4 ms·

So your visual cortex isn't in your brain? Would you care to point out which region(s) of the brain only receive hundreds of bits/sec? Somebody should tell the

by dTal 9y ago

So your visual cortex isn't in your brain? Would you care to point out which region(s) of the brain only receive hundreds of bits/sec? Somebody should tell the lossy video compression folks.

oh_sigh 9y ago
Yes, it is in your brain. But if you think that your visual cortex receives anything akin to a high fidelity "picture", then you are mistaken. Regarding lossy image compression, you're free to look at something briefly and try to redraw it from scratch. Even if your drawing skills are perfect, you will find that your picture will be filled with confabulations and stereotypes. > Because of a limited number of axons in the optic nerves (approximately 1 million axons in each) only ~6x10^6 bits/sec leave the retina and only 10^4 make it to layer IV of V1 [22,23]. These data clearly leave the impression that visual cortex receives an impoverished representation of the world, a subject of more than passing interest to those interested in the processing of visual information [24]. Parenthetically, it should be noted that estimates of the bandwidth of conscious awareness itself (i.e. what we ‘see’) are in the range of 100 bits/sec or less [22,23] Estimates of quantified human sensory system throughput. Available from: https://www.researchgate.net/post/Estimates_of_quantified_human_sensory_system_throughput10 https://www.researchgate.net/post/Estimates_of_quantified_hu... [accessed Jun 20, 2017].
- ClassyJacket 9y ago
  You seem to be confusing the idea of the brain storing information in long term memory with the brain receiving information. Not all information processed is stored. If the brain didn't receive hundreds of megabits of information per second, nobody would be able to tell the difference between SD and HD video.
  - dredmorbius 9y ago
    I'd argue this isn't a confusing but a distinguishing. oh_sigh is being downvoted for truth.
  - oh_sigh 9y ago
    Considering the optic nerve can only tramsit ~6 Mbits/sec, and layer 4 of v1 in your visual cortext only gets ~10 kbits/sec, I would say you are wrong. To test this, try seeing if you can distinguish HD from SD without the use of your fovea. You have one highly detailed section of your eye, and the rest is low quality input which is "upgraded" through previous sightings with the fovea and your brains knowledge of how it thinks the world works. See 'foveated rendering' which will be important in the VR world, to learn more: https://en.wikipedia.org/wiki/Foveated_rendering https://en.wikipedia.org/wiki/Foveated_rendering
  - extr 9y ago
    I would argue that you're confusing "brain receiving complete information" with "brain doing inference on what information it does receive to get you close enough". You don't need the full screen to tell that the image is SD vs HD, you just need to glance at a small segment. That's not 100s of mb/sec. You know that the rest of the video is happening in your peripheral, and maybe you can tell what's going on. But in actuality you're receiving a very low bit rate version of that, and your brain is simply telling you "X & Y are happening in HD in your peripheral" and it's convincing enough.
- dredmorbius 9y ago
  I've been tackling this from a different PoV (see recent comments) of audio bitrate sensing (20 Hz is the beat/tone boundary, where beats become tones, corresponding to about 0.2 MB/day of data acquisition), or of speaking and reading rates. At 100 words/min spoken speech, humans can transmit about 1.1 MB/day sustained (24 hours without interruption). At 600 words/min reading rate (a very high rate, roughly double the college-educated adult average), a human can absorb a maximum of less than 7 MB/day. https://news.ycombinator.com/item?id=14599050 https://news.ycombinator.com/item?id=14599050
  - stan_rogers 9y ago
    If you think that the information transferred by human speech consists only of the words spoken, you have a rather shallow view of language. You're also processing information taken from pace, pitch, timbre, intonation, volume, timing and direction (among other things). The written word is to speech what choreographic notation is to dance - it's enough to give you the gist, but you wouldn't mistake it for the real thing.
    - dredmorbius 9y ago
      You're arguing a claim I didn't make.
  - pwildani 9y ago
    Each beat is probably better considered a symbol, so by your analysis the human audio channel is around 20 baud not 20 bits/s. The symbol size obviously has a large impact on the information bit rate. We can estimate the size of a symbol though: 13b for primary tones(20khz range at about 3Hz resolution) + 4b for rising/falling/etc tonal patterns + 7b for volume (1dB detection over 120db range) + (42 phonemes in english so round up to 256 for convenience) 8b for phoneme patterns + 2 ears preprocessed for 2d directions is maybe 4b direction and 4b distance gives a total of around 40b per symbol. So with that wild approximation, it's at 800 bps, or 8.64 MB / 24h
    - dredmorbius 9y ago

by dTal 9y ago

So your visual cortex isn't in your brain? Would you care to point out which region(s) of the brain only receive hundreds of bits/sec? Somebody should tell the lossy video compression folks.

