3.2 How we see and how we hear

Question 1

wavelength

Answer 1

the distance in one cycle of a wave, from one crest to the next.

Question 2

amplitude

Answer 2

The amount of energy in a wave, its intensity, which is the height of the wave at its crest.

Question 3

frequency

Answer 3

the number of times a wave cycles in 1 second.

Question 4

transduction

Answer 4

The conversion of physical energy into neural signals that the brain can understand.

Question 4

accommodation

Answer 4

The focusing of light waves from objects of different distances directly on the retina.

Question 5

nearsightedness

Answer 5

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.

Question 6

farsightedness

Answer 6

A visual problem in which the light waves from nearby objects come into focus behind the retina, blurring the images of these objects.

Question 7

blindsight

Answer 7

A condition in which a blind person has some spared visual capacities in the absence of any visual awareness.

Question 7

retina

Answer 7

The light-sensitive layer of the eye that is composed of three layers of cells— ganglion, bipolar, and receptor (rods and cones).

Question 8

rods

Answer 8

Receptor cells in the retina that are principally responsible for dim light and achromatic vision.

Question 9

cones

Answer 9

Receptor cells in the retina that are principally responsible for bright light and color vision.

Question 10

fovea

Answer 10

A tiny pit in the center of the retina filled with cones.

Question 11

dark adaptation

Answer 11

the process by which the rods and cones through internal chemical changes become more and more sensitive to light in dim light conditions.

Question 12

trichromatic theory

Answer 12

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.

Question 13

additive mixtures

Answer 13

Direct mixtures of different wavelengths of light in which all of the wavelengths reach the retina and are added together.

Question 14

subtractive mixtures

Answer 14

Mixtures of wavelengths of light in which some wavelengths are absorbed (subtracted) and so do not get reflected from the mixtures to the retina.

Question 15

complementary colors

Answer 15

Wavelengths of light that when added together produce white.

Question 16

opponent-process theory

Answer 16

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.

Question 17

cochlea

Answer 17

A snail-shaped structure in the inner ear that contains the receptor cells for hearing.

Question 18

hair cells

Answer 18

The receptor cells for hearing. They line the basilar membrane inside the cochlea.

Question 19

conduction deafness

Answer 19

Hearing loss created by damage to one of the structures in the ear responsible for mechanically conducting the auditory information to the inner ear.

Question 20

nerve deafness

Answer 20

Hearing loss created by damage to the hair cells or the auditory nerve fibers in the inner ear.

Question 21

place theory

Answer 21

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.

Question 22

frequency theory

Answer 22

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.

Question 23

volley principle

Answer 23

Cells taking turns firing will increase the maximum firing rate for a group of cells.