Chapter 5.1: Visual Coding

Question 1

What happens when you see something ?

Answer 1

Light rays reflect off the object and strike your retina

Question 2

What is the route from retinal receptors to the brain?

Answer 2

Receptors connect to bipolars, which connect to ganglion cells, which send axons to the brain

Question 3

Where does the optic nerve exit from the retina?

Answer 3

At the blind spot

Question 4

Why is vision most acute at the fovea?

Answer 4

Each receptor in the fovea has a direct line to the brain

Question 5

Vision in the periphery of the retina has poor sensitivity to detail but great sensitivity to faint light. Why?

Answer 5

Toward the periphery, the retina has has more convergence of input

Question 6

Why do some people have greater than average sensitivity to brief, faint, or rapidly changing visual stimuli?

Answer 6

They have more axons from the retina to the brain

Question 7

Suppose you perceive something as red. According to the trichromatic theory, what is the explanation?

Answer 7

Light from the object has excited your long-wavelength comes more strongly than your other cones

Question 8

If you stare at a white circle surrounded by a green background, and then look at a white surface, you perceive a green circle surrounded by a red background. What does this observation imply about the opponent-process theory?

Answer 8

Opponent-process color perception depends on the visual cortex, not just the cells in the retina

Question 9

An object that reflects all wavelengths equally ordinarily appears gray, but it may appear yellow, blue, or any other color, depending on what?

Answer 9

Contrast with surrounding objects

Question 10

Color vision deficiency demonstrates which fundamental point about perception?

Answer 10

Color is in the brain and not in the light itself