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Why Is the Human Brain So Efficient? (2018)

nautil.us

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Re: Why Is the Human Brain So Efficient? (2018)

#121

Post by ALittleLight »

jbay808 wrote: post #97
derefr wrote: post #80

Earlier quoted context omitted.

> memory accuracy There are individuals with very good memories for all sorts of things, who seem to manage to reconsolidate their memories near-losslessly (at least within the confines of the mental schema they organize said memories into.) Surgeons with anatomy, lawyers and judges with case-law, etc. At this point I’m convinced that the lossy method humans intuitively reconsolidate memories with, isn’t so much a fe…

I remember when I first took a data structures course, learning things like trees and linked lists, I had a total paradigm shift with respect to how I understood my own mind. I had never really thought about the different ways that data could be organized, and how they perform differently. I figured that since this was so basic to computer science, my own mind couldn't be doing something completely different. It migh…

Recently I was thinking about how my brain answers the question "What's your favorite movie?" and how I can easily answer that question, but it's harder to answer a question like "What's your favorite movie where a gun is fired?"

It seems to me that whenever I watch a movie, if I really liked it, I check my perceived quality of the movie against the quality of my current favorite movie, and if the new movie beats the old favorite, I update the "favorite movie" pointer to point to the new movie. When someone asks "What's your favorite movie?" I just return the name of whatever the favorite_movie points to.

The question of "Favorite movie where a gun is shot" is much harder, I think, because my memories aren't really indexed that way. I can't query by "gun is shot" so I can't get the subset of movies I've seen with gun shots and pick my favorite.

To me, it seems like my brain, at least for movies, has something of a key value store, which I can scan, slowly and imperfectly, but not query with complex questions. Or, maybe, if the queries are too complex they timeout and I don't get back any results.

Re: Why Is the Human Brain So Efficient? (2018)

#122

Post by jcims »

rantwasp wrote: post #114
stared wrote: post #103

Earlier quoted context omitted.

Fruit flies can drink wine. Doing maths - well, it is a common trope that we extrapolate skills of a fraction of humans on the entire population. For an average human 1/3 + 1/2 can be problematic. Abstract counting up 5 or so - well, many birds can do that, including pigeons.

the wine part was a joke. especially because fruit flies definitely appear to be attracted to fruit, wine, etc i believe you are underestimating how capable humans really are. all of us can learn to do math and i’m talking serious math not basic math.

My point from above is that 'humans playing tennis' isn't a great benchmark for the efficiency of our brains.

Re: Why Is the Human Brain So Efficient? (2018)

#123

Post by Digit-Al »

jbay808 wrote: post #97
derefr wrote: post #80

Earlier quoted context omitted.

> memory accuracy There are individuals with very good memories for all sorts of things, who seem to manage to reconsolidate their memories near-losslessly (at least within the confines of the mental schema they organize said memories into.) Surgeons with anatomy, lawyers and judges with case-law, etc. At this point I’m convinced that the lossy method humans intuitively reconsolidate memories with, isn’t so much a fe…

I remember when I first took a data structures course, learning things like trees and linked lists, I had a total paradigm shift with respect to how I understood my own mind. I had never really thought about the different ways that data could be organized, and how they perform differently. I figured that since this was so basic to computer science, my own mind couldn't be doing something completely different. It migh…

Some very interesting points.

I would like to say that the hardware is a bit of a mess as well. There are weird redundant bits of legacy hardware that aren't required any more, but nobody's bothered to remove them from the system (appendix, wisdom teeth). There are oddly paired systems (genitals combine waste removal with reproduction; the nose combines air filtering with scent detection; the mouth combines food intake and air intake/outlet). And oddly co-dependent systems (lose your sense of smell and your sense of taste takes a significant hit).

Re: Why Is the Human Brain So Efficient? (2018)

#124

Post by jbay808 »

p1esk wrote: post #119
jbay808 wrote: post #110

Earlier quoted context omitted.

> The brain has no such constraint. It is analog, and therefore infinite in State representation. This is a common misconception. I'm sure you are aware that analog signals can be approximated by digital values -- a 10 bit ADC will read a channel to one part in 1024, etc. You might say that even a 64 bit representation is a poor approximation of a real life signal, which is a real number with infinite precision... Bu…

Given how robust a brain is against noise, I'd be surprised if any brain signals are more precise than an equivalent of 3-4 bits.

I agree, and I think in practice the brain's noise floor is also much higher than the theoretical thermal-noise minimum. But I guess the main point is that once we acknowledge that even 32 bits is more than enough, the difference between an analog and digital machine loses a lot of its philosophical weight.

Re: Why Is the Human Brain So Efficient? (2018)

#125

Post by marvy »

simiones wrote: post #87
marcosdumay wrote: post #73

Earlier quoted context omitted.

> In what way can this be proven? Proven? Nothing in science is ever proven. But on half a millenium we have failed to find anything that can't be simulated by math, and Turing completeness means a computer can simulate anything that can be simulated by math. We also can simulate all the smallest components of a brain. At this point the claim that math can not simulate it is highly extraordinary.

