Matt Mahoney wrote:
--- Richard Loosemore <[EMAIL PROTECTED]> wrote:
Matt Mahoney wrote:
--- "John G. Rose" <[EMAIL PROTECTED]> wrote:
Is there really a bit per synapse? Is representing a synapse with a bit
an
accurate enough simulation? One synapse is a very complicated system.
A typical neural network simulation uses several bits per synapse. A
Hopfield
net implementation of an associative memory stores 0.15 bits per synapse.
But
cognitive models suggest the human brain stores .000001 bits per synapse.
(There are 10^15 synapses but human long term memory capacity is 10^9
bits).
Sorry, I don't buy this at all. This makes profound assumptions about
how information is stored in memory, averagng out the "net" storage and
ignoring the immediate storage capacity. A typical synapse actually
stores a great deal more than a fraction of a bit, as far as we can
tell, but this information is stored in such a way that the system as a
whole can actually use the information in a meaningful way.
In that context, quoting "0.000001 bits per synapse" is a completely
meaningless statement.
I was referring to Landauer's estimate of long term memory learning rate of
about 2 bits per second. http://www.merkle.com/humanMemory.html
This does not include procedural memory, things like visual perception and
knowing how to walk. So 10^-6 bits is low. But how do we measure such
things?
I think my general point is that "bits per second" or "bits per synapse"
is a valid measure if you care about something like an electrical signal
line, but is just simply an incoherent way to talk about the memory
capacity of the human brain.
Saying "0.000001 bits per synapse" is no better than opening and closing
one's mouth without saying anything.
Richard Loosemore.
-------------------------------------------
singularity
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