Vision

Question 1

Vision (operational definition)

Answer 1

process of light energy being transduced (converted; translated) into neural impulses that the brain interprets to produce perpetual experience of sight

Question 2

Physical energy for vision

Answer 2

electromagnetic radiation (light waves)

Question 3

Electromagnetic radiation definition

Answer 3

a collection of one or more photons (light particles) propagating through space as electromagnetic waves

Question 4

Light travels in a combined ____ and ____ waveform

Answer 4

electric and magnetic

*electric (up or down)and magnetic field (left or right) are going in opposite directions but are going together

Question 5

Wavelength

Answer 5

the distance from identical points in consecutive waves eg. crest to crest; trough to trough; halfway through to halfway through

Question 6

Amplitude

what is it, what does it effect

Answer 6

the distance from origin to crest or from origin to trough; the size of the wave itself Large vs small
“how big wave”
-effects the brightness

Question 7

Frequency

what is it, what does it effect

Answer 7

the number of waves that pass a point per unit in time; number of wavelengths in a given period
e.g. number of waves per second; one wavelength per second
“how many waves”
-affects perception of color

Question 8

Larger amplitude, _____

Smaller amplitude, ______

Answer 8

brighter; dimmer

Question 9

High frequency, _______

Low frequency, ______

Answer 9

lots of waves; less waves

blueish colors; reddish colors

Question 10

What is light?

Answer 10

Physical energy in the form of electromagnetic radiation

Question 11

Visible light

Answer 11

only a small portion of the range of electromagnetic radiation; only one in electromagnetic radiation that can be seen with the naked eye

Question 12

what has the highest frequency in electromagnetic radiation

Answer 12

gamma rays

Question 13

what has the lowest frequency in electromagnetic radiation

Answer 13

radio waves

Question 14

Order from highest to lowest frequency for electromagnetic radiation

Answer 14

gamma rays, x-rays, UV, visible light (purple to red; rainbow backwards); Infrared; radio waves

Question 15

Sclera

What is it; function; external or internal

Answer 15

External anatomy of eye

“whites” of the eyes (protective outer layer)

Question 16

Iris

what is it; function; external or internal

Answer 16

External anatomy of eye
the most visible part of the eye
-regulates amount of light that enters the eye
-color is determined by amount of pigment (melanin) in eye (low pigment = lighter iris
higher pigment= darker iris)

Question 17

Pupil

What is it; function; external or internal

Answer 17

External anatomy of eye
black circular opening in the middle of the iris
1) constricts
-allows less light in but sharpens the image falling on the retina
2) dilates
-allows more light in but image is less sharp

Question 18

Cornea

What is it; function; external or internal

Answer 18

External anatomy of eye

• transparent layer forming the front part of the eye
• protects eye and helps refract (bend; not reflect) the light

Question 19

Lens

What is it; function; external or internal

Answer 19

Internal anatomy of eye

• transparent structure behind the iris
• helps refract the light on the retina by changing shape

Question 20

Retina

What is it; function; external or internal

Answer 20

Internal anatomy of eye

• neural tissue lining the internal back surface of the eye
• absorbs light, processes images, and sends visual info to brain (optic nerve)

Question 21

Fovea

What is it; function; external or internal

Answer 21

Internal anatomy of eye

-center of retina; best visual acuity (sharpness of vision)

Question 22

Optic nerve

What is it; function; external or internal

Answer 22

Internal anatomy of eye

• bundle of nerve axons exiting the back of the eye
• transmits visual information from the eye to brain
• causes to have blind spot in our vision

Question 23

why is there a blind spot in optic nerve

Answer 23

there is no photoreceptors

Question 24

Photoreceptors

where are they found, what are they

Answer 24

retina contains specialized sensory receptor cells (PHOTO-receptors) that are sensitive to light

1) rods
- vision in dim light; peripheral vision; FOUND ONLY in peripheral retina
2) cones
- vision in bright light, color vision, fine details; highest concentration in fovea

Question 25

Journey of light

Answer 25

1) rays of light enter the eye through the cornea, where they are partly bent (refracted) 2) move through the pupil which keeps extra light out 3) the rays of light pass through the transparent lens, which changes shape in order to fine-focus the image (accommodation ) 4) light continues through the fluid matter, vitreous humor, within the eyeball and shines an upside down image onto the retina lining 5) light rays fall on retina, which processes and converts incident light to neuron signals using rod and cone cells 6) optic nerve sends to brain

Question 26

What did Young & von Helmholtz discover?

Answer 26

Trichromatic theory of color - discovered the retina contains three types of color receptors (cones) 1. blue (short) 2. green (medium) 3. red (long) - the light stimulation of these colors in varying combinations produces the perception of all visible colors e. g stimulating red and green cones on retina causes us to perceive yellow

Question 27

What did Edwald Hering discover?

Answer 27

Opponent process theory of color -he noted that some color combinations we never see (reddish-green, yellowish blue) -argued that light is processed in an opponent manner -some color pairs are processed the same neural pathway -Photoreceptors can only process one color in each pathway at a time -when one is activated the other is inhibited

Question 28

What are the pairs of opposing color responses

Answer 28

red-green yellow-blue white-black

Question 29

What happens when you stare at one color too long according to the opponent process theory?

Answer 29

causes photoreceptors to become fatigued -when the color is removed, the opposing photoreceptors are free to fire along the same pathway and leads to the perception of after images

Question 30

Trichromatic theory vs opponent process theory | Which one is correct?

Answer 30

both to a certain extent trichromatic theory is correct in a sensory receptor level: some cones are sensitive to red, some to green, some to blue Opponent process theory is correct in neural processing level: as the signal travels from the visual receptors in the occipital lobe, some neurons are activated by one color (red) and deactivated by different color (green) and then they compensate