4.2- the visual system

Question 1

binocular depth cues

Answer 1

cues that are based on the differing perspective of both eyes (using both eyes)

Question 2

cones

Answer 2

photo receptors that are sensitive to the different wave lengths of light that we perceive as colour (seeing colour)

Question 3

convergence

Answer 3

occurs when the eye muscles contract so that both eyes focus on one single object

Question 4

cornea

Answer 4

clear layer that covers the front portion of the eye and also contributes to the eyes ability to focus

Question 5

dark adaptation

Answer 5

the processes by which the rods and cones become increasingly sensitive to light under low levels of illumination (seeing things more clear the longer your in the dark)

Question 6

dorsal stream

Answer 6

extends from the visual cortex to the parietal lobe (essential to function normal vision)

Question 7

feature detection cells

Answer 7

these cells respond selectively to simple and specific aspects of a stimulus (angles and edges)

Question 8

fovea

Answer 8

the central region of the retina (cones are clustered around them)

Question 9

lens

Answer 9

a clear structure that focuses light onto the back of the eye (behind the pupil)

Question 10

monocular cues

Answer 10

depth cues that we can perceive with only one eye (only using one eye)

Question 11

opponent- process theory

Answer 11

a colour perception- which states that we perceive colour in terms of opposing pairs (red-green, yellow-blue, black-white)

Question 12

optic chiasm

Answer 12

the point at which the optic nerves cross at the midline of the brain

Question 13

optic nerve

Answer 13

dense bundle of fibres that connect to the brain

Question 14

perceptual constancy

Answer 14

the ability to perceive objects as having constant shape, size, and dolour- despite changes in perspective (your cat is still your cat- regardless of noon or night)

Question 15

iris

Answer 15

a round muscle that adjusts the size of the pupil, it also gives the eyes that character colour

Question 16

pupil

Answer 16

regulates the amount of light that enters by changing its size. (dilates ‘expands’ to let more in) (shrinks to allow less light in)

Question 17

retina

Answer 17

lines the inner surface of the back of the eye, consists of specialized receptors that absorb light and sound signals related to the properties of light to the brain

Question 18

Retinal disparity

Answer 18

the difference in relative position of an object as seen by both eyes, which provides info to the basic depth, (looking at a pen, opening and closing both eyes “ pen moves”)

Question 19

rods

Answer 19

photoreceptors that occupy perpherial regions of the retina; they are highly sensitive under low light levels (seeing black and white)

Question 20

selera

Answer 20

the white, outer surface of the eye

Question 21

trichromatic theory

Answer 21

young Helmholtz theory: maintains that colour vision is determined by three different cone types that are sensitive to short, medium, and long wave lengths of light.

Question 22

ventral stream

Answer 22

extends from the visual cortex to the lower part of the temporal lobe (opposite to dorsal)