Mrs. Perl
AP Psychology
Organizational Principles Underlying Perception
Questions to consider: How do we take various neural stimuli that come to us broken into various components and put
them together in order to make sense of the world? How do we perceive distance and depth?
I. Form Perception
Term
Gestalt Principles
Pragnanz
Figure-Ground
Definition
Organized
whole. Tendency
to integrate
pieces of
information into
meaningful
wholes. Brain
follows "rules" to
order sensory
information into
wholes.
Reality is
organized or
reduced to the
simplest form
possible. Don't
see 5 individual
circles but as a
whole.
Our eyes focus
on what is in the
forefront of a
picture. Even if it
reverses, we still
organize the
stimulus into a
figure seen
against a ground.
Same stimulus
can trigger more
than one
perception.
Example
Illusion (if applicable)
Grouping- Proximity We group nearby
figures together.
See three sets of
two lines not six
separate lines.
Grouping- Similarity
Vertical columns
of similar shapes
and not a
horizontal row of
dissimilar
shapes.
GroupingContinuity
We perceive
smooth,
continuous
patterns rather
than
discontinuous
one. One wavy
line and one
straight line and
not alternating
semicircles.
Uniform and
linked we
perceive each set
of two dots and
the line between
them as a single
unit.
Fill in gaps to
create a
complete, whole
object. Assume
the circles are
complete but
partially blocked
by the triangle.
GroupingConnectedness
Grouping- Closure
II. Depth and Distance Perception
Depth PerceptionBinocular cues.
Convergence and
retinal disparity
2 dimensional
objects that fall
on our retina
that our brain
puts together as
a 3 dimensional.
Eyes are about 2
inches apart and
the image will
fall on the retina
slightly
differently. The
manner in which
our eyes need to
converge on the
image can help
us determine
how far the
object is from us.
(convergence)
Retinal disparity-
Depth perception- Monocular Cues-One eye
Perceptual
Constancy- Shape
and size constancy
Relative Height
Recognize
objects without
being confused
by changes in
size and shape.
In our mind the
size and shape
remain constant.
Perceive the
object as the
same even
though the
retinal image
changes.
Once we know
the usual size of
an object, we
can infer
something about
the height of an
object or
distance of an
object when we
compare it to
each other.
We perceive
objects higher in
our field of vision
as farther away.
Relative Size
Assume two
objects are
similar in size so
the one that
casts a smaller
retinal image is
perceived as
farther away.
Interposition
If one objects
partially blocks
the other we
perceive it as
closer.
Linear perspective
Parallel lines
appear to
converge in the
distance. The
more they
converge, the
greater the
distance.
Texture Gradient
Fine details on
objects can be
seen on closer
objects than on
farther objects.
Light and shadow
Nearby objects
reflect more light
to our eyes so
the dimmer one
seems farther
away.
Relative motion
Objects appear
to move even
while stable. Fix
your gaze on an
object-objects
beyond the
fixation point
move with you
and the objcts in
front of the
fixation point
seem to move
backwards.
Motion Perception
and the phi
phenomenon
Perceptual
constancyLightness/Brightnes
s constancy
(relative luminance)
Large objects
appear to more
more slowly than
smaller objects.
Stroboscopic
movement: rapid
series of slightly
varying images
Phi
phenomenon-If a
light next to
another light is
turned on and
off quickly it
looks like one
light is moving
Recognize
objects without
being deceived
by changes in
their size, shape,
brightness, or
color.
Perceive an
object as having
a constant
lightness even
while its
illumination
varies.
Relative
luminanceamount of light
an object reflects
relative to its
surroundings.
May perceive a
color as brighter
depending upon
the context.
Color constancy
Color depends
upon context
but familiar
objects will
maintain their
color regardless
of the changing
illumination. eg.
red apple will
appear red
regardless.
d) Illusions
a. Moon illusion
Compare the moon to the context clues and it appears larger than when it is in the sky and
there is othing else to compare it to.
b. Ponzo illusion
2 bars cast the same retinal image on our eyes. But, because of the linear perspective, we
assume that it is farther away and thus perceive it as being larger than the line in front.
c. Ames Room
Brain makes the assumption that the room is normal and that the girls have to be a different
size. since they are the same distance from us.
d. horizontal-vertical illusion
e. Mueller-Lyer illusion
II. Perceptual Interpretation
1. Question: Kant vs. Locke-Inborn vs. Learned?
a. Visual Cliff
b. Sensory Deprivation and Restored vision
c. Perceptual adaptation
d. Perceptual set
e. Context Effects
f. Emotion and Motivation
2. Bio-psycho-social phenomenon