How does a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity?

Much of the nervous system can be viewed as a massively parallel, distributed system of highly specialized but unconscious processors. Conscious experience on the other hand is traditionally viewed as a serial stream that integrates different sources of information but is limited to only one internally consistent content at any given moment. Global Workspace theory suggests that conscious experience emerges from a nervous system in which multiple input processors compete for access to a broadcasting capability; the winning processor can disseminate its information globally throughout the brain. Global workspace architectures have been widely employed in computer systems to integrate separate modules when they must work together to solve a novel problem or to control a coherent new response. The theory articulates a series of increasingly complex models, able to account for more and more evidence about conscious functioning, from perceptual consciousness to conscious problem-solving, voluntary control of action, and directed attention. Global Workspace theory is consistent with, but not reducible to, other theories of limited-capacity mechanisms. Global workspace architectures must show competition for input to a neural global workspace and global distribution of its output. Brain structures that are demonstrably required for normal conscious experience can carry out these two functions. The theory makes testable predictions, especially for newly emerging, high-speed brain imaging technology.