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)

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.

The aim of this paper is to argue that the phenomenal similarity between perceiving and visualizing can be explained by the similarity between the structure of the content of these two different mental states. And this puts important constraints on how we should think about perceptual content and the content of mental imagery.

I argue that perceptual content is always affected by the allocation of one’s attention. Perception attributes determinable and determinate properties to the perceived scene. Attention makes (or tries to make) our perceptual attribution of properties more determinate. Hence, a change in our attention changes the determinacy of the properties attributed to the perceived scene.

Five aspects of visual change detection are reviewed. The first concerns the concept of change itself, in particular the ways it differs from the related notions of motion and difference. The second involves the various methodological approaches that have been developed to study change detection; it is shown that under a variety of conditions observers are often unable to see large changes directly in their field of view. Next, it is argued that this “change blindness” indicates that focused attention is (...) needed to detect change, and that this can help map out the nature of visual attention. The fourth aspect concerns how these results affect our understanding of visual perception—for example, the implication that a sparse, dynamic representation underlies much of our visual experience. Finally, a brief discussion is presented concerning the limits to our current understanding of change detection. (shrink)

Most contemporary theorists regard the traditional thesis that perception is essentially conscious as just another armchair edict to be abandoned in the wake of empirical discovery. Here I reconsider this dramatic departure from tradition. My aim is not to recapture our prelapsarian confidence that perception is inevitably conscious (though much I say might be recruited to that cause). Instead, I want to problematize the now ubiquitous belief in unconscious perception. The paper divides into two parts. Part One is more purely (...) philosophical. It explains how standard arguments for unconscious perception rely on contentious background assumptions concerning the relation between ordinary perception and the explanatory constructs of scientific psychology. Part Two, in contrast, offers detailed engagement with relevant empirical work. It exposes how, even setting aside the concerns identified in Part One, a dilemma confronts the believer in unconscious perception. This dilemma arises because ordinary perception is an individual-level state or occurrence, yet criteria sufficiently stringent to guarantee that a putatively perceptual state is unconscious vitiate the grounds for its attribution to the individual. The dilemma foments a hypothesis, namely that the conditions for genuine, individual-level perception are sufficient conditions for perceptual consciousness. The viability of this hypothesis should unnerve anyone who thinks unconscious perception is simply an empirical given. (shrink)

This chapter argues that attention is a distinctive mode of consciousness, which plays an essential functional role in making information accessible for use in the rational control of thought and action. The main line of argument can be stated quite simply. Attention is what makes information fully accessible for use in the rational control of thought and action. But what makes information fully accessible for use in the rational control of thought and action is a distinctive mode of consciousness. Therefore, (...) attention is a distinctive mode of consciousness. In a slogan: attention is rational-access consciousness. (shrink)

Theories of picture perception aim to understand our perceptual relation to both the picture surface and the depicted object. I argue that we should talk about not two, but three entities when understanding picture perception: the picture surface, the three dimensional object the picture surface visually encodes and the three dimensional depicted object. As and can come apart, we get a more complex picture of picture perception than normally assumed and one where the notion of twofoldness, which has played an (...) important albeit controversial role in understanding picture perception is replaced by the concept of threefoldness. (shrink)

Dehaene and Naccache, Dennett and Jack and Shallice “see convergence coming from many different quarters on a version of the neuronal global workspace model†(Dennett, p. 1). (Boldface references are to papers in this volume.) On the contrary, even within this volume, there are commitments to very different perspectives on consciousness. And these differing perspectives are based on tacit differences in philosophical starting places that should be made explicit.  Indeed, it is not clear that different uses of “consciousness†and (...) “awareness†in this volume can be taken to refer to the same phenomenon. More specifically, I think there are three different concepts of consciousness in play in this issue. The global workspace model makes much more sense on one of these than on the others. (shrink)

Large changes in a scene often become difficult to notice if made during an eye movement, image flicker, movie cut, or other such disturbance. It is argued here that this _change blindness_ can serve as a useful tool to explore various aspects of vision. This argument centers around the proposal that focused attention is needed for the explicit perception of change. Given this, the study of change perception can provide a useful way to determine the nature of visual attention, and (...) to cast new light on the way that it is?and is not?involved in visual perception. To illustrate the power of this approach, this paper surveys its use in exploring three different aspects of vision. The first concerns the general nature of _seeing_. To explain why change blindness can be easily induced in experiments but apparently not in everyday life, it is proposed that perception involves a _virtual representation_, where object representations do not accumulate, but are formed as needed. An architecture containing both attentional and nonattentional streams is proposed as a way to implement this scheme. The second aspect concerns the ability of observers to detect change even when they have no visual experience of it. This _sensing_ is found to take on at least two forms: detection without visual experience (but still with conscious awareness), and detection without any awareness at all. It is proposed that these are both due to the operation of a nonattentional visual stream. The final aspect considered is the nature of visual attention itself?the mechanisms involved when _scrutinizing_ items. Experiments using controlled stimuli show the existence of various limits on visual search for change. It is shown that these limits provide a powerful means to map out the attentional mechanisms involved. (shrink)

