Transcript 164463_SandP_notes_3

Hearing:The Psychology of Sound
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Sound waves are really air
molecules being pushed about.
Frequency: The length of the
sound wave.
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Pitch
Amplitude: The height of the
sound wave.
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Loudness
Timbre: Complexity of sound,
mixtures of tones
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Allows us to recognize a
friends voice on the
phone.
How We Hear
There are four steps involved in the transduction of sound waves into neural
impulses.
1. Airborne sound waves must be relayed to the inner ear.
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Strike the eardrum which transmits vibrations to tiny bones in middle ear;
hammer, anvil and stirrup.
Passed on to the cochlea.
2. Cochlea focuses vibration on the basilar membrane.
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Vibration of stirrup against oval window of cochlea sets the fluid in the
membrane into motion.
3. The basilar membrane converts the vibrations into neural messages.
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Tiny hair cells sway in response to vibrating basilar membrane, stimulating
sensory nerve endings connected to them.
These excited neurons transform the mechanical vibrations into neural activity.
4. Neural messages travel to the auditory cortex in the brain.
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Neural signals leave the cochlea in a bundle of neurons called the auditory nerve.
Neurons from both ears meet in the brain stem which passes the auditory
information to both sides of the brain. Ending up in the auditory cortex.
An Ear on the World
Theories of Pitch
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Place Theory: As sound waves pass through the inner ear,
the basilar membrane vibrates. Different frequencies
activate different locations on the membrane.
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Frequency Theory: Neurons on the basilar membrane will
fire and different rates with different sound wave
frequencies.
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Different places of the basilar membrane send different neural
codes for different pitches.
Explains our ability to hear high pitches.
Volley Principle
Helps explain our ability to hear low pitches.
Our hearing is a combination of the two.
Deafness
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Conduction Deafness:The ways
in which sound waves are
converted to nerve energy has
been interfered with.
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Specifically the conduction of
vibration.
Most cases in the middle ear;
ear drum, hammer, anvil, and
stirrup.
Nerve Deafness: (Sensorineural)
Damage to the hair cells causing
problems with sending the
messages to the brain.
Auditory Localization
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Sounds from different
directions are not identical
as they arrive at left and
right ears
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Loudness
Timing
Phase
The brain calculates a
sound’s location by using
these differences.
Sense of Body Position
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To act purposefully and
gracefully we need constant
information about where our
limbs and other body parts
are in relation to each other
and objects in the
environment.
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We have two physical
mechanisms for keeping
track of body position,
movement and balance.
Vestibular Sense
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Vestibular Sense: The body position
sense that orients us with respect to
gravity.
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Tells how our bodies, especially our
heads, are oriented.
Also tells us how we are moving.
Semicircular canals and vestibular
sacs move when the head moves,
stimulating their hairlike receptors.
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These receptors send messages to
the cerebellum enabling us to sense
our body position and maintain our
balance.
Kinesthetic Sense
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Keeps track of body parts
relative to each other.
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Provides constant
feedback about what
the muscles in your
body are doing during
motor activities.
Receptors reside in
joins, muscles, and
tendons.
Connects to processing
regions in parietal
lobes.
Taste Buds
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Your tongue is covered with little
bumps called papillae.
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Each little bump has 200 or more
taste buds.
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Fungiform, vallate and foliate
When stained with food coloring
the fungiform papillae will appear
almost white.
Each bud contains a pore that
catches food chemicals.
10,000 taste buds line the tongue
and mouth.
Four Tastes
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Four basic tastes
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Salty, sour, bitter
and sweet.
Most other tastes
are a mixture of
these four.
Children have more
taste buds than
adults.
Facts about Taste
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Our taste receptors
reproduce about every10
days.
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Let’s us taste after
burning our tongues.
Smoking and alcohol use
accelerate the decline in
taste bud sensitivity.
Our emotional responses
to taste are “hard wired”
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Babies respond in the
same way adults do.
More Facts about Taste
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People with no tongues
and still taste with
receptors in the back
and roof of the mouth.
The middle of your
tongue has few taste
receptors.
Smell and color are an
important part of taste.
