Consciousness as sensory quality and as implicit self-awareness

When a mental state is conscious – in the sense that there is something it is like for the subject to have it – it instantiates a certain property F in virtue of which it is a conscious state. It is customary to suppose that F is the property of having sensory quality. The paper argues that this supposition is false. The first part of the paper discusses reasons for thinking that unconscious mental states can have a sensory quality, for example in cases of absent-minded perception. If unconscious mental states can have a sensory quality, then sensory quality is an insufficient condition for consciousness. The second part of the paper argues that there are even better reasons to think that sensory quality is an unnecessary condition for consciousness. The idea is that mental states can be conscious even when they lack sensory quality, for example, in the case of certain conscious propositional attitudes. In the third part of the paper, an alternative to the rejected supposition, drawn from the phenomenological tradition, is offered: that consciousness is a matter of implicit self-awareness, rather than of sensory quality. According to this alternative, a mental state is conscious when, and only when, it involves implicit self-awareness.     

Evidence for perceptual learning with repeated stimulation after partial and total cortical blindness

Lesions of occipital cortex result in loss of sight in the corresponding regions of visual fields. The traditional view that, apart from some spontaneous recovery in the acute phase, field defects remain permanently and irreversibly blind, has been challenged. In patients with partial field loss, a range of residual visual abilities in the absence of conscious perception (blindsight) has been demonstrated (Weiskrantz, 1986). Recent findings (Sahraie et al., 2006, 2010) have also demonstrated increased visual sensitivity in the field defect following repeated stimulation. We aimed to extend these findings by systematically exploring whether repeated stimulation can also lead to increased visual sensitivity in two cases with total (bilateral) cortical blindness. In addition, for a case of partial blindness, we examined the extent of the recovery as a function of stimulated region of the visual field, over extended periods of visual training. Positive auditory feedback was provided during the training task for correct detection of a spatial grating pattern presented at specific retinotopic locations using a temporal two alternative forced-choice paradigm (Neuro-Eye Therapy). All three cases showed improved visual sensitivity with repeated stimulation. The findings indicate that perceptual learning can occur through systematic visual field stimulation even in cases of bilateral cortical blindness.     

Introspection and subliminal perception

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.     

Deaf hearing: Implicit discrimination of auditory content in a patient with mixed hearing loss

We describe a patient LS, profoundly deaf in both ears from birth, with underdeveloped superior temporal gyri. Without hearing aids, LS displays no ability to detect sounds below a fixed threshold of 60 dBs, which classifies him as clinically deaf. Under these no-hearing-aid conditions, when presented with a forced-choice paradigm in which he is asked to consciously respond, he is unable to make above-chance judgments about the presence or location of sounds. However, he is able to make above-chance judgments about the content of sounds presented to him under forced-choice conditions. We demonstrated that LS has faint sensations from auditory stimuli, but questionable awareness of auditory content. LS thus has a form of type-2 deaf hearing with respect to auditory content. As in the case of a subject with acquired deafness and deaf hearing reported on a previous occasion, LS’s condition of deaf hearing is akin in some respects to type-2 blindsight. As for the case of type 2 blindsight the case indicates that a form of conscious hearing can arise in the absence of a fully developed auditory cortex.     

SELF OR NO-SELF? CONVERGING PERSPECTIVES FROM NEUROPSYCHOLOGY AND MYSTICISM

Abstract. The nature of self is examined in relation to psychological observations which reveal some form of dissociation of knowledge from consciousness. Such dissociations are apparent in cases of blindsight, and amnesic patients displaying implicit memory effects, among others. While amnesic patients, for example, are unable consciously to recall material previously presented, such material does influence subsequent physiological and psychological processes. Thus, it is not the memories themselves that have been lost, but the ability to make conscious connection to them. In attempting to account for such observations, theoreticians generally have posited some kind of "consciousness system" that may become dissociated from brain modules dealing with specific processing.
It is argued here that a view of self along the lines of the Buddhist concepts of no-self and the conditioned nature of "I" introduces a more parsimonious perspective on the neuropsychological data. A theory of the nature of self is presented that constitutes a synthesis between key ideas drawn from Buddhist and other mainly mystical traditions and the scientific observations in psychology. Central to this theory is the role that the left hemisphere's interpreter (Gazzaniga 1985; 1988a; 1988b) plays in constructing a unified "I." This "I" is, in effect, a hypothesis that the mind generates to introduce some coherence into otherwise fragmentary mental elements. Although it appears to be the causal focus of the individual's behavior and experience, it is in fact a retrospective construction and not a true causal structure of the mind. This theoretical view is discussed in relation to various meanings of the term consciousness and also in relation to the relevant neuropsychological cases.     

The case for characterising type-2 blindsight as a genuinely visual phenomenon

Type-2 blindsight is often characterised as involving a non-visual form of awareness that blindsight subjects experience under certain presentation conditions. This paper evaluates the claim that type-2 awareness is non-visual and the proposal that it is a cognitive form of awareness. It is argued that, contrary to the standard account, type-2 awareness is best characterised as visual both because it satisfies certain criteria for being visual and because it can accommodate facts about the phenomenon that the cognitive account cannot. The conclusion is made that type-2 blindsight is best characterised as involving a form of abnormal, degraded visual awareness.