Psychology 110-04 Lecture 2 Sensation and Perception

  1. Vision
    1. Transducer is triggered by photons, characterized by parallel, distributed processing system
    2. Structure of the Eye
      1. Optics - Lenses - Cornea - Lens
        1. Optics are poor quality
        2. Range of focus - nearsightedness, farsightedness, and image location
        3. Pathology - cataracts, stiffness in aging
      2. Light Modulation - Iris/Pupil
      3. Retina
        1. Gross Anatomy
          1. Nerves among epithelium separate layer
          2. Layers of Cells - Photoreceptors (Rods, Cones), Horizontal, Bipolar, Amacrine
          3. "Backwards" layout, receptors in for metabolism support
          4. Rods, black & white, more sensitive (fewer photons) night vision
          5. Cones, color, red, green, blue photopigments?
          6. Different dark adaptation curves
          7. Heterogeneous distribution, central fovea, peripheral
          8. Neural Processing
    3. Physiological history: tissue, eyecup, and intact eye, in vivo
      1. Lateral Antagonism, Excitation & inhibition
      2. Sombrero model, sharpens focus
      3. Color
      4. Motion, X- (parvocellular), Y- (magnocellular) cells
    4. Optic Pathway
      1. Optic Nerve
      2. Retinotopic Mapping
      3. Partial Decussating
      4. Synapse in the Lateral Geniulate nucleus
      5. Pathologies
    5. Secondary Radiations
      1. Superior Colliculus, motion, other sensory inputs
      2. Principal Optic Pathway
    6. Visual Cortex, posterior brain, retinotopic mapping continues
      1. Orientation of edges, Motion direction
      2. Magno - motion, depth, Parvo - form, color, texture
      3. Hubel & Weisel decipher retinal processing
    7. Importance of illusions
      1. additional constraints for hypothesized mechanism
      2. must satisfy veridical and illusory phenomenon to be complete
  2. Color Processing
    1. Nature of color
      1. Color is not simply a matter of wavelength
      2. Hue, brightness and purity, mixing does not purely wavelength
      3. Controversy of how color is perceived
      4. Trichromatic theory Newton, Young, Helmholtz 3-color rgb theory
    2. Matches physics, also colorblindness dichromats, monochromats
      1. Color Opponent theory Herring
    3. Red-Green, Blue-yellow, black-white, explains color afterimages
    4. Both Theories Are Correct!!!
      1. Receptors proven to be rgb, Wald, critical experiment
      2. But processing discovered to be red-green, blue-yellow, black-white
  4. Form Processing
      1. Bottom-Up processing
      2. Feature extraction
    1. Step further is the grandmother detector cell, disputed
      1. From points, to edges, to lines, to primal sketch
      2. Top-Down processing
      3. Hypothesis formation & testing
  5. Gestalt Phenomenon
    1. Phi effect, Figure ground, Proximity, Similarity, Continuity, Simplicity, Closure
    2. Ambiguous figures, girl/old women
    3. Reversible figures, Necker cube
    4. Depth Perception
  6. Binocular cues, disparity, convergence
    1. Monocular cues, motion parallax, linear perspective, texture gradients, interposition,
    2. relative size, height in plane, light and shadow
    3. Cultural & experiential effects
    4. Plurality of awareness
  7. Proffitt's study on inclines
    1. Ames room, lunar illusion and size consistency
    2. Impossible figures, Escher

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