Do We Really See What's There - Visual Perception

[Psamathe]

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:

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

 

[Drago]

What black dots? I can see black squares?

 

[Beebo]

What black dots? I can see black squares?

The black dots are in peripheral vision when you focus on the white dots.

 

[ebikeerwidnes]

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!!

 

[Drago]

The black dots are in peripheral vision when you focus on the white dots.

Nope.

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

 

[Fastpedaller]

I've not seen (maybe I should say experienced) that one previously. Also, if the viewer looks for several seconds at the 'whole black picture' and then moves their gaze to the right (ie to the white area 5 inches to the right) the viewer sees white squares separated by dark lines!
That demonstrates how the retina 'holds an image' for a short while. I may not have the correct terms
Several similar effects are on display at the National Trust Woolsthorpe Manor Museum in Lincolnshire where Sir Isaac Newton was born, saw the apple fall, and carried out many of his studies into light during a 'lockdown' to contain plague (sounds familiar).
Well worth a visit.

 

[Fastpedaller]

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:
View attachment 759752
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

It seems less noticeable when either eye is closed.
I await someone saying it's not noticeable with both eyes closed

 

[ebikeerwidnes]

The effect can be quite dangerous

Our brain filters stuff out- but ouside conscious control which means outside the realm of out intelligence

Hence when doing things like driving we have very little control over what it filters out

which could include a cyclist because we were looking for cars etc
I have seen quite a few article in the press where this would explain an accident - not "didn;t look" but "didn't see" and due to the brain not registering because it was a cyclist

(in other words - cyclists are not real road users so are not on the list of what the driver needs to look for)

 

[Andy in Germany]

(in other words - cyclists are not real road users so are not on the list of what the driver needs to look for)

I wonder if that's because we instinctively look for dangers, and cyclists are less of a danger. I have seen this with pedestrians who step out in front of me while looking directly at me

 

[Fastpedaller]

Indeed, many of us will have noticed drivers who even consciously (so not just filtered) look around us to see if there are any real vehicles .
There is also the 'saccadic masking' effect, where when moving eyes or head quickly between two vistas 'misses' out the view in between. This can be overcome by being aware of the effect and looking more than once/moving the eyes more slowly. I understand fighter pilots have training to avoid saccadic masking, and IMHO it should be highlighted to road users.

 

[Psamathe]

I have seen quite a few article in the press where this would explain an accident - not "didn;t look" but "didn't see" and due to the brain not registering because it was a cyclist

Very early in my driving I was taught that when waiting to turn at a junction if you see an oncoming (motor)bike you say "bike" either out loud or silently. Apparently (I was taught) it ensures you register the oncoming bike rather than unconciously filter it our.

Since being taught that I always and stillo do it every time (silently).

Ian

 

[All uphill]

The effect can be quite dangerous

Our brain filters stuff out- but ouside conscious control which means outside the realm of out intelligence

Hence when doing things like driving we have very little control over what it filters out

which could include a cyclist because we were looking for cars etc
I have seen quite a few article in the press where this would explain an accident - not "didn;t look" but "didn't see" and due to the brain not registering because it was a cyclist

(in other words - cyclists are not real road users so are not on the list of what the driver needs to look for)

That's why I welcome all road users that challenge the idea that our highways are for cars, lorries and buses only.

Pedelecs, bicycles, motorbikes, horses, joggers, mobility scooters. We all help change perceptions.

 

[Drago]

Skilled and diligent drivers don't let their eyes rest on the same point, thus eliminating the chance of the mind disguising, editing or misrepresenting something.

Conversely the average driver is lazy and undisciplined and stares pretty much constantly dead ahead at a point in the intermediate distance and can easily fall foul of such a phenomenon.