Sunday, March 29, 2009

Emergence 7: Global Workspace Theory

New Scientist has a very interesting article out this week, entitled Firing on all neurons:  Where consciousness comes from (hat tip to Ron).  It explains a several-decade-old theory of consciousness, the Global Workspace Theory, that is finding significant support in new studies.  While the article never mentions "Emergence," it direclty addresses the attributes of structures that give rise to strongly emergent phenomena such as (I argue) consciousness.

Briefly, the Global Workspace Theory, first advanced by Bernard Baars in 1983, suggests that "non-conscious experiences are processed locally within separate regions of the brain, like the visual cortex.  According to this theory, we only become conscious of this information if these signals are broadcast to an assembly of neurons distributed across many different rgions of the brain - the 'global workspace.'"  Recent evidence, as noted in the New Scientist article, suggests that "widespread 'broadcast' of signals across the global workspace [distributed parts of the brain]" is a key precipitant of the emergence of conscious awareness of these signals.  The article does not, notably, address how consciousness emerges in the first place, but I think there is likely some correlation between how signals enter conscious awareness and how consciousness emerges initially.

Additionally, the article emphasises that "long-distance connections may be the architecture that links the many separate regions together during conscious experience," something that I have long argued as a key to information processing efficiency in distributed systems.  For example, outside the brain, it is the distant/disparate and weak connections that most efficiently and effectively facilitate information processing in human social networks.

The New Scientist article raises two more interesting facets of the global workspace theory.  First, the article notes that one key appears to be a lack of conflict in the signals broadcast across the global workspace.  When multiple contradictory signals are received and processed by the brain, the brain subconsciously discriminates and selects an "approved" signal, which is then broadcast across the workspace and enters conscious perception.  It is not clear whether this is also a prerequisite of consciousness, but one can hypothesize that there must be a unity of message across the network for strong emergence to occur?  This raises interesting questions about the role of hierarchy (one way of message discrimination) in this process.  However, it's worth noting that this unity of message appears to be a prerequisite for a message to enter conscious perception, not for the creation or emergence of that conscious perception in the first place.

Second, the article notes that the global workspace theory addressed what it terms the "easy problem," that is, describing the correlation between patterns of brain activity and consciousness.  It does not address--and doesn't really even begin to open the door to how one would address--the "hard problem" of how and why that consciousness (strongly emergent phenomenon) emerges in the first place.

Regardless, I think this higher-resolution understanding of the neuronal patterns from which consciousness emerges is informative.  We're still largely groping in the dark, but this evidence seems to support my general theory that weak and long distance connections, and dense networks of these connections, are key attributes of a structure that will give rise to strong emergence.  What seems much less clear (or, increasingly unclear) is the degree to which a unified message must be broadcast over that network to either (a) enter consciousness that already exists, or (b) allow that consciousness to emerge in the first place.  This latter issue seems to be more problematic for any efforts to spawn strong emergence in human social and economic networks -- more on that next week!

1 comment:

usofc said...

It's not that simple Jeff: Is an amoeba conscious - Maturana and Varella's theory of autopoesis can account for consciousness, how do we know consciousness exists? There is no evidence that consciousness is just an (emergent) property of the mind/body.

I gave up my own research on the topic because in aviation simulators I got to the point where the awareness - the consciousness of the moment and the ability to predict future system states became indistinguishable in the data between states of the simulator and variables within the person - and always after the fact.

Consciousness does not exist as some state of awareness. It is what Damasio calls 'the feeling of what happens': self-representation of reality. If that self-representation is generated as much by the ecology (and after the fact) then it is not consciousness at all but an illusion.

It may be an emergent property but it is just a part of a chain of properties (varying power law) related to interaction with the environment, and the automatic process of that chain (living systems) is far more functional as a form of consciousness.

The overall person-action-ecology process is one characterised by self-organised criticality: we are most effectual when criticality is approached and as turbulence begins to occur. It is when the turbulence is occuring that we actually become aware enough of emerging sub-states (subconscious automaticity) to be able to interact and juggle them briefly (creativity-intelligence?) before the system stablises and works back towards criticality again.

Criticality is not emergent, it is merely energy accruing in a dissipative structure which as it gives creates a momentary (mentally effortful) awareness of some salient system states. We are not conscious in this any more than an amoeba is conscious when interacting adaptively with its environment, our environments are simply different. Where is consciousness?