Beyond what our Eyes Perceive
it is often said
that we don’t see through our eyes but
instead
with our brain the eyes enable light to
enter our system
but in order to make sense of the world
around us
the electrically powered piece of meat
we are carrying inside our skulls
needs to get working so what kind of
work does the brain need to do
well the simple answer as in most
psychological research
is pretty straight we are not sure yet
but before i tell you how my institution
spends resources in order for me
to waste hours drinking coffee and
thinking over this
let me give you some examples on how the
brain sees
an obvious example would be dreaming or
imagination
that extraordinary ability of
experiencing images
without them actually being them many
scientists
are curious about understanding this
phenomenon despite
the many practical difficulties but
unfortunately for you unfortunately for
them
i’m not one of those scientists so i
can’t really tell you much on the topic
however i’m kind of curious about stuff
like this
this is the widely known penrose
triangle
it’s quite funny i got this t-shirt
really cheap
because the whole triangle is misspelled
on it
let me make it a bit easier for you to
see
at first glance it looks like an
ordinary triangle
but the more you stare at it the more
you realize that
in reality this shape cannot exist
it’s an optical illusion optical
illusions
are an interesting way to understand
that
beyond one rise perceive beyond the
visual information that’s right in front
of our eyes
the brain does all the hard work to put
that information together
and of course as i know from my personal
life too
hard work does not necessarily mean good
work
sorry boss i know that you’re probably
watching this
arise get constantly bombarded by a huge
influx of visual information and many
times
the brain can get confused distracted
or even miss some of the information
here’s an example of the brain getting
confused
these are the rotating snakes by
akioshikitoka
even though this picture is static our
brains pick up spontaneous movement
as if the snakes are rotating i know
brains are really weird now
of course the way that we perceive the
world
has a lot to do with where and how we
pay attention
where the focus is now
i don’t usually take selfies but i think
there’s
no better way to explain this so i want
you to have a look
here keep going
depending on where you focus your
attention your brain
interprets the perspective of this photo
differently
despite having only one image in front
of your eyes
the brain puts it together in a
prejudiced way
what’s right in front of you in
combination with what we know
about that something for the example
here
the brain has learned that faces can
only have one single perspective
it searches beyond the single image
that’s right in front of
the eyes and puts it all somehow
together
based on what makes sense for the brain
as i mentioned earlier brains can also
get
distracted or even miss some of the
information
for example you probably haven’t noticed
that i switched to what i was wearing
from my right hand to my left hand
there’s a number of reasons why this
happens one reason
is that your brain uses existing
knowledge some sort of
common sense in order to save energy
while figuring things out
if you saw the watch before you know i’m
wearing it
it doesn’t really make sense for me to
switch hands
so why would your brain pay any more
attention to it
it assumes when it sees the watch that
it’s always been
on my left hand
unless of course somebody is trying to
make a point
i know what you’re thinking the screen
is small
the watch is even smaller the setup is
quite big
i have a very pretty face it’s easy to
get away with it
but let me give you a better example our
brains
know that in order to change clothes we
need
to take the ones we’re currently wearing
off and change them with other ones
and one does not simply do that while
giving a speech
or at least that’s what the organizers
told me
that could explain why you probably
haven’t noticed that the word triangle
is now spelled correctly on my t-shirt
trust me this would have been much
cooler if i was doing this on stage
i pointed at my t-shirt before you saw
it you probably read what was written on
it
and your brain processed the information
it knows that the print on it is not
something likely to change
so why give it any more attention the
brain
prefers to save its resources and tries
to avoid
what it thinks is unnecessary it uses
this
common sense to
assume that the t-shirt will remain the
same
or that the watch was always on my left
hand
similarly to how when you see somebody
with glasses
you assume that they have some sort of a
visual impairment
well guess what these glasses
have no lenses in them
well i told you i was trying to make a
point
this brain limitation is something that
magicians have come across and um
often they use this destruction
to impress us with their magic
so try and remember that next time you
spot a magician
now knowing that the brain has all these
capabilities
and limitations we now understand
that somehow the brain using specific
processes
turns all this visual influx into
conscious representations
so beyond polarized perceived
something is happening in some areas of
the brain
that actually allow us to understand the
world around us
such a process is visual short-term
memory
in simple words visual short-term memory
is our brain’s ability
to handle visual information just for a
few seconds
while that information is no longer
available
and therefore we can achieve some goals
to help you understand i want you to
imagine
