We live 1/10 second ahead of the real world

Wordsmith

LE
Book Reviewer
#1
I was recently advised to read "The Vision Revolution" by Mark Changizi as its pertinent to a field I'm doing some work on. It's about how our sight works. (It's 'popular science' - but will probably require a couple of reads to get full sense out of it).

Changizi is full of insight as to how our vision works and this one in particular interested me. Because it takes about 1/10 of a second between light hitting our eyes and our reflexes kicking in, our brain pre-processes the information and what we actually see is the brain's interpretation of where an object will be allowing for our reflexes. The result can be seen in the diagram below.
Ball Catch.png
In the diagram on the left, if we saw the balls' actual position, our reflexes would mean that we'd always be grabbing at the ball a tenth of a second after where it actually was - and get it in the face. What actually happens is on the right. We 'see' the ball a tenth of a second on from its actual position - so allowing for the time lag in our reflexes. So the errors cancel out and we can catch the ball.

So we don't see the real world - we see our brains' projection of how it thinks things will be 1/10th of a second into the future - and we never realise it.

This has been proven using simple experiments.
Light.png
In the diagram on the left a light bulb has been set to flash the precise second that a ball passes it. However, when people are asked to estimate the relative positions of the ball and light, they always 'see' the ball a fraction in front of the light as that's the mental image we are presented with.

The truth is stranger than fiction.

Wordsmith

(Cue lots of jokes about people who live 1/10 second behind the real world).
 
#2
Are you trying to make excuses as to why you were always picked last at school?
 
#5
I always try to catch the ball as it hits my face. Does this mean I am more honest than my sporty brother?

If not, please send key setting.
 
#6
On a serious note, that 'proof' is nothing of the sort. Experiments have shown that people cannot actually see two things at once (that's why linesmen have such difficulty judging offside, as they have to see both the ball as it is played, and the offending player, who is somewhat separated from the ball as it is played), so the ball/light experiment merely helps demonstrate the difficulty of seeing two concurrent events, and really is a measure of how long it takes for someone to change from one point of observation to another.
 
#7
Good point, joe-p - I saw a great demonstration of this on tv using some eye tracking software - subject looked at large screen, and computer changed details in picture, removing people whenever subject was looking elsewhere. Subject never noticed changes. It's how some stage magic works.
 
M

MrsBee

Guest
#12
Good point, joe-p - I saw a great demonstration of this on tv using some eye tracking software - subject looked at large screen, and computer changed details in picture, removing people whenever subject was looking elsewhere. Subject never noticed changes. It's how some stage magic works.
What your referring to is what's known as change blindness to psychologist.
 
#13
On a sort of related note there seems to be some sort of mechanism in the body that allows for the nerves to make the body react/move with no input from the brain.

For instance if you grab hold of something very hot the hand/skin will make you let go faster than the time required to let the pain signal travel up to the brain and back down to the hand.

This sounds ok and sort of possible

BUT

If you have picked up something valuable* (and hot) then your reflexes will say let go but before you can your brain can/will override this and make you hold on until you can put it down safely.

So is the pain signal getting to the brain faster than the nerves actually allow it or is there something wierder going on?


*valuable in the sense of not wanting to drop it.
 
#14
On a sort of related note there seems to be some sort of mechanism in the body that allows for the nerves to make the body react/move with no input from the brain.

For instance if you grab hold of something very hot the hand/skin will make you let go faster than the time required to let the pain signal travel up to the brain and back down to the hand.

This sounds ok and sort of possible

BUT

If you have picked up something valuable* (and hot) then your reflexes will say let go but before you can your brain can/will override this and make you hold on until you can put it down safely.

So is the pain signal getting to the brain faster than the nerves actually allow it or is there something wierder going on?


*valuable in the sense of not wanting to drop it.
Surely, for your example to work, the brain must have disengaged the reflex before you touch the valuable item.
 
#15
Good point, joe-p - I saw a great demonstration of this on tv using some eye tracking software - subject looked at large screen, and computer changed details in picture, removing people whenever subject was looking elsewhere. Subject never noticed changes. It's how some stage magic works.
Try this website, we were shown the video in a H&S course - probably the only interesting bit on the course.

The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us

S_R
 
#16
Surely, for your example to work, the brain must have disengaged the reflex before you touch the valuable item.
Now thats an idea.

Does the brain override the reflex before you start on a "just in case" basis?
 

Wordsmith

LE
Book Reviewer
#17

TheresaMay

ADC
Moderator
DirtyBAT
#18
Ah the invisible gorilla test. I was one of the smug students that actually saw it. A result of inattentive blindness; or overload of mental tasking. Of course, the opposite can have the same effect too. How many times have you driven 300+ miles on a journey and barely remembered a single detail about it?

I read somewhere that an image lasts 0.1 seconds on the retina as well - otherwise we'd never see anything or everything would be blurred (one of the two).

Try this one - stare at the four vertical dots for 30 seconds without moving your eyes or blinking. Then afterwards stare at a blank sheet of paper or a white/magnolia wall and hold your gaze.

Apologies if you've already seen it:
 

Attachments

#19
So what time do we turn up for the parade? 5 minutes before, 5 minutes before or 5 Minutes and a tenth so leaving 4 minutes and 9 tenths to be before the parade. Or shall I just be late with an excuse i am bound to get away with.

Looks for watch marked in tenths of seconds to prove shouty man wrong...
 

Wordsmith

LE
Book Reviewer
#20
Are you saying we learn from example? Or that repetitive training reduces the chance of error?

Or are you just saying that things are interesting?
Mainly that our brains give us an 'edited' version of the real world that enables us to function more effectively in that real world. Vision is an interesting subject - for example the area we actively focus on at any moment in time is equivalent to your thumbnail held out at arms length. That's an astonishingly small area compared to our field of view.

But I believe there is a learning process when we move at different speeds. I think that's one reason very new learner drivers drive slower, even on straight clear roads - they're still developing the ability to 'project ahead' the movement of other cars at those speeds.

I guess a similar thing must apply when you learn to fly a fast jet low - there must be a learning process for you to calibrate your eyes and learn to instinctively project ahead the motion of the aircraft relative to your reflex time. At 600 mph, the aircraft is travelling at 880ft a second. Get your distance perception wrong and there's going to be a big hole in the ground.

Wordsmith
 

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