oh_sigh 9y ago

Yes, it is in your brain. But if you think that your visual cortex receives anything akin to a high fidelity "picture", then you are mistaken. Regarding lossy image compression, you're free to look at something briefly and try to redraw it from scratch. Even if your drawing skills are perfect, you will find that your picture will be filled with confabulations and stereotypes. > Because of a limited number of axons in the optic nerves (approximately 1 million axons in each) only ~6x10^6 bits/sec leave the retina and only 10^4 make it to layer IV of V1 [22,23]. These data clearly leave the impression that visual cortex receives an impoverished representation of the world, a subject of more than passing interest to those interested in the processing of visual information [24]. Parenthetically, it should be noted that estimates of the bandwidth of conscious awareness itself (i.e. what we ‘see’) are in the range of 100 bits/sec or less [22,23] Estimates of quantified human sensory system throughput. Available from: https://www.researchgate.net/post/Estimates_of_quantified_human_sensory_system_throughput10 https://www.researchgate.net/post/Estimates_of_quantified_hu... [accessed Jun 20, 2017].

ClassyJacket 9y ago
You seem to be confusing the idea of the brain storing information in long term memory with the brain receiving information. Not all information processed is stored. If the brain didn't receive hundreds of megabits of information per second, nobody would be able to tell the difference between SD and HD video.
- dredmorbius 9y ago
  I'd argue this isn't a confusing but a distinguishing. oh_sigh is being downvoted for truth.
- oh_sigh 9y ago
  Considering the optic nerve can only tramsit ~6 Mbits/sec, and layer 4 of v1 in your visual cortext only gets ~10 kbits/sec, I would say you are wrong. To test this, try seeing if you can distinguish HD from SD without the use of your fovea. You have one highly detailed section of your eye, and the rest is low quality input which is "upgraded" through previous sightings with the fovea and your brains knowledge of how it thinks the world works. See 'foveated rendering' which will be important in the VR world, to learn more: https://en.wikipedia.org/wiki/Foveated_rendering https://en.wikipedia.org/wiki/Foveated_rendering
- extr 9y ago
  I would argue that you're confusing "brain receiving complete information" with "brain doing inference on what information it does receive to get you close enough". You don't need the full screen to tell that the image is SD vs HD, you just need to glance at a small segment. That's not 100s of mb/sec. You know that the rest of the video is happening in your peripheral, and maybe you can tell what's going on. But in actuality you're receiving a very low bit rate version of that, and your brain is simply telling you "X & Y are happening in HD in your peripheral" and it's convincing enough.
dredmorbius 9y ago
I've been tackling this from a different PoV (see recent comments) of audio bitrate sensing (20 Hz is the beat/tone boundary, where beats become tones, corresponding to about 0.2 MB/day of data acquisition), or of speaking and reading rates. At 100 words/min spoken speech, humans can transmit about 1.1 MB/day sustained (24 hours without interruption). At 600 words/min reading rate (a very high rate, roughly double the college-educated adult average), a human can absorb a maximum of less than 7 MB/day. https://news.ycombinator.com/item?id=14599050 https://news.ycombinator.com/item?id=14599050
- stan_rogers 9y ago
  If you think that the information transferred by human speech consists only of the words spoken, you have a rather shallow view of language. You're also processing information taken from pace, pitch, timbre, intonation, volume, timing and direction (among other things). The written word is to speech what choreographic notation is to dance - it's enough to give you the gist, but you wouldn't mistake it for the real thing.
  - dredmorbius 9y ago
    You're arguing a claim I didn't make.
- pwildani 9y ago
  Each beat is probably better considered a symbol, so by your analysis the human audio channel is around 20 baud not 20 bits/s. The symbol size obviously has a large impact on the information bit rate. We can estimate the size of a symbol though: 13b for primary tones(20khz range at about 3Hz resolution) + 4b for rising/falling/etc tonal patterns + 7b for volume (1dB detection over 120db range) + (42 phonemes in english so round up to 256 for convenience) 8b for phoneme patterns + 2 ears preprocessed for 2d directions is maybe 4b direction and 4b distance gives a total of around 40b per symbol. So with that wild approximation, it's at 800 bps, or 8.64 MB / 24h
  - dredmorbius 9y ago