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Hearing
MODULE OVERVIEW
Introduction and The Stimulus Input: Sound
Waves (214-215)
This module describes the sense of hearing, including
the structure of the ear and the process through
which the stimulus energy is transmitted through the
ear and interpreted in the brain. It concludes with a
discussion of types of hearing loss and the views of
Deaf culture advocates regarding cochlear implants.
In this module there are many terms to learn.
Many of the terms are related to the structures of the
ear. Doing the module review several times, labeling
the diagram of the ear, and rehearsing the material
frequently will help you to memorize the parts of the
various structures and their functions.
NOTE: Answer guidelines for all Module 14 questions begin on page 173.
David Myers at times uses idioms that are unfamiliar to some readers. If you do not know
the meaning of the following expressions in
the context in which they appear in the text,
refer to page 175 for an explanation: sensitive to
faint sounds, an obvious boon; A piccolo produces
much shorter, faster sound waves than does a tuba.
-
Objective 14-1: Define audition, and describe the pressure waves we experience as sound.
1. The stimulus for hearing, or
~ __
~
~_
, is sound waves, created by
the compression and expansion of
MODULE REVIEW
2. The amplitude of a sound wave determines the
First, skim each section, noting headings and boldface
items. After you have read the section, review each
objective by answering the fill-in and essay-type
questions that follow it. As you proceed, evaluate
your performance by consulting the answers on page
173. Do not continue with the next section until you
understand each answer. If you need to, review or
reread the section in the textbook before continuing.
sound's ~
_
3. The pitch of a sound is derived from the
~
of its wave.
4. Sound energy is measured in units called
________
. The absolute threshold for
hearing is arbitrarily defined as
________
such units.
The Ear (pp. 216-219)
If you do not know the meaning of any of the
following words, phrases, or expressions in the
context in which they appear in the text, refer
to page 175 for an explanation: earlids; If a car to
the right honks; cock your head.
169
170
Module 14 Hearing
Objective 14-2:Describe the three regions of the ear,
and outline the series of events that triggers the electrical impulses sent to the brain.
1. The ear is divided into three main parts: the
~
________
________
ear, the
ear, and the
ear.
7. A second theory proposes that neural impulses,
2. The outer ear channels sound waves toward the
________
vibrates.
cochlea's basilar membrane; this is the
________
theory. This theory has difficulty accounting for how we hear
________
-pitched sounds, which do
not have such localized effects.
, a tight membrane that then
3. The middle ear transmits the vibrations through a
piston made of three small bones: the
,and
sent to the brain at the same frequency as the
sound wave, allow the perception of different
pitches. This is the
theory.
This theory fails to account for the perception of
________
-pitched sounds, because
individual neurons cannot fire faster than
________
times per second.
8. For the higher pitches, cells may alternate their
4. In the inner ear, a coiled tube called the
~
contains the receptor cells
for hearing. The incoming vibrations cause the
________
~
to
vibrate the fluid that fills the tube, which causes
ripples in the ~
_
________
, which is lined with
________________
. This
movement triggers impulses in adjacent nerve
fibers that converge to form the auditory nerve,
which carries the neural messages (via the
________
)to the
_
lobe's auditory cortex. The brain interprets loudness from the
of hair cells a
sound activates.
5. (Close-Up) On tasks requiring alert performance,
people in noisy environments work
________
(more/less) efficiently.
People who live in noisy environments suffer elevated rates of
-related disorders such as
_
,and
firing to match the sound's frequency, according
to the
principle.
Objective 14-4:Describe how we pinpoint sounds.
9. We locate a sound by sensing differences in the
_
and
_
with which it reaches our ears.
10. A sound that comes from directly ahead will be
________
(easier/harder) to locate
than a sound that comes from off to one side.
11. As with visual information, the brain uses
_
~
as
specialized neural teams work on different auditory tasks simultaneously.
Hearing loss and Deaf Culture (pp. 219-222)
If you do not know the meaning of the following expression in the context in which it
appears in the text, refer to pages 175-176 for
an explanation: the culprits are ... ear-splitting
noise or music.
-----
Noise is especially stressful when it is
~
or
Objective 14-5:Contrast the two types of hearing
loss, and describe some of their causes.
_
Objective 14-3:Contrast place and frequency theories, and explain how they help us to understand
pitch perception.
6. One theory of pitch perception proposes that different pitches activate different places on the
1. Problems in the mechanical conduction of sound
waves through the outer or middle ear may cause
2. Damage to the cochlea's hair cell receptors or
their associated auditory nerves can cause
________
hearing loss. It may be
caused by disease, but more often it results from
the biological changes linked with
________
and prolonged exposure to
ear-splitting noise or music.
