Wednesday, March 14, 2007

"Second Person, Present Tense" and the Zombie Within

“Flick your eyes to the left,” he told me one afternoon. “Now glance to the right. Did you see the room blur as your eyes moved?” He waited until I did it again. “No blur. No one sees it.”

This is the kind of thing that gets brain doctors hot and bothered. Not only could no one see the blur, their brains edited it out completely. Skipped over it—left view, then right view, with nothing between—then fiddled with the person’s time sense so that it didn’t even seem missing.

The scientists figured out that the brain was editing out shit all the time. They wired up patients and told them to lift one of their fingers, move it any time they wanted. Each time, the brain started the signal traveling toward the finger up to 120 milliseconds before the patient consciously decided to move it. Dr. S said you could see the brain warming up right before the patient consciously thought, now.

This is weird, but it gets weirder the longer you think about it. And I’ve been thinking about this a lot.
Daryl Gregory's short story "Second Person, Present Tense" takes a look at the relationship between consciousness and self perception. In his notes on the story, Gregory discusses the science that inspired him:

So, if consciousness is an add-on, what would a brain and body look like without consciousness? (This is a thought experiment that philosophy of consciousness guys call The Zombie problem—what, exactly, do we need consciousness for?)

A lot of the recent neurological research suggests that consciousness is exactly this kind of bottom-up process: there is no little man at the controls inside your head, only a little man being told what to think. Some folks, like Roger Penrose, argue that even if sometimes conscious awareness occurs after the action, perhaps this is only for actions that require quick reactions, and that there must still be a role for a consciousness (and free will) in more contemplative modes, when deeper thought is required and the "I" has to choose what to think about, choose what to do.

The concept of consciousness really straddles the divide between philosophy and biology. From what I've read, Francis Crick, along with CalTech biology and engineering professor Christof Koch, played a major role in bringing the study of consciousness into mainstream neuroscience. LA Weekly's profile of Koch and his research, "The Zombie Within", gives a non-technical overview:
So much of our human fluidity results from automatic processes buried deep in the mind far below perception, what Koch refers to in his forthcoming book, The Quest for Consciousness, as “an army of unconscious sensory-motor agents” or “zombie agents.” He insists that for much of our lives we are in effect zombies. “You drive to work on autopilot, move your eyes, brush your teeth, tie your shoelaces, talk, and all the other myriad chores that constitute daily life.” Indeed, he says, “Any sufficiently well-rehearsed activity is best performed without conscious, deliberate thought. Reflecting too much about any one action is likely to interfere with its seamless execution.”
However, consciousness is necessary for flexibility in response to changing situations and environment.

In principle, Koch says, there is no reason why consciousness is necessary to life. With enough “input sensors and output effectors,” it is conceivable that “A zombie could pretty much do anything.” But since every zombie behavior must be hard-wired, the more situations it must respond to, the more complex its internal mechanism must become. Instead, “Evolution has chosen a different path, synthesizing a much more powerful and flexible system” that we call “consciousness.” The main function of this innovation, he and Crick propose, is to enable organisms to deal rapidly with unexpected events and to plan for the future. As Koch likes to say, consciousness puts us “online,” allowing us to override our instinctual “offline” programming.

(For a technical discussion see Crick & Koch, "A Framework for Consciousness", Nature Neuroscience 6:119-126 (2003) (pdf))

Koch's lab is currently attempting to find and understand the "neuronal correlates of consciousness" - the regions of the brain where consciousness resides. If you are interested in more details, check out Koch's popular science book, The Quest For Conciousness: A Neurobiological Approach (website,, or watch the videos from his CalTech course on the neurological basis of consciousness.

"Second Person, Present Tense" takes a look at what might happen when consciousness becomes completely divorced from action. It was nominated for a Nebula Award (but failed to make the final ballot), so can read it for free at, at least for the time being.

(Thanks to Michael Kingsley for the story suggestion and link to Gregory's web site!)

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  1. This is dogone interesting stuff. Thanks! I'm putting in a bookmark.

  2. Anonymous10:50 AM

    Robert J. Sawyer wrote a novel called Mindscan that dealt heavily with these issues. The book was essentially about android "clones" of humans who would have the same memories and personality as their original. There's a scene in the story where an android is sued by his original, and a complex argument about "zombies" and the soul follows.


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