
Vision scientists discover why people literally don't see eye to eye - ClarendonDrive
https://news.berkeley.edu/2020/07/13/vision-scientists-discover-why-humans-literally-dont-see-eye-to-eye/
======
Steve44
This clicked with me when I watched The Brain with David Eagleman [1] on BBC a
little while ago. I've always know there is a disconnect between reality and
what you interpret but the way he described it stuck. Note this is my layman's
way of describing how I understand it.

Firstly your eyes are not connected directly to your "brain". You don't see
what is in front of you.

Your eyes write a rough scan of elements of what is in front of you to a
"frame buffer". Your brain looks at this "frame buffer" and interprets what it
thinks you are seeing. At this stage it can fill in blanks and do all sorts of
manipulations to make it look smooth and complete.

What can also happen is your brain can write to this "frame buffer", this is
indistinguishable from the information the eyes have put there. This is pretty
much how psychosis works - those monsters/spiders/people/objects seem as real
as if they are there.

[1]
[https://www.bbc.co.uk/programmes/b06yjrdp](https://www.bbc.co.uk/programmes/b06yjrdp)

~~~
k__
It's also multiple frame buffers. The nerves before the brain already do some
interpretation, and the brain an optimized version.

And the brain can rewrite the history it saved if it finds logical errors that
came up because of it filling in gaps wrong.

Brains are awesome and scary.

~~~
therein
That's the ultimate eventual consistency.

When you realize your previous approximation leads to a discontinuous function
after new data arrives, just roll back your instruction pointer as well as
your perception of time.

This ability to retroactively error-correct without affecting perceived
continuity could also be affording our brains a greater margin of error.

~~~
XMPPwocky
Maybe, but then it turns out that your brain's cache isn't rolled back when
you mispredict, and you have to close your eyes for ten seconds after looking
at anything secret until another few hundred generations of evolution fix the
bug.

------
lkrubner
My father was a photographer and over the decades he worked with many other
photographers in his darkroom (this was in the era of chemical photography).
After several hundred occasions when he and another photographer were looking
at a print under the color balancer, he realized they were literally seeing
different colors. My father, who was scientifically inclined, eventually
worked out the average variation, which I want to say was two clicks on the
projector, but I’d need to check to find out what that actually meant in terms
of frequencies. It’s a small variation, but it was certainly real. Remember,
these were all professionals with years of skill at judging color.

------
watertom
I watched a program on PBS back in the mid 80's about San Fransisco and the
Haight Asbury Free clinic.

They were speaking with a doctor about "acid casualties" LSD. What the doctor
said was really interesting.

People who have flashbacks get scared thinking their brain is fried, and it's
usually triggered by something visual. The patients have visual
"abnormalities" and it scares them into thinking a new acid trip will start.
In reality what LSD, Mushrooms, Peyote, etc. can do is strip away all the
adaptations in the visual system. He said in most cultures that use
psychedelics they usually talk about cleansing, or stripping away when using
psychedelics, and with the visual system it's a true statement.

When he went on to say was that when we are born our visual system is like a
blank downloadable computer, and as we grow, the visual part of our brain is
making adaptations based on what it knows vs what is 'senses'. He said that
due to small eye movements the sensing would jiggle, especially in our
peripheral vision, but we learn the the world doesn't jiggle, so the visual
system makes sure that stable items don't jiggle. Tons of adaptations take
place, depending on our lives and experiences some of us have more adaptions
than others.

Sometimes when taking psychedelics all those adaptations get stripped out, or
only some get stripped out, leaving people with the untrained system, and that
untrained system doesn't present things in the same way. Colors don't look the
same, sometimes things in the peripheral vision jiggle or move, moving our
heads quickly while quickly moving our eyes can cause 'trails'. All
indications that our visual system has had some adaptations erased.

The doctor said that eventually over time things get usually restored to
normal. However he said for colors, it's interesting because for people that
grew up in a different area of the country and had their color perception set
at that location, they sometimes find the when wipe out the adaptions and
reset things the colors sometimes don't matched. Depending on where they grew
up vs where the adaptations get reset the color of the sunlight can be
different, and that will alert the color adaptation.

------
ta1234567890
Relevant Ted talk: "Your brain hallucinates your conscious reality | Anil Set"
[https://m.youtube.com/watch?v=lyu7v7nWzfo](https://m.youtube.com/watch?v=lyu7v7nWzfo)

~~~
core-questions
Timothy Leary was telling everyone this decades ago, of course.

~~~
h2odragon
Crowley also mentioned it, very likely others before them too

~~~
jagannathtech
[https://en.wikipedia.org/wiki/Maya_(religion)](https://en.wikipedia.org/wiki/Maya_\(religion\))

------
someusername99
n=9 ...

[https://royalsocietypublishing.org/doi/10.1098/rspb.2020.082...](https://royalsocietypublishing.org/doi/10.1098/rspb.2020.0825#d47172744e1)

~~~
pas
9 might be okay if the effect size is large enough. (If the study was pre-
registered there should have been a power analysis to determine the sample
size given the hypothesized effect size.)

------
Daub
The article and its associated paper did not really engage me. Perhaps I am
missing something.

However, I was reminded of something that I learned when taking drama lessons
as a teenager, and which I have used as a teacher. Our attention of an object
(such as another human) oscillates from eye to eye. However, it is biased to
one eye. Generally this is the one on the opposite site to our writing norm
(i.e. left handed = right eyed). If you really want to hold a scene when being
filmed, look unwaveringly out of the eye that is nearest the camera. It will
feel unnatural, but look dam cool on the screen. Look carefully... you can see
Laurence Olivier and others doing precisely this.

As a teacher I use it in class to hold attention. But it’s best effect is on
the screen.

