color perception visual illusions can be
fun but have you ever wondered how they
work
our brains construct our reality visual
illusions are a window to how seeing
color all starts with light light is
made up of different wavelengths
corresponding to different colors we see
objects as colorful because they absorb
all the other wavelengths of light and
reflect their color into our eyes light
travels through the eye where it hits
the retina which is made up of millions
of tiny cells called rods and cones this
is then converted into electricity that
brain cells use to understand color
seeing color is one of the simplest
processes our brains do rods are what we
use for seeing in the dark they are
pretty ineffective in sunlight as they
prefer low-level lighting conditions
when you turn off the lights at night
and initially can't see anything this is
because the rods have not yet adapted to
the dark if you wait for five minutes
you start seeing faint outlines of
things because the rods start to kick
into action rods don't contain at any
colored pigments which is why you don't
see any color all our color vision is
due to the cones in our eyes they come
in three varieties long medium and short
for the wavelengths they prefer so how
does the human eye detect millions of
different shades of color
well it is actually very similar to a
computer screen computers only have
three types of colored pixels they are
just so small that our eyes are not able
to pick up each individual color our
brain cells combine the levels of red
green and blue lights that they receive
to form all the colors we can see but
our vision can be easily fooled
in 2015 the internet was hit by the
dress the gold and white or blue and
black dress debate continues to confuse
many because it seems nonsensical that
one person can see a blue dress and
another can see it white interestingly
night owls or late risers are more
likely to see the dress as black and
blue and early birds are more likely to
see the dress as white and gold
critically colored light changes an
object's color artificial lights as a
yellow hue daylight is more blueish
which we can see in these pictures of
shaded snow early risers see a white
dress as their minds remove the blue
daylight tint they are used to seeing
late risers think that this is lit by an
artificial yellow light and attribute
the blue to the dress itself here a and
B are the exact same color but because B
looks as though it's in shade the brain
registers that B must be more reflective
we use our expectations to guide what we
see
did you see the doc if I said look for
the mammal you may be more likely to see
the rabbit then the faces seem to switch
back and forth between each what we
perceive at first is guided by
expectations the dress is unusual in
this respect as the color we see remains
consistent this is because of the
realism of the photo and we expect the
lighting to remain constant like in our
day-to-day life
what does all this mean what we see is
often based on what we expect to see any
comparison of our visual system to
photographs is wrong as we continually
reconstruct a scene to understand what
we are seeing in terms of what we have
seen before or what we are expecting to
see just remember what you see might not
be what your neighbor sees