Its hard to tell though. The shortest route is not always the fastest (i.e. slowing down around a sharp corner, as opposed to walking slightly wider around it), nor is the fastest necessarily the most energy efficient (climbing rocks or following a paved path). Its clearly recalculating the proper trajectory many many times based upon visual (and to a lesser extent other the other senses') cues. What isn't clear to me is whether or not the brain subconciously is coming up with (near) optimal solutions by some algorithm aside from the obvious "don't run into anything, and go that way" method.
Nice point zakk. if the brain was uncosiously doing all that processing such as breath, keep walking, balance yourself, not too fast, watch that person, oh wall here need to find another way. I don't think that kind of thought process is mimicable for a computer.
I think the main difference is multitasking... the brain has a myriad number of seperate threads to use, but a computer has a very real and limited number... for example, if you get a program to do some real heavy mathematical stuff, your system slows to a crawl, but if you (as a human) are doing a mathematical problem, your heart won't stop...
I think the brain decides where to go (subconsciously) based on other things, like how much energy you have, if you're in a rush, etc.
Good points. A multi-processor SGI or Cray would then seem to serve as a much better comparison than a PC.
Of course, with a human, the "threads" which control such functions as heart rate are very hard to consciously access. Much more so than threads on a computer.
Of course, an underlying operating system could protect certain threads from being accessed easily.