Perceptual Consciousness Research Articles

Dream experiences and the neural correlates of perceptual consciousness and cognitive access.

This paper approaches the debate whether perceptual consciousness requires cognitive access from the perspective of dream studies, and investigates what kind of findings could support the opposing views of this debate. Two kinds of arguments are discussed, one that claims that the hypoactivity of the dorsolateral prefrontal cortex in rapid eye movement sleep is directly relevant, and another that proposes that locating the neural correlates of dream experiences can indirectly inform the debate. It is argued that under closer reflection, neither the classical claim about dorsolateral prefrontal cortex hypoactivity nor the more recent emphasis on general posterior hot zone activity during dreaming stand up to scrutiny. White dreaming is identified as the phenomenon that, nevertheless, holds the most promise to have an impact on the debate. Going beyond the topic if studying dreams can contribute to this debate, it is argued that cognitive access is not a monolithic phenomenon, and its neural correlates are not well understood. There seems to be a relevant form of cognitive access that can operate in the absence of activity in the dorsolateral prefrontal cortex, and maybe also in the whole frontal region. If so, then exclusive posterior activation during conscious experiences might very well be compatible with the hypothesis that perceptual consciousness requires cognitive access.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Reorganization of the connectivity between elementary functions as a common mechanism of phenomenal consciousness and working memory: from functions to strategies.

In the present communication, phenomenal consciousness, access consciousness and the closely related concept of working memory are presented in the context of a neurocognitive model-the REF (reorganization of elementary functions) framework. The REF framework is based on connectionist networks within which the 'units' are advanced processing modules called elementary functions (EFs). In this framework, the focus is on dynamically changeable 'strategies'-based on reorganizations of the connectivity between EFs-rather than on the more traditional 'cognitive functions'. The background for the REF framework and especially how the neural correlate of consciousness is understood within these models is summarized. According to the REF framework, phenomenal consciousness cannot 'overflow' availability of information for action. Phenomenal consciousness may, however, overflow working memory because working memory in the present context is seen as a surface phenomenon reflecting underlying dynamic strategies-influenced by both experience and situational factors.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Challenges for theories of consciousness: seeing or knowing, the missing ingredient and how to deal with panpsychism.

Significant progress has been made in the study of consciousness. Promising theories have been developed and a wealth of experimental data has been generated, both guiding us towards a better understanding of this complex phenomenon. However, new challenges have surfaced. Is visual consciousness about the seeing or the knowing that you see? Controversy about whether the conscious experience is better explained by theories that focus on phenomenal (P-consciousness) or cognitive aspects (A-consciousness) remains, and the debate seems to reach a stalemate. Can we ever resolve this? A further challenge is that many theories of consciousness seem to endorse high degrees of panpsychism-the notion that all beings or even lifeless objects have conscious experience. Should we accept this, or does it imply that these theories require further ingredients that would put a lower bound on beings or devices that have conscious experience? If so, what could these 'missing ingredients' be? These challenges are discussed, and potential solutions are offered.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

The offline stream of conscious representations.

When do we become conscious of a stimulus after its presentation? We would all agree that this necessarily takes time and that it is not instantaneous. Here, I would like to propose not only that conscious access is delayed relative to the external stimulation, but also that it can flexibly desynchronize from external stimulation; it can process some information 'offline', if and when it becomes relevant. Thus, in contrast with initial sensory processing, conscious experience might not strictly follow the sequence of events in the environment. In this article, I will review gathering evidence in favour of this proposition. I will argue that it offers a coherent framework for explaining a great variety of observations in the domain of perception, sensory memory and working memory: the psychological refractory period, the attentional blink, post-dictive phenomena, iconic memory, latent working memory and the newly described retro-perception phenomenon. I will integrate this proposition to the global neuronal workspace model and consider possible underlying brain mechanisms. Finally, I will argue that this capacity to process information 'offline' might have made conscious processing evolutionarily advantageous in spite of its sluggishness and capacity limitations.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Facing up to the hard question of consciousness.

