It’s often held that undetectable inversion of mental qualities is, if not possible, at least conceivable. It’s thought to be conceivable that the mental quality your visual states exhibit when you see something red in standard conditions is literally of the same type as the mental quality my visual states exhibit when I see something green in such circumstances. It’s thought, moreover, to be conceivable that such inversion of mental qualities could be wholly undetectable by any third-person means. And since (...) first- person access is limited to a single individual, and so could not reveal a disparity in mental quality between us, third-person undetectability means undetectability tout court. (shrink)

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. (shrink)

Overgaard, Timmermans, Sandberg, and Cleeremans ask if the conscious experience of people in implicit learning experiments can be explored more fully than just confidence ratings allow. We show that confidence ratings play a vital role in such experiments, but are indeed incomplete in themselves: in addition, use of structural knowledge attributions and ratings of fringe feelings like familiarity are important in characterizing the phenomenology of the application of implicit knowledge.

When the stored representation of the meaning of a stimulus is accessed through the processing of a sensory input it is maintained in an activated state for a certain amount of time that allows for further processing. This semantic activation is generally accompanied by conscious identification, which can be demonstrated by the ability of a person to perform discriminations on the basis of the meaning of the stimulus. The idea that a sensory input can give rise to semantic activation without (...) concomitant conscious identification was the central thesis of the controversial research in subliminal perception. Recently, new claims for the existence of such phenomena have arisen from studies in dichotic listening, parafoveal vision, and visual pattern masking. Because of the fundamental role played by these types of experiments in cognitive psychology, the new assertions have raised widespread interest. (shrink)

Subliminal perception (SP) is today considered a well-supported theory stating that perception can occur without conscious awareness and have a significant impact on later behaviour and thought. In this article, we first present and discuss different approaches to the study of SP. In doing this, we claim that most approaches are based on a dichotomic measure of awareness. Drawing upon recent advances and discussions in the study of introspection and phenomenological psychology, we argue for both the possibility and necessity of (...) using an elaborated measure of subjective states. In the second part of the article, we present findings where these considerations are implemented in an empirical study. The results and implications are discussed in detail, both with reference to SP, and in relation to the more general problem of using elaborate introspective reports as data in relation to studies of cognition. (shrink)

Sandberg et al. show that the Perceptual Awareness Scale scale is sensitive compared to confidence ratings and wagering in detecting accurate perception. They go on to argue that the PAS scale is hence a sensitive measure of conscious perception compared to confidence ratings, a claim disputed here. The fact that some visual content is conscious does not entail that the visual content relevant to making a discrimination is conscious. For example, if one saw a square but was only aware of (...) seeing a flash of something, then one has not consciously seen a square. When PAS and confidence ratings come in conflict, we suggest that it is confidence ratings that more reliably indicate the conscious status of contents allowing discrimination. (shrink)

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

I propose that primary conscious awareness arises from synchronized activity in dendrites of neurons in dorsal thalamic nuclei, mediated particularly by inhibitory interactions with thalamic reticular neurons. In support, I offer four evidential pillars: consciousness is restricted to the results of cortical computations; thalamus is the common locus of action of brain injury in vegetative state and of general anesthetics; the anatomy and physiology of the thalamus imply a central role in consciousness; neural synchronization is a neural correlate of consciousness.

The influence of prior familiarity with components on the implicit learning of relations was examined using artificial grammar learning. Prior to training on grammar strings, participants were familiarised with either the novel symbols used to construct the strings or with irrelevant geometric shapes. Participants familiarised with the relevant symbols showed greater accuracy when judging the correctness of new grammar strings. Familiarity with elemental components did not increase conscious awareness of the basis for discriminations but increased accuracy even in its absence. (...) The subjective familiarity of test strings predicted grammaticality judgments. However, prior exposure to relevant symbols did not increase overall test string familiarity or reliance on familiarity when making grammaticality judgments. Familiarity with the symbols increased the learning of relations between them thus resulting in greater familiarity for grammatical versus ungrammatical strings. The results have important implications for models of implicit learning. (shrink)

