Consciousness

Consciousness is topical, for reasons including its renewed respectability among psychologists, rapid progress in the neuroscience of perception, memo ry and action, advances in artificial intelligence and dissatisfaction with the dualistic separation of mind and body. Consciousness is an ambiguous t erm, It can refer to (i) the waking state; (ii) experience; and (iii) the p ossession of any mental state. Self-consciousness is equally ambiguous, wit h senses including (i) proneness to embarrassment in social settings; (ii) the ability to detect our own sensations and recall our recent actions; (ii i) self-recognition; (iv) the awareness of awareness; and (v) self-knowledg e in the broadest sense. The understanding of states of consciousness has b een transformed by the delineation of their electrical correlates, of struc tures in brainstem and diencephalon which regulate the sleep-wake cycle, an d of these structures' cellular physiology and regional pharmacology. Clini cal studies have defined pathologies of wakefulness: coma, the persistent v egetative 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 exp erience are being defined. Experiments exploiting circumstances in which vi sual experience changes while external stimulation is held constant are tig htening the experimental link between consciousness and its neural correlat es. Work on unconscious neural processes provides a complementary approach. 'Unperceived' stimuli have detectable effects on neural events and subsequ ent action in a range of circumstances: blindsight provides the classical e xample. Other areas of cognitive neuroscience also promise experimental ins ights into consciousness, in particular the distinctions between implicit a nd explicit memory and deliberate and automatic action. Overarching scienti fic theories of consciousness include neurobiological accounts which specif y anatomical or physiological mechanisms for awareness, theories focusing o n the role played by conscious processes in information processing and theo ries envisaging the functions of consciousness in a social context, Whether scientific observation and theory will yield a complete account of conscio usness remains a live issue, Physicalism, functionalism, property dualism a nd dual aspect theories attempt to do justice to three central, but controv ersial, intuitions about experience: that it is a robust phenomenon which c alls for explanation, that it is intimately related to the activity of the brain and that it has an important influence on behaviour.