The so-called hard problem of consciousness is a chimera, a distraction from the hard question of consciousness, which is once some content reaches consciousness, ‘then what happens?’. This question is seldom properly asked, for reasons good and bad, but when asked it opens up avenues of research that promise to dissolve the hard problem and secure a scientifically sound theory of how the human brain produces the (sometimes illusory) convictions that mislead us.This article is part of the theme issue ‘Perceptual consciousness and cognitive access'.

If perception is probabilistic, why does it not seem probabilistic?

The success of the Bayesian perspective in explaining perceptual phenomena has motivated the view that perceptual representation is probabilistic. But if perceptual representation is probabilistic, why does normal conscious perception not reflect the full probability functions that the probabilistic point of view endorses? For example, neurons in cortical area MT that respond to the direction of motion are broadly tuned: a patch of cortex that is tuned to vertical motion also responds to horizontal motion, but when we see vertical motion, foveally, in good conditions, it does not look at all horizontal. The standard solution in terms of sampling runs into the problem that sampling is an account of perceptual decision rather than perception. This paper argues that the best Bayesian approach to this problem does not require probabilistic representation.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

The relationship between attention and consciousness: an expanded taxonomy and implications for 'no-report' paradigms.

Tensions between global neuronal workspace theory and recurrent processing theory have sparked much debate in the field of consciousness research. Here, we focus on one of the key distinctions between these theories: the proposed relationship between attention and consciousness. By reviewing recent empirical evidence, we argue that both theories contain key insights and that certain aspects of each theory can be reconciled into a novel framework that may help guide future research. Alternative theories are also considered, including attended intermediate-level representations theory, integrated information theory and higher order thought theory. With the aim of offering a fresh and nuanced perspective to current theoretical debates, an updated taxonomy of conscious and non-conscious states is proposed. This framework maps a wider spectrum of conscious states by incorporating contemporary views from cognitive neuroscience regarding the variety of attentional mechanisms that are known to interact with sensory processing. Whether certain types of attention are necessary for phenomenal and access consciousness is considered and incorporated into this extended taxonomy. To navigate this expanded space, we review recent 'no-report' paradigms and address several methodological misunderstandings in order to pave a clear path forward for identifying the neural basis of perceptual awareness.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

The methodological puzzle of phenomenal consciousness.

Is phenomenal consciousness constitutively related to cognitive access? Despite being a fundamental issue for any science of consciousness, its empirical study faces a severe methodological puzzle. Recent years have seen numerous attempts to address this puzzle, either in practice, by offering evidence for a positive or negative answer, or in principle, by proposing a framework for eventual resolution. The present paper critically considers these endeavours, including partial-report, metacognitive and no-report paradigms, as well as the theoretical proposal that we can make progress by studying phenomenal consciousness as a natural kind. It is argued that the methodological puzzle remains obdurately with us and that, for now, we must adopt an attitude of humility towards the phenomenal.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Consciousness without report: insights from summary statistics and inattention 'blindness'.

We contrast two theoretical positions on the relation between phenomenal and access consciousness. First, we discuss previous data supporting a mild Overflow position, according to which transient visual awareness can overflow report. These data are open to two interpretations: (i) observers transiently experience specific visual elements outside attentional focus without encoding them into working memory; (ii) no specific visual elements but only statistical summaries are experienced in such conditions. We present new data showing that under data-limited conditions observers cannot discriminate a simple relation (same versus different) without discriminating the elements themselves and, based on additional computational considerations, we argue that this supports the first interpretation: summary statistics (same/different) are grounded on the transient experience of elements. Second, we examine recent data from a variant of 'inattention blindness' and argue that contrary to widespread assumptions, it provides further support for Overflow by highlighting another factor, 'task relevance', which affects the ability to conceptualize and report (but not experience) visual elements.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Downgraded phenomenology: how conscious overflow lost its richness.