Large changes that occur in clear view of an observer can become difficult to notice if made during an eye movement, blink, or other such disturbance. This change blindness is consistent with the proposal that focused visual attention is necessary to see change, with a change becoming difficult to notice whenever conditions prevent attention from being automatically drawn to it. -/- It is shown here how the phenomenon of change blindness can provide new results on the nature of visual attention, (...) including estimates of its capacity and the extent to which it can bind visual properties into coherent descriptions. It is also shown how the resultant characterization of attention can in turn provide new insights into the role that it plays in the perception of scenes and events. (shrink)

I aim to show that perception depends counterfactually on the action we want to perform. Perception is not all-purpose: what we want to do does influence what we see. After clarifying how this claim is different from the one at stake in the cognitive penetrability debate and what counterfactual dependence means in my claim, I will give a two-step argument: one’s perceptual attention depends counterfactually on one’s intention to perform an action and one’s perceptual processing depends counterfactually on one’s perceptual (...) attention. If we put these claims together, what we get is that one’s perceptual processing depends counterfactually on one’s intention to perform an action. (shrink)

The idea that attention is necessary for consciousness (the “Necessity Thesis”) is frequently advocated by philosophers and psychologists alike. Experiments involving inattentional and change blindness are thought to support the Necessity Thesis, but they do so only if subjects failing to notice the target stimulus are also not conscious of it. This article uses commonsense phenomenological observations supplemented with empirical data to argue that some subjects failing to notice the target stimulus nonetheless experience its color. Since subjects not noticing the (...) target are commonly assumed to be not attending to it, these scenarios would be instances of consciousness without attention: instead of inattentional and change blindness supporting the Necessity Thesis, they would present counterexamples to it. (shrink)

Once upon a time, people thought that all perception was conscious. Indeed, it was widely believed that all mental states are conscious, so the problem of explaining consciousness collapses into the problem of explaining mentality. But things have changed. Most people now believe that a lot goes on unconsciously. Indeed, some people believe that mental states that are not perceptual in nature are never conscious. That’s a matter of controversy. Less controversial is the claim that perceptual states are conscious some (...) of the time, but not all of the time. This raises a question. When are perceptual states conscious? A theory of consciousness is, in large part, an answer to that question. In this chapter, I will offer a few critical remarks on one answer that has been popular in philosophy, and then I will offer a defense of another answer that has emerged out of cognitive science. To avoid undue suspense, the answer that I favor is that perceptual states become conscious when and only when the perceiver is attending. (shrink)

& Awareness of change within a visual scene only occurs in subjects were aware of, replicated those attentional effects, but the presence of focused attention. When two versions of a.

(No abstract is available for this citation).

In a series of three experiments, we explored the nature of implicit representations in change blindness . Using 3 × 3 letter arrays, we asked subjects to locate changes in paired arrays separated by 80 ms ISIs, in which one, two or three letters of a row in the second array changed. In one testing version, a tone followed the second array, signaling a row for partial report . In the other version, no PR was required. After Ss reported whether (...) a change had been detected and the PR had been completed , they were asked to identify a degraded letter trigram that was either novel, or from a previously shown row . Our findings indicate that when CB occurs, both the pre-change and post-change stimulus information primes despite its unavailability to consciousness. Surprisingly, findings also indicate that when change detection occurs only the post-change information primes. (shrink)

People’s awareness of tactile stimuli has been investigated in far less detail than their awareness of stimuli in other sensory modalities. In an attempt to fill this gap, we provide an overview of studies that are pertinent to the topic of tactile consciousness. We discuss the results of research that has investigated phenomena such as “change blindness”, phantom limb sensations, and numerosity judgments in tactile perception, together with the results obtained from the study of patients affected by deficits that can (...) adversely affect tactile perception such as neglect, extinction, and numbsense. The similarities as well as some of the important differences that have emerged when visual and tactile conscious information processing have been compared using similar experimental procedures are highlighted. We suggest that conscious information processing in the tactile modality cannot be separated completely from the more general processing of spatial information in the brain. Finally, the importance of considering tactile consciousness within the larger framework of multisensory information processing is also discussed. (shrink)

