Seeing

Question 1

cornea

Answer 1

clear covering protects eye and begins focusing incoming light

Question 2

pupil

Answer 2

small opening

Question 3

iris

Answer 3

surrounds pupil (coloured part) 
- complete adaptation to dark may take 20 mins

Question 4

lens

Answer 4

beyond pupil

- focuses light on the retina

Question 5

retina

Answer 5

layer of tissue at back of eye that contains photoreceptors

Question 6

visual accomodation

Answer 6

process of changing curvature of the lens to keep the light entering eye focused on retina

• rays from top of image strike bottom of retina and vice versa
• rays from left side of image strike right side of retina and vice versa

Question 7

nearsighted

Answer 7

when focus is in front of retina

Question 8

farsighted

Answer 8

when focus is behind retina

Question 9

optic nerve

Answer 9

collection of millions of ganglion neurons

• sends info vio thalamus to brain
• retina & optic nerve are active processors of visual info

Question 10

fovea

Answer 10

central part of retina

Question 11

blind spot

Answer 11

hole in vision because there are no photoreceptor cells at the place where the optic nerves leave the retina
one eye makes up for blind spot of the other

Question 12

feature detector neurons

Answer 12

specialized neurons located in visual cortex

• respond to strength, angles, shapes, edges & movements of a visual stimulus
• work in parallel
  ex: parallel line, horizontal line, and red colour detectors work together to detect red square

Question 13

perceiving colour

Answer 13

human visual system can detect & discriminate among 7 million colour variations
* variations created by combinations of red, green, and blue

Question 14

hue

Answer 14

shade of colour
-conversed by wavelength of light that enters eye
short wL = more blue
longer wL = more Red
*detect brightness from intensity or height of wavelength

Question 15

colour blindness

Answer 15

inability to detect green and/or red colours

• 1/50 lack green or red - sensitive cones
• but can see yellow which doesn’t explain the theory

Question 16

opponent-process colour theory

Answer 16

proposes we analyze sensory information not in terms of 3 colours, but rather in 3 sets of opponent colours
= red-green, yellow-blue, white-black
* some neurons excited by a colour but inhibited by another

Question 17

gestalt

Answer 17

meaningful organized whole

- “whole is more than the sum of its parts”

Question 18

depth perception

Answer 18

ability to perceive 3D space and judge distance

Question 19

visual cliff

Answer 19

mechanism that gives perception of a dangerous drop-off, In which infants can be safely tested for their perception of depth

Question 20

depth cues

Answer 20

messages from bodies and external environment that supply us with info about space and distance

Question 21

binocular depth cues

Answer 21

cues created by retinal image disparity (space btw eyes)- require coordination in both eyes
- visual cortex automatically merges 2 images into one

Question 22

convergence

Answer 22

inward turning of our eyes that is required to focus on objects less than 50 feet away
- visual cortex uses to judge objects distance

Question 23

accomodation

Answer 23

helps determine depth

- only effective at short viewing distances

Question 24

monocular depth cues

Answer 24

depth cues that help us to perceive depth using only one eye

Question 25

beta effect

Answer 25

perception of motion that occurs when different images are presented next to each other in succession

Question 26

phi phenomenon

Answer 26

perceive a sensation of motion caused by the appearance and disappearance of objects that are near each other

• looks like a moving zone or cloud of background surrounding flashing objects
• beta & phi = importance of Gestalt