1. Audition Frequency and Amplitude
the sense of hearing
Frequency
the number of complete wavelengths that pass a point in a given time = pitch
Pitch (wave frequency, Hz)
High frequency = high pitch
low frequency = low pitch

2. Amplitude Amplitude: height of sound wave = loudness of sound
Timbre: quality, complexity of sound
Average human: hears tones from 20Hz to 20,000Hz.
Women tend to hear higher frequencies
Theory: men = Louder activities more often…

3. The Intensity of Some Common Sounds
A recent U of Tenn. study found that 60 percent of college students suffer some high-frequency hearing loss
Loud music is believed to be the culprit
Live concerts—120 + decibels, louder than jack hammer, chainsaw
OSHA says that 85 decibels (food processor) 8 hours, 5 days a week will eventually cause permanent hearing loss
For each 5 decibel increase, the time it takes to cause lasting injury drops by half
Try: hold finger up as if taking a court room oath, rub thumb, finger together and should hear a scrtiching sound---if not, MAY have hearing loss

5. From Waves to Sound Outer Ear Middle Ear Inner Ear
Channels sound wave through auditory canal to eardrum
Middle Ear
Eardrum: Membrane/ converts wave to vibrations
Vibrations pass through piston (hammer, anvil, stirrup: smallest bones in human body!) piston concentrates vibrations of the eardrum on the cochlea’s oval window
Inner Ear
Cochlea: converts vibrations into neural activity (vibration = ripples in basilar membrane fluid
Bending hair cells = auditory neural impulse

6. In other words…
From sound waves to vibrations to fluid waves to neural impulse to auditory cortex (temporal lobe) = hearing!

7. Hair Cells: Basilar Membrane

8. How do we discern pitch? Place Theory
Specific places along the basilar membrane match a tone with a particular pitch
Frequency Theory
rate of sound wave = rate of neural impulses to the brain (# of neural impulses determines pitch) ex. 100 sound waves/second = 100 neural impulses = pitch)

9. How We Locate Sounds
Brain analyzes differences in what is heard by each ear to determine where sound is coming from… (3 dimensional)
Experiment—have someone sit in front of class with eyes closed. Clap hands around head and ask student to identify where the sound comes from—will be able to do so when the sounds come from one side or the other, but less clearly able to do so when the sounds overhead in back or in front
The perceived difference in sounds is related to the time at which the sound is received

10. Hearing Loss Most common physical disability
35 million Americans (500 million worldwide)
Recent study: 60% of American college students suffer from high frequency hearing loss.
Each 5 db increase, time it takes for permanent damage cut in half (after 85)
Men: greater degree of hearing loss at every age (loud music or changes in cochlea that restrict blood supply to neural elements?)

11. Audition Conduction Hearing Loss Nerve Hearing Loss
caused by damage to the mechanical system that conducts sound waves to the cochlea (Ear drum, hammer, anvil, stirrup)
Nerve Hearing Loss
hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve (hairs in basilar membrane not regenerative)
Ringing in the ears is called tinnitus, affects more than 36 million Americans
Most common cause is exposure to loud noises, but also can be caused by certain drugs, ear infections, food allergies
In most severe form, this ailment is incapacitating

12. Tinnitus Damage to auditory ear (ringing in ears)
Advanced case is incapacitating
Shell shock (combat zones)
tinnitus masker: “ocean waves or radio static”

13. Helen Keller What would be more difficult, being blind or deaf?
“…deafness to be a much greater handicap than blindness… Blindness cuts people off from things. Deafness cuts people off from people.”

14. Cochlear Implants Nerve deafness “bionic ear”
Stimulates sites on auditory nerve

15. Audition
Older people tend to hear low frequencies well but suffer hearing loss for high frequencies 1
time 10
times
100
1000 32 64
128
256
512
1024
2048
4096
8192
16384
Frequency of tone in waves per second
Low
Pitch
High
Amplitude required for
perception relative to
20-29 year-old group

16. True or False? 1. Hard of hearing people need all sounds amplified.
2. Blind musicians are more likely than sighted ones to develop perfect pitch.
3. Deaf people’s auditory cortex becomes responsive to touch and visual input.
Sensory Compensation / plasticity

17. Touch Skin senses: pressure, warmth, cold, pain
Which is the only sensation identifiable with skin receptors?
Pressure
The Rubber hand illusion (demo)

18. Touch
Touch localization demonstration, concentrate on where the sensations of touch are felt:
Touch two index fingers together, feel it in both
Touch finger to bottom lip, light taps, felt mostly in lip even though both are being stimulated
Touch ankle, now its felt mostly in finger
Touch localization depends on the relative lengths of the pathways from the stimulated parts to the brain

19. Pain Pain = sensation + brain + expectation “No brain, no pain”
More complex / no one stimulus / neural cord, no special receptors
Research shows extent of pain is more influential than duration (medical procedures)

