Consciousness.

Consciousness is an ambiguous term with multiple meanings: the waking state, experience, or possession of any mental state. Self-consciousness is similarly ambiguous. Understanding of consciousness has been transformed by electrical correlates and brain structures regulating sleep-wake cycles. Clinical studies define pathologies of wakefulness like coma and persistent vegetative state. Research on visual perception is defining neural correlates of real and illusory experience. Unconscious neural processes show 'unperceived' stimuli affect neural events and action, exemplified by blindsight. Cognitive neuroscience explores implicit versus explicit memory and deliberate versus automatic action. Overarching scientific theories include neurobiological accounts, information-processing roles, and social functions. Whether science will fully explain consciousness remains debated, with physicalism, functionalism, property dualism, and dual-aspect theories addressing experience's relation to brain activity and behavior.

Study at a glance

Abstract

Consciousness is topical, for reasons including its renewed respectability among psychologists, rapid progress in the neuroscience of perception, memory and action, advances in artificial intelligence and dissatisfaction with the dualistic separation of mind and body. Consciousness is an ambiguous term. It can refer to (i) the waking state; (ii) experience; and (iii) the possession of any mental state. Self-consciousness is equally ambiguous, with senses including (i) proneness to embarrassment in social settings; (ii) the ability to detect our own sensations and recall our recent actions; (iii) self-recognition; (iv) the awareness of awareness; and (v) self-knowledge in the broadest sense. The understanding of states of consciousness has been transformed by the delineation of their electrical correlates, of structures in brainstem and diencephalon which regulate the sleep-wake cycle, and of these structures' cellular physiology and regional pharmacology. Clinical studies have defined pathologies of wakefulness: coma, the persistent vegetative state, the 'locked-in' syndrome, akinetic mutism and brain death. Interest in the neural basis of perceptual awareness has focused on vision. Increasingly detailed neuronal correlates of real and illusory visual experience are being defined. Experiments exploiting circumstances in which visual experience changes while external stimulation is held constant are tightening the experimental link between consciousness and its neural correlates. Work on unconscious neural processes provides a complementary approach. 'Unperceived' stimuli have detectable effects on neural events and subsequent action in a range of circumstances: blindsight provides the classical example. Other areas of cognitive neuroscience also promise experimental insights into consciousness, in particular the distinctions between implicit and explicit memory and deliberate and automatic action. Overarching scientific theories of consciousness include neurobiological accounts which specify anatomical or physiological mechanisms for awareness, theories focusing on the role played by conscious processes in information processing and theories envisaging the functions of consciousness in a social context. Whether scientific observation and theory will yield a complete account of consciousness remains a live issue. Physicalism, functionalism, property dualism and dual aspect theories attempt to do justice to three central, but controversial, intuitions about experience: that it is a robust phenomenon which calls for explanation, that it is intimately related to the activity of the brain and that it has an important influence on behaviour.