J. R. posted a note about a review of a recent book by Pierre Baldi:
An included quote:
> Baldi adds a number of intriguing back-of-the-envelope calculations to
> this discussion, including an estimate of how much information is
> contained in a lifetime of experience, or brain inputs: By his estimation,
> the amount is 2.2x10^18 bits (about 2.7x10^17 bytes), which at current rates
> of memory storage advances will be within the memory capacity of a typical
> personal computer in 27 years. Based on this, Baldi then investigates the
> information size of what he calls the external self, a complete genomic
> sequence together with the recording of all inputs and outputs of an
> individuals brain over a lifetime, which he estimates to be still on the
> order of 10^18 bits, within reach of modern computer technology. The
> internal self, the amount of information required to capture the relevant
> structure of your brain that defines your identity, is largerat least 10^27
> bits but might still be within reach of emerging technologies.
People should take these numbers with a *very* large grain of salt
for they *are* back-of-the-envelope calculations.
Based on , human long term memory capacity is no more than of the
order of 10^9 bits (a few hundred megabytes). This is for "recall"
memory, which may be somewhat different from "recognition" memory.
It is very doubtful that humans store a "lifetime" of experience
(e.g. ~10^18 bits). It is highly likely that chunking and compression
occurs. I'm also very doubtful of the 10^27 bits of structural information.
At ~10^10 neurons and 10^4 synapses per neuron that only gets you to 10^14
connections. I'm very doubtful that there is 10^13 bits of "significant"
information per synapse. I'd be interested in what Anders thinks.
 Landauer, T. K., "How Much Do People Remember? Some Estimates of the Quantity
of Learned Information in Long-term Memory", Cognitive Science 10:477-493 (1986).
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