Abstract
Global Workspace theory is a simple cognitive architecture that has been developed to account qualitatively for a large set of matched pairs of conscious and unconscious processes (Baars, 1983, 1988, 1993, 1997). Such matched contrastive pairs of phenomena can be either psychological or neural. Psychological phenomena include subliminal priming, automaticity with practice, and selective attention. Neural examples include coma and blindsight. Like other cognitive architectures, GW theory may be seen in terms of a theater metaphor of mental functioning. Consciousness resembles a bright spot on the theater stage of Working Memory (WM), directed there by a spotlight of attention, under executive guidance. The rest of the theater is dark and unconscious. This architectural approach leads to specific neural hypotheses. For sensory consciousness the bright spot on stage is likely to require the corresponding sensory projection areas of the cortex. Sensory consciousness in different modalities may be mutually inhibitory, within approximately 100-ms time steps. Sensory cortex can be activated internally as well as externally, resulting in conscious inner speech and imagery. Once a conscious sensory content is established, it is broadcast widely to a distributed “audience” of expert networks sitting in the darkened theater, probably using corticocortical and corticothalamic fibers. This is the primary functional role of consciousness: to allow a “blackboard” architecture to operate in the brain, in order to integrate, provide access, and coordinate the functioning of very large numbers of specialized networks that otherwise operate autonomously (Mountcastle, 1978). All the elements of GW theory have reasonable brain interpretations, allowing us to generate a set of specific, testable brain hypotheses about consciousness and its many roles in the brain. This approach is compatible with a number of other proposals (Crick, 1984; Crick & Koch, 1990; Damasio, 1989; Edelman, 1989; Llinas & Ribary, 1992; Newman, this issue; Newman & Baars, 1993; Shallice, 1976; Posner, 1992).