Attention is necessary for the conscious perception of any object. Objects not attended to are not seen. What is it that captures attention when we are engaged in some attention-absorbing task? Earlier research has shown that there are only a very few stimuli which have this power and therefore are reliably detected under these conditions . The two most reliable are the observer’s own name and a happy face icon which seem to capture attention by virtue of their meaning. Three (...) experiments are described which explore whether these stimuli are detected under conditions, heretofore unexamined, which either cause inattentional blindness or are associated with a perceptual failure associated with the limits of attention. The evidence obtained indicates that these stimuli have a unique capacity to capture and extend the limits of attention under conditions in which this has been deemed highly unlikely. (shrink)

In the not-too-distant past, vision was often said to involve three levels of processing: a low level concerned with descriptions of the geometric and photometric properties of the image, a high level concerned with abstract knowledge of the physical and semantic properties of the world, and a middle level concerned with anything not handled by the other two. The negative definition of mid-level vision contained in this description reflected a rather large gap in our understanding of visual processing: How could (...) the here-and-now descriptions of the low levels combine with the enduring knowledge of the high levels to produce our perception of the surrounding world? A number of experimental and theoretical efforts have been made over the past few decades to solve this "mid-level crisis". One of the more recent of these is based on the phenomenon of change blindness—the difficulty in seeing a large change in a scene when the transients accompanying that change no longer convey information about its location (Rensink, O'Regan, & Clark, 1997; Rensink, 2000a). Phenomenologically, this effect is quite striking: the change typically is not seen for several seconds, after which it suddenly snaps into awareness. During the time the change remains "invisible", there is an apparent disconnection of the low-level descriptions (which respond to the change) from subjective visual experience (which does not). As such, this effect would seem to have the potential to help us understand how mid-level mechanisms might knit low- and high-level processes into a coherent representation of our surroundings. -/- It is argued here that this potential can indeed be realized, and that change blindness can teach us much about the nature of mid-level vision.3 A number of studies are first reviewed showing that the perception of a scene does not involve a steady buildup of detailed representation: rather, it is a dynamic process, with focused attention playing one of the main roles, viz., forming coherent object representations whenever needed. It is then argued that change blindness can also shed considerable light on the nature of focused attention itself, such as its speed, capacity, selectivity, and ability to bind together visual properties into coherent structures. (shrink)

Several studies (e.g., Becklen & Cervone, 1983; Mack & Rock, 1998; Neisser & Becklen, 1975) have found that observers attending to a particular object or event often fail to report the presence of unexpected items. This has been interpreted as inattentional blindness (IB), a failure to see unattended items (Mack & Rock, 1998). Meanwhile, other studies (e.g., Pashler, 1988; Phillips, 1974; Rensink et al., 1997; Simons, 1996) have found that observers often fail to report the presence of large changes in (...) a display when these changes occur simultaneously with a transient such as an eye movement or flash of the display. This has been interpreted as change blindness (CB), a failure to see unattended changes (Rensink et al., 1997). In both cases there is a striking failure to report an object or event that would be quite visible under other circumstances. And in both cases there is a widespread (although not universal) belief that the underlying cause has to do with the absence of attention. The question then arises as to how these effects might be related. Is CB the same thing as IB? If not, what is the relation between them? And given that these phenomena deal with failures of subjective perception, what can they teach us about the nature of our visual experience? In particular, what can they teach us about the role played by visual attention? (shrink)

In a recent commentary, Memmert critiqued claims that attentional misdirection is directly analogous to inattentional blindness and cautioned against assuming too close a similarity between the two phenomena. One important difference highlighted in his analysis is that most lab-based inductions of IB rely on the taxing of attention through a demanding primary task, whereas attentional misdirection typically involves simply the orchestration of spatial attention. The present commentary argues that, rather than reflecting a complete dissociation between IB and attentional misdirection, this (...) difference highlights potential grounds for delineating mechanistically distinct forms of IB: spatial inattentional blindness, which stems from the covert misallocation of spatial attention, and central inattentional blindness, which stems from disruption or preoccupation of perceptual mechanisms that interface with higher-level processes such as working memory. Recognition of such distinctions can help situate theoretical understanding of IB more firmly within the context of the broader attention literature. (shrink)

Existentialist accounts maintain that visual phenomenal content takes the logical form of an existentially quantified sentence. These accounts do not make phenomenal content specific enough. Singularist accounts posit a singular content in which the seen object is a constituent. These accounts make phenomenal content too specific. My account gets the specificity of visual phenomenal content just right. My account begins with John Searle's suggestion that visual experience represents an object as seen, moves this relation outside the scope of the existential (...) quantifier and then replaces it with the relation of objects being ‘present as accessible’, as described by Alva Noë. (shrink)

This paper discusses several key issues concerning consciousness and human vision. A brief overview is presented of recent developments in this area, including issues that have been resolved and issues that remain unsettled. Based on this, three Hilbert questions are proposed. These involve three related sets of issues: the kinds of visual experience that exist, the kinds of visual attention that exist, and the ways that these relate to each other.

