week 7/8 - color and light constancy

Question 1

color constancy

Answer 1

perception of colors as relatively constant in spite of changing light sources

Question 2

Uchikawa experiment (green paper)

Answer 2

Observers shown sheets of colored paper in 3 conditions:
- Baseline: green paper and observer in white light
- Observer not adapted: paper illuminated by red light; observer by white
- Observer adapted: paper and observer in red light

Question 3

What was the result of the Uchikawa experiment?

Answer 3

Partial color constancy was shown in the condition where the observer was adapted

Question 4

What is the connection between memory and color?

Answer 4

Past knowledge of an object’s color will always contribute to our perception of it, even if it is actually not that color

Question 5

Hansen experiment (memory and color)

Answer 5

• Observers saw photos of fruits with gray background
• Adjusted color of fruit and a spot of light
• When spot was adjusted to physically match the background, spot appeared
• But when done with fruits, they were still perceived as being slightly colored

Question 6

Oculomotor cues

Answer 6

• based on sensing the position of the eyes and muscle tension (moving your eyes)
• convergence and accomodation

Question 7

convergence

Answer 7

inward movement of the eyes when we focus on nearby objects

Question 8

accommodation

Answer 8

change in the shape of the lens when we focus on objects at different distances

Question 9

monocular cues

Answer 9

• come from one eye
• pictorial and motion-produced cues

Question 10

occlusion

Answer 10

• focuses on information in the retinal image that is correlated with depth in scene
• when one object partially covers another; reveals that t he object is closer/farther from you

Question 11

relative height

Answer 11

objects below the horizon that are higher in the field of vision are more distant

Question 12

relative size

Answer 12

when objects are equal size, the closer one will take up more of your visual field

Question 13

perspective convergence

Answer 13

parallel lines appear to come together in the distance

Question 14

familiar size

Answer 14

distance information based on knowledge of object size

Question 15

atmospheric perspective

Answer 15

distance objects are fuzzy and have blue tint

Question 16

texture gradient

Answer 16

equally spaced elements are more closely packed as distance increases

Question 17

shadows

Answer 17

• indicate where objects are located
• enhance 3-D of objects

Question 18

pictorial cues

Answer 18

• occlusion
• relative height
• relative size
• perspective convergence
• familiar size
• atmospheric perspective
• texture gradient
• shadows

Question 19

motion-produced cues

Answer 19

• motion parallax
• deletion and accretion

Question 20

motion parallax

Answer 20

close objects in direction of movement glide rapidly past by objects in the distance appear to move slowly

Question 21

deletion and accretion

Answer 21

• objects are covered or uncovered as we move
  relative to them
• Covering an object is deletion
• Uncovering an object is accretion

Question 22

binocular disparity

Answer 22

differences in images from two eyes

Question 23

streopsis

Answer 23

• the impression of depth that results from information provided by binocular disparity
• ex.) 3-D movies

Question 24

strabismus

Answer 24

• eyes do not point in same direction
• “lazy eye”

Question 25

binocular depth cells/disparity selective cells

Answer 25

respond best to a specific degree of absolute disparity between images on both retinas

Question 26

depth perception neurons

Answer 26

receive that information as to the difference between the images being projected onto your eyes

Question 27

Black and Hirsch experiment (cats)

Answer 27

• Used cats and reared them by alternating vision between two eyes
• Results:
• Had few binocular neuron
• Unable to use binocular disparity to perceive depth

Question 28

Holway and Boring experiment (hallway)

Answer 28

• placed subjects at the intersection of two hallways and provided luminous circles on each one (different distances) one was comparison and one was a test one
• Observer was told to adjust the diameter of test circle to match the comparison

Question 29

What occurred in Holway and Boring when they provided observers with depth cues?

Answer 29

• Judgments based on physical size
• Accurate estimations

Question 30

What occurred in Holway and Boring when there was no depth information provided?

Answer 30

• judgments of size based on size of retinal images
• Inaccurate estimations
• When all monocular clues are taken away, we rely solely on the amount of room each object is taking up in our retina

Question 31

size estimation

Answer 31

Based on actual sizes of objects when there is good depth perception

Question 32

size constancy

Answer 32

• perception of an object’s size remains relatively constant
• Effect remains even if the size of the retinal image changes

Question 33

What are the prices of constancy?

Answer 33

• Inappropriate interpretations of physical reality

Question 34

What are examples of inaccurate constancy interpretations?

Answer 34

• Converging lines are corners → Muller-Lyer illusion
• Linear perspective cues → Ponzo illusion
• Rooms are rectangular → Ames room