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Sensory interaction
“Tasters”
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About 20% of
people are “supertasters”
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Most are female
About 20% are
“non-tasters”
The remaining 60%
are somewhere in
between
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“average-tasters”
Which are you?
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We are going to conduct an experiment to see
which type of taster you are.
Please keep the following in mind and we work
through the lab.
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Do not touch the tips of your Q-tips. Hold them in
the center.
Do not put you Q-tip down on the desk.
Do not touch any one else’s equipment.
Remember, this is voluntary.
Smell
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Like taste, smell is a
chemical sense.
We smell when molecules
of a substance carried in
the air reach a tine cluster
of 5 million receptor cells
at the top of each nasal
cavity.
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Olfactory receptor cells
recognize individual odors.
Smell: The Sense of Scents
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Airborne chemical molecules enter the nose and
circulate through the nasal cavity.
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Vapors can also enter through the mouth and pass into
nasal cavity.
Olfactory System
The Olfactory System
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Odor molecules come in
many shapes and sizes.
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We need many different
receptors to detect them.
Unlike color, we do not
have specific receptors for
specific odors.
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Perhaps some odors signal
a combination of receptors.
Humans can detect 10,000
odors.
Learning about smell
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The attractiveness of a smell depends on learned
associations.
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We don’t come with built in preferences
Babies have to learn the smell of their mother
Smell and Memory
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Odors have the power to
evoke memories and
feelings.
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A hotline runs between the
brain area that gets
information from the nose
and the brains limbic
centers associated with
memory and emotion.
Pleasant odors can evoke
pleasant memories
Touch
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Our sense of touch is a
combination of four distinct
skin senses:
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Pressure, warmth, cold and
pain
Others are a variation of these
basic four.
Within the skin are different
types of specialized nerve
endings.
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Some spots more sensitive than
others to the four skin senses.
Sensitivity to Touch
Pain
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Like all sensation, pain is a
property of both the region
of the body in which we
feel it and the brain.
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Think “phantom Limb”
However, there is no one
single stimulus for pain
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Nor are there any special
receptors for pain.
Gate-Control Theory of Pain
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Ronald Melzack and Patrick Wall.
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Spinal cord contains a neurological “gate” that either blocks
pain signals or allows them to pass on to brain.
The spinal cord contains small nerve fibers that conduct most
pain signals.
When tissue is injured, these small fibers activate and open
the neural gate, and you feel pain.
Activity in the large nerve fibers of the spinal cord will
close the pain gate.
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The gate can also be closed by messages sent from the brain
Gate-Control Theory of Pain
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Experience of pain
depends (in part) on
whether the pain
impulse gets past
neurological “gate” in
the spinal cord and
thus reaches the brain.
Perceptual Powers: Origins and
Influences
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Inborn abilities
Critical periods
Psychological and cultural Influences on
perception
Critical Periods
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If infants miss out on
experiences during a crucial
period of time, perception
will be impaired.
When adults who have been
blind since birth have
vision restored, they may
not see well
Other senses such has
hearing may be influenced
similarly.
Psychological and Cultural Influences
on Perception
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We are more likely to perceive something when
we need it.
What we believe can affect what we perceive.
Emotions, such as fear, can influence perceptions
of sensory information.
Expectations based on our previous experiences
influence how we perceive the world.
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Perceptual Set
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A habitual way of perceiving, based on expectations.
All are influenced by our culture.
Extrasensory Perception
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Extrasensory Perception (ESP):
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The ability to perceive something without
ordinary sensory information
This has not been scientifically demonstrated
Three types of ESP:
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Telepathy – Mind-to-mind communication
Clairvoyance – Perception of remote events
Precognition – Ability to see future events
Parapsychology
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The study of purported psychic phenomena
such as ESP and mental telepathy.
Persinger suggests that psychic phenomena
are related to signs of temporal lobe
epilepsy in otherwise neurologically
normal individuals.
Most ESP studies produce negative
findings and are not easily replicated.
Parapsychology
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J. B. Rhine conducted many experiments on ESP
using stimuli such as these.
Rhine believed that his evidence supported the
existence of ESP, but his findings were flawed.