Flashcards in 4.2 Seeing Deck (32):
1
electromagnetic energy
pulses of energy waves that can carry information from place to place
2
wavelength
the distance between one wave peak and the next wave peak
3
visible spectrum
our eyes detect only the range from about 400 to 700 billionths of a meter
4
cornea
a clear covering that protects the eye and begins to focus the incoming light
5
pupil
a small opening in the center of the eye
6
iris
the colored part of the eye that controls the size of the pupil by constricting or dilating in response to light intensity
7
lens
a structure that focuses the incoming light on the retina
8
retina
the layer of tissue at the back of the eye that contains photoreceptor cells
9
visual accomodation
the process of changing the curvature of the lens to keep the light entering the eye focused on the retina
10
nearsighted
if focus is in front of retina
11
farsighted
the focus is behind the retina
12
optic nerve
a collection of millions of ganglion neurons that sends vast amounts of visual information, via the thalamus, to the brain
13
Rods
visual neurons that specialize in detecting black, white, and gray colors
14
Cones
visual neurons that are specialized in detecting fine detail and colors
15
fovea
which is the central point of the retina
16
blindspot
there are no photoreceptor cells at the place where the optic nerve leaves the retina
17
feature detector neurons
specialized neurons, located in the visual cortex, that respond to the strength, angles, shapes, edges, and movements of a visual stimulus
18
hue
- the shade of a color
- conveyed by the wavelength of the light that enters the eye (we see shorter wavelengths as more blue and longer wavelengths as more red)
19
intensity
height of the wave (bigger or more intense waves are perceived as brighter)
20
Hermann von Helmholtz (1821–1894)
he theorized that color is perceived because the cones in the retina come in three types
21
Young-Helmholtz trichromatic color theory
what color we see depends on the mix of the signals from the three types of cones
22
color blindness
the inability to detect either green and/or red colors
23
opponent-process color theory
proposes that we analyze sensory information not in terms of three colors but rather in three sets of “ opponent colors‖: red-green, yellow-blue, and whiteblack
24
gestalt
a meaningfully organized whole
25
Depth perception
the ability to perceive three-dimensional space and to accurately judge distance
26
visual cliff
a mechanism that gives the perception of a dangerous drop-off, in which infants can be safely tested for their perception of depth
27
depth cues
messages from our bodies and the external environment that supply us with information about space and distance
28
Binocular depth cues
depth cues that are created by retinal image disparity—that is, the space between our eyes, and thus which require the coordination of both eyes
29
convergence
the inward turning of our eyes that is required to focus on objects that are less than about 50 feet away from us
30
Monocular depth cues
depth cues that help us perceive depth using only one eye
31
beta effect refers
the perception of motion that occurs when different images are presented next to each other in succession
32