Download 1145010Module Hearing 08JS

Myers PSYCHOLOGY
Hearing
(Do you hear
what I hear?)
Hearing
Audition - the sense of hearing
 Measured in decibels
 Absolute threshold - zero
The Intensity of Some
Common Sounds
Audition
Amplitude (strength)
 determines loudness
Frequency
 the number of wavelengths
determines Pitch - a tone’s
highness or lowness
Ear is divided into 3 parts
Outer
Middle
Inner
See diagram
Audition- The Ear
1. Outer Ear - visible part & canal
2. Middle Ear - chamber between
eardrum and cochlea
 HAS three tiny bones
HAS (like a piston - hammer, anvil, stirrup)
that concentrate the vibrations of the
eardrum on the cochlea’s oval window
Audition
3. Inner Ear
 contains the cochlea, semicircular
canals, and vestibular sacs
 Cochlea
coiled, bony, fluid-filled tube in the
inner ear through which sound waves
trigger nerve impulses
 Hair cells line the basilar membrane
I am sound, where do I go?
 Ear canal to Eardrum (vibrations)
 Piston - HAS
Hammer
Anvil
Stirrup
 Cochlea
Movement of Hair cells - basilar membrane
Auditory nerve
 Neural message to the brain
Thalamus
Auditory cortex of Temporal lobe
How do we hear?
1. Place Theory (Helmholtz)
 the theory that links the pitch we hear with
the place where the cochlea’s membrane is
stimulated;
 best for high-pitched sounds
How do we hear?
2. Frequency Theory
 the theory that the rate of nerve impulses
traveling up the auditory nerve matches the
frequency of a tone, thus enabling us to
sense its pitch;
 best for low-pitched sounds
How We Locate
Sounds?
Locating sound
We locate sound by detecting differences
in the intensity (loudness) and timing
(speed) of the sounds received by each
ear
Why can’t I hear?
1. Conduction Hearing Loss
 hearing loss caused by damage to
the mechanical system that
conducts sound waves to the
cochlea
 Ex. Damage to eardrum, broken
HAS
Why can’t I hear?
2. Sensorineural Hearing Loss
 hearing loss caused by damage
to the cochlea’s receptor cells or
to the auditory nerve
 also called nerve deafness
 Crunched the shag carpet - hair
cells perm. damaged
Audition
 Older people tend to hear low
frequencies well but suffer hearing loss
for high frequencies
Amplitude required for
perception relative to
20-29 year-old group
1
time
10
times
100
times
1000
times
32
64
128
256
512
1024 2048 4096
8192 16384
Frequency of tone in waves per second
Low
Pitch
High
Cochlea implants - clip on Amazing brain
Sign language