Odor memory: Review and analysis

We critically review the cognitive literature on olfactory memory and identify the similarities and differences between odor memory and visual-verbal memory. We then analyze this literature using criteria from a multiple memory systems approach to determine whether olfactory memory can be considered to be a separate memory system. We conclude that olfactory memory has a variety of important distinguishing characteristics, but that more data are needed to confer this distinction. We suggest methods for the study of olfactory memory that should make a resolution on the separate memory system hypothesis possible while simultaneously advancing a synthetic understanding of olfaction and cognition.     

How many kinds of consciousness?

Ned Block's influential distinction between phenomenal and access consciousness has become a staple of current discussions of consciousness. It is not often noted, however, that his distinction tacitly embodies unargued theoretical assumptions that favor some theoretical treatments at the expense of others. This is equally so for his less widely discussed distinction between phenomenal consciousness and what he calls reflexive consciousness. I argue that the distinction between phenomenal and access consciousness, as Block draws it, is untenable. Though mental states that have qualitative character plainly differ from those with no mental qualities, a mental state's being conscious is the same property for both kinds of mental state. For one thing, as Block describes access consciousness, that notion does not pick out any property that we intuitively count as a mental state's being conscious. But the deeper problem is that Block's notion of phenomenal consciousness, or phenomenality, is ambiguous as between two very different mental properties. The failure to distinguish these results in the begging of important theoretical questions. Once the two kinds of phenomenality have been distinguished, the way is clear to explain qualitative consciousness by appeal to a model such as the higher-order-thought hypothesis.     

Access is mainly a second-order process: SDT models whether phenomenally (first-order) conscious states are accessed by reflectively (second-order) conscious processes

Access can either be first-order or second-order. First order access concerns whether contents achieve representation in phenomenal consciousness at all; second-order access concerns whether phenomenally conscious contents are selected for metacognitive, higher order processing by reflective consciousness. When the optional and flexible nature of second-order access is kept in mind, there remain strong reasons to believe that exclusion failure can indeed isolate phenomenally conscious stimuli that are not so accessed. Irvine’s [Irvine, E. (2009). Signal detection theory, the exclusion failure paradigm and weak consciousness—Evidence for the access/phenomenal distinction? Consciousness and Cognition.] partial access argument fails because exclusion failure is indeed due to lack of second-order access, not insufficient phenomenally conscious information. Further, the enable account conforms with both qualitative differences and subjective report, and is simpler than the endow account. Finally, although first-order access may be a distinct and important process, second-order access arguably reflects the core meaning of access generally.     

A global workspace model for phenomenal and access consciousness

Both the global workspace theory and Block’s distinction between phenomenal and access consciousness, are central in the current debates about consciousness and the neural correlates of consciousness. In this article, a unifying global workspace model for phenomenal and access consciousness is proposed. In the model, recurrent neural interactions take place in distinct yet interacting access and phenomenal brain loops. The effectiveness of feedback signaling onto sensory cortical maps is emphasized for the neural correlates of phenomenal consciousness. Two forms of top-down attention, attention for perception and attention for access, play differential roles for phenomenal and access consciousness. The model is implemented in a neural network form, with the simulation of single and multiple visual object processing, and of the attentional blink.     

Methodological Encounters with the Phenomenal Kind

Block's well-known distinction between phenomenal consciousness and access consciousness has generated a large philosophical literature about putative conceptual connections between the two. The scientific literature about whether they come apart in any actual cases is rather smaller. Empirical evidence gathered to date has not settled the issue. Some put this down to a fundamental methodological obstacle to the empirical study of the relation between phenomenal consciousness and access consciousness. Block (2007) has drawn attention to the methodological puzzle and attempted to answer it. While the evidence Block points to is relevant and important, this paper puts forward a more systematic framework for addressing the puzzle. To give it a label, the approach is to study phenomenal consciousness as a natural kind. The approach allows consciousness studies to move beyond initial means of identifying instances of the kind like verbal report, and to find its underlying nature. It is well-recognised that facts about an underlying kind may allow identification of instances of the kind that do not match the initial means of identification (cp. non-liquid samples of water). This paper shows that the same method can be deployed to investigate phenomenal consciousness independently of access consciousness.     

Block's Overflow Argument

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 (or better) 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.     

Two neural correlates of consciousness

Neuroscientists continue to search for "the" neural correlate of consciousness (NCC). In this article, I argue that a framework in which there are at least two distinct NCCs is increasingly making more sense of empirical results than one in which there is a single NCC. I outline the distinction between phenomenal NCC and access NCC, and show how they can be distinguished by experimental approaches, in particular signal-detection theory approaches. Recent findings in cognitive neuroscience provide an empirical case for two different NCCs.     