Our in-the-moment experience of the world can feel vivid and rich, even when we cannot describe our experience due to limitations of attention, memory or other cognitive processes. But the nature of visual awareness is quite sparse, as suggested by the phenomena of failures of awareness, such as change blindness and inattentional blindness. I will argue that once failures of memory or failures of comparison are ruled out as explanations for these phenomena, they present strong evidence against rich awareness. To accommodate and explain these massive failures of awareness, any theory of phenomenal consciousness must downgrade phenomenology to a degree where it is functionless or, ironically, does not reflect what we experience.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Inflation versus filling-in: why we feel we see more than we actually do in peripheral vision

Do we perceive fine details in the visual periphery? Here, we propose that phenomenology in the visual periphery can be characterized by an inflated sense of perceptual capacity, as observers overestimate the quality of their perceptual inputs. Distinct from the well-known perceptual phenomenon of 'filling-in' where perceptual content is generated or completed endogenously, inflation can be characterized by incorrect introspection at the subjective level. The perceptual content itself may be absent or weak (i.e. not necessarily filled-in), and yet such content is mistakenly regarded by the system as rich. Behaviourally, this can be reflected by metacognitive deficits in the degree to which confidence judgements track task accuracy, and decisional biases for observers to think particular items are present, even when they are not. In two experiments using paradigms that exploit unique attributes of peripheral vision (crowding and summary statistics), we provide evidence that both types of deficits are present in peripheral vision, as observers' reports are marked by overconfidence in discrimination judgements and high numbers of false alarms in detection judgements. We discuss potential mechanisms that may be the cause of inflation and propose future experiments to further explore this unique sensory phenomenon.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Realistic Reasoning and the Unreal World

The ancient Indian philosopher/theologian Gaudapada (probably fifth century ce) is credited with having founded the school of Advaita Vedanta. He unfolds his doctrines in four separate but related treatises which tradition has always transmitted under the title Gaudapadiya-karika. Gaudapada's treatises evince a persistent tendency towards illusionism; he uses logic to argue for the unreality of the perceivable world. Especially in book 4, he develops his argument that the world was never created, that therefore it is an illusion or magic, maya, and that it is only our perceiving consciousness. What is most baffling is the fact that in order to develop his arguments against the reality of the world, he uses the logical terminology and methodology of the early Nyaya, a school whose outlook on the world is realistic and thus the exact opposite of the outlook Gaudapada is espousing. This article will try to discuss and resolve the seeming contradiction between Gaudapada's illusionism and the realism of early Nyaya.

Enactive or inactive? Cranially envatted dream experience and the extended conscious mind

When we dream, it is often assumed, we are isolated from the external environment. It is also commonly believed that dreams can be, at times, accurate, convincing replicas of waking experience. Here I analyse some of the implications of this view for an enactive theory of conscious experience. If dreams are, as described by the received view, “inactive”, or “cranially envatted” whilst replicating the experience of being awake, this would be problematic for certain extended conscious mind theories. Focusing specifically on Alva Noë’s enactive view, according to which the vehicles of perceptual experience extend beyond the brain, I argue that dreams are a quandary. Noë’s view is that dreaming is consistent with enactivism because even if dreams are inactive and shut off from the external environment, they are not “full-blown” perceptual consciousness, and also, there is some reason to reject the inactive claim. However, this view rests on an unjustified and reductive account of dreams which is not supported by empirical evidence. Dreams can indeed replicate waking phenomenal experience during inactive periods of sleep, and we have no reason to suspect that dreams which are more inactive are less “full-blown”. Taken together, this shows that dreams are indeed relevant to extended conscious mind theories and need to be taken into account by enactivists.

El fenómeno de la percepción en Aristóteles y Merleau-Ponty

Se realiza un estudio comparativo del problema de la percepción en Aristóteles y Maurice Merleau-Ponty, considerando el marco antropológico en el que se inscriben sus propuestas. Se establecen sus posibles puntos de contacto y sus diferencias más importantes. Se presta especial atención al vínculo entre el acto senso-perceptual yel movimiento, así como al problema de la conciencia perceptual y a la cuestión de la actualidad común entre el sentiente y el sensible.

