Chapter 6: Notes

Question 1

How are auditory signals sensed?

Answer 1

Periodic compressions of air, water, or other media.

Question 2

Amplitude

Answer 2

The intensity of a soundwave, measured in decibels (not the same as loudness)

Question 3

Loudness

Answer 3

The psychological experience of amplitude (not the same as amplitude)

Question 4

Frequency

Answer 4

The number of compressions per second, measured in hertz

Question 5

Pitch

Answer 5

Psychological experience of frequency

Question 6

Timbre

Answer 6

Tone quality or tone complexity

Question 7

Prosody

Answer 7

Conveying emotional information by tone of voice

Question 8

What does the outer ear do?

Answer 8

It helps us locate the source of a sound. It includes the pinna.

Question 9

Where does sound go in the middle ear?

Answer 9

Through the auditory canal and then to the tympanic membrane (ear drum) in the middle ear which transmits vibrations to three tiny bones in the oval window.

Question 10

What are the three bones in the oval window?

Answer 10

Malleus (Hammer)
Incus (Anvil)
Stapes (Stirrup)

Question 11

What is the net effect system?

Answer 11

Sound waves are converted into waves of greater pressure on small oval window.

Question 12

Cochlea

Answer 12

Snail-shaped structure in the inner ear containing three long fluid-filled tunnels

Question 13

What happens when the fluid in the cochlea is displaced by noise?

Answer 13

When displaced by vibrations in the fluid of the cochlea, they excite hair cells of the auditory nerve and open the ion channel in its membrane

Question 14

Place theory

Answer 14

Basilar membrane resembles the strings of a piano, each area along the membrane tuned to a specific frequency.

Question 15

What is the problem with Place theory?

Answer 15

The basilar membrane is not constructed to do that; it varies in stiffness unlike a piano’s strings.

Question 16

Frequency theory

Answer 16

Basilar membrane vibrates in synchrony with a sound, causing auditory nerve axons to produce action potentials at the same frequency in the auditory nerve

Question 17

What is the problem with Frequency theory?

Answer 17

Single receptors are limited in their firing frequency

Question 18

Current theory

Answer 18

Combination of Place and Frequency theories; for low-frequency sounds (<100 Hz), basilar membrane vibrates with sound waves like frequency theory, and at higher frequencies, neuron’s action potentials are phase-locked to peaks of the sound waves.

Question 19

Volley principle

Answer 19

Auditory nerve as a whole produces volleys of impulses for sounds of up to 4,000 per second, even though no individual axon approaches that frequency

Question 20

Where does most human hearing take place?

Answer 20

Below 4000 Hz

Question 21

Amusia

Answer 21

Tone deafness; inability to identify tone changes. Affects roughly 4% of people.
*A genetic disorder where the auditory cortex, though otherwise appearing normal, has fewer connections to the frontal cortex.

Question 22

Absolute pitch/pitch-perfect

Answer 22

Opposite of tone deaf; ability to identify any note.
*Likely genetic, music training early on can help. Found mostly in native tonal language speakers, such as Vietnamese and Chinese.

Question 23

Superior temporal cortex

Answer 23

Includes areas important for detecting motion of sounds

Question 24

For what is Area A1 (primary auditory cortex) important?

Answer 24

Auditory imagery

Question 25

What does the auditory system require for development?

Answer 25

Experience

Question 26

What does Area A1 do?

Answer 26

Processes auditory information; it’s important for thinking about concepts related to hearing.

Question 27

What do the individual cells in Area A1 do?

Answer 27

Each cell has a preferred tone and will give a prolonged response to the tone (likely a complex one) and little to no response to sounds outside of its preferred one.

Question 28

How does one determine the distance and direction of a sound?

Answer 28

By comparing the response of both ears to the sound
*Time of arrival to one ear versus another
*Difference in intensity between the two ears
*Phase difference between the ears

Question 29

What are the two categories of hearing loss?

Answer 29

Conductive deafness (middle-ear hearing loss)
Nerve deafness (inner-ear hearing loss)

Question 30

Conductive deafness (middle-ear hearing loss)

Answer 30

Results from disease, infection, or tumorous bone growth, which prevent the middle-ear from transmitting sound properly to the cochlea

Question 31

Nerve deafness (inner-ear hearing loss)

Answer 31

Results from damage to the cochlea, hair cells, or auditory nerve.

Question 32

Tinnitus

Answer 32

Frequent or constant ringing in the ears sometimes occurring after damage to the cochlea
*Similar to a phantom limb

Question 33

Why do older people have problems with understanding speech despite wearing hearing aids?

Answer 33

Brain areas responsible for language comprehension have become less active

Question 34

What does the loss of inhibitory neurotransmitters in the brain lead to?

Answer 34

*Problems shutting out irrelevant noise
*Auditory cortex had gradual, spread-out responses to each sound instead of quick and sharp ones; overlap in responses