There are conflicting views concerning the electrophysiological correlates of visual consciousness. Whereas one view considers a relatively late positive deflection as a primary correlate of consciousness, another model links consciousness with earlier negativity . The present experiment utilized metacontrast masking in investigating the electrophysiological correlates of visual consciousness. The participants were presented with target-mask sequences in three stimulus onset asynchronies. The target stimuli were followed by either a metacontrast mask or a similar-looking, but ineffective pseudomask. The results showed that the (...) first deflection that correlated with target visibility was VAN which was followed by LP. We argue that the VAN is the primary correlate target visibility, while the LP reflects later, postperceptual processing stages. (shrink)

One of the more compelling beliefs about vision is that it is based on representations that are coherent and complete, with everything in the visual field described in great detail. However, changes made during a visual disturbance are found to be difficult to see, arguing against the idea that our brains contain a detailed, picture-like representation of the scene. Instead, it is argued here that a more dynamic, "just-in-time" representation is involved, one with deep similarities to the way that users (...) interact with external displays. It is further argued that these similarities can provide a basis for the design of intelligent display systems that can interact with humans in highly effective and novel ways. (shrink)

An extensive research program surrounding a phenomenon called inattentional blindness is reported by Mack and Rock in their book of the same name. The general conclusion that is drawn from the work is that no conscious perception can occur without attention. Because the bulk of the evidence surrounding inattentional blindness comes from memorial reports of displays, it is possible that inattentional blindness reflects a problem with memory, rather than a problem with perception. It is argued here that at least some (...) instances of inattentional blindness are better characterized as memorial failures than perceptual failures. The extent to which unattended stimuli fail to engage perceptual processing is an empirical question that the combination of inattentional blindness and online measures of processing can be used to address. (shrink)

Is attention both necessary and sufficient for consciousness? Call this central question of this treatise, “Q.” We commonly have the experience of consciously paying attention to something, but is it possible to be conscious of something you are not attending to, or to attend to something of which you are not conscious? Where might we find examples of these? This treatise is a quest to find an answer to Q in two parts. Part I reviews the foundations upon which the (...) discourse on Q is built. Different inputs to Q produce different answers. After consideration of the many ways “attention” and “consciousness” have been defined, I settle upon phenomenal consciousness and Executive Attention (defined as a suite of strategies for structuring cognition for further processing implemented by the executive of working memory) as the most interesting inputs to Q, and the ones on which Part II focuses. Attention without consciousness seems relatively easy to establish empirically, but consciousness without attention is much harder. The putative candidates all seem to have major problems, but I build a strong abductive case for the hitherto ignored case of foveal phenomenal overflow. We consciously see far more detail in our foveal fields than we can Executively Attend, although there is a serious obstacle to our ever confirming that empirically—identifying conscious content relies on Executive Attentional report. Triangulating the capacity limitations of attention, consciousness, and working memory strengthens this case for consciousness without attention, and suggests that cognition must work something like my “Witches’ Hat Model,” on which content can become conscious outside of Executive Attention or working memory. I conclude with some reflections on the implications of my arguments for the discourse on Q, and for other discourses such as the ontologies of attention and consciousness, theories of consciousness, some other cognitive concepts, and ethical considerations in humans, animals, and machines. A conclusive answer to Q continues to elude us. It may perhaps be an ultimately insoluble conundrum. But it is the very essence of humanity to seek an answer, and in so doing, to improve our understanding of our own nature: “The proper study of mankind is man.”1. (shrink)

The review first discusses componential explanations of automaticity, which specify non/automaticity features (e.g., un/controlled, un/conscious, non/efficient, fast/slow) and their interrelations. Reframing these features as factors that influence processes (e.g., goals, attention, and time) broadens the range of factors that can be considered (e.g., adding stimulus intensity and representational quality). The evidence reviewed challenges the view of a perfect coherence among goals, attention, and consciousness, and supports the alternative view that (a) these and other factors influence the quality of representations in (...) an additive way (e.g., little time can be compensated by extra attention or extra stimulus intensity) and that (b) a first threshold of this quality is required for unconscious processing and a second threshold for conscious processing. The review closes with a discussion of causal explanations of automaticity, which specify factors involved in automatization such as repetition and complexity, and a discussion of mechanistic explanations, which specify the low-level processes underlying automatization. (shrink)