Hearing:The Psychology of Sound Sound waves are really air

molecules being pushed about. Frequency: The length of the

sound wave. Pitch

Amplitude: The height of the sound wave. Loudness

Timbre: Complexity of sound, mixtures of tones Allows us to recognize a

friends voice on the phone.

How We HearThere are four steps involved in the transduction of sound waves into neuralimpulses.

1. Airborne sound waves must be relayed to the inner ear. 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. 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. 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. 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 Place Theory: As sound waves pass through the inner ear, the basilar

membrane vibrates. Different frequencies activate different locations on the membrane. Different places of the basilar membrane send different neural codes for

different pitches. Explains our ability to hear high pitches.

Frequency Theory: Neurons on the basilar membrane will fire and different rates with different sound wave frequencies. Volley Principle Helps explain our ability to hear low pitches.

Our hearing is a combination of the two.

Deafness Conduction Deafness:The ways

in which sound waves are converted to nerve energy has been interfered with. 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 Sounds from different

directions are not identical as they arrive at left and right ears Loudness Timing Phase

The brain calculates a sound’s location by using these differences.

Sense of Body Position 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. We have two physical

mechanisms for keeping track of body position, movement and balance.

Vestibular Sense Vestibular Sense: The body position

sense that orients us with respect to gravity. 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. These receptors send messages to

the cerebellum enabling us to sense our body position and maintain our balance.

Kinesthetic Sense Keeps track of body parts

relative to each other. 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 Your tongue is covered with little

bumps called papillae. Fungiform, vallate and foliate When stained with food coloring

the fungiform papillae will appear almost white.

Each little bump has 200 or more taste buds. Each bud contains a pore that

catches food chemicals. 10,000 taste buds line the tongue

and mouth.

Four Tastes Four basic tastes

Salty, sour, bitter and sweet.

Most other tastes are a mixture of these four.

Children have more taste buds than adults.

Facts about Taste Our taste receptors

reproduce about every10 days. 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” Babies respond in the

same way adults do.

More Facts about Taste 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. Sensory interaction

“Tasters” About 20% of

people are “super-tasters” Most are female

About 20% are “non-tasters”

The remaining 60% are somewhere in between “average-tasters”

Which are you? 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. 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 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. Olfactory receptor cells

recognize individual odors.

Smell: The Sense of Scents

Airborne chemical molecules enter the nose and circulate through the nasal cavity. Vapors can also enter through the mouth and pass into

nasal cavity.

Olfactory System

The Olfactory System Odor molecules come in

many shapes and sizes. We need many different

receptors to detect them.

Unlike color, we do not have specific receptors for specific odors. Perhaps some odors signal

a combination of receptors. Humans can detect 10,000

odors.

Learning about smell The attractiveness of a smell depends on learned associations.

We don’t come with built in preferences Babies have to learn the smell of their mother

Smell and Memory Odors have the power to

evoke memories and feelings. 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 Our sense of touch is a

combination of four distinct skin senses: Pressure, warmth, cold and pain Others are a variation of these

basic four.

Within the skin are different types of specialized nerve endings. Some spots more sensitive than

others to the four skin senses.

Sensitivity to Touch

Pain Like all sensation, pain is a

property of both the region of the body in which we feel it and the brain. Think “phantom Limb”

However, there is no one single stimulus for pain Nor are there any special

receptors for pain.

Gate-Control Theory of Pain Ronald Melzack and Patrick Wall.

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. The gate can also be closed by messages sent from the brain

Gate-Control Theory of Pain 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

Inborn abilities Critical periods Psychological and cultural Influences on

perception

Critical Periods 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

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. Perceptual Set

A habitual way of perceiving, based on expectations.

All are influenced by our culture.

Extrasensory Perception Extrasensory Perception (ESP):

The ability to perceive something without ordinary sensory information

This has not been scientifically demonstrated Three types of ESP:

Telepathy – Mind-to-mind communication Clairvoyance – Perception of remote events Precognition – Ability to see future events

Parapsychology 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

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.