PERCEPTION
CRASH COURSE
The process of organizing and interpreting
information, enabling us to recognize meaningful
objects and events.
Seeing the world as it isn't
Stare at the blue dot in the middle. You should see the outer edges of the circle
fade away!
Troxler’s fading
It occurs because even if our eyes move a little when we are fixating a point, away
from that point, in the perception field, the movements aren’t large enough to
observe other elements; in conclusion the neurons remain focused on the main
object and our visual system doesn’t involve new ones for the other elements.
You are about to witness the perpetrator of a
crime!
Describe who you saw at the crime
scene. Keep in mind your eyewitness
testimony could be used in a court of
law.
Was she a young girl or an old woman???
Perceptual Ideas
an illusion
Perceptual set: a mental predisposition to perceive one
thing and not another.
Context Effects
• Based on immediate context, not
schemas.
• You do not hear the word, but can guess
at it based on the context it was said in.
Top-Down Processing
• We perceive by filling
the gaps in what we
sense.
• I _ant ch_co_ate ic_
cr_am.
• Based on our
experiences and
schemas.
• Perceptual Set – a
mental predisposition;
the experiences,
assumptions, and
expectations that
influence our perception
Perceptual Adaptation
inverted vision
program 7: start @ 15:39
• The ability to adjust to an artificially
altered visual field
Are the red lines parallel???
http://www.michaelbach.de/ot/
Gestalt Psychology
• Gestalt – an organized whole; from German
for “form” or “whole”
• Gestalt psychologists emphasized the
tendency to integrate pieces of information
into a meaningful whole.
• Gestalt Psychology says that we innately
look at things in groups, not as isolated
elements.
• “The whole is greater than the sum of its
parts.”
Grouping & Gestalt Psychology
Khan Academy
• Proximity - group objects
that are close together as
being part of same group
• Similarity - objects
similar in appearance are
perceived as being part of
same group
• Continuity - objects that
form a continuous form
are perceived as same
group
• Connectedness – objects
that are uniform and
linked are perceived as
single units
• Closure - we fill gaps to
create a whole or
complete image
Closure
Figure Ground Relationship
Visually, our first
perceptual decision
is “What is the
figure?” in the
image and “What is
the ground?”
(background).
The figure ground relationship can also
be applied as a principle of auditory
perception.
Depth Perception
• Eleanor Gibson - Visual
Cliff Experiment
• If you are old enough
to crawl, you are old
enough to see depth
perception.
• We see depth by
using two cues that
researchers have put
in two categories:
– Monocular Cues
– Binocular Cues
Sensory Restriction
Blakemore & Cooper, 1970
Kittens raised
without exposure to
horizontal lines later
had difficulty
perceiving horizontal
bars.
Binocular Cues
Khan Academy
• We need both of our
eyes to use these cues.
• Retinal Disparity - as
an object comes closer
to us, the differences
in the images for our
eyes becomes greater.
 “finger sausage”
 3-D movies
• Convergence - as an
object comes closer,
our eyes have to come
together to keep
focused on the object
Monocular Cues
khanacademy(start 2:00)
• You really only need
one eye to use these
(used in art classes
to show depth).
– Linear Perspective
– Interposition
– Relative Size
– Texture Gradient
– Light / Shadowing
Motion Perception
• Stroboscopic Effect
 a rapid series of slightly
varying images perceived
as moving images (flip
book, “old” movies)
• Phi Phenomenon
illusion of movement created when two or more ----lights next to each other blink on and off
Constancy
khanacademy(start @ 6:10)
• Objects change in our
eyes constantly as we or
they move….but we are
able to maintain content
perception
 Shape Constancy
 Size Constancy
 Color Constancy
 Brightness Constancy
o However, color and
brightness also depends on
context!
Parapsychology
• the study of
paranormal phenomena,
including ESP and
psychokinesis
• ESP – extrasensory
perception; perception
outside of sensory
perception
– Telepathy
– Clairvoyance
– Precognition
FINISHED FILES ARE THE
RESULT OF YEARS OF
SCIENTIFIC STUDY
COMBINED WITH THE
EXPERIENCE OF MANY
YEARS.
FINISHED FILES ARE THE
RESULT OF YEARS OF
SCIENTIFIC STUDY
COMBINED WITH THE
EXPERIENCE OF MANY
YEARS.