Module 5

Question 1

sensation vs. perception

Answer 1

• sensation: processing of external world through receptors in sense organs
  
  • pattern of light hitting retina
• perception: organizing and interpreting sensory info
  
  • experience of seeing

Question 2

empiricist vs. nativists on infant perception

Answer 2

• empiricist: infants perceive very poorly; experience vital for sense development
• nativists: perceptual development progresses through maturation, not experience

Question 3

acuity development

Answer 3

• newborns don’t see well
  
  • 20/ 200 at birth
  • 20/100 by 8 months; 20/50 by 10 months
  • recall chick contact lenses study
• 20/20 by age 6

Question 4

vision development

Answer 4

• many abilities poor at birth, but near-adult levels by 8 months
  
  • control eye movements
    
    • can’t do smooth pursuit until 4 months
      
      • improvements due to maturation, not experience
    • scanning abilities limited
      
      • focus on open corner of object, outline-wherever there is high contrast

Question 5

color vision

Answer 5

• not present at birth
• young infants only sensitive to bright colors and large patches of color
• rapid development of 3 types of foveal cones- short/blue, medium/green, long/red
  
  • humans are trichromatic= see color by comparing how diff cones respond to light

Question 6

categorical perception

Answer 6

• perceiving clusters of likeness that don’t necessarily transfer to physical likeness
  
  • cultures without color words, or with fewer color cords, perceive same categorical boundaries

Question 7

nature and nurture in color perception

Answer 7

• clearly maturation of cones important
• however experience also matters:
  
  • humans born above arctic circle, especially int eh fall, less sensitive to color
  • monkeys raised with only monochromatic light (not full wavelengths) don’t categorize color the way humans/typical monkeys do (had more than 2 clusters)

Question 8

3 types of depth cues

Answer 8

• binocular cues: involves having 2 eyes (1 month)
• monocular/ pictorial cues: exist in 2D pictures (4 months)
• dynamic cues: seeing objects moving (7 months)

Question 9

binocular cues: 2 eyes

Answer 9

• binocular disparity: retinal image of each eye slightly different
• our visual system fuses the two. images so we don’t see double
  
  • closer objects have more disparity
  • using binocular cues to see depth called stereopsis
• convergence: eye muscles more tense when looking at closer objects

Question 10

berkeley’s theory of development of depth perception

Answer 10

• if you have 2 eyes, you feel convergence
• babies reach for objects
• babies learn to associate binocular cues with depth by building association btw amount of eye strain and length of reach over time
• empiricist view

Question 11

sensitive period for stereopsis?

Answer 11

• often true in first few months; fixes itself by 2 months
• 4% kids have it beyond this period; eventually brain suppresses input from less clear eye
• stereopsis worse if strabismus not surgically fixed by age 2

Question 12

strabismus/ amblyopia

Answer 12

two eyes misaligned

Question 13

pictorial cues: in 2D images

Answer 13

• interposition: overlapping shapes in front
• convergence in distance: parallel lines meet at the horizon
• texture gradients: repeating patterns get smaller when farther away

Question 14

the ames window

Answer 14

testing pictorial depth; with one eye covered, 7 month olds reach to long side- suggests pictorial cue develops around 6 mos

Question 15

motion parallax

Answer 15

• relative movement of near and far objects to motion of eye
  
  • when you move your head left, near object move faster/ more right than far objects

Question 16

optical expansion

Answer 16

• retinal image of objects expand in size as they get nearer to you; the nearer of two objects expands more quickly
  
  • 1 month olds blink at expanding images (presumably because they see them as coming toward them)