SV: Capacity of the brain

donald tees donald at
Thu Sep 16 22:44:27 EST 1999

You are not talking about the CPU, you are talking about a specialized
hardware input device.  It communicates to the brain via an interrupt
scheme, and the data is pre-processed to the point that the brain does a
"double take" on higher priority interrupts VS the normal data flow.

Comparing the eye to an Ethernet card would be a lot closer analogy.

Does the internet pass the Turing test?

Shez wrote in message ...
>One way of comparing the brain's power to a computer is to look at
>how much computing power would be required to perform specific
>tasks accomplished by the brain, if these were implemented in software
>on a normal computer.
>For instance there are neurones attached to the retina which do real
>time visual pre-processing - they find lines and edges in the images
>coming from our eyes. This is a task which is also done in machine
>vision work, so we can work out how much computing power it would
>require to execute the algorithms for edge finding etc. I worked out last
>year that it require the computer power of five 200MHz pentiums to do
>the visual pre-processing done by these neurones.
>Extrapolating this to the number of neurones in the whole brain implied
>the power of about a thousand pentiums, or perhaps one decent sized
>supercomputer. (The pentium figure discounts networking overhead - in
>practice I suspect you'd probably have to network more like 4000
>pentiums to get 1000 times the power of one pentium.)
>However, it is quite possible that the brain proper can do more
>powerful computations than the extrapolation, eg. by virtue of greater
>interconnectedness of the neurones. The brain is not a random access
>device with information loaded at arbitrary addresses - the localisation
>of functions to specific neurones means the "network" or "memory"
>address of a neurone is intrinsically meaningful, whereas on a general
>purpose computer you would have the added overhead, in both
>memory and processing cycles, of using a look-up table to determine
>what is being stored where.
>     "Irrationality is the square root of all evil" -- Douglas Hofstadter
>Take a break at the Last Stop Cafe at <URL:>

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