Consciousness: The last 50 years (and the next)

Abstract

The mind and brain sciences began with consciousness as a central concern. But for much of the 20th century, ideological and methodological concerns relegated its empirical study to the margins. Since the 1990s, studying consciousness has regained a legitimacy and momentum befitting its status as the primary feature of our mental lives. Nowadays, consciousness science encompasses a rich interdisciplinary mixture drawing together philosophical, theoretical, computational, experimental, and clinical perspectives, with neuroscience its central discipline. Researchers have learned a great deal about the neural mechanisms underlying global states of consciousness, distinctions between conscious and unconscious perception, and self-consciousness. Further progress will depend on specifying closer explanatory mappings between (first-person subjective) phenomenological descriptions and (third-person objective) descriptions of (embodied and embedded) neuronal mechanisms. Such progress will help reframe our understanding of our place in nature and accelerate clinical approaches to a wide range of psychiatric and neurological disorders.

Keywords: Consciousness; neural correlates of consciousness; predictive coding; selfhood; volition.

Figure 1.

(a) The Libet Paradigm. The participant makes a voluntary action and reports the time they felt the ‘conscious urge’ to move, by noting the position of the dot on the screen. Brain signals are measured using EEG and the timing of the actual movement through electromyography (EMG) attached to the wrist. Courtesy of Jolyon Troscianko (http://www.jolyon.co.uk). (b) Schematised readiness potentials in the scalp EEG. Critically, the readiness potential begins to rise before the participant is aware of their decision to move. Source: Jolyon Troscianko (http://www.jolyon.co.uk/illustrations/consciousness-a-very-short-introduction-2/; free for academic non-profit use).

Figure 2.

Conscious perception of (a) words or (b) sounds is often associated with widespread activation of the brain, whereas unconscious perception is associated with local activation in specialist processing areas. The data show functional MRI responses time-locked to stimulus presentation. Source: Dehaene and Changeux (2011).