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Human brain, being a very recent, and thus highly un-tuned, product of evolutionary development, is very energy inefficient machine. It consumes disproportional

Human brain, being a very recent, and thus highly un-tuned, product of evolutionary development, is very energy inefficient machine. It consumes disproportionally significant amount of resources when it really works. Thus highly creative brain activity quickly burns through glucose and may quickly make you feel hungry (please don't mistake with a pure psychological trick of switching to snack in situations when your brain is forced to work intensely, and it tries every escape route to avoid/delay the task )

gwern 16y ago
Energy inefficient? You have no idea what you are talking about. Estimates for how much computation a human brain is doing start at 10^14 flops and only go up from there (Kurzweil, known for his optimism, puts the brain at 10^16). Current record-holding supercomputers, BTW, are just barely at 10^15 or so. And the brain does this on a watt or two, not 1.3 megawatts (http://www.top500.org/lists/2008/06/highlights/power http://www.top500.org/lists/2008/06/highlights/power).
- icegreentea 16y ago
  Voted the OP back up, cause I think it's really just a poor choice of diction. The brain DOES consume a lot of your body's total energy budget. Like roughly 20% when resting, and it goes up when thinking harder [1]. Granted, compared to supercomputers, we might have godly energy efficiency, but when our source of power isn't a 240V outlet, but food, then we have to evaluate the actual energy consumption a bit different. [1] http://hypertextbook.com/facts/2001/JacquelineLing.shtml http://hypertextbook.com/facts/2001/JacquelineLing.shtml
  - VladRussian 16y ago
    thanks for the link. "Einstein's brain weighed only 1,230 grams, which is less than the average adult male brain (about 1,400 grams). .... However, the density of neurons in Einstein's brain was greater. In other words, Einstein was able to pack more neurons in a given area of cortex." Personally for me, that completely confirms my theories. Moore's Law for the brain :)
- VladRussian 16y ago
  i compare it to the other brains in the Nature. How much flops does cat's/lion's/wolf's brain perform before the jump or orchestrating pack attack. You compare it to even more recent and even more inefficient devices - computers, which themselves are just very primitive products of human brain.
- jules 16y ago
  That doesn't make sense. Flops is how many flops a device can compute, not how many it uses internally in some model, or how many you'd need to simulate it on a computer. My brain has less than one 32 bit flops. Otherwise I'm going to claim that a glass of water has more than 10^20 flops, which is what you need to simulate the waves on it to a certain degree of accuracy.

gwern 16y ago

Energy inefficient? You have no idea what you are talking about. Estimates for how much computation a human brain is doing start at 10^14 flops and only go up from there (Kurzweil, known for his optimism, puts the brain at 10^16). Current record-holding supercomputers, BTW, are just barely at 10^15 or so. And the brain does this on a watt or two, not 1.3 megawatts (http://www.top500.org/lists/2008/06/highlights/power http://www.top500.org/lists/2008/06/highlights/power).

icegreentea 16y ago
Voted the OP back up, cause I think it's really just a poor choice of diction. The brain DOES consume a lot of your body's total energy budget. Like roughly 20% when resting, and it goes up when thinking harder [1]. Granted, compared to supercomputers, we might have godly energy efficiency, but when our source of power isn't a 240V outlet, but food, then we have to evaluate the actual energy consumption a bit different. [1] http://hypertextbook.com/facts/2001/JacquelineLing.shtml http://hypertextbook.com/facts/2001/JacquelineLing.shtml
- VladRussian 16y ago
  thanks for the link. "Einstein's brain weighed only 1,230 grams, which is less than the average adult male brain (about 1,400 grams). .... However, the density of neurons in Einstein's brain was greater. In other words, Einstein was able to pack more neurons in a given area of cortex." Personally for me, that completely confirms my theories. Moore's Law for the brain :)
VladRussian 16y ago
i compare it to the other brains in the Nature. How much flops does cat's/lion's/wolf's brain perform before the jump or orchestrating pack attack. You compare it to even more recent and even more inefficient devices - computers, which themselves are just very primitive products of human brain.
jules 16y ago
That doesn't make sense. Flops is how many flops a device can compute, not how many it uses internally in some model, or how many you'd need to simulate it on a computer. My brain has less than one 32 bit flops. Otherwise I'm going to claim that a glass of water has more than 10^20 flops, which is what you need to simulate the waves on it to a certain degree of accuracy.