3. Scientists have discovered ways to
~
hair cell regeneration.
Objective 14-6:Describe how cochlear implants function, and explain why Deaf culture advocates object
to these devices.
4. An electronic device that restores hearing among
nerve-deafened people is a
_
5. Advocates of
_
~
object to the use of these
implants on
before they
have learned to
. The basis
for their argument is that deafness is not a
6. Sign language
(is/is not) a
completelanguage,~
_
(with/without) its own grammar, syntax, and
semantics. Those who learn only sign language
during childhood
(have/ do
not have) difficulty later learning to read and
write.
7. People who lose one channel of sensation (such
as hearing)
(seem to/do not
seem to) compensate with a slight enhancement
in their other sensory abilities. Thus, people who
become deaf, or who lose another channel of sensation, often experience
_
________
in another ability.
8. (Close-Up) Deaf children raised in a household
where sign language is used express higher
~
and feel more ~
_
PROGRESS TEST
Multiple-Choice Questions
Circle your answers to the following questions and
check them with the answers beginning on page 173.
If your answer is incorrect, read the explanation for
why it is correct and then consult the appropriate
pages of the text.
1.
Progress Test
171
_
is to
Frequency is to pitch as
a.
b.
c.
d.
wavelength; loudness
amplitude; loudness
wavelength; intensity
amplitude; intensity
2. The place theory of pitch perception cannot account for how we hear:
a. low-pitched sounds.
b. middle-pitched sounds.
c. high-pitched sounds.
d. chords (three or more pitches
simultaneously).
3. The hearing losses that occur with age are especially pronounced for:
a. low-pitched sounds.
b. middle-pitched sounds.
c. high-pitched sounds.
d. chords.
4. Nerve deafness is caused by:
a. wax buildup in the outer ear.
b. damage to the eardrum.
c. blockage in the middle ear because of
infection.
d. damage to the cochlea.
5. The frequency theory of hearing is better than
place theory at explaining our sensation of:
a. the lowest pitches.
b. pitches of intermediate range.
c. the highest pitches.
d. all of the above.
6. Which of the following is the most accurate
explanation of how we discriminate pitch?
a. For all audible frequencies, pitch is coded
according to the place of maximum vibration
on the cochlea's basilar membrane.
b. For all audible frequencies, the rate of neural
activity in the auditory nerve matches the frequency of the sound wave.
c. For very high frequencies, pitch is coded according to place of vibration on the basilar
membrane; for lower pitches, the rate of neural activity in the auditory nerve matches the
sound's frequency.
d. For very high frequencies, the rate of neural
activity in the auditory nerve matches the frequency of the sound wave; for lower frequencies, pitch is coded according to the place of
vibration on the basilar membrane.
172
Module 14 Hearing
7. Which of the following correctly lists the order of
structures through which sound travels after entering the ear?
a. auditory canal, eardrum, middle ear, cochlea
b. eardrum, auditory canal, middle ear, cochlea
c. eardrum, middle ear, cochlea, auditory canal
d. cochlea, eardrum, middle ear, auditory canal
8. Dr. Frankenstein has forgotten to give his monster an important part; as a result, the monster
cannot transduce sound. Dr. Frankenstein omitted the:
a. eardrum.
c. semicircular canals.
b. middle ear.
d. basilar membrane.
Summing Up
Use the diagram to identify the parts of the ear, then
list them in the order in which they contribute to
hearing. Also, briefly explain the role of each structure.
1.
2.
3.
4.
5.
6.
7.
8.
9. Seventy-five-year-old Claude has difficulty hearing high-pitched sounds. Most likely his hearing
problem involves:
a. his eardrum.
b. his auditory canal.
c. the bones of his middle ear.
d. the hair cells of his inner ear.
Answers
173
Matching Items
Match each of the structures, theories, or conditions
with its function or description.
Structures or Conditions
1.
2.
3.
4.
5.
6.
place theory
frequency theory
conduction hearing loss
sensorineural hearing loss
pitch
frequency
Key Terms
Using your own words, on a piece of paper write a
brief definition or explanation of each of the following terms.