The fish in the creek is sentient, even if I can’t speak with it

Abstract: In this paper I argue that Velmens’ reflexive model of perceptual consciousness is useful for understanding the first-person perspective and sentience in animals. I then offer a defense of the proposal that ray-finned bony fish have a first-person perspective and sentience. This defense has two prongs. The first prong is presence of a substantial body of evidence that the neuroanatomy of the fish brain exhibits basic organizational principles associated with consciousness in mammals. These principles include a relationship between a second-order sensory relay, the preglomerular complex, and the fish pallium which bears a resemblance to the relationship between the mammalian thalamus and the neocortex, the existence of feedback/feedforward and reentrant circuitry in the pallium, and structural and functional differences among divisions of the fish pallium. The second prong is the existence of behaviors in fish that exhibit significant flexibility in the presence of environmental change and require relational learning among stimuli distributed in space, over time, or both. I conclude that, although they are instantiated differently, a first-person perspective and sentience are present in fish.

Multisensory processing and perceptual consciousness: Part II

AbstractThe first part of this survey article offered a cartography of some of the more extensively studied forms of multisensory processing. In this second part, I turn to examining some of the different possible ways in which the structure of conscious perceptual experience might also be characterized as multisensory. In addition, I discuss the significance of research on multisensory processing and multisensory consciousness for philosophical debates concerning the modularity of perception, cognitive penetration, and the individuation of the senses.

Split-brain syndrome and extended perceptual consciousness

In this paper I argue that split-brain syndrome is best understood within an extended mind framework and, therefore, that its very existence provides support for an externalist account of conscious perception. I begin by outlining the experimental aberration model of split-brain syndrome and explain both: why this model provides the best account of split-brain syndrome; and, why it is commonly rejected. Then, I summarise Susan Hurley’s argument that split-brain subjects could unify their conscious perceptual field by using external factors to stand-in for the missing corpus callosum. I next provide an argument that split-brain subjects do unify their perceptual fields via external factors. Finally, I explain why my account provides one with an experimental aberration model which avoids the problems typically levelled at such views, and highlight some empirical predictions made by the account. The nature of split-brain syndrome has long been considered mysterious by proponents of internalist accounts of consciousness. However, in this paper I argue that externalist theories can provide a straightforward explanation of the condition. I therefore conclude that the ability of externalist accounts to explain split-brain syndrome gives us strong reason to prefer them over internalist rivals.

Why and How. The Future of the Central Questions of Consciousness.

In this review, we deal with two central questions of consciousness how and why, and we outline their possible future development. The question how refers to the empirical endeavor to reveal the neural correlates and mechanisms that form consciousness. On the other hand, the question why generally refers to the “hard problem” of consciousness, which claims that empirical science will always fail to provide a satisfactory answer to the question why is there conscious experience at all. Unfortunately, the hard problem of consciousness will probably never completely disappear because it will always have its most committed supporters. However, there is a good chance that its weight and importance will be highly reduced by empirically tackling consciousness in the near future. We expect that future empirical endeavor of consciousness will be based on a unifying brain theory and will answer the question as to what is the function of conscious experience, which will in turn replace the implications of the hard problem. The candidate of such a unifying brain theory is predictive coding, which will have to explain both perceptual consciousness and conscious mind-wandering in order to become the truly unifying theory of brain functioning.

Perceptual Consciousness as a Mental Activity

AbstractI argue that perceptual consciousness is constituted by a mental activity. The mental activity in question is the activity of employing perceptual capacities, such as discriminatory, selective capacities. This is a radical view, but I hope to make it plausible. In arguing for this mental activist view, I reject orthodox views on which perceptual consciousness is analyzed in terms of (sensory awareness relations to) peculiar entities, such as, phenomenal properties, external mind‐independent properties, propositions, sense‐data, qualia, or intentional objects.

Does Perceptual Consciousness Overflow Cognitive Access? The Challenge from Probabilistic, Hierarchical Processes

AbstractDoes perceptual consciousness require cognitive access? Ned Block argues that it does not. Central to his case are visual memory experiments that employ post‐stimulus cueing—in particular, Sperling's classic partial report studies, change‐detection work by Lamme and colleagues, and a recent paper by Bronfman and colleagues that exploits our perception of ‘gist’ properties. We argue contra Block that these experiments do not support his claim. Our reinterpretations differ from previous critics' in challenging as well a longstanding and common view of visual memory as involving declining capacity across a series of stores. We conclude by discussing the relation of probabilistic perceptual representations and phenomenal consciousness.