Module 18 Flashcards
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
Q
binocular depth cues
A
- 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
Q
feature detectors
A
neurons that respond to specific features, such as shape, angle, and movement
27
Q
parallel processing
A
- different aspects of an object are processed in different brain areas and then integrated into a whole
28
Q
color and light constancy
A
- the brain adjusts our perception of color to keep colors constant under different lighting conditions
- simplifies perception in the real world
