Transcript Introductory Psychology Concepts

Introductory Psychology Concepts
Hearing
Instructor name
Class Title, Term/Semester, Year
Institution
© 2011 The McGraw-Hill Companies, Inc.
Introductory Psychology Concepts : Hearing
Hearing

Transduction of sound waves
The waves produced by different stimuli are transmitted—usually through
the air — in different patterns, with lower frequencies indicated by fewer
peaks and valleys per second.
Lower frequency
(lower pitch)
(Source: Seeley, Stephens, & Tate, 2000.)
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Higher frequency
(higher pitch)
Introductory Psychology Concepts : Hearing
Hearing

Sound: pitch (frequency); loudness and timbre (purity)
Frequency (Hz)
determines pitch (tone)
Low pitch
High pitch
Amplitude determines
intensity (loudness) (dB)
Soft
Loud
Auditory stimuli.
• Sound waves are a form of mechanical energy.
• As the tuning fork vibrates, it produces successive waves of compression and expansion of
air molecules.
• The number of maximum compressions per second is its frequency, measured in hertz (Hz).
• The height of the wave above zero air pressure represents the sound’s amplitude.
• Frequency determines pitch, amplitude determines loudness, measured in decibels (dB).
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© 2011 The McGraw-Hill Companies, Inc.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear
Ossicles
Tympanic
membrane
(eardrum)
Malleus Incus Stapes
(hammer) (anvil) (stirrup)
Semicircular
canals
Auditory
vestibular nerves
(to brain)
Cochlea
External auditory
canal
Oval Round Vestibular
window window
sacs
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© 2011 The McGraw-Hill Companies, Inc.
Auditory
tube
A cross section of
the ear shows the
structures that
transmit sound
waves from the
auditory canal to
the cochlea.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear
Ossicles
Tympanic
membrane
(eardrum)
Malleus Incus Stapes
(hammer) (anvil) (stirrup)
Semicircular
canals
Auditory
vestibular nerves
(to brain)
Cochlea
External auditory
canal
Oval Round Vestibular
window window
sacs
5
© 2011 The McGraw-Hill Companies, Inc.
Auditory
tube
Sound waves
travel into an
auditory canal
leading to the
eardrum, a
membrane that
vibrates in
response to the
sound waves.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear
Ossicles
Tympanic
membrane
(eardrum)
Malleus Incus Stapes
(hammer) (anvil) (stirrup)
Semicircular
canals
Auditory
vestibular nerves
(to brain)
Cochlea
External auditory
canal
Oval Round Vestibular
window window
sacs
6
© 2011 The McGraw-Hill Companies, Inc.
Auditory
tube
Beyond the
eardrum is the
middle ear, a
cavity housing the
three smallest
bones in the body:
the hammer, anvil,
and stirrup.
The vibrating
activity of these
bones amplifies
the sound waves
more than 30
times.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear
Ossicles
Tympanic
membrane
(eardrum)
Malleus Incus Stapes
(hammer) (anvil) (stirrup)
Semicircular
canals
Auditory
vestibular nerves
(to brain)
Cochlea
External auditory
canal
Oval Round Vestibular
window window
sacs
7
© 2011 The McGraw-Hill Companies, Inc.
Auditory
tube
The stirrup
(stapes) is
attached to the
oval window, a
membrane which
forms the
boundary
between the
middle ear and
the inner ear.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear
Ossicles
Tympanic
membrane
(eardrum)
Malleus Incus Stapes
(hammer) (anvil) (stirrup)
Semicircular
canals
Auditory
vestibular nerves
(to brain)
Cochlea
External auditory
canal
Oval Round Vestibular
window window
sacs
8
© 2011 The McGraw-Hill Companies, Inc.
Auditory
tube
The inner ear
contains the
cochlea, a snailshaped tube
about 1.4 inches
in length that is
filled with fluid and
vibrates in
response to
sound.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear : inside the cochlea
Vestibular
membrane
Tectorial
membrane
Scala
vestibuli
Scala media
(cochlear duct)
Organ of
Corti
Hair
cells
Basilar
membrane
Auditory nerve
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© 2011 The McGraw-Hill Companies, Inc.
Scala
tympani
In the cochlea,
sound waves are
translated into fluid
waves that
stimulate hair cells
in the organ of corti.
Introductory Psychology Concepts : Hearing
Hearing

Parts of the ear : inside the cochlea
Vestibular
membrane
Tectorial
membrane
Scala
vestibuli
Scala media
(cochlear duct)
Organ of
Corti
Hair
cells
Auditory nerve
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© 2011 The McGraw-Hill Companies, Inc.
Scala
tympani
In the cochlea,
sound waves are
translated into fluid
waves that
stimulate hair cells
in the organ of corti.
The resulting
impulses reach the
brain via the
auditory nerve.
Introductory Psychology Concepts : Hearing
Hearing

Perception of Sound
Place theory of pitch perception:
The specific point in the cochlea where the fluid wave peaks and most
strongly bends the hair cells serves as a frequency coding cue.
Varying frequencies
stimulate different areas
of the basilar membrane.
High-frequency waves
peak quickly and
stimulate the membrane
close to the oval window.
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© 2011 The McGraw-Hill Companies, Inc.
Introductory Psychology Concepts : Hearing
Hearing

Perception of Sound
Frequency Theory of Pitch Perception:
Nerve impulses sent to the brain match the frequency of the sound
wave.
Both Frequency and Place Theories are applicable in their own
ways.
• At low frequencies:
Frequency Theory best explains sound wave frequency coding.

At higher frequencies:
Place Theory best explains the frequency of a sound wave coding.
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© 2011 The McGraw-Hill Companies, Inc.
Introductory Psychology Concepts : Hearing
Hearing

In the United States alone, more than 20 million people
suffer from impaired hearing.
They suffer from two major types of hearing loss:

Conduction Hearing Impairment
•

Nerve and Hearing Impairment caused by:
•
•
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Problems with the mechanical system that transmits sound
waves to the cochlea
Damaged inner ear receptors or
Damage to the auditory nerve itself
© 2011 The McGraw-Hill Companies, Inc.