1. audition
2. pitch and frequency
3. middle ear
4. cochlea
5. inner ear
6. place theory
7. frequency theory
8. conduction hearing loss
9. sensorineural hearing loss
Functions or Descriptions
a. the number of complete wavelengths that can
pass a point in a given time
b. results from damage to the outer or middle ear
c. a tone's highness or lowness
d. sound waves trigger activity at different places
on the cochlea's basilar membrane
e. results from damage to the auditory receptors of
the cochlea or the auditory nerve
f. the nerve impulses in the auditory nerve match
the frequency of a tone
4. cochlea; oval window; basilar membrane; hair
cells; thalamus; temporal; number
5. less; stress; high blood pressure; anxiety; feelings
of helplessness; unanticipated; uncontrollable
6. place; low
7. frequency; high; 1000
8. volley
9. speed (timing); loudness
10. harder
11. parallel processing
Hearing Loss and Deaf Culture
1. conduction hearing loss
2. sensorineural; aging
3. stimulate
10. cochlear implant
4. cochlear implant
5. Deaf culture; children; speak; disability
ANSWERS
6. is; with; have
7. seem to; sensory compensation
8. self-esteem; accepted
Module Review
Introduction and The Stimulus Input: Sound Waves
1. audition; air molecules
2. loudness
3. frequency
4. decibels; 0
The Ear
1. outer; middle; inner
2. eardrum
3. hammer; anvil; stirrup
Progress Test
Multiple-Choice
Questions
1. b. is the answer. Just as wave frequency determines pitch, so wave amplitude determines loudness.
a. Amplitude is the physical basis of loudness;
wavelength determines frequency and thereby
pitch.
c. & d. Wavelength, amplitude, and intensity are
physical aspects of light and sound. Because the
174
Module 14 Hearing
question is based on a relationship between a
physical property (frequency) of a stimulus and
its psychological attribute (pitch), these answers
are incorrect.
2. a. is the answer.
b. & c. Although the localization of low-pitched
sounds along the basilar membrane is poor, that
for sounds of middle and, especially, high pitch is
good. Therefore, place theory accounts well for
high-pitched sounds and, together with frequency theory, can account for middle-pitched
sounds.
d. As long as the notes of a chord are within the
range of responsiveness of the basilar membrane,
chord perception can be accounted for by place
theory.
3. c. is the answer.
d. Chord perception, except for chords comprised
exclusively of high-frequency notes, shows no
age-dependent decline.
4. d. is the answer. Sensorineural hearing loss is
caused by destruction of neural tissue as a result
of problems with the cochlea's receptors or the
auditory nerve.
a. & c. Wax buildup and blockage because of
infection are temporary states; sensorineural
hearing loss is permanent. Moreover, sensorineural hearing loss involves the inner ear, rather
than the outer or middle ear.
b. Damage to the eardrum impairs the mechanical system that conducts sound waves; it could
therefore cause conduction hearing loss, not sensorineural hearing loss.
5. a. is the answer. Frequency theory best explains
the lowest pitches. Place theory best explains the
highest pitches, and some combination of the two
theories probably accounts for our sensation of
intermediate-range pitches.
6. c. is the answer.
a. This answer describes how pitch is sensed in
the case of high-pitched, but not low-pitched,
sounds.
b. This answer describes how pitch is sensed in
the case of low-pitched, but not high-pitched,
sounds.
d. This answer is incorrect because it reverses the
range of frequencies.
7. a. is the answer.
8. d. is the answer. The hair cells, which transduce
sound energy, are located on the basilar membrane.
a. & b. The eardrum and bones of the middle ear
merely conduct sound waves to the inner ear,
where they are transduced.
c. The semicircular canals are involved in the
vestibular sense, not hearing.
9. d. is the answer. Hearing losses that result from
aging are greatest in the higher frequencies and
involve damage to the hair cells on the basilar
membrane of the cochlea.
a' b" & c. Damage to the eardrum, auditory
canal, or bones of the middle ear would probably
cause conduction hearing loss and reduced sensitivity to sounds of all frequencies.
I
Summing Up
1. Outer ear. Hearing begins as sound waves enter
the auditory canal of the outer ear.
2. Auditory canal. Sound waves passing through
the auditory canal are brought to a point of focus
at the eardrum.
3. Eardrum. Lying between the outer and middle
ear, this membrane vibrates in response to sound
waves.
4. Middle ear. Lying between the outer and inner
ear, this air-filled chamber contains the hammer,
anvil, and stirrup.
5. Hammer, anvil, and stirrup. These tiny bones of
the middle ear concentrate the eardrum's vibrations on the cochlea's oval window.
6. Inner ear. This region of the ear contains the
cochlea and the semicircular canals, which play
an important role in balance.
7. Cochlea. This fluid-filled multichambered structure contains the hair cell receptors that transduce
sound waves into neural impulses.
8. Auditory nerve. This bundle of fibers carries
nerve impulses from the inner ear to the brain.
