Perception
Selective Attention
focus of conscious
awareness on a
particular stimulus



https://www.youtube.com/watch?v=lHd_L7dg3U4
http://www.learner.org/series/discoveringpsychology/07/e07expand.html
http://www.dailymotion.com/video/xq1rfl_national-geographic-test-your-brain-episode-2perception_shortfilms
Testing Selective
Attention
Selective Attention
Selective Attention means that at any
moment, awareness focuses on only a limited
aspect of all that we are capable of
experiencing. For example, even if a stimulus
figure can evoke more than one perception, we
consciously experience only one at a time.
Another example of selective attention: the
cocktail party effect
also limits our perception, as many stimuli will
pass by unnoticed.
Inattentional Blindness
What is Inattentional Blindness?
Selective attention also limits our perception, as
many stimuli will pass by unnoticed. This lack
of awareness is evident in studies of
inattentional blindness.
Forms of this include:
change blindness
change deafness
choice blindness
http://www.gocognitive.net/sites/default/files/change_blindness.v.0.93_0.swf
What is Choice Blindness
Petter Johansson and Lars Hall, the
researchers who originally coined the
term, people " ...often fail to notice
glaring mismatches between their
intentions and outcomes, while
nevertheless being prepared to offer
introspectively derived reasons for why
they chose the way they did."
http://channel.nationalgeographic.com/channel/brain-games/videos/choiceblindness/
Obj. Describe the interplay between
attention and perception.
Answer the following question (in your own
words) on the back of the paper that was
placed on your desk: How does attention
impact our perception? Use the
following terms in your answer:
Choice-blindness
Inattentional blindness
Cocktail party effect
Selective attention
Top-Down
Perceptual Illusions
Muller-Lyer Illusion-
Perceptual Illusions
Perceptual Illusions
Perceptual Illusions
Watch This: How Brains
Learn to See
http://www.ted.com/talks/pawan_sinha_o
n_how_brains_learn_to_see
Object Recognition
Blindness http://www.ted.com/talks/pawan_sinha_on_how_
brains_learn_to_see
Data-Driven Processing (look at the handout 6-4)
b. Abe Lincoln (matched with objects in our long term memory and b.) the 1st picture on
the page (a cow) data-driven and conceptually driven processing
 Visual agnosia – syndrome in which all parts of
the visual field are seen, but are without meaning
– Read The Man Who Mistook His Wife for a Hat,
by Oliver Sacks
Visual object agnosia – no damage to the eye but
unable to recognize familiar objects.
4. Simultagnosia – cannot pay attention to
more than one stimulus at a time. Not
being able to see objects simultaneously.
5. Spatial agnosia – trouble negotiating
their way through the world (wrong
turns, lost in own home)
Perceptual OrganizationGestalt
Visual Capture
tendency for vision to dominate the
other senses
Grouping
the perceptual tendency to organize
stimuli into coherent groups
Perceptual OrganizationGestalt
Gestalt- an organized whole
tendency to integrate pieces of information
into meaningful wholes
Grouping Principles
proximity- group nearby figures together
similarity- group figures that are similar
continuity- perceive continuous patterns
closure- fill in gaps
connectedness- spots, lines and areas are
seen as unit when connected
Perceptual OrganizationIllusory Contours
Perceptual Organization
Figure and Ground
organization of the
visual field into objects
(figures) that stand
out from their
surroundings (ground)
PerceptualOrganizationGrouping Principles
PerceptualOrganizationGrouping Principles
Gestalt
grouping
principles
are at
work here.
Perceptual OrganizationDepth Perception
Depth Perception
ability to see objects in three dimensions
allows us to judge distance
Binocular cues
retinal disparity
images from the two eyes differ
closer the object, the larger the disparity
convergence
neuromuscular cue
two eyes move inward for near objects
Perceptual OrganizationDepth Perception
Visual Cliff
Perceptual OrganizationDepth Perception
Monocular Cues
relative size
smaller image is more distant
interposition
closer object blocks distant object
relative clarity
hazy object seen as more distant
texture
coarse --> close
fine --> distant
Perceptual OrganizationDepth Perception
Relative Size
Perceptual OrganizationDepth Perception
Perceptual OrganizationDepth Perception
Monocular Cues (cont.)
relative height
higher objects seen as more distant
relative motion
closer objects seem to move faster
linear perspective
parallel lines converge with distance
relative brightness
closer objects appear brighter
Perceptual OrganizationDepth Perception
Perspective Techniques