Wired reflexes

Fans of the cyberpunk genre, or perhaps people who played the Cyberpunk or Shadowrun roleplaying games will be familiar with the concept of “wired reflexes.” The notion here is that you somehow have been modified to react much faster than a normal person. The normal in-genre and in-game consequences of wired reflexes are impressive, leading to the kind of perceptual differences shown in The Matrix, when the Agents and Neo simply see the world around them as moving in very slow motion and conversely are seen as moving very fast, and Underworld, in which a vampire assassin pulls a trigger so fast her semiautomatic handgun appears to be firing on full auto.
Based on the name and some genre ideas, this kind of reflex modification mainly involves replacing your main nervous system transmission routes with a faster mechanism — fiber optics sound good for this. Assuming away the time needed to convert between the chemical nervous signal to the fiber optic and then back again at the brain, what kind of time could we gain by such a replacement?
Nerve transmission speeds vary depending on the nerves involved, but one reasonable average is about 50 meters/second. At this speed, it should take about 40 milliseconds for a signal to travel one-way along the longest route in your body (foot to brain), or 80 milliseconds for a round trip. This suggests that we could shave that 80 milliseconds off your reaction time by using fiber optics (again, assuming away the time needed to convert the signal).
So how much do you gain from this 80 milliseconds?
Human reaction times differ based on the test conditions, but “recognition reaction times” that require identifying and choosing between two objects average 384 milliseconds. This rises as the number of valid choices increases, making it hard to estimate what that translates to in real life — how many “valid choices” are present for our cyberpunk protagonist when she’s faced by an alley full of scrubs? Even sticking with 384 milliseconds, that means that our wired individual gets an 80 millisecond head start, cutting 21% of her reaction time. Not shabby, but not amazing.
This suggests that someone with wired reflexes would, over time, tend to act slightly before those without, but certainly not so much as to appear to move differently or be a blur. Especially given that another 60 milliseconds or more of even the simplest act is taken up by muscle action, there just may not be a lot to shave off of that reaction time should one be able to speed up the brain part of the decision-making process.


Ported comments:
speed etc
(Anonymous)
2005-07-02 03:37 am UTC (link) DeleteFreezeScreen Select
Alex,
You knew I couldn’t help weigh in on this.
I think the decision making part is huge, but not as big as the muscle speed factor. Some people, no matter how much you train them, are never going to have lots of handspeed.
It’s a function (in my totally unscientific opinion) of the percentage of fast twitch muscle a person has in their arms.
Tim
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Re: speed etc
[info]qadgop
2005-07-05 02:33 am UTC (link) DeleteFreezeScreen Select
While I enjoyed Underworld as much as the next fellow, I would have thought that pulling a handgun’s trigger that many times in such rapid succession wouldn’t give the chemical reactions a chance to actually happen, so you’d end up only getting one or two shots off. No?
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Re: speed etc
[info]parakkum
2005-07-05 05:38 am UTC (link) DeleteFreezeScreen Select
It wouldn’t be an issue of the chemical reactions. As the movie gimmick goes, she fires about as fast as a fully automatic weapon. True automatic weapons operate via sequential firings — you pull the trigger once, then the expanding gasses from the round just fired cycle the action, loading the next round in and firing it. So she’s not operating faster than bullets can fire on their own.
I’d wonder, however, if the action of a semiautomatic weapon could work that fast, or if the slide would still be rocking back into position when you attempted the next trigger pull.
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Re: speed etc
[info]parakkum
2005-07-05 05:42 am UTC (link) DeleteFreezeScreen Select
The obvious cyberpunk solution, then, is to add artificial fast-twitch muscle.
Of course, even if you could halve the contraction time, the decision-making part is, as you indicated, huge. So true, cyberpunk-style augmented reflexes would have to include speeding up the brain.
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nice
[info]mplaster
2005-07-19 11:03 pm UTC (link) DeleteFreezeScreen Select
good job. (cyberpunk is my thing)