Most ?theories of consciousness? are based on vague speculations about the properties of conscious experience. We aim to provide a more solid basis for a science of consciousness. We argue that a theory of consciousness should provide an account of the very processes that allow us to acquire and use information about our own mental states ? the processes underlying introspection. This can be achieved through the construction of information processing models that can account for ?Type-C? processes. Type-C processes can (...) be specified experimentally by identifying paradigms in which awareness of the stimulus is necessary for an intentional action. The Shallice (1988b) framework is put forward as providing an initial account of Type-C processes, which can relate perceptual consciousness to consciously performed actions. Further, we suggest that this framework may be refined through the investigation of the functions of prefrontal cortex. The formulation of our approach requires us to consider fundamental conceptual and methodological issues associated with consciousness. The most significant of these issues concerns the scientific use of introspective evidence. We outline and justify a conservative methodological approach to the use of introspective evidence, with attention to the difficulties historically associated with its use in psychology. (shrink)

A series of five experiments investigated the extent of subliminal processing of negation. Participants were presented with a subliminal instruction to either pick or not pick an accompanying noun, followed by a choice of two nouns. By employing subjective measures to determine individual thresholds of subliminal priming, the results of these studies indicated that participants were able to identify the correct noun of the pair – even when the correct noun was specified by negation. Furthermore, using a grey-scale contrast method (...) of masking, Experiment 5 confirmed that these priming effects were evidenced in the absence of partial awareness, and without the effect being attributed to the retrieval of stimulus–response links established during conscious rehearsal. (shrink)

This paper considers two subjective measures of the existence of unconscious mental states - the guessing criterion, and the zero correlation criterion - and considers the assumptions underlying their application in experimental paradigms. Using higher order thought theory the impact of different types of biases on the zero correlation and guessing criteria are considered. It is argued that subjective measures of consciousness can be biased in various specified ways, some of which involve the relation between first order states and second (...) order thoughts, and hence are not errors in measurement of the conscious status of mental states; but other sorts of biases are measurement errors, involving the relation between higher order thoughts and their expression. Nonetheless, it is argued this type of bias does not preclude subjective measures - both the guessing criterion and the zero correlation criterion - as being amongst the most appropriate and useful tools for measuring the conscious status of mental states. (shrink)

Recent evidence suggests that consciousness of encoding is not necessary for the rapid formation of new semantic associations. We investigated whether unconsciously formed associations are as semantically precise as would be expected for associations formed with consciousness of encoding during episodic memory formation. Pairs of faces and written occupations were presented subliminally for unconscious associative encoding. Five minutes later, the same faces were presented suprathreshold for the cued unconscious retrieval of face-occupation associations. Retrieval instructions required participants to classify the presented (...) individuals according to their putative regularity of income, length of education, and creativity value of occupational activity. The three instructions yielded more classifications consistent with a person’s occupation if the person had been subliminally presented with his written occupation versus a meaningless word . This suggests that consciousness is not necessary to encode, long-term store, and retrieve semantically precise associations between primarily unrelated items. (shrink)

Conscious perception, like the sight of a coffee cup, seems to involve the brain identifying a stimulus. But conscious input activates more brain regions than are needed to identify coffee cups and faces. It spreads beyond sensory cortex to frontoparietal association areas, which do not serve stimulus identification as such. What is the role of those regions? Parietal cortex support the ‘first person perspective’ on the visual world, unconsciously framing the visual object stream. Some prefrontal areas select and interpret conscious (...) events for executive control. Such functions can be viewed as properties of the subject, rather than the object, of experience – the ‘observing self’ that appears to be needed to maintain the conscious state. (shrink)

