Do We Really See What's There - Visual Perception

[presta]

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Mantis shrimp can see a remarkable 12 to 16 different colors, according to Nature and Cell Press.

This is significantly more than the three color receptors (red, green, blue) in the human eye.

They also perceive a range of ultraviolet and polarized light

"Despite having all these fancy receptors, mantis shrimp aren’t actually better at distinguishing colors than we are. In fact, they’re worse at it!"

Try the Farnsworth Munsell test.

 

[Psamathe]

"Despite having all these fancy receptors, mantis shrimp aren’t actually better at distinguishing colors than we are. In fact, they’re worse at it!"

Try the Farnsworth Munsell test.

But do that variety of sensors provide them with other advantages. Insect eyes are not great optically but I remember doing tests on locust descending contralateral movement detectors nerves that give them very fast reactions to movement.

I don't know details but can imagine vision related advantages beyond straight seeing colour.

 

[Mad Doug Biker]

Maybe a bit seperate from optical illusions, there are some visual effects I think really weird but that maybe illustrate how we process things we see. Good example:
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Try and focus on the black dots (where the lines cross). As soon as you do they disappear and become white dots.

My understanding as to what's happening is it's a bit like contrast enhancement in the eye, sharpening edges where light-sensitive receptors in your eye switch their neighbouring receptors off to enhance edges. Not normally noticable like in the example above but happens eg when your visual system is separating eg a building from the background, making edges more pronounced. Lateral inhibition.

But do correct me if I have the technicalities wrong or my understanding is wrong.

But at whatever level I find it interesting.

Ian

Oh yeah, I see that instantly. Always have.

Yes - it is all weird

Basically you see everything but then your brain gets involves and edits it

It tries to make the important things clearly and ignores things that it things are not relevant

for example - I can look for a can opener, for example, and not find it - only for my wife to poitn out that it is on the worktop exactly where I was looking
but I was looking for a can opener that was the right way up and it was upside down so my brain edited it out and not what I was looking for


I have sort of learned to realise this and get round it - but it still happens

it is just my brain getting involved and doing what it decides are right - before my "mind" can get involved

It is like having a rather over active Civil Service involved in you whole life - right out of Yes Minister!!

I always think of what I am looking for and it usually works.

Concentrate, look for a can opener.

Nope.

Mind you, I could never the the dinosaurs just those magic eye picture things either.

Neither could I, but that original one just hurts my eyes, as do others.

 

[ebikeerwidnes]

Oh yeah, I see that instantly. Always have.

I always think of what I am looking for and it usually works.

Concentrate, look for a can opener.

Neither could I, but that original one just hurts my eyes, as do others.

Now that is where I have always had a problem

I can look for a can opener - actually that i sone thing I have lost a lot - and NOT see it
focus very specifically on the can opener

there have been times when I can see that I have been looking for a view of it that was the other way up
but sometimes no view works

then go out of the room for some reason
and come back and it is right there in the middle of the worktop

which leads to my theory of mischevious imps living in an alternate dimersion

but really it is just my brain editing it out



BTW - you brain edits a LOT of stuff out
for example if it tried to work fully with everything when you turn your head then it would go crazy
so it basically ignores everything except a few bits
then starts again when you stop moving your head

 

[presta]

But do that variety of sensors provide them with other advantages.

Further down the same reference:

"Even tho they can’t see more colors than us, mantis shrimp still have some pretty amazing visual abilities:

1. UV Vision: They can see ultraviolet light
2. Polarized Light: They can detect different types of polarized light
3. Fast Processing: Their visual system works super quickly
4. Independent Eye Movement: Each eye can move separately"

 

[ebikeerwidnes]

Further down the same reference:

"Even tho they can’t see more colors than us, mantis shrimp still have some pretty amazing visual abilities:

1. UV Vision: They can see ultraviolet light
2. Polarized Light: They can detect different types of polarized light
3. Fast Processing: Their visual system works super quickly
4. Independent Eye Movement: Each eye can move separately"

yes - but can the see the point in the policies of [Enter political party name here]

 

[Fnaar]

Was shown another interesting visual misinterpretation the other day. I''s a "movie" so needs playing. The boxes are not actually moving (apparently)