20. Pain Gate-Control Theory
Theory: spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain
Small nerve fibers: conduct pain signals
Small nerve fibers open / activate neural gate
Large nerve fibers close gate (shut off pain)
Pain is an important signal to our bodies
The experience of pain can be influenced by information from the brain
Chronic pain—est. that over 100 million people suffer from this
One study had teen age burn patients undergo a few minutes of wound treatment while they played Nintendo or while they were in a virtual reality environment—the patients felt less pain and spent less time thinking about their pain in virtual reality than Nintendo due to concept of “presences”—illusion of going inside another world. Pain requires attention

21. Chronic Pain Pain= physiological and psychological
Treat by stimulating large neural fibers (to close the gate…)
Acupuncture, massage, electrical stimulation)
1 in 6 Americans:100 billion total expenses

22. Reactions to pain.. Why do we rub something when we hurt it?
Create competing stimulation that will block some of the pain impulses… (“Makes it feel better…”)

23. Taste Taste Sensations Sensory Interaction sweet sour salty Bitter
Umami (meaty taste) monosodium glutamate
Sensory Interaction
the principle that one sense may influence another (all senses)
Ex: the smell of food influences its taste
Some taste sensations are genetically programmed, such as sweet, and finding bitter and sour foods unpleasant
A study of babies had sweet eliciting smiles, lip smacking, and sour eliciting protrusion of tongue
These reactions make good evolutionary sense
Animals tend to be neophobic, and human children are reluctant to try new things
One experiment asked a group of subjects to taste two groups of food (that were the same). When the items were accurately named (chopped tomatoes, oatmeal, beefsteak) more willing them when given novel names (pendula fruit, lat, langua steak)
However, as true with other stimuli , mere exposure makes us like them more

24. Taste: A Chemical Sense
Each bump on your tongue = 200 taste buds
Taste sensitivity decreases with age
Sensory interaction: taste + texture +smell = flavor
T-F
You can taste without your tongue.
(Taste receptors in back and roof of mouth.)

25. New Studies Tongue and taste: Place theory outdated
Taste is comprehensive over tongue

26. Senses Influence Each Other…
Sensory Interaction
the principle that one sense may influence another (all senses)
Ex: the smell of food influences its taste
Synaesthesia (“to perceive together”)
joining of senses / one sense stimulates another
Feels shapes when taste / smell food
See colors in response to pain
Most common: see numbers / letters in colors
Recent study: 1 in 2, male to 6 female
Theory: cross-activation of adjacent brain regions

27. Smell Olfaction A chemical sense Process
Molecules of substance / air / 5 million receptor top of each nasal cavity
Impulse sent to brain through axon fibers
Odors recognized individually
Odor molecules / neural receptors (key and lock)
10,000 odors detected! Peak at early adulthood
Olfactory bulb > amygdala > hippocampus > cortex (why smell evokes emotions, memories)

28. Smell nerve Olfactory bulb Receptor cells in Nasal olfactory membrane
passage
Olfactory
bulb
nerve

29. Gender and Senses Detecting men from women: smell
Research confirms: “hands, breath and shirts”-
can distinguish the genders (pheromones)
Women better “sniffers” than men

30. Age, Sex and Sense of Smell
Women
Men
Age Group 4 3 2
Number
of correct
answers
Women and young adults
have best sense of smell
Smell can be used to identify gender
The phenomenon of women in the same home having the same menstrual cycle is related to smell—researcher Martha McClintock discovered this 30 years ago while at Wellesley College; now a researcher at the U of Chicago found that smell can stimulate ovulation
Citrus odors make people more alert, spiced apple helps relaxation
Pumping certain pleasant food odors cut by 40 percent shoving, pushing in New York subways
People in New York mall were more likely to help strangers when there was the aroma of roasting coffee or baking cookies
Good and Plenty licorice combined with cucumber increased female blood flow by 14 percent (anything over 10 percent was considered stimulating), baby talc 13 percent, lavender + pumpkin pie 11 percent
Cherry cut flow by 18 percent, charcoal barbecue 15 percent, men’s cologne by 1 percent
Women seem to be excited by things that remind them of childhood, or are fresh smelling, relating to safety and security needed in order to feel sexual

31. Body Position and Movement (Sensorimotor Coordination)
Kinesthesis
the system for sensing the position and movement of individual body parts
Vestibular Sense
Monitors head (and thus bodies) movement
Sense of balance (equalibrium)
Inner ear: semicircular canals, vestibular sacs = fluid = hair-like receptors = impulse to cerebellum (Vertigo)
Ian Waterman, after viral infection, lost his sense of light touch and body position and movement—can walk but must look at limbs to direct them
When lights go out, he falls and cannot get up again until they come back on
When he is not looking at his body, he moves very little, unlike most of us who move around quite a bit
Synesthesia—sensory condition in which stimulating one modality leads to perception in another (to perceive together)
1 in 2,000 occurrence, females outnumber 6 to 1, seems to run in families so there may be a genetic base

32. Make sense now…?