There is growing interest in the effect of sound on visual motion perception. One model involves the illusion created when two identical objects moving towards each other on a two-dimensional visual display can be seen to either bounce off or stream through each other. Previous studies show that the large bias normally seen toward the streaming percept can be modulated by the presentation of an auditory event at the moment of coincidence. However, no reports to date provide sufficient evidence to (...) indicate whether the sound bounce-inducing effect is due to a perceptual binding process or merely to an explicit inference resulting from the transient auditory stimulus resembling a physical collision of two objects. In the present study, we used a novel experimental design in which a subliminal sound was presented either 150 ms before, at, or 150 ms after the moment of coincidence of two disks moving towards each other. The results showed that there was an increased perception of bouncing when the subliminal sound was presented at or 150 ms after the moment of coincidence compared to when no sound was presented. These findings provide the first empirical demonstration that activation of the human auditory system without reaching consciousness affects the perception of an ambiguous visual motion display. (shrink)

Visual targets which follow a prime stimulus and a mask can be identified faster when they are incompatible rather than compatible with the prime . According to the self-inhibition hypothesis, the initial activation of the motor response is elicited by the prime based on its identity. This activation leads to benefits for compatible trials and costs for incompatible trials. This motor activation is followed by an inhibition phase, leading to an NCE if perceptual evidence of the prime is immediately removed (...) by the mask. The object-updating and mask-triggered inhibition hypotheses emphasize the role of the mask content . We show that the NCE may appear even if nonmasking neutral flankers are presented instead of a mask. Moreover, although with target-like flankers the NCE is larger, it occurred if flankers and targets are built from dissimilar elements. Therefore, masks/flankers can evoke an inhibition phase independently of whether or not they remove evidence for the prime and whether they are similar to the targets. (shrink)

Reading in the Brain (Les neurones de la lecture, 2007) examined the origins of human reading abilities in the light of contemporary cognitive neuroscience. It argued that reading acquisition, in all cultures, recycles preexisting cortical circuits dedicated to invariant visual recognition, and that the organization of these circuits imposes strong constraints on the invention and cultural evolution of writing systems. In this article, seven years later, I briefly review new experimental evidence, particularly from brain imaging studies of illiterate adults, which (...) indicates that reading acquisition invades culturally universal cortical circuits and competes with their prior function, including mirror-invariant visual recognition and face processing. In response to my critics, I emphasize how brain plasticity and brain constraints can be reconciled within the Bayesian perspective on learning. I also discuss the importance of a newly discovered gesture system in reading and writing. Finally, I argue that there is consistent evidence for deep cross-cultural universals in writing systems, as well as for the multiple subtypes of dyslexia that are expected given the broad set of areas recruited by the reading task. (shrink)

Visual stimuli that are made invisible by masking can affect motor responses to a subsequent target stimulus. When a prime is followed by a mask which is followed by a target stimulus, an inverse priming effect has been found: Responses are slow and frequently incorrect when prime and target stimuli are congruent, but fast and accurate when prime and target stimuli are incongruent. To functionally localize the origins of inverse priming effects, we applied the psychological refractory period paradigm which distinguishes (...) a perceptual level, a central bottleneck, and a level of motor execution. Two dual-task experiments were run with the PRP-paradigm to localize the inverse priming effect relative to the central bottleneck. Together, results of the Effect-Absorption and the Effect-Propagation Procedure suggest that inverse priming effects are generated by perceptual mechanisms. We suggest two perceptual mechanisms as the source of inverse priming effects. (shrink)

Four experiments demonstrate category congruency priming by subliminal prime words that were never seen as targets in a valence-classification task and a gender-classification task . In Experiment 1, overlap in terms of word fragments of one or more letters between primes and targets of different valences was larger than between primes and targets of the same valence. In Experiments 2 and 3, the sets of prime words and target words were completely disjoint in terms of used letters. In Experiment 4, (...) pictures served as targets. The observed subliminal priming effects for novel primes cannot be driven by partial analysis of primes at the word-fragment level; they suggest instead that primes were processed semantically as whole words contingent upon prime duration. (shrink)