Kind: captions
Language: en
i am going to turn myself into an
optical illusion
by going through this window right here
okay not good
i was gonna say i'm good i'm not good
okay so
you're looking at this window and it
looks like it's turning around
except here it stops now i keep rotating
but the window is rotating through me
what is happening
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let me back up for a second this is the
first part of a
three-part illusion what do you see
well there's a window and it's turning
except it stops and reverses direction
so the window is oscillating back and
forth
that's what most people see when they
look at this illusion except
that's not what the window's actually
doing it's on this turntable
and it is rotating continuously this is
known as the ames window illusion
and i saw it on an old australian tv
program called the curiosity show
and i was curious so in this video i'm
going to dig deeper into this illusion
than
anyone has before you know the window
itself
is not a rectangle but a trapezoid you
can see
this side here is much shorter than
this side over here and that is
essential to the illusion
also essential it is shaded to make it
look 3d but it's actually just
a two-dimensional card with the same
image on both sides
so now that you know exactly what this
object looks like and what it's doing
can you correctly perceive the rotation
rather than the oscillation
i still can't it still looks to my brain
like this window is going back and forth
okay here's an idea i'm going to attach
this
rubik's cube to the short side
of the trapezoid so we can keep track of
it as it goes around
are you ready okay
okay the rubik's cube is going around
everything seems normal
but now what is that
it looks like the rubik's cube is
continuing to go
around but the window is oscillating
back and forth
there goes the rubik's cube around the
back i don't even know what's happening
whoa look at that it looks like the
rubik's cube is out drifting by itself
out in front of the whole illusion what
is happening
okay new plan i'm going to take off the
rubik's cube
and i'm going to put a ruler right
through the middle of the window
and so we can't possibly be fooled by
the illusion
right okay here we go
[Music]
okay the ruler is rotating around
but wait now the window is going
backwards whoa whoa
the ruler is going through the window
it is doing things which i know are
physically impossible but
that is how my brain is seeing it
look here we go again the the ruler is
turning around with the window
but right about here the window starts
going backwards but the ruler keeps
coming
what is even like how is this possible
this doesn't make any sense but that is
the way my brain
interprets this it clearly prefers the
illusion
over seeing what's really happening the
continuous rotation
so why is this how does the illusion
work
well it was created by adelbert ames
back in 1947
and before becoming a researcher he
wanted to be a visual
artist so he was fascinated by how
people perceive
shapes and shading and according to him
the key to this illusion is that we're
all used to living in
rectangular boxes essentially you know
houses
and rooms where virtually all of the
corners we see
are 90 degree angles doors windows
tables and chairs are full of 90 degree
angles
this is called the carpentered
environment
but unless we're looking straight on at
something the angles we actually see
are not 90 degrees i mean the images
that form on our retinas are typically
trapezoids
of different shapes and sizes now from
extensive experience our brains know
they really should be
rectangles and right angles so our
brains use these strange shapes to infer
depth information
which in our rectilinear world is almost
always correct
but not in the case of a trapezoidal
window that our brains assume to be
rectangular
hence the illusion now if this
carpentered world hypothesis
is correct well then you'd expect people
with less experience of rectangles in
their environments to be
less susceptible to the illusion and to
test exactly this
in 1957 harvard psychologists tried the
ames window illusion in south africa
with 80 children aged 10 to 14.
40 of them were living in the city of
durban full of rectangular buildings
doors and windows
the other 40 were from nearby rural
communities
where they lived in round huts with few
prominent 90 degree angles
when subjects were seated 10 feet away
from the rotating aims window with
both eyes open 60 percent of the urban
group reported seeing the window
oscillating
but in the rural group only 17.5 percent
saw the same thing so the results were
consistent with the carpentered world
hypothesis
the kids with less experience of
rectangles were less likely to fall for
the illusion
but that's not the whole story when
seated 20 feet away and with one eye
closed
the illusion was much more convincing
now 90
of all participants saw the window
oscillating and there was no significant
difference between urban and rural
groups
that means something else must be going
on over
and above our experience with rectangles
in fact
you can get a similar illusion without
any straight lines at all
this is the de here circle when rotating
continuously
it also appears to oscillate back and
forth so
what's going on well both of these
illusions make use of a technique called
anamorphosis which has been used by
artists
for centuries if not millennia
this is a painting from 1533
called the ambassadors by hans holbein
the younger
it clearly shows two prominent figures
but there is also
this distorted shape over the floor
only when viewed from the correct
position either the top right or bottom
left
does it become clear that the image is
actually a detailed depiction of a human
skull
it's suspected that the painting was
meant to be hung in a stairwell where
presumably out of the corner of your eye
you would spot the striking image of the
skull
reminding you of your own mortality but
if you were to look at the painting head
on
well the skull would be pretty hard to
see anamorphosis
involves making a distorted projection
of an object so to see its proper
proportions you need to look at the work
from a particular position or with a
particular device
often a mirror there are earlier
examples like
leonardo's eye by leonardo da vinci
which only takes its proper form when
viewed from the side
