Date: Sat, 23 Dec 2006 11:06:51 -0500
To: WSFA members <WSFAlist at KeithLynch.net>
From: "Mike B." <omni at omniphile.com>
Subject: [WSFA] Re: Data processing by the human brain (was: modems)
Reply-To: WSFA members <WSFAlist at KeithLynch.net>

At 12/23/2006 01:13 AM, ronkean at juno.com wrote:

>While on the subject of 300 bps data streams, I note that 300 bps happens
>to be roughly the speed limit at which a person can read English text,
>assuming that each character of text represents 7 or 8 bits.

300 baud is not 42.8 or 37.5 characters per second.  There are extra
bits (or more correctly, "mark" or "space" data) sent to mark the
start of a byte and the end of a byte.  A better approximation is
that the cps rate is about 1/10 the baud rate, so 300 baud would do
about 30 characters per second.  You can easily read at this
rate...I've done it when using a 300 baud modem to connect to a BBS
system.  A bit faster would have been nice.

>Since
>English text can be data compressed by a ratio of about three to one,

Or more...

>I would conclude that a human reader can handle a true data input rate of
>only about 100 bps.  That estimate is roughly consistent with the
>estimate that conversational speech has a data content rate of about 50
>bps, and that most people can probably follow rapid speech at two or
>three times the normal conversational rate.

Since I'm not sure if your "bps" is "bits per second" or "bytes per
second", I won't comment on the estimates, but I know for sure that
at least some people can handle spoken data at a rate several times
what most people actually use.  Text to speech software for blind
people often outputs at several times the usual spoken rate, and with
some practice, they have no trouble following it.

>So, here's the question.  If people can accept information input only up
>to a rate of about 100 bps, reading text, why is it that people can
>easily 'take in' a movie, which requires a streaming data rate of perhaps
>tens of millions of bits per second, for a wide screen movie theater
>presentation?

Different parts of the brain are involved, and vision has peripheral
processors in the eyes too.  Also:

"All of the books in the world contain no more information than
  is broadcast as video in a single large American city in a single
  year. Not all bits have equal value."
                                         -- Carl Sagan

-- Mike B.
--
"She had lost the art of conversation, but not, unfortunately, the power of
  speech."
                                         -- George Bernard Shaw