Module 18 Flashcards
(28 cards)
1
Q
how does light travel
A
- in waves
- through air, empty space, and some liquids and solids
2
Q
amplitude for light
A
- intensity of energy
- determines the brightness of light
3
Q
wavelength in light
A
- length in space of each cycle of the wave
- determines the hue of light
4
Q
frequency
A
- how fast the wave cycles
- measure in Hz (cycles per second)
- inversely related to wavelength
5
Q
two light waves
A
- light is made of two waves at 90° angles from each other
- one is magnetic and the other is electrical
6
Q
the electromagnetic spectrum
A
- visible light is only a small portion of waves that exist
- light is a linear spectrum, but we perceive it as a circle
- combine red and violet frequencies to make magenta
7
Q
lense
A
- focuses light
8
Q
cornea
A
- protective layer
- helps focus light in towards the eye
9
Q
pupil
A
- lets light into the eye
- appears black from outside
10
Q
iris
A
- muscle that makes the pupil dialate
- adjusts for the amount of light coming in
- colored part of the eye
11
Q
optical nerve
A
- transmits visual information to the brain
- creates a blind spot in the eye because no photoreceptors
12
Q
fovea
A
- focal point in the retina
13
Q
retina
A
- layer of photoreceptors in the eye
14
Q
the visual pathway
A
- light that hits the right side of the eye goes to the right side of the brain (comes from left)
- has to do with where in the eye the light hits, not which eye
15
Q
animals that don’t have a blind spot
A
- cephalopods (octopi)
- photoreceptors are in front of the neurons they connect to so the retina doesn’t need a hole for the optic nerve
16
Q
two types of photoreceptors in the retina
A
cones and rods
17
Q
rods
A
- night vision
- motion
- more in periphery
- more sensitive to light and motion
18
Q
cones
A
- allow color perception
- more in fovea
- short, medium, and long wavelength receptive cones
19
Q
three cone types
A
- for short, medium, and long wavelengths
- ratios of firing rates between different cone types tell us the hues of light
- no single cone type on its own gives us color information
20
Q
how color vision deficiency occurs
A
- “colorblindness”
- one cone type is absent
- one cone type isn’t fully functional
- has a tuning curve that is not sufficiently different from another cone type
- most common involves lack of sensation of redness vs. greenness
21
Q
Helmholtz’s trichromatic theory of color perception
A
- any color can be represented (at least approximately) as a combination of red, green, and blue light
- light color is additive
22
Q
opponent process theory of color perception
A
- red vs. green
- yellow vs. blue
- white vs. black
- demonstrated by negative afterimages
- desensitization to a color increases sensitivity to the opposite color
23
Q
opponent processing of motion
A
-waterfall illusion
- desensitization to unchanging direction of motion causes aftereffect of perceived motion in the opposite direction
24
Q
monocular depth perception
A
- only one eye needed
- cues include size and height
- determines closeness to the horizon
- linear perspective
- parallel lines converge in the visual field as they get farther away
- texture gradient
- textures appear more densely packed, less spread out and detailed when they are farther away
- atmospheric/Ariel perspective (haze)
- more distant objects look fainter, blurrier, and bluer
- relative motion
- when youre moving, closer objects move across your visual field faster than distant objects
- interposition/occlusion
25
binocular depth cues
- require two eyes at once
- binocular/retinal disparity
- the farther away an object is, the more similar its position on the two retinas
- convergence
- how much you have to cross your eyes to focus on the object
26
feature detectors
neurons that respond to specific features, such as shape, angle, and movement
27
parallel processing
- different aspects of an object are processed in different brain areas and then integrated into a whole
28
color and light constancy
- the brain adjusts our perception of color to keep colors constant under different lighting conditions
- simplifies perception in the real world
