Where is it going

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Where is it going?

• Motion Perception

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Motion Perception

• Neural pathways in the brain combine information
  about eye-muscle activity, the changing retinal
  image, and the contrast of the moving object to
  the stationary background.
• Brain views larger objects as moving more slowly
  than smaller objects
• Brain assumes shrinking objects are retreating
  and enlarging objects are approaching

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Stroboscopic Motion

• The illusion of motion by the rapid projection of
  slightly changing images
• The concept a motion picture (movie) uses

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Phi Phenomenon

• The illusion of motion when fixed lights are
  turned on and off in a sequence
• To see how this works click below
• Stare at the X in the middle and notice what
  happens. Is the Green Dot Moving?
• Lilac Chaser Illusion
• OR goto
• http//www.weeville.com/eyetest.htm

Want to know more about this? Click here to find
out.
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Induced Motion

• Karl Duncker studied this with the dot and moving
  rectangle.
• Rectangle moved but people thought it was the dot
  moving.
• This because of top-down processing (people
  expected the dot to move) and our assumption that
  the background is stationary.

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Induced Motion Demo Click below to view
videoThe Flying Airplane

• The plane is stationary, the background is what
  is moving.
• Check out more Induced Motion at the link below
• Induced Motion

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Spiral Motion Detectors

• Research shows that different neural pathways in
  the cerebral cortex process information about the
  depth of objects, movement, form, and color.
• As you view the spiral motion your spiral motion
  receptors are being used. When you look at a
  stationary object, they are still on for a brief
  instant causing the illusion.

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Spiral Motion
Check it out by clicking on video below Spiral
Motion Buddha Stare without blinking at the
center of the spiral.
To view an even better spiral motion demo click
on Spiral Motion Detectors Demo
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Motion Blindness

• Look steadily at one stationary point, such as
  one of the white discs. Dont blink as blinks
  and sudden eye movements destroy the illusion.
  Notice that one, two or all of the white discs
  will disappear and reappear.
• Deals with your selective attention

Click on the link to view Motion Blindness Demo
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Perceptual Constancy
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Perceptual Constancy

• Perceiving objects as stable or constant (having
  consistent lightness, color, shape, and size)
  even as illumination and retinal images change
• Example as a person walks away from you their
  retinal image decreases in size
• Example A car in the distance is still known to
  be the same color and size as it was when it was
  driving past you.
• Important function of the perceptual system is to
  represent constancy in our environment even when
  the retinal image varies

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Perceptual Constancy Size Constancy
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Size Constancy

• A persons understanding that as an object moves
  further or closer to them its actual size stays
  the same
• As an object appears to become larger we realize
  it is getting closer, not bigger.
• As an object appears to become smaller we realize
  it is moving farther away, not getting smaller.
• Perceptions of the world depend on our experience
  - Colin Turnbulls experiment with Kenge

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Relationship Between Perceived Size and
Perceived Depth

• To perceive the size of objects accurately we
  must also perceive their distance accurately
• Thus, many visual illusions occur simply because
  a particular image lacks sufficient depth cues

This figure shows that image size depends upon
both object size and distance
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Size Constancy

• People are the same size even though their image
  sizes differ
• The depth cues such as linear perspective and
  relative size help the visual system judge the
  size accurately

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Size Distance Relationship
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Size Distance Relationship
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Size Distance Relationship
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Perceptual Constancy Shape Constancy
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Shape Constancy

• The understanding that an objects shape remains
  the same even though the angle of view makes the
  shape appear changed

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Shape Constancy

• It is hard to tell if the figure on the upper
  right is a trapezoid or a square slanted
  backward.
• If we add texture, the texture gradient helps us
  see that it is actually a square

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Perceptual Constancy Lightness Constancy
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Light (Brightness) Constancy

• The ability to see an object as having a constant
  level of brightness no matter how the lighting
  conditions change
• If you look at a sheet of paper in bright
  sunlight it looks blazingly white. View the same
  sheet in a dimly lit room, and it appears gray.
• Has the paper changed? Of course not!
• We know the paper stays white no matter what
  the lighting conditions are.

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Brightness Contrast

• Perceived lightness stays roughly constant as
  long as the context or surroundings stay the
  same.
• When the context changes you may perceive the
  color as changing.
• Although the interior squares are in fact
  identical, we perceive the one as lighter or
  darker because of the contrast with its
  surroundings.

• Want to see more of these perceptions? Goto
  http//www.skidmore.edu/hfoley/Perc4.htmlightcon
  

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Brightness Constancy Example

• Obviously A is a dark square in light and B is a
  light square in shadow, right?

• Both A and B are identical shades of gray! Can
  you believe that they are sending the identical
  level of light energy to your retina? The
  organization of the scene into lighted areas and
  shadowed areas must play a role in determining
  the perceived lightness of the squares.

• The white square (Square B) is reflecting so
  little light that it is reflecting the same
  amount of light as a black square in direct light
  (Square A).

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Illusion of the Camera

• Play Lights, Camera, Magic! (1253) Segment 10
  from Scientific American Frontiers Video
  Collection for Introductory Psychology (2nd
  edition).

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Perceptual Interpretation

• To what extent do we learn to perceive?
• If our eyes were covered with blinders during our
  early years, would we enjoy normal perception if
  they were later removed?
• The adaptation goggles show us that our brain can
  adapt to changes that occur later in life.

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Sensory Deprivation Restored Vision

• Early visual experience can have a profound
  effect on perception. Blakemore Coopers
  restricted environment with kittens.
• Do the kittens ever fully regain normal
  sensitivity to horizontal or vertical lines? NO.
• The Use it or lose it phenomenon.

