SENSATIONHEARING AND OTHER SENSESAP Psych, Myers, Ch. 5

AUDITION AND THE EAR

AUDITION – THE SENSE/ACT OF HEARING

We hear via sound waves Loudness –

strength/amplitude of wave (measured in decibels – dB) Loud sounds have high

amplitudes softer sounds have smaller

amplitudes

AUDITION – THE SENSE/ACT OF HEARING

Pitch – a tone’s experienced highness or lowness, depends on frequency Frequency – number of wavelengths that pass a

point in a period of time Low frequency sounds = bass High frequency sounds = high ringing

OUTER EAR

External auditory canal – channels sound waves to the eardrum

Pinna – outer ear/lobe

MIDDLE EAR – EARDRUM, 3 BONES

Eardrum – thin membrane that vibrates when a sound waves hits it Vibrations felt by 3

small ossicle bones – hammer, anvil, and stirrup – and sent to inner ear

INNER EAR - COCHLEA, SEMICIRCULAR CANALS, AND VESTIBULAR AREAS

Cochlea – a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses Moving fluid in cochlea

triggers hair cells in the cochlea’s basilar membrane stimulates neurons to produce electrical impulses

Auditory nerve – sends neural impulses from the cochlea to the brain (thalamus temporal lobe)

Hearing Animation

HOW DO WE HEAR PITCH?

Links the pitch we hear with the place where the cochlea’s membrane is stimulated

High pitch sounds

The rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

Low pitch sounds

Place Theory (Helmholtz) Frequency Theory

Audition and Pitch Theories

Cochlea Animation

We use both theories to hear all

pitches.

LOCATING SOUNDS

Distance between ears allows us to place sounds in space.

Equidistant sounds – cock our heads to distinguish location

HEARING LOSS

Conduction Damage to the mechanical

elements (eardrum, H, A, or S) that conduct sound waves to the cochlea

Sensorineural Damage to the cochlea’s receptor

cells or to the auditory nerve, also called nerve deafness

Hearing can be slightly restored with a cochlear implant (if there is a healthy nerve) device for converting sounds into

electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

Must have a functioning auditory nerve

COCHLEAR IMPLANTS

Pro Experience sounds

and oral communication

Helps deaf children with talking

Children who rely solely on ASL before learning to speak have more difficulty learning to read and write later in life

Con

Deafness is not a disability

ASL is a complete and functioning language

Deafness ≠ linguistically impaired

SENSORY COMPENSATION

People who lose one channel of sensation often compensate for it with a slight enhancement of other sensory abilities

Also a product of brain plasticity

OTHER 3 SENSESOlfaction, Taste, Touch

OLFACTION – SENSE OF SMELL Chemical sense - Odors

are composed of chemical molecules which are sensed by olfactory receptor cells at the top of the nasal cavity.

Receptors in nasal cavity (transduction) olfactory bulb olfactory nerve primary smell cortex (temporal lobe) only sense not to pass

through the thalamus

OLFACTION AND MEMORY/EMOTION

Odors invoke memories or feelings because the part of the brain that interprets odors is directly linked with the limbic system which processes memories and emotions

GUSTATION – SENSE OF TASTE

Evolutionary purpose – survival

5 basic tastes Sweet Salty Sour Bitter Umami (best experienced by the flavor enhancer MSG, most

commonly found in Asian food – described as “savory”)

Wrong

GUSTATION - TASTE

Chemical sense – taste buds (200+ per bump on tongue) catch food chemicals via receptor cells Receptor cells can be more

sensitive to different tastes

Receptors on taste buds (transduction) facial nerve medualla thalamus primary gustatory region (temporal lobe)

SENSORY INTERACTION

The principle that one sense may influence another, as when the smell of food influences its taste To savor taste we normally breathe the aroma

through the nose Sight of spoken words and the audition of spoken

words influence each other

Vision and audition We use the auditory info from the sound of words

and the visual info from the moving of the mouth to quickly comprehend speech.

However, this sensory interaction can also lead us astray…

FLAVOR Combination of odor, texture, temperature, and

taste “taste blindness” – lack of sensitivity to certain taste Sensitivities can be inherited

Tea Flavors

Chocolate Flavors

TOUCH - SKIN SENSES

4 distinct skin senses Pressure Warmth Cold Pain These senses are combined to produce

sensations such as: hot, tickling, itchy, wetness, etc

Only the sensation of pressure has specialized nerves in the skin; the rest of the nerve endings can feel warmth, cold, and pain in various combinations

TOUCH PATHWAY

Skin receptors (transduction) nerves (PNS) spinal cord (CNS) medulla thalamus sensory cortex

PAIN

Something is WRONG!

Perception of Pain

Biological•Activity in spinal cord’s large and small fibers (gate-control theory)•Genetic differences in endorphin production•The brain’s interpretation of CNS activity

Psychological•Attention to pain•Learning based on experiences•Expectations of pain

Social Cultural•Presence of others•Empathy for other’s pain•Cultural expectations

GATE-CONTROL THEORY

The spinal cord acts as a gate that controls if pain signals reach the brain. Small nerve fibers conduct pain signals, while larger

neural fibers conduct most other sensory signals. When tissue is injured, the smaller nerve fibers activate

and open the neural gate to send pain to the brain. Larger-fiber activity closes the pain gate, turning pain

off.

Using this theory, people believe that activating large neural fibers can block pain Ex: acupuncture Ex: rubbing painful areas stimulates large neural fibers

than can block pain Ex: electrical stimulation of painful area

PAIN CONTROL

Pain can be treated physically and psychologically Drugs, surgery, acupuncture, electrical

stimulation, massage, exercise, hypnosis, relaxation training, thought distraction, etc

Because pain is perceived in the brain, diverting the brain’s attention can bring relief

THE 6TH AND 7TH SENSESKinesthesis and Vestibular Sense

KINESTHESIS

AKA Proprioception The system for sensing the

position and movement of individual body parts Enabled by millions of

proprioreceptors in muscles, tendons, and joints

Proprioreceptors (transduction) nerves spinal cord brain (cerebellum)

VESTIBULAR SENSE

The sense of body movement and position, including the sense of balance Monitors the head’s position which usually dictates

what the body is doing

Fluid in semicircular canals hair cells in vestibular sacs vestibular nerve brain (medulla and cerebellum)