PERCEPTION
Chapter 4.5
Gestalt Principles
Gestalt
principles are
based on the idea that the
whole is greater than the
sum of the parts.
These principles allow us
to make sense of what we
see.
1.
Closure: the tendency to
perceive a complete or whole
figure even when there is
part of it missing; there are
gaps in what our senses tell
us.
2.
Figure-Ground
Perception: the perception
of figures against a
background; what you see
depends on which you are
looking at and it can change
as your eyes move from one
area to another
3.
Proximity: the
perceptual tendency to group
together visual and auditory
events that are near each
other; we group things
together because they are
close to each other
4.
Similarity: the
perceptual tendency to group
things together because they
are alike
5.
Continuity: the
perceptual tendency to group
stimuli into continuous
patterns
6.
Common Fate: the
tendency to perceive objects
that are moving together as
belonging together
7.
Law of Good Form –
the tendency to organize
forms in simplest way
possible
We
see the following figure
as a rectangle and a circle
instead of one figure with a
rounded part on the bottom.
8.
Relative size –
objects farther away
appear to be smaller while
objects that are larger
appear to be closer
9.
Height in plain –
distant objects in a picture
appear higher while closer
objects are lower in the
visual field
Movement
1.
Phi Phenomenon:
mistaking apparent
movement for the real thing
2.
Stroboscopic Motion:
the illusion of movement
produced by the rapid
progression of images or
objects that are not moving
at all; example: movies
Depth Perception
This
allows us to develop the
ability to judge depth or
distance away of objects. We
perceive this distance by
using monocular and
binocular cues.
 There
is evidence that depth
perception begins to develop
early in life.
 The visual cliff experiment
showed this. Very young infants
seemed to unafraid when placed
on the cliff at the edge of the
apparent drop-off.

But by nine months,
infants responded
with fear to the
drop-off. Other
studies showed that
they wouldn’t even
cross the “cliff”
when called by their
mothers. Crawling
apparently signaled
the need to sense
this danger.

The only animal
that would regularly
cross the “cliff” was
a rat. This was
because they don’t
use their vision to
sense danger.
Their whiskers told
them that the
surface was still
solid so they moved
across it.
Monocular Cues
There
are several of these
which allow us to judge how
close or far away objects are.
1.
Linear Perspective: the
tendency to see parallel lines
as coming closer together, or
converging, as they move
away from us
2.
Interposition (overlap,
relative position): the
tendency to perceive an
object as being closer if it
blocks another object
3.Shadows
and Highlights:
Objects with highlights on
their surface and shadows
beneath appear to be closer
4.
Texture Gradient: the
more texture or detail we see
in an object, the closer we
perceive it to be
5.
Motion Parallax: the
tendency of objects to seem
to move forward or backward
depending on how far away
they are from the viewer; an
example is looking at nearby
things out the car window
versus objects farther away
6.
Atmospheric
Perspective: the tendency
to perceive hazy or smokey
objects as farther away
Binocular Cues
Both
eyes are needed to
perceive these cues.
1.
Retinal Disparity:
binocular cue for perceiving
depth based on the difference
between two images of an
object that the retina receives
as the object moves closer; as
the object gets closer, the
disparity gets greater
2.
Convergence:
movement of eye muscles
that cause pupils to come
closer together as an object
is brought closer
Perceptual Constancies
Each
person’s experience
creates perceptual
constancies – constancies of
size, color, shape, and
brightness.
1.
Size Constancy: the
tendency to perceive an
object as being on one size
no matter how far away the
object is.
2.
Color Constancy: the
tendency to perceive objects
as keeping their color even
though different light might
change the appearance of
their color
3.
Shape Constancy: the
tendency to perceive the
same shape in an object no
matter what angle you view it
from
4.
Brightness Constancy:
the tendency to perceive an
object as being equally bright
even when the intensity of
the light around it changes
Optical Illusions
This
is a false visual
perception of a stimulus
These are not hallucinations
where there is no external
stimulus. They exist; we just
see them inaccurately.
Do you see the word?
Seal or Donkey?
Old or Young?
Are there circles?
Old Man or Couple Kissing?
Do you see the Dalmation?
Do the stairs go up or down?
Do you see a man or the word liar?