Hearing!
• Audition the sense or act
of hearing.
• We hear a best of sounds
with frequencies in a range
corresponding to that of the
human voice.
• Frequency  the number of
complete wavelengths that
pass a point in a given time
(i.e. per second).
• Pitch  a tone’s experienced
highness or lowness;
depends on frequency.
Sound Waves
• Sound waves are essentially changes in air
pressure that our ears are able to detect.
• This is why you can feel vibrations in very loud or
low pitched sounds.
• Amplitude refers to their loudness.
• The ears turn the vibrating air into nerve impulses,
which are decoded into sounds.
• Long waves = low frequencies = low pitch.
• Short waves = high frequencies = high pitch.
• Sound is measured in decibels.
How does the ear hear?
• Conversion of sound waves into neural activity.
• First the outer ear channel sound waves through the auditory canal to the
ear drum, which is a tight membrane that vibrates with waves.
• The middle ear  (the chamber between the eardrum and cochlea
containing three tiny bones (hammer, anvil, and stirrup) that concentrate
the vibrations of the eardrum on the cochlea’s oval window.) then
transmits the eardrum’s vibrations through a piston made of 3 tiny bones
(hammer, anvil and stirrup).
• This signal is sent to the cochlea  a coiled, bony, fluid-filled tube in the
inner ear through which sound waves trigger nerve impulses, which is
found in the inner ear  the innermost part of the ear, containing the
cochlea, semicircular canals, and vestibular sacs.
• These vibrations cause the cochlea’s inner tube to vibrate, jostling the
fluid in the tube.
• This then causes small hairs to bend, which then sends the auditory
signals to the temporal lobes of the brain.
The structure of the ear
The ear is divided into the outer, middle and
inner ear.
The sound waves travel down the auditory canal
to the eardrum.
Eardrum = tight membrane that vibrates when
struck by sound waves.
The structure of the ear
Eardrum
The structure of the ear
Bones of the middle ear = the hammer, anvil,
stirrup which vibrate with the eardrum.
The structure of the ear
Hammer
The structure of the ear
Anvil
The structure of the ear
Stirrup
The structure of the ear
Oval window = where the stirrup connects to the
cochlea.
The structure of the ear
Cochlea = a coiled, bony, fluid-filled tube in the
inner ear through which sound waves trigger
nerve impulses.
The structure of the ear
Oval Window
The structure of the ear
Cochlea
The structure of the ear
Fluid in the cochlea
The structure of the ear
Hair cells in the cochlea
The structure of the ear
Auditory nerve = nerve which sends the auditory
message to the brain via the thalamus.
The structure of the ear
Nerve fibers
The structure of the ear
Auditory nerve
Neural impulse to the brain
Perceiving Loudness
• It’s the number of activated hair cells that
creates the perception of a sound being
louder.
• If the sensitivity of hair cells decreases,
hearing loss may ensure.
• However, because it has to do with the
number of hair cells activates, people with
hearing difficulties perceive a sound to be
loud, just like someone with normal hearing.
Perceiving Pitch
• Both are theories on how we hear… either is
seen as correct depending on how you look at
it.
• Place Theory  in hearing, the theory that
links the pitch we hear with the place where
the cochlea’ s membrane is stimulated.
• Best explains how we hear high pitched
sounds
• High frequencies produced large vibrations
near the beginning of the cochlea’s
Locating Sounds
• Placement of our ears
allows us to have
stereophonic (‘threedimensional’) hearing.
• Looks at intensity and
the speed of the sound.
• Think of if you heard a
car honking on your
right side – your right
ear receives a more
intense sound and
receives the sound
Hearing Loss and Deaf Culture
Conduction Hearing Loss  hearing loss
caused by damage to the mechanical
system that conducts sound waves to the
cochlea.
• Problems with the eardrum or three
bones of the middle ear.
• Sensorineural Hearing Loss  hearing
loss caused by damage to the cochlea’s
receptor cells or to the auditory nerves;
also called nerve deafness.
• Cochlea Implant  a device for
Touch
• Vital in motherhood and upbringing.
• Types of Touch:
– Pressure
– Warmth
– Cold
– Pain
• Some spots will be more sensitive to pain,
pressure, warmth, cold, etc.
• Self induced touch is less activating than non-
Top Down Influence in Touch – Rubber
hand illusion
• Kinesthesis  the
system for sensing
the position and
movement of
individual body
parts.
• Ex – Case where a
viral infection
caused the nerves
that enabled his
sense of light touch
and body
position/movement.
Person felt
Pain
• Pain is the way your body tells you something
is wrong.
• https://www.youtube.com/watch?v=n6iOUW
523BE
• However, think of people who live with
chronic pain. It’s like an alarm that won’t shut
off.
• Pain is detected by nociceptors, which are
sensory receptors that detect harmful
temperatures, pressures or chemicals.
• Gate-Control Theory of Pain  the theory that
The pain circuit
Psychological Influences of Pain :
Understanding Pain
• Psychological Influences of Pain:
– Rubber hand illusion again, but bend the finger,
less on real hand, more on rubber hand, people
perceive as their own hand, feel the pain more
severely.
– Pain memories – We tend to remember the most
severe moments of pain, or the peak, as well as
the pain at the very end, not necessarily how long
we were in pain. Think childbirth.
• Social Cultural Influences – Playing a sport
through injury.
Biopsychosocial approach to
pain
Pain Control
• Physical Methods – drugs, surgery,
acupuncture, electrical stimulation,
massage, exercise.
• Psychological Methods – hypnosis,
relaxation training, thought distraction,
placebo effect.
• Should be used together to effectively
control pain. However, the physical is
more commonly prescribed by doctors.
Taste... Yum!
• Basic Tastes – sweet, salty, sour, bitter and
umami (taste of savory meat).
• We equate different tastes to different basic
functions of survival.
• Ex. Protein rich = good! Very bitter = bad!
Maybe poison?
• We taste with our taste buds and it is a
considered a chemical sense. We sense
different molecules as different tastes that are
sent as signals to the
Taste and Sensory Interaction
• Sensory Interaction  the principle that one
sense may influence another, as when the
smell of food influences its taste.
• McGurk Effect.
• Interaction of other senses – Ex. Seeing
the mouth movements of ‘Ga’, while
hearing ‘Ba’, we will perceive the sound as
‘Da’.
• Synesthesia – joined senses.
• https://www.youtube.com/watch?v=qiN5kS
What’s that… smell?
• 20,000 daily inhales and exhales of air a day,
always with a smell attached.
• Olfaction, or smell is a chemical sense, like
taste.
• Smell with our 5 million receptor cells at the
top of each nasal cavity.
• These send the signals to the brain, via the
olfactory nerve, by passing the thalamus
entirely, to the olfactory bulb, located behind
the eyes.
Smell (olfaction)
Smell and age