~~~
vikramkr
Do you have a link with a video or a visual explanation? I dont get what
looking unwaveringly out of the eye closest to the camera means - what does it
mean to look out of one eye?

~~~
Daub
Here is Michal Caine talking about this:

[https://youtu.be/bZPLVDwEr7Y?t=184](https://youtu.be/bZPLVDwEr7Y?t=184)

He tell a bunch of actors to always 'pick an eye' when in front of a camera.
What Michel Cain does not say is that some actors prefer looking out of their
'handed' eye, believing it to have more impact.

As a demo of 'handedness' in eyes, try this experiment:

1\. Hold one finger around one foot in front of your face. Hold the other at
arms length. Whilst try to look out of both eyes, ensure that the fingers are
visually aligned with each other. This will be difficult, as the images from
each eye will not correspond.

2\. Slowly open and close one eye. Then do the same with the other. The slow
blink from one eye (eye A) will not affect the correspondence of the fingers,
whilst the slow blink from the other (eye B) will.

The reason is that eye B is adjusting itself to match eye A.

Edit:
[https://en.wikipedia.org/wiki/Ocular_dominance](https://en.wikipedia.org/wiki/Ocular_dominance)

Its called ocular dominance apparently.

~~~
quietbritishjim
He does mention choosing which of his own eyes to look out of, but when he
says "pick an eye" he's clearly talking about picking one of the other
person's eyes to look at. That's also clearly the source of the flicking back
and forth that he talks about (and demonstrates).

------
ilaksh
My understanding is that you only have a relatively small area in the center
of your vision where you get a clear image. And so your eye moves back and
forth so rapidly that you can't tell without slow motion, sort of scanning in
the environment into a 3d map.

So maybe some of the variability is in that mapping circuitry.

------
brmgb
Is there an expert who could explain what's novel here ?

The layman summary seems to imply specialists are surprised that people judge
distance differently which seem crazy to me. I mean we have known for decades
that vision is the result of a complex process involving different parts of
the visual system and that people results on tasks involving mainly vision
(and coordination admittedly) vary.

What's the surprising part here ?

~~~
gchamonlive
Not only that, Kant himself structured the idea of the world outside our field
of experience in a critique of pure reason. Since then the idea that our
experience is a perfect one and that all our ideas come from our experience
has been questioned.

This is why when the interviewed said "We assume our perception is a perfect
reflection of the physical world around us" it was really strange for me. Only
those unaware of hundreds of years of advance in philosophy assume that. And
this highlights possibly a field that is very much lacking in science, the
critique of thought itself.

~~~
slfnflctd
> Only those unaware of hundreds of years of advance in philosophy assume that

So then, nearly all children, and most of your average working-class people?
Seems to me the author was just tailoring the piece for a layperson audience,
which is kinda the default writing approach.

~~~
ta1234567890
I would say even a lot of very educated people, despite maybe having read
about these topics, will still feel and act as if what they are perceiving is
reality itself.

I'm actually very surprised to see so many comments here dismissing the
article as something almost obvious.

~~~
gchamonlive
that is because this thread is about a scientific publication in a respectable
university site, it suffers a different level of scrutiny.

------
throwaway_kufu
> “We assume our perception is a perfect reflection of the physical world
> around us, but this study shows that each of us has a unique visual
> fingerprint,”

I don’t think anyone makes that assumption. I think most people know we don’t
actually “see” the physical world, our eyes receive electrical signals from
photons and our brain interprets those signals and for lack of a better word
we hallucinate the physical world (in the form of the visual light spectrum).

By its very nature, from a common sense point of view photons don’t hit our
eyes at the same time or the same angle; therefore, electric impulses will be
different reflected Differently in our hallucinations. And even if 2 people
had the same distance/angle, there are sometimes other issues differentiating
our hallucinations, just one example being color blindness, where for various
reasons one person hallucinates different colors than another based on the
same electric impulses from photons. Even without color blindness this happens
regularly (think of the blue/white dress vs black/gold viral photo a few years
back)

~~~
dan_hawkins
Anecdotally I've always perceived that dress as blue/brown from the very
beginning and I can't "switch" my vision to perceive it otherwise. It's
incomprehensible to me that someone can see it as blue/white or even worse as
black/gold :)

~~~
nitrogen
I don't want to trigger another thread about this old image, but I will point
out that there are significant differences in monitor gamut and gamma across
devices. Some cheap laptop LCDs crush blacks and whites _significantly_ if you
aren't looking at perpendicular dead center.

It is for this reason that using light blue or light yellow backgrounds to
demarcate ads is sinister -- one can A/B test their marker into literal
invisibility for many users.

~~~
dan_hawkins
I'm an amateur photographer and have got quite good monitors that I calibrate
regularly :) But I've got trained sight, especially for color balance because
of that - I can see people faces greenish when they stand under a tree in a
sunny day so that's that.

