3.2 How we see and how we hear Flashcards
wavelength
the distance in one cycle of a wave, from one crest to the next.
amplitude
The amount of energy in a wave, its intensity, which is the height of the wave at its crest.
frequency
the number of times a wave cycles in 1 second.
transduction
The conversion of physical energy into neural signals that the brain can understand.
accommodation
The focusing of light waves from objects of different distances directly on the retina.
nearsightedness
A visual problem in which the light waves from distant objects come into focus in front of the retina, blurring the images of these objects.
farsightedness
A visual problem in which the light waves from nearby objects come into focus behind the retina, blurring the images of these objects.
blindsight
A condition in which a blind person has some spared visual capacities in the absence of any visual awareness.
retina
The light-sensitive layer of the eye that is composed of three layers of cells— ganglion, bipolar, and receptor (rods and cones).
rods
Receptor cells in the retina that are principally responsible for dim light and achromatic vision.
cones
Receptor cells in the retina that are principally responsible for bright light and color vision.
fovea
A tiny pit in the center of the retina filled with cones.
dark adaptation
the process by which the rods and cones through internal chemical changes become more and more sensitive to light in dim light conditions.
trichromatic theory
A theory of color vision that assumes that there are three types of cones, each only activated by wavelength ranges of light corresponding roughly to blue, green, and red. It further assumes that all of the various colors that we can see are mixtures of various levels of activation of the three types of cones. If all three are equally activated, we see white.
additive mixtures
Direct mixtures of different wavelengths of light in which all of the wavelengths reach the retina and are added together.
subtractive mixtures
Mixtures of wavelengths of light in which some wavelengths are absorbed (subtracted) and so do not get reflected from the mixtures to the retina.
complementary colors
Wavelengths of light that when added together produce white.
opponent-process theory
A theory of color vision that assumes that there are three opponent- process cell systems (red-green, blue-yellow, and black-white) that process color information after it has been processed by the cones. The colors in each system oppose one another in that if one color is stimulated, the other is inhibited.
cochlea
A snail-shaped structure in the inner ear that contains the receptor cells for hearing.
hair cells
The receptor cells for hearing. They line the basilar membrane inside the cochlea.
conduction deafness
Hearing loss created by damage to one of the structures in the ear responsible for mechanically conducting the auditory information to the inner ear.
nerve deafness
Hearing loss created by damage to the hair cells or the auditory nerve fibers in the inner ear.
place theory
A theory of pitch perception that assumes that there is a specific location along the basilar membrane that will maximally respond to a particular frequency, thereby indicating the pitch to the brain. As this location goes down the basilar membrane from the oval window, the pitch goes down from 20,000 Hz to 20 Hz.
frequency theory
A theory of pitch perception that assumes that the frequency of the sound wave is mimicked by the firing rate of the entire basilar membrane.