Fantasy,defense, and the representational world

This paper discusses the manipulation of mental representations, particularly in relation to the psychoanalytic concepts of conscious or unconscious fantasy. A distinction is made between the unconscious phenomenal (experiential) aspect of representations and the nonexperiential, quasi-structural aspect. The concept of the representational world is described and elaborated, and its development is seen as a consequence of the infant's interaction with itself and the external world. Processes such as identification and projection can be seen in terms of changes in self and object representations, and the same is true for all the mechanisms of defense. The content of unconscious wishes is transformed, by use of such mechanisms, into representations that are acceptable to consciousness. Major transformations of unconscious representational content occur in the process of creating unconscious (preconscious) fantasy, and further transformations are frequently needed before such (preconscious) fantasies are permitted access to consciousness. The concept of projective identification is considered in the light of the ideas put forward in the paper.     

Accounting for the computational basis of consciousness: a connectionist approach

This paper argues for an explanation of the mechanistic (computational) basis of consciousness that is based on the distinction between localist (symbolic) representation and distributed representation, the ideas of which have been put forth in the connectionist literature. A model is developed to substantiate and test this approach. The paper also explores the issue of the functional roles of consciousness, in relation to the proposed mechanistic explanation of consciousness. The model, embodying the representational difference, is able to account for the functional role of consciousness, in the form of the synergy between the conscious and the unconscious. The fit between the model and various cognitive phenomena and data (documented in the psychological literatures) is discussed to accentuate the plausibility of the model and its explanation of consciousness. Comparisons with existing models of consciousness are made in the end.     

Unconscious vision spots the animal but not the dog: Masked priming of natural scenes

The functional role of consciousness has been traditionally assumed to be related to high-level executive functions, but recent theories of visual consciousness suggest qualitative differences between conscious and unconscious processes also in lower level visual processes. We tested how specific is the information that can be extracted by unconscious processes from natural scenes. Prime images which were suppressed from consciousness by continuous flash suppression facilitated categorization of visible targets at superordinate level (animal vs. non-animal) when the prime shared a category membership with the target. Suppressed prime images did not have any effect on categorization at the basic level (e.g., horse vs. other animal). Priming occurred at basic level categorization only when the prime images were available to consciousness. This pattern supports a “coarse-to-fine” model in which the visual system can unconsciously access coarse representations, but consciousness is needed for finer analysis of visual scenes.     

Phenomenal consciousness, attention and accessibility

This article re-examines Ned Block??s (1997, 2007) conceptual distinction between phenomenal consciousness and access consciousness. His argument that we can have phenomenally conscious representations without being able to cognitively access them is criticized as not being supported by evidence. Instead, an alternative interpretation of the relevant empirical data is offered which leaves the link between phenomenology and accessibility intact. Moreover, it is shown that Block??s claim that phenomenology and accessibility have different neural substrates is highly problematic in light of empirical evidence. Finally, his claim that there can be phenomenology without cognitive accessibility is at odds with his endorsement of the 'same-order-theory' of consciousness.     

Attention versus consciousness in the visual brain: differences in conception, phenomenology, behavior, neuroanatomy, and physiology.

A common confound between consciousness and attention makes it difficult to think clearly about recent advances in the understanding of the visual brain. Visual consciousness involves phenomenal experience of the visual world, but visual attention is more plausibly treated as a function that selects and maintains the selection of potential conscious contents, often unconsciously. In the same sense, eye movements select conscious visual events, which are not the same as conscious visual experience. According to common sense, visual experience is consciousness, and selective processes are labeled as attention. The distinction is reflected in very different behavioral measures and in very different brain anatomy and physiology. Visual consciousness tends to be associated with the "what" stream of visual feature neurons in the ventral temporal lobe. In contrast, attentional selection and maintenance are mediated by other brain regions, ranging from superior colliculi to thalamus, prefrontal cortex, and anterior cingulate. The author applied the common-sense distinction between attention and consciousness to the theoretical positions of M. I. Posner (1992, 1994) and D. LaBerge (1997, 1998) to show how it helps to clarify the evidence. He concluded that clarity of thought is served by calling a thing by its proper name.     

The Feeling of Knowing: Some Metatheoretical Implications for Consciousness and Control

The study of the feeling of knowing may have implications for some of the metatheoretical issues concerning consciousness and control. Assuming a distinction between information-based and experience-based metacognitive judgments, it is argued that the sheer phenomenological experience of knowing (“noetic feeling”) occupies a unique role in mediating between implicit-automatic processes, on the one hand, and explicit-controlled processes, on the other. Rather than reflecting direct access to memory traces, noetic feelings are based on inferential heuristics that operate implicitly and unintentionally. Once such heuristics give rise to a conscious feeling that feeling can then affect controlled action. Examination of the cues that affect noetic feelings suggest that not only do these feelings inform controlled action, but they are also informed by feedback from the outcome of that action.     

Access,phenomenology and sorites

The non‐transitivity of the relation looks the same as has been used to argue that the relation has the same phenomenal character as is non‐transitive—a result that jeopardizes certain theories of consciousness. In this paper, I argue against this conclusion while granting the premise by dissociating lookings and phenomenology; an idea that some might find counter‐intuitive. However, such an intuition is left unsupported once phenomenology and cognitive access are distinguished from each other; a distinction that is conceptually and empirically grounded.     

