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The way mantis shrimp see is nonetheless super cool and interesting. They likely have no conception of 2D color at all, and can only sense the 12 different colors in general. Furthermore, only the midband of their eyes see color, when the eyes are moving and scanning for prey, they don’t see color at all, which probably helps offload mental load for their small brains. Once they do see something, they then stop moving their eyes to determine the color of what they’re looking at.
Also, mantis shrimp have 6 more photoreceptors in addition to the 12 colored ones, to detect polarized light. They likely see them the same way that they see color, so they probably don’t consider them anything different than wavelength which is what we interpret as color.
Ed Yong’s An Immense World has a section on this and I’d highly recommend it. The ways animals sense and perceive the world are often so different for ours and it’s so fascinating.
For anyone wondering why they would need to see polarized light: I actually looked into this a few months ago!
Other animals that are trying to blend in with the environment often use countershading appear less conspicuous. The problem with this is that this method can’t replicate the polarization of the light behind them, making them stand out if you can see that sort of thing. ((Sunlight in the ocean is always polarized based on the direction of the sun (look up fresnel equations for s and p polarized light))). Even transparent creatures will interrupt the polarization in some way, so this is a very useful skill to have.
More specifically, polarization changes with the angle of reflection of the surface towards the detector / eye / camera, so every bump in the surface gets a color gradient different from the surroundings when seen by a polarization sensitive eye
“Spiders can detect danger coming their way with an early-warning system called eyes.”
Really fantastic book. I did have some notes though. Firstly, if honeybees have such low dpi vision, how can they see each other dance? I assume it’s because they’re experiencing the dance some other way, but how? (Also it’s hella dark in there, isn’t it?)
He says many times that humanity’s umwelt is dominated by sight, but I very much disagree. To lose my hearing or sense of touch would make me feel quite blind, as I use them to perceive things outside my cone of vision constantly. Being in deep water is unnerving for this reason, because I can’t “see” what’s around me, and I have this whole new area below that I can’t hear either. So I have to wonder whether other people feel the way he does or whether my usage is more unique.
He really blew my mind when describing exafference and reafference because these things are reliant on a sense of self in the first place, which means that even the worm in his example must have some form of ego.
You show that you are dominated by sight even as you say you aren’t.
Losing your hearing or touch would remove peripheral senses, yes, and certainly that would be unnerving, but think how much worse it would be to lose sight. Hearing wasn’t even a factor for you beyond your peripheral, because what you can see is so much clearer, so much more comprehensive, than what you can hear, that hearing is negligible where you have sight.
Hearing is a backup sense. Something you lean on when you don’t have sight, but its fidelity is poor enough in people that we rely nearly wholly on sight, when we can.
Losing that cone of vision impacts us far more than our hearing, although of course losing either is massively detrimental.
I have heard that the incidence of suicide is higher in deaf people then in blind people, which would suggest that, while our senses are sight dominated, losing our hearing has a bigger impact in some way. That said I can’t find a citation for that, so make of it what you will.
Or maybe the blind people just miss more.
I think this speaks to a significant misunderstanding that most people hold of the way vision actually works.
Most people imagine that vision is a relatively simple process by which our eyes detect and transmit to us the nature of the world. Not so.
Eyes are complex and interesting organs in their own right but fundamentally what they do is relatively simple. They are able to detect and report to the brain certain qualities of the light that hits them. Primarily these are: intensity, direction, and proximity to three points on the frequency spectrum (what we perceive as red, green, and blue). But this data alone is not vision. Vision is a conscious experience our brains create by interpreting and processing this data into the visual field before us—basically, a full scale 3D model of the world in front of us, including the blended information on reflection and emission that color entails.
Quite amazing! Most of this takes place in the human brain, and not the eyes. From this perspective, it is not terribly surprising that an organism with more complex eyes but a much simpler brain might have worse vision than we do.
Reminds me a little of CD digital audio. The original Red Book audio standard hasn’t really been improved upon because it’s uncompressed audio which covers basically all of the range of human hearing within the capabilities of any speaker we could build. It’s uncompressed because in the early 80’s when the tech hit the market, it was completely unfeasible to include the CPU and RAM needed to decompress audio in real time.
Shrimp has more color receptors because he doesn’t have enough neurons to run trichromacy, so he sees in EGA.
Oh man.
12 year old me waiting for hours to rip mp3s from cds always wondered about this.
Like why isn’t it already compressed?
The answer is that storage was available but processing wasn’t. Amaze.
Mp3 is already compressed, as is the MP2 CDs use.
If it wasn’t conpressed, you’d be looking at CDs per track, instead of tracks per CD.
What are you on about? CD-DA, aka audio CD, aka red book audio, is uncompressed 16-bit PCM sampled at 44100Hz. It is lossless.
MP3 (MPEG-1/2 Audio Layer III) is a lossy encoding standard commonly used for online audio distribution and steaming. MP2 usually refers to MPEG-1 Audio Layer 2, which was most commonly used in Digital Audio Broadcast.
Neither are used in ‘regular’ CD audio.
It is lossless.
I’m not sure that’s the right word for uncompressed digital audio, because it’s lossless compared to what? Presumably an analog recording or the original input signal? Because Shannon-Nyquist, with CD audio you can’t get anything higher than what? 16kHz out of it, but within that limitation you can reproduce any arbitrary waveform within a speaker’s ability to produce given the laws of physics regarding inductance and inertia.
MP3 does use a lossy compression, but you can maintain listenable quality while cramming about 10 times as much audio into a given space. You can get just over an hour of Red Book audio on a CD, and about 11 hours of mp3s, give or take. You might get lower audio bandwidth or various kinds of artifacts but it’ll still sound pretty good, it’s way more practical to store and transmit over the internet. We didn’t Napster no .wav files.
FLAC and similar formats use lossless compression, kind of like a .zip file. If you rip a CD to FLAC, and you were to then burn a CD from that FLAC, the data on the new CD would be identical to the old one. So you get as-perfect-as-we-can-do digital audio, but only 5 or 6 hours worth would fit on a CD. Someone somewhere on this earth has filled a compact disc with FLAC files, I’m sure.