Matching Items
1. d
2. f
3. b
4. e
5. c
6. a
Key Terms
1. Audition refers to the sense of hearing.
2. The pitch of a sound is determined by its frequency, that is, the number of complete wavelengths that can pass a point in a given time.
Frequency, in turn, is directly related to wavelength: longer waves produce lower pitch; shorter
waves produce higher pitch.
Focus on Vocabulary and Language
3. The middle ear is the chamber between the
eardrum and cochlea containing the three bones
(hammer, anvil, and stirrup) that concentrate
the eardrum's vibrations on the cochlea's oval
window.
4. The cochlea is the coiled, bony, fluid-filled tube
of the inner ear where the transduction of sound
waves into neural impulses occurs.
5. The inner ear contains the semicircular canals
and the cochlea, which includes the receptors that
transduce sound energy into neural impulses.
Because it also contains the vestibular sac, the
inner ear plays an important role in balance, as
well as in audition.
6. The place theory of hearing states that we hear
different pitches because sound waves of various
frequencies trigger activity at different places on
the cochlea's basilar membrane.
Memory aid: Place theory maintains that the place
FOCUS ON VOCABULARY AND LANGUAGE
Introduction and the Stimulus Input: Sound Waves
We also are remarkably sensitive to faint sounds, an
obvious boon for our ancestors' survival when hunting or being hunted or detecting a child's whimper.
Humans are very good at detecting very quiet noises (faint sounds), which was clearly beneficial (a boon)
to our predecessors' ability to survive when they
were both predator (hunter) and prey (being hunted).
Likewise, the ability to notice and respond to a
youngster's quiet cry of distress (a child's whimper)
would have had adaptive value. We are also very
sensitive to changes in sounds and we have the
ability to differentiate among thousands of human
voices.
A piccolo produces much shorter, faster sound waves
than does a tuba. Musical instruments produce stimulus energy called sound waves~molecules of air
that bump and push each other along~and these
may be long (low frequency) or short (high frequency). A tuba (a large, deep-toned, brass-wind instrument) produces low-frequency sound waves and
thus has a lower pitch than a piccolo (a small flute),
which produces high-frequency waves and has a
higher pitch.
175
of maximum vibration along the cochlea's membrane is the basis of pitch discrimination.
7. The frequency theory of hearing presumes that
the rate, or frequency, of nerve impulses in the
auditory nerve matches the frequency of a tone,
thus enabling us to sense its pitch.
8. Conduction hearing loss refers to the hearing
loss that results from damage in the mechanics of
the outer or middle ear, which impairs the conduction of sound waves to the cochlea.
9. Sensorineural hearing loss (nerve deafness) is
hearing loss caused by damage to the auditory
receptors of the cochlea or to the auditory nerve
due to disease, aging, or prolonged exposure to
ear-splitting noise.
10. A cochlear implant is an electronic device that
converts sounds into electrical signals that stimulate the auditory nerve.
The Ear
(Close-Up): If only our ears had earlids. Myers makes
it clear that prolonged exposure to loud and unpredictable noise can affect our well-being and seriously damage our hearing. So, in a noisy urban environment it would be nice if we could close our ears
(with earlids) as we can our eyes (with eyelids).
If a car to the right honks, your right ear receives a
more intense sound, and it receives sound slightly
sooner than your left ear. We locate sounds because
our ears are about 6 inches apart and there is a time,
as well as a loudness difference, between auditory
reception in each ear. If we hear the sound of a car
horn (it honks) to our right, the left ear receives a less
intense sound somewhat later than the right ear, and
thus we locate the direction of the sound to the
right.
That is why, when trying to pinpoint a sound, you
cock your head, so that your two ears will receive
slightly different messages. When a sound is
equidistant from our two ears (directly ahead,
behind, or above), and there is no visual clue, we
have trouble locating (pinpointing) the source. In
this situation it helps to tilt (cock) our heads so that
each ear receives a slightly different message
(the sound will be a little louder and sensed a little
176
Module 14 Hearing
sooner by one ear, and the brain uses this information to detect where the sound is coming from).
Hearing Loss and Deaf Culture
Occasionally, disease causes sensorineural hearing
loss, but more often the culprits are biological
changes linked with heredity, aging, and prolonged
exposure to ear-splitting noise or music (Figure 14.5).
Sensorineural
hearing loss, or nerve deafness
(cochlear damage), can sometimes be caused by illness, but the agents responsible (the culprits) are
more likely to be age-related biological factors and
extended encounters with extremely loud (earsplitting) music or noise. While digital hearing aids
are a partial remedy, the latest cochlear implants can
restore hearing for children and most adults.