How chromatic phenomenality largely overflow its cognitive accessibility

It has been suggested (Block, 2007) that the core neural bases for visual phenomenal consciousness and for access consciousness are located in anatomically separate regions. If this is correct, and if, as Block suggests, the core neural substrate of visual phenomenality is located early in the visual cortex where detailed chromatic information is available, then it would be reasonable to infer that our intuitions of chromatically rich visual phenomenality are plausible. It is furthermore suggested that during perception cognitive access to this chromatic cornucopia is mediated through mereologically superordinate (MS) concepts that regionally characterize both semantic and quantitative integrated properties within complex visual percepts. Such concepts contain much less information than do the particulars that they characterize, implying that the information represented in phenomenal consciousness greatly exceeds the information in the accompanying access consciousness.     

Do We Know How Happy We Are? On Some Limits of Affective Introspection and Recall

This paper aims to show that widespread, serious errors in the self‐assessment of affect are a genuine possibility—one worth taking very seriously. For we are subject to a variety of errors concerning the character of our present and past affective states, or “affective ignorance.” For example, some affects, particularly moods, can greatly affect the quality of our experience even when we are unable to discern them. I note several implications of these arguments. First, we may be less competent pursuers of happiness than is commonly believed, raising difficult questions for political thought. Second, some of the errors discussed ramify for our understanding of consciousness, including Ned Block's controversial distinction between access consciousness and phenomenal consciousness. Third, empirical results based on self‐reports about affect may be systematically misleading in certain ways.     

The temporal evolution of pre-stimulus slow cortical potentials is associated with an upcoming stimulus’ access to visual consciousness

Slow cortical potentials (SCPs) have been proposed to be essential for the formation of conscious experience. To examine their temporal characteristics, we recorded electroencephalography during a visual backward-masking task, which required participants to localize the missing part of a target stimulus. A subsequent confidence rating was used as a proxy for the target’s access to consciousness. Event-related potentials (ERPs) of all correct trials were determined relative to a brief period immediately before the target and then compared among consciousness levels. In an interval ranging from 2 s prior to target presentation up to this period, a negative relationship between slowly fluctuating ERP values and the level of consciousness became evident. After target presentation, high conscious awareness was characterized by an enhanced visual awareness negativity, an increased P3 component, and associated positive SCPs. Together, these findings add new evidence to the proposed role of SCPs in the emergence of visual consciousness.     

Olfactory learning in individually assayed Drosophila larvae

Insect and mammalian olfactory systems are strikingly similar. Therefore, Drosophila can be used as a simple model for olfaction and olfactory learning. The brain of adult Drosophila, however, is still complex. We therefore chose to work on the larva with its yet simpler but adult-like olfactory system and provide evidence for olfactory learning in individually assayed Drosophila larvae. We developed a differential conditioning paradigm in which odorants are paired with positive (“+” fructose) or negative (“-” quinine or sodium chloride) gustatory reinforcers. Test performance of individuals from two treatment conditions is compared—one received odorant A with the positive reinforcer and odorant B with a negative reinforcer (A+/B-); animals from the other treatment condition were trained reciprocally (A-/B+). During test, differences in choice between A and B of individuals having undergone either A+/B- or A-/B+ training therefore indicate associative learning. We provide such evidence for both combinations of reinforcers; this was replicable across repetitions, laboratories, and experimenters. We further show that breaks improve performance, in accord with basic principles of associative learning. The present individual assay will facilitate electrophysiological studies, which necessarily use individuals. As such approaches are established for the larval neuromuscular synapse, but not in adults, an individual larval learning paradigm will serve to link behavioral levels of analysis to synaptic physiology.     

Nietzsche on the Nature of the Unconscious

Abstract

This paper argues that Nietzsche develops a novel and compelling account of the distinction between conscious and unconscious mental states: he argues that conscious mental states are those with conceptual content, whereas unconscious mental states are those with nonconceptual content. I show that Nietzsche’s puzzling claim that consciousness is ‘superficial’ and ‘falsifying’ can be given a straightforward explanation if we accept this understanding of the conscious/unconscious distinction. I originally defended this view in my ‘Nietzsche’s Theory of Mind: Consciousness and Conceptualization’ (2005, European Journal of Philosophy 13: 1–31); since then, the view has come under criticism on several fronts. Brian Leiter and others suggest that there is not enough textual evidence for the view. In addition, Leiter, Mattia Riccardi and Tsarina Doyle argue that, rather than aligning the conscious/unconscious distinction with the conceptual/nonconceptual distinction, Nietzsche endorses a higher-order thought model of consciousness. Riccardi also objects that Nietzsche must treat some unconscious mental states as conceptual. In this essay, I defend the interpretation in light of these objections. I provide new textual evidence for the interpretation, show that Nietzsche extracted aspects of the view from Schopenhauer’s work on consciousness, consider the possibility that Nietzsche endorses a higher-order thought theory, and respond to Riccardi’s objection.