> Turing completeness means a computer can simulate anything that can be simulated by math Technically, it is not proven that Turing machines can compute all computable functions, so there is some purely theoretical possibility that the brain could be able to compute functions that a Turing machine can't. Personally I find that extremely unlikely, and agree that it would be extremely surprising. But it wouldn't inval…

It would imply that our brains are using currently-unknown physics, since all current theories are computable.

Re: Why Is the Human Brain So Efficient? (2018)

#126

Post by jbay808 »

Digit-Al wrote: post #123
jbay808 wrote: post #97

Earlier quoted context omitted.

I remember when I first took a data structures course, learning things like trees and linked lists, I had a total paradigm shift with respect to how I understood my own mind. I had never really thought about the different ways that data could be organized, and how they perform differently. I figured that since this was so basic to computer science, my own mind couldn't be doing something completely different. It migh…

Some very interesting points. I would like to say that the hardware is a bit of a mess as well. There are weird redundant bits of legacy hardware that aren't required any more, but nobody's bothered to remove them from the system (appendix, wisdom teeth). There are oddly paired systems (genitals combine waste removal with reproduction; the nose combines air filtering with scent detection; the mouth combines food inta…

What do you mean? That sounds just like a modern CPU to me! :)

Re: Why Is the Human Brain So Efficient? (2018)

#127

Post by jakeogh »

canjobear wrote: post #81
kristopolous wrote: post #69

They aren't the same thing. They are different classes of objects, different tasks. This comparison is kind of silly. I'd hate my computer to have the memory accuracy or the computational accuracy of my brain. I'd hate to have the creativity and inspiration of a computer. Delete being such a nontrivial operation is probably a good thing for humans. Copy being imperfect probably has something to do with the phenomenon…

When we say the brain has poor computational accuracy, we’re usually talking about the conscious brain we’re aware of. But our low-level motor actions and perceptions, coordinated by the brain, require a lot of precise computation. These low-level brain computations are the thing to compare to AI, not our conscious thinking. Our conscious mind is more like low-precision software running on top of an enormously powerf…

It's unlikely we compute in any conventional sense, the hardware is reality, and is going to exploit every available effect that is energetically efficient.

Letting FPGA's "go" into the analog realm is an interesting window: https://news.ycombinator.com/item?id=21253267

Glial brain cells: https://news.ycombinator.com/item?id=22161192

Re: Why Is the Human Brain So Efficient? (2018)

#128

Post by kyuudou »

tegeek wrote: post #15
est31 wrote: post #9

One kind of efficiency which hasn't been talked about is the energy loss of things like state switching and keeping the current state enabled. I think that brains build on much more efficient primitives than the silicon transistors computer chips use and thus can perform far more computations for far less energy than a desktop CPU. Another difference between CPUs and brains is that brains are much less general purpos…

Comparing Human Brain with a CPU is misconception. In the past when we didn't have digital computers we used to compare Brain with other machines. And now with a CPU. A Brain from a primitive neuron to higher level is not comparable to any machine at all including the CPU.

"...the question of whether Machines Can Think, a question of which we now know that it is about as relevant as the question of whether Submarines Can Swim."

Edsger Dijkstra, EWD898, 1984

Re: Why Is the Human Brain So Efficient? (2018)

#129

Post by jacobr1 »

cmehdy wrote: post #102
jacobr1 wrote: post #74

Earlier quoted context omitted.

The argument isn't "something like, or a little better, than current CPUs can perform everything a brain can," but something more like "a turing machine can perform everything a brain can or more." This is more an ontological exercise, not an empirical one. If you reduce everything to a "black box" model with inputs and outputs, then sure, the mathematical abstractions of theoretical brains and theoretical CPUs have…

Being skeptical of the claim that a certain qualia is not modelable in machine is just as valid as being skeptical of the exact opposite. This is exactly why I asked if there was anything beyond what the original poster said. Without it, a post based on the exact opposite assumption could have been written and considered just as valid.

Fair criticism, I didn't tackle that head-on. The following doesn't actually make a cogent argument either, but I'll elaborate that my intuition is that qualia (conceived as something nearly tangible) are more like "the soul" or "spirits" and that, as such, thinking they exist in the brain or a turing-machine is nonsense. To the extent they are more like some combination of memory and emotional-stimuli, then they just represent a particularly interesting set of internal states, but are still something that can be mathematically modeled.

Re: Why Is the Human Brain So Efficient? (2018)

#130

Post by maskboy »

joesb wrote: post #112
canjobear wrote: post #81

Earlier quoted context omitted.

When we say the brain has poor computational accuracy, we’re usually talking about the conscious brain we’re aware of. But our low-level motor actions and perceptions, coordinated by the brain, require a lot of precise computation. These low-level brain computations are the thing to compare to AI, not our conscious thinking. Our conscious mind is more like low-precision software running on top of an enormously powerf…

> But our low-level motor actions and perceptions, coordinated by the brain, require a lot of precise computation. But we don't actually do that precise computation though. try repeating any action exactly and you will see some inaccuracy.

no, you will see some variability
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