Schiffman, Chapter 7

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Schiffman, Chapter 7
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Figure-Ground

• Figurestands out, smaller, seen as solid object
• Groundrecedes, larger than object, encloses
  figure
• Ambiguous figure-ground, as in Escher artworks

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Impossible trident explanation

• Figure is impossible in 3-D, and cant be
  visually resolved in 2-D (drawing) because of
  shifting of elements from figure to ground
• See Impossible Trident for longer explanation

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Figure-ground

• Such perception apparently innate
• Even insects perceive figure-ground
• Neurological basisprimary visual cortex has
  higher level of neural firing for figure than for
  ground (must perceptually interpret as figure or
  ground first)

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Gestalt Laws of Perception

• PSYC 10 Lesson 4 Notes

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Common fate
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Subjective Contours
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Subjective contour theories

• Contour is apparent edge of a surface seen in 3-D
• Seeing central figure that partially overlaps
  elements at the edge of figurepartial overlap is
  depth cue. Butwhen overlapped figures are
  figures themselves, less subjective contour effect

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Subjective contour theories

• Top-down processinglightness of figure relative
  to ground is invention of higher brain center
• Familiarity with figure helps see it as a figure
  with contours especially helpful when there is
  no overlap

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Visual agnosia

• Inability to recognize common objects
• Best known subtypeprosopagnosia inability to
  recognize faces (even own face)
• How do we perceive faces? Does normal
  orientation matter? The Thatcher Illusion

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Figure orientation

• Frame of referencemust determine for each figure
  to be able to perceive figure
• Environmental orientationshape perceived in
  relation to gravity, environment, and viewers
  frame of reference (not position on retina) very
  Gestalt!

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Stroop effect

• Usually assumed to be due to automaticity of
  naming during reading so automatic we cant
  completely suppress it
• Demo of Stroop Effect