PERCEPTION
is the process of organizing and interpreting
sensory information.
A
BIRD
IN THE
THE HAND
Selective Attention
The focusing of conscious awareness on a
particular stimulus.
For example:
1. “the cocktail party effect”
2. in a restaurant when you listen to other
people have a conversation.
3. What other examples can you think of?
PERCEPTUAL ILLUSIONS
Muller-Lyer Illusion
Which line is bigger?
The Ames Room
Visual Capture:
vision dominates the other senses.
Example: 3D movie, roller coaster ride
PERCEPTUAL ORGANIZATION
FORM PERCEPTION
Figure and Ground-the
organization of the visual
into objects (the figures)
that stand out from their
surroundings. (the ground
is the background in
which the individual
stands)
-The following slides are
examples of figure &
ground
FORM PERCEPTION
Can you see
the old
woman?
Can you see
the young
woman?
Do you see a vase? Or two faces?
What do you see in this image?
Is this a bunny or is this a
duck?
Examples of Grouping
Grouping-we organize the figure into a
meaningful form so that people can make
sense of what they see.
Figure & Ground
(previous slides are examples of- the vase
or 2 faces, and the dog)
Proximity-group nearby figures together.

Similarity-we group together figures similar to
one another.
Continuity-we perceive smooth continuous
patterns rather than discontinuous ones.
Form Perception

Connectedness-when they are uniform and
linked, we perceive spots, lines or areas as a
single unit.
Form Perception
Closure-we fill in
the gaps to create
a complete, whole
object.
Depth Perception
Is the ability to see objects in 3 dimensions.
Binocular cues-depth cues, that depend on the
use of two eyes.
Examples:
1. Retinal Disparity-by comparing 2 images from the
eyeballs, the brain computes distance-the greater the
disparity (difference) between the 2 images, the closer
the object.
-Try the floating finger sausage.
Visual Cliff-a laboratory device for testing
depth perception in infants.
Monocular cues-distance cues available to
either eye alone
Examples:
1. Relative size-if we assume that 2 objects
are similar in size, we perceive the one
that casts the smaller image to be further
away.
2. Interposition-if one object blocks the view
of another, we perceive it to be closer.
3. Relative Clarity-because light from
distant objects passes through more
atmosphere, we perceive hazy objects
as farther away than sharp, clear objects.
4. Texture gradient-a gradual change from
a coarse, distinct texture signals
increasing distance. Objects further
away appear smaller and more densely
packed.
5. Relative Height-we perceive objects higher in
our field of vision as farther away
6. Relative Motion-as we move, objects that are
stable may appear to move.
For example: if while riding in a train you fix your
gaze on an object-house-the objects closer to
the house appear to move backward. The
nearer an object is, the faster it seems to
move.
7. Linear Perspective-parallel lines such as
railroads appear to converge with
distance. The more the lines converge,
the greater their perceived distance.
8. Light and shadow-nearby objects reflect
more light to our eyes. Thus given 2
identical objects, the dimmer one seems
farther away.
MOTION PERCEPTION
Stroboscopic movement is when the brain
interprets a rapid series of slightly varying
images. By flashing 24 still pictures each
second, a motion picture creates
perceived movement. (a flip book)
The PHI PHENOMENON
is created when 2 or more
adjacent lights blink on and off in
succession, creating the illusion
of movement.
PERCEPTUAL CONSTANCY
Perceiving objects as unchanging, in size,
color, shape, brightness, location and light.
Is the ability to recognize than object
remains the same even when it produces
different images on the retina.
PERCEPTUAL INTERPRETATION
Sensory Deprivation-Infancy is a critical period
during which experience must activate the
brain’s innate visual mechanisms.
Perceptual Adaptation-Human vision is
adaptable. Given glasses that shift the world to
the left or right or upside down, humans can
adapt and see with ease.
PERCEPTUAL SET
Perceptual Set is the readiness to see objects
in a particular way based on expectations,
experiences, emotions & assumptions.
Perceptual set influences our everyday
perceptions.
Human Factors Psychology
(p255)
A branch of psychology that explores how
people and machines interact and how
machines & physical environments can be
adapted to human behaviors.
Perceptions vary and may not be what a
designer assumes so human factors
studies how machines & physical
environments can be improved i.e. safety
EXTRASENSORY PERCEPTION
The claim that perception can occur apart from
sensory input.
Parapsychology is the study of paranormal
phenomena, including ESP (astrology, psychic
healing, communication with the dead, out of body
experiences.
Types:
telepathy-mind to mind communication
clairvoyance-perceiving remote events
precognition-perceiving future events
psychokinesis-mind over matter
The Ganzfeld Procedure
Is the use of sensory deprivation to minimize
distractions, hoping to detect faint
telepathy signals.