clearly leonardo knew how to give side
eye
and some might argue that the cave
paintings at lasco france from 17
000 years ago provide the first examples
of anamorphic art
due to the uneven painting surface
artists would have had to consider
how their animal figures would be
perceived from different vantage points
anamorphosis is also central to perhaps
aim's most
famous illusion the ames room ames
designed his first
distorted room in 1934 and with one eye
from one privileged perspective it just
looks like an ordinary room
but when people move around the room
it becomes obvious that something is not
quite right
an ames room is constructed by taking an
ordinary rectangular room
and adding a diagonal wall through the
middle of it then
draw lines connecting all the key parts
of the room like
corners windows and so on to the
privileged
viewpoint mark where those lines
intersect the diagonal wall
then add a floor and a ceiling if the
projection is done
properly they will not only be tilted
but also
warped then connect the floor and
ceiling with
trapezoidal walls and voila you have
an ames room
[Music]
ames realized there are an infinite
number of different
distorted room geometries which when
viewed from the privileged position
create virtually identical images of a
normal room
so our perceptions far from
transparently representing external
reality
are constantly faced with ambiguity and
our brains
below the level of consciousness have to
decide which of the infinite
possibilities
we're actually looking at
one form of ambiguity relates to depth
perception
which of these masks protrudes outwards
towards the camera
and which is an impression only through
motion does it become obvious which is
which
we are subconsciously attuned to visual
cues that indicate how close or far away
something is
closer objects are typically bigger and
brighter plus they obscure objects
behind them
but we can play with these attributes in
order to create situations that defy our
expectations
now i have been obsessed with getting
the aims window illusion to work
look at how many different aims windows
i have been making
and i made them small initially and then
bigger there used to be
a disco ball in this room i never
thought that this would come in handy
then i thought about the question how
could i make myself
like the ruler that passes through the
aims window
of course then i would need a very large
ames window so it's been
this holiday season like we're living in
a weird surreal art museum or something
it needed to be at least eight feet on
its longest dimension
it's actually made out of six pieces of
plywood glued screwed together
one of the challenges is to make it
really thin because ideally it should
just be two-dimensional
so we had to bevel these edges here
so then i would twist up these metal
cables that hang it to the ceiling
and then jump in the window and let them
unwind
okay so i'll show you some of the best
shots i was able to get and you let me
know
does this work for you do you see it
oscillating or do you just see it
as it actually is i found
lighting is really important the
lighting needs to be really even on both
sides to convince you
that it is really oscillating
when the large side of the trapezoid is
close to us we perceive it rotating
exactly as it is but when the large side
moves around to the back
it is still larger in our field of view
than the small side
so our brain perceives it as closer and
rotating in the opposite direction
this is why the window appears to
oscillate half the time we're seeing the
window as it is
and half the time we're seeing the
bigger side as closer to us
even though it's farther away
but how do we develop the ability to
interpret depth cues in the first place
well it seems to be an innate ability
which
forms very early in our development
they've actually shown
babies in three different age groups
five and a half months
seven and a half months and nine months
the ames window illusion
do they see the window oscillating and
how would we know
if they did well babies have a
well-known preference for novelty
they look longer at things that are new
to them so experimenters
first exposed them to an ordinary
rotating circle
and then they showed them simultaneously
the aims window and a rotating
rectangular window
the five and a half month old babies
showed no special preference for the
ames window
but the seven and a half and nine month
olds were significantly more interested
in the ames window suggesting they
perceive it as doing something different
presumably oscillating
[Music]
the reason i have been so obsessed with
this illusion
is because i think it confronts one of
the big misconceptions about science
which is this idea that scientists
propose competing theories
and then all you have to do is look at
the data to decide
which is the best theory the truth is
there are many circumstances in which
the same data could come from very
different
external realities to use a classic
example
does the sun go around the earth or does
the earth rotate
on its axis the observation of the sun
moving across the sky doesn't in itself
resolve that debate or to use more
modern examples
when you make a quantum measurement does
the wave function collapse
or does it branch the universe
is the speed of light really the same in
all directions
or does it differ and only the round
trip speed
is c as of right now the data do not
discriminate between those theories
and i think we can extend this beyond
science i mean maybe the ames illusions
are a good metaphor
for life we feel as though we can
directly perceive external reality like
a person looking into an ames room
but the truth is there are an infinite
number of different geometries that
would all
look the same you know these days a lot
of people
are getting basically the same
fundamental information but
coming to very different conclusions
about the state of reality
so i think in that context it's
important to remember that something as
simple
as a little rotating picture can fool
our brains in fairly spectacular ways
so we should approach the world and our
conclusions about it
with a little more humility and a little
less certainty
[Music]
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know you're thinking
his channel is named for an element but
he's wearing a different
element on his shirt oh the irony