From the time their eyes first opened, and until
the age of 5 months, these kittens were removed
from darkness each day to spend 5 hours alone in
a black-and-white striped cylinder with a clear
glass floor. A stiff collar prevented the kittens
from seeing anything else, even their own bodies.
Afterward, these kittens had difficulty
perceiving horizontal forms, compared with other
kittens exposed only to horizontal forms.
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Sensory Deprivation Restored Vision

• These experiments show that lacking stimulation,
  the cortical cells had not developed normal
  connections making them functionally blind to
  shape.
• A sensory restriction does no permanent damage if
  it occurs later in life. This suggests that
  visual experiences during infancy are a critical
  period for normal sensory and perceptual
  development. Experience guides the organization
  of the brains neural connections.
• If deafness or blindness is corrected as an
  infant, it awakens the pertinent brain area.
  Nurture sculpts what nature has endowed.

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Perceptual Set
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Perceptual Set

• A mental predisposition to perceive something one
  way and not another
• If we believe we are going to see or hear
  something, we often do
• Example of top-down processing
• Influence of the power of suggestion
  (subliminal perception)
• Guided by schemas concepts or mental frameworks
  that organize and interpret information

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Schemas

• Childrens drawings reflect their schemas of
  reality, as well as their abilities to represent
  what they see. This drawing by 4-year-old Anna
  illustrates that the face has far greater
  importance than the body in young childrens
  schemas of essential human characteristics.

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Face Schemas

• Which is the real Margaret Thatcher?
• We dont have a schema for upside down faces.
• As it rotates youll find out when you cannot
  assimilate her mouth and eyes to into your schema
  for faces

Click to below to view The Thatcher Illusion
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Perceptual Set

• The influence of prior assumptions and
  expectations on perceptual interpretations

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Perceptual Set

• What do you see in the center picture a male
  saxophonist or a womans face? Glancing first at
  one of the two unambiguous versions of the
  picture is likely to influence your
  interpretation.

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Subliminal Perception

• Play Studying the Effects of Subliminal
  Stimulation on the Mind (446) Segment 9 from
  The Mind Psychology Teaching Modules (2nd
  edition).

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Context

• The setting or environment in which we interpret
  sensory stimuli
• Culture can also influence how we perceive
  information.
• Nativist Position people throughout the world
  view the world the same way because they share
  the same biological perceptual rules.
• Empiricist Position People actively construct
  their perceptions by drawing on their prior
  learning and cultural experiences.
• Carpentered-World Hypothesis People living in
  urban and industrialized environments where there
  are more right angles and straight lines will be
  more susceptible to the Muller-Lyer Illusion than
  people in non-carpentered natural environments.

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Context Culture

• What is above the womans head? In one study,
  nearly all the East Africans who were questioned
  said the woman was balancing a metal box or can
  on her head and that the family was sitting under
  a tree. Westerners, for whom corners and boxlike
  architecture are more common, were more likely to
  perceive the family as being indoors, with the
  woman sitting under a window.

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Context Effects

• The magicians cabinet Is the box in the far
  left frame lying on the floor or hanging from the
  ceiling? What about the one on the far right? In
  each case, the context defined by the inquisitive
  rabbits guides our perceptions.

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Illusions
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Illusions

• When we misperceive the true characteristics of
  an object or image.
• Help researchers understand how sensation and
  perception normally works

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Müller-Lyer Illusion

• Perceptual psychologists have hypothesized that
  the top horizontal line looks longer because it
  also looks farther away
• Specifically, the inward pointing arrows signify
  that the horizontal line is closest to you, and
  the outward pointing arrows signify the opposite
  case

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Müller-Lyer Illusion
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Müller-Lyer Illusion
Most people think segment AB equals BC. In
reality AB is much longer than BC.
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Müller-Lyer Illusion
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Müller-Lyer Illusion
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Müller-Lyer Illusion
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Müller-Lyer Illusion
Click below to view a video of how this
works Muller-Lyer Illusion Explanation
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Ponzo Illusion

• Converging lines indicate that top line is
  farther away than bottom line

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• The interplay between perceived size and distance
  (a) The monocular cues for distance make the
  pursuing monster look larger than the pursued. It
  isnt. (b) This visual trick, called the Ponzo
  illusion, is based on the same principle as the
  fleeing monsters. The two red bars cast
  identical-sized images on our retinas. But
  experience tells us that a more distant object
  can create the same-sized image as a nearer one
  only if it is actually larger. As a result, we
  perceive the bar that seems farther away as
  larger.

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Moon Illusion

• Moon appears larger when it is on the horizon
  than when it is directly overhead.
• Objects on the horizon are perceived as farther
  away than those above us
• The moon appears to be behind those objects on
  the horizon. Since it is bigger than those
  object it is perceived as huge! (click on box
  below for explanation)

Click Below to View an Explanation Moon Illusion
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Ames Room Illusion Secret Revealed
When in fact it is a trapezoid!
We perceive the room to be as we are used to, a
perfect square or rectangular.
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Poggendorff Illusion
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Impossible Figures

• These grouping principles help us construct
  reality but perceptual contradictions can lead us
  astray

See how this and others like it are done
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More Impossible Figures
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More Impossible Figures
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Eschers Impossible Scenes
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Chrysanthemum
Is this 3-D?
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Toying with your Perception
Want to see more Optical Illusions? Optical
Illusion Montage 1 Optical Illusion Montage
2 Contrast Asynchrony Illusion Contrast
Asynchrony illusion
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Water or Monks?
Heads or Houses?
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Rocks or Horses?
In or out of the picture?
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Ghost Perceptions?

• Watch the car commercial closely. What
  perceptual concept causes you to see the faint
  image of the ghost?

Click Below to view Ghostly Car Ad