these sections are each divided into three subsections containing books in each of the main areas of research. The third section is divided into 12 subsections, with 10 subject headings for philosophical articles along with two additional subsections for articles in cognitive (...) science and neuroscience. Of course the division is somewhat arbitrary, but I hope that it makes the bibliography easier to use. This bibliography has first been compiled by Thomas Metzinger and David Chalmers to appear in print in two philosophical anthologies on conscious experience . From 1995 onwards it has been continuously updated by Thomas Metzinger, and now is freely available as a PDF-, RTF-, or HTML-file. This bibliography mainly attempts to cover the Anglo-Saxon and German debates, in a non-annotated, fully formatted way that makes it easy to "cut and paste" from the original file. To a certain degree this bibliography also contains items in other languages than English and German - all submissions in other languages are welcome. Last update of current version: July 13th, 2001. (shrink)