that you’re building one of those model
aeroplanes or a model boat
you have all these pieces laid in front
of you in the table and of course you
have this huge
booklet with instructions you open up
the instruction manual to the first page
and have a look at the first piece
you’re going to need
what you’re doing is you’re trying to
remember the image
of the first piece in your mind
and you put the instructions away you
turn to all the pieces on the table
trying to find the one that you’re
holding into your memory
trying to remember and handle all this
visual information
which is no longer present is what the
visual short-term memory process
is in our lab
we don’t really build mobile aeroplanes
or model boats but part of our work
relates to which brain areas are
involved during visual short-term memory
specifically we study the primary visual
cortex
which is an area on the back of the
brain somewhere around here
the primary visual cortex is the first
brain area
that processes visual information right
after the light
passes through our eyes and the optic
nerve
it even consists of special cells
special neurons
which have been shown to be particularly
responsible for processing some basic
visual features
in other words some neurons in the
primary visual cortex
are exclusively there to process some
basic
visual characteristics such as contrast
and orientation
however we are still not sure whether
this brain area
is able to hold on to this visual
characteristics
let’s say whether the primary visual
cortex
is able to remember them or whether
other brain areas need to be recruited
in order to do so
so how do we find out well
the first thing we need to do is design
some tasks
computer tasks which will present to
people
visual information and people will have
to remember it
think of it as some sort of a very
boring video game
so basically what we do is we present
an image to the participants
the image then disappears and the
participants are trying to remember it
after a few seconds a second image
appears
then participants need to tell us if the
second image
is the same as the first one or if it’s
a different one
so far so good
these kinds of computer tasks have been
used in cognitive science for decades
and it is something we use in our lab as
well
apparently part of my job is to spend
hours
designing these very boring memory games
while of course
making sure the whole lab’s computer
system doesn’t crash
these tasks help us gather evidence
about visual short-term memory enabling
us to study it
and explore it but
that’s the easy part we still need to
figure out a way
to investigate how the primary visual
cortex
is involved during the process of visual
short-term memory
now the most reliable way to do this
and bear with me that’s the best way to
do it
is the following we bring people to the
lab
to play these very boring video games we
design which the goal is to remember
something visually so
we show them the first image and when
the first image disappears
we slice open the skulls surgically
remove the primary visual cortex
completely from the brain
and put it right back just before the
second image appears
while of course keeping them conscious
and alive
and uh by the way we only have about
two seconds to do so before the second
image
appears of course when i told my lab
team this idea
they were staring at me as if i was
standing naked in the room
i almost lost my job and some people
won’t talk to me anymore
so obviously this is not a realistic
scenario
it might indeed be the best way to find
out
but clearly is not something that can be
done
so what now after the shock of that
meeting called down
and my supervisor decided to start
talking to me again
we turned to state-of-the-art technology
to find the answers we were looking for
non-invasive
brain stimulation science and technology
have developed amazing techniques that
today
allow us to interfere with the brain’s
regular activity
as if we are removing a brain part in a
safe
non-invasive and reliable way we use
magnetic stimulation
to target the primary visual cortex
disrupt its regular activity
and study how this temporal disruption
affects cognitive processes
such as visual short-term memory
at the start of this talk i mentioned
that the brain is electrically powered
this exact fat is what makes brain
stimulation
possible we use magnetic energy
which we know is safe for humans because
this energy can manipulate electrical
fields
such as the one our brain generates
therefore by manipulating the brain’s
regular activity
during visual short-term memory we can
study how the primary visual cortex
is involved during this process
now as in all sciences a very important
question needs to be asked
which is probably something you’re
thinking right now
so what what’s the importance of this
why do we do it well first of all
it is because we are curious scientists
want to know why
or how the world works
this is what has driven science
throughout the years and this is what
drives
many scientists around the world today
the brain is very difficult to
understand
these experiments add a very small piece
to the puzzle
of unraveling how the brain works
they help us better understand
mesmerizing questions
like why or how are we conscious
further this kind of work can be
translated into the practical world
helping us solve everyday problems
for example many accidents are caused by
the human factor
and often by how our brains get confused
distracted or even misinformation
with this said i want to close by saying
that
beyond every scientist work was an
infinite stream of curiosity
and a dream of making the world a better
place
thank you