
16 bits per second - the bandwidth of consciousness (2007) - ColinWright
http://fm.schmoller.net/2007/03/16_bits_per_sec.html?utm_source=twitterfeed&utm_medium=twitter
======
pygy_
That statistic comes from a book[0] that was written in 1998, and is based on
little evidence. The science of consciousness has tremendously advanced in the
last 14 years, and I'm not sure it is still seen as correct.

There is a preconscious reduction of bandwidth (lot's of pruning). The input
is transformed, from lots of points in low dimensional spaces to fewer points
in a higher dimensional one, and it is hypothesized that consciousness is
isomorphic to the integration process[1] that performs that transformation.

That theory has the big advantage of being neither anthropo- nor neurocentric.
It can be related to any physical system (biological or otherwise).

Stephen Hawking has been spotted at consciousness conferences recently.

[0]
[http://www.amazon.co.uk/s/ref=ntt_athr_dp_sr_1?_encoding=UTF...](http://www.amazon.co.uk/s/ref=ntt_athr_dp_sr_1?_encoding=UTF8&field-
author=Tor%20Norretranders&search-alias=books-uk)

[1] <http://en.wikipedia.org/wiki/Integrated_Information_Theory>

_edit: corrected and refined._

~~~
wamatt
The field may or may not have progressed dramatically. However, ironically
your claim of a lack of evidence, is not evidential itself, and I suspect the
dismissal is unwarranted. Tor Nørretranders[0] was expanding on the work of
German engineer Karl Küpfmüller[1].

Furthermore Kupfmuller,Nørretranders are not alone in this regard:

 _"We can therefore conclude that the maximal information flow of the process
of conscious sensory perception is about 40 bits/second -- many orders of
magnitude below that taken in by receptors [nerve endings]."_

\-- Manfred Zimmermann. "Neurophysiology of Sensory Systems" in Robert F.
Schmidt ed., Fundamentals of Sensory Physiology (1986) p.116

 _"... If we do not act in the way we think we do, the reason is partly to do
with the bandwidth of consciousness - its ability to transmit information
measured in terms of bits per second. [...] The bandwidth of consciousness is
around eighteen bits."_

\--John N Gray (2002) [3][4]

First prize would be evidence for a refutation of the 'consciousness operates
at a low information rate' hypothesis, as opposed to conjecture or
speculation.

[0] <http://en.wikipedia.org/wiki/Tor_N%C3%B8rretranders>

[1] <http://en.wikipedia.org/wiki/Karl_K%C3%BCpfm%C3%BCller>

[2] [http://www.amazon.com/Fundamentals-Sensory-Physiology-
Spring...](http://www.amazon.com/Fundamentals-Sensory-Physiology-Springer-
Edition/dp/0387158707)

[3] [http://www.amazon.com/Straw-Dogs-Thoughts-Humans-
Animals/dp/...](http://www.amazon.com/Straw-Dogs-Thoughts-Humans-
Animals/dp/0374270937)

[4] [http://books.google.com/books?id=k5PkZXJEQqoC&lpg=PA45&#...</a>

~~~
pygy_
I put the number in question because the people who made these estimations
didn't have a proper grasp of what consciousness may be.

That being said, I didn't read the papers in question, and they may have a
valid argument.

However, I don't understand how you can encode in 16 per second the evolution
of your current experience out of all the possible states your brain may be in
and go to.

There is a lot of compression due to expectations, but I still find it hard to
believe that it is so low.

Edit: For serial tasks (say, reading, listening to someone speak), the 16-40
bps range makes some sense, but I don't think that visual experience can be
reduced that much.

Edit 2: Take, say, music. You can encode the audible note tones on 6-7 bit.
You can easily listen 4 notes chords played 4 times per second. We're already
in the 100 bps ball park, and we haven't taken timbre and loudness into
account.

------
JeffJenkins
I can't speak to the truth of that, but the conclusion the author tries to
draw from it:

"and hence how designers of e-learning materials need to avoid creating
cognitive overload."

is totally ridiculous. His conclusion might be true, but unless he wants to
posit the number of these consciousness bits expended on parts of e-learning
software it doesn't follow from the premise.

------
Gring
"only a minuscule proportion of the sensory data processed by the unconscious
mind (capable of processing approximately 11 million bits per second) is
referred to the conscious mind (capable of processing approximately 50 bits
per second)."

By that measure, a two-hour movie can be compressed down to 22.5 kilobytes...
:-)

~~~
wamatt
_> By that measure, a two-hour movie can be compressed down to 22.5
kilobytes... :-)_

I can't speak for other's but for myself that sort of compression ratio seems
at least possible.

Most of the conscious mind is dealing with a highly compressed stream of
symbols (compressed abstracted versions of the actual audio-visual stream),
and how they relate to one another in time and space.

More concretely, imagine yourself watching a movie in the theatre:

 _"That actor's accent is a bit off" "Why do her teeth look so bright?" "I
forgot who directed this, hmm was it that Swedish guy.. the guy who directed
'Heaven', wait... was he Swedish? Aargh I wish I could go on IMDB now and
check" ".. ugh that kid in the front row's phone is distracting" "The visual
style reminds me of this other movie". "The music is getting ominous,
something bad is about to happen." "Oh crap the main character is screwed, how
he is going to escape this trap?" "I wonder if my gf is enjoying the movie?"_
etc

~~~
idupree
For each viewer, that seems likely to me. For viewers collectively, there is
more information; some viewer's girlfriend is going to be someone who studies
trees, and another viewer is going to think some character looks kind of like
the President. This effect of viewer diversity might justify the video file
being more than a megabyte!

------
andrewsfreeman
16/40 bits per second? Then why is the quality of my vision so precise and I'm
still able to hear the sounds of my environment? I've heard 2 bits/sec before
as well.

Is this referring to conscious sensations recorded in memory, then maybe I can
be warmed up to the idea. Long term memory is definitely spotty, although why
can I recall my favorite latest dance track with such precision? The lead,
bass, kick, clap and atmospherics themselves must compose more than 16
bits/sec.

What about what is processed by the unconscious, to be remembered later? Like
when you didn't notice something at the time, but in the future something
sparks your memory to remember it. Does the unconscious (that can become
conscious) operate on a separate port with its own bandwidth?

But consciously? I strictly, abhorrently refuse. This music is FLAC, baby.

On the other hand, if it is true, then maybe our brain's compression
algorithms are insane. Maybe we process sensations in relation to all our past
sensation - I hear only the unique parts of this epic bassline, but the data
contains pointers to all the basslines I've heard before, turning my
consciousness into a complex amalgam of current and past. Then a two-hour
movie in 22.5 kilobytes could make sense.

~~~
duaneb
I believe the idea is that sensory input happens far lower than our conscious
mind (I.e. thoughts we perceive in our head). Our reaction to input: what we
notice about a picture, what we hear- can be compressed to 16/40bits per
second.

------
jellyksong
I'm curious. How do they quantify the amount of sensory information our brain
receives vs. the amount that we consciously perceive?

~~~
pygy_
The input bandwidth can be estimated by the amount of afferent nerve fibers,
and the neuronal firing rate.

For an example of the estimation of the conscious bandwidth while listening to
music, see the second edit of this comment:
<http://news.ycombinator.com/item?id=4829147>

------
kghose
What is the definition of 'consciousness'? I have read papers where it seems
that the definition of 'consciousness' is verbal report, or report that
corresponds to almost 100% detectability of a signal.

~~~
pygy_
Consciousness is defined as the ability to experience things subjectively.

There are active paradigms to detect it in non-communicating subjects (playing
tennis in one's head while in an FMRI, for example), and research is under way
to find passive paradigms.

See for example: _Preserved feedforward but impaired top-down processes in the
vegetative state._ <http://www.ncbi.nlm.nih.gov/pubmed/21566197> , or this:
[http://blogs.nature.com/news/2012/10/a-tool-to-quantify-
cons...](http://blogs.nature.com/news/2012/10/a-tool-to-quantify-
consciousness.html)

------
andrewcooke
so there should be an audio compression algorithm that can reduce 5min tracks
to 5k files (and still sound equivalent to uncompressed tracks)? that seems a
little optimistic to me.

~~~
bermanoid
No. If we accept the article's claims at face value (which is another
question) all we can say is that there should be a different audio compression
algorithm _for each person_ that could reduce 5 min tracks to 5k files. But
the algorithm tailored to your auditory processing system would not work for
me, because I might be more or less sensitive to certain types of changes than
you.

~~~
sukuriant
I wonder how much space a midi of the same song (minus the vocals) usually
comes to.

~~~
ars
A few tens of KB usually, and can be compressed to just a few KB.

