1. Audition

2. The Stimulus Input: Sound Waves
Sound waves are composed of compression and rarefaction of air molecules.
OBJECTIVE 11| Describe the pressure waves we experience as sound.
Acoustical transduction: Conversion of sound waves into neural impulses in the hair cells of the inner ear.

3. Sound Characteristics
Frequency (pitch)
Intensity (loudness)
Quality (timbre)

4. Frequency (Pitch)
Frequency (pitch): The dimension of frequency determined by the wavelength of sound.
Wavelength: The distance from the peak of one wave to the peak of the next.

5. Intensity (Loudness)
Intensity (Loudness): Amount of energy in a wave, determined by the amplitude, relates to the perceived loudness.

6. Loudness of Sound
Richard Kaylin/ Stone/ Getty Images
120dB
70dB

7. Quality (Timbre)
Quality (Timbre): Characteristics of sound from a zither and a guitar allows the ear to distinguish between the two.
Zither
Guitar

8. Overtones: Makes the distinction among musical instruments possible.

9. The Ear
Dr. Fred Hossler/ Visuals Unlimited
OBJECTIVE 12| Describe the three regions of the ear, and outline the series of events that triggers the electrical impulses sent to the brain.

10. The Ear Outer Ear: Pinna. Collects sounds.
Middle Ear: Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window.
Inner Ear: Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

11. Cochlea
Cochlea: Coiled, bony, fluid-filled tube in the inner ear that transforms sound vibrations to auditory signals.

12. Theories of Audition
Place Theory suggests that sound frequencies stimulate the basilar membrane at specific places resulting in perceived pitch.
OBJECTIVE 13| Contrast place and frequency theories, and explain how they help us to understand pitch perception.

13. Theories of Audition
Frequency Theory states that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
Auditory Nerve
Action Potentials
Sound
Frequency
200 Hz
100 Hz

14. Localization of Sounds
Because we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.
OBJECTIVE 14| Describe how we pinpoint sounds.

15. 1. Intensity differences
Localization of Sound
1. Intensity differences
2. Time differences
Time differences as small as 1/100,000 of a second can cause us to localize sound. The head acts as a “shadow” or partial sound barrier.

16. Hearing Loss
Conduction Hearing Loss: Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
Sensorineural Hearing Loss: Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve, also called nerve deafness.
OBJECTIVE 15| Contrast two types of hearing loss, and describe some of their causes.

17. Hearing Deficits
Older people tend to hear low frequencies well but suffer hearing loss when listening for high frequencies.

18. Deaf Culture
Cochlear implants are electronic devices that enable the brain to hear sounds.
OBJECTIVE 16| Describe how cochlear implants function, and explain why Deaf culture advocates object to these devices. Where these implants are pertinent for hearing parents with deaf children, deaf culture advocate not using them especially on children deafened before learning to speak.
Wolfgang Gstottner. (2004) American
Scientist, Vol. 92, Number 5. (p. 437)
EG Images/ J.S. Wilson ©
Deaf Musician
Cochlear Implant

19. Other Important Senses
The sense of touch is a mix of four distinct skin senses—pressure, warmth, cold, and pain.
OBJECTIVE 17| Describe the sense of touch. “Touch is both the alpha and omega of affection” (James, 1890).
Bruce Ayers/ Stone/ Getty Images

20. Touch Considered the most comforting sense
Plays a crucial role in human development (infants)
Our skin is our largest sense organ
Various skin receptors give rise to sensation of pressure, temperature & pain
Brain can anticipate certain touch stimulation (tickling yourself vs. someone else doing it)
Fingertips & face are most sensitive to touch (recall 2 point threshold)
Skin can also undergo sensory adaptation (adjusting to hot or cold water)
Two types of skin: hairy skin ~ has hair cells, which detect movement & pressure & glabrous skin ~ no hair cells, so receptors here are more sensitive; found mainly on palms of hands, bottom of feet & lips.

21. Skin Senses
Only pressure has identifiable receptors. All other skin sensations are variations of pressure, warmth, cold and pain.
Pressure
Vibration
Vibration
Burning hot
Cold, warmth and pain

22. Ashley Blocker (right) feels neither pain
Pain tells the body that something has gone wrong. Usually pain results from damage to the skin and other tissues. A rare disease exists in which the afflicted person feels no pain.
OBJECTIVE 18| State the purpose of pain, and describe the biopsychosocial perspective on pain.
AP Photo/ Stephen Morton
Ashley Blocker (right) feels neither pain
nor extreme hot or cold.

23. Biopsychosocial Influences

24. Gate-Control Theory
Melzak and Wall (1965, 1983) proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed.
One way to treat chronic pain is to stimulate it through massage by electrical stimulation or acupuncture. Rubbing causes competitive stimulation to pain thus reduces its effect.
Gary Comer/ PhototakeUSA.com

25. Pain Control
Pain can be controlled by a number of therapies including, drugs, surgery, acupuncture, exercise, hypnosis, and even thought distraction.
Burn victims can be distracted by allowing them to engage in illusory virtual reality. Their brain scans show differences in pain perceptions.
Todd Richards and Aric Vills, U.W.
©Hunter Hoffman,

26. proteins to grow and repair tissue
Taste
Our tongues have receptors for five different types of tastes, each of which may have had survival functions.
Bitter:
potential poisons
Sweet:
energy source
Umami: (savoriness)
proteins to grow and repair tissue
Salty: sodium essential to physiological processes
Click to show labels.
Tastes may exist to attract humans to energy and protein-rich foods that are typically sweet or “umami,” and to avert them from potentially toxic or harmful substances that are often bitter or sour. Umami is a recently identified, savory taste that is associated with monosodium glutamate, meats, mushrooms, seaweed, and aged cheeses (such as Parmesan).
Salty tastes also attract humans to replenish essential salts.
Sour:
potentially toxic acid

27. Neurochemistry of Taste
There are no regions of the tongue, just different types of taste receptor cells projecting hairs into each taste bud’s pore.
These cells are easily triggered to send messages to the temporal lobe of the brain.
Burn your tongue? Receptors reproduce every week or two. But with age, taste buds become less numerous and less sensitive.
Top-down processes still can override the neurochemistry; expectations do influence taste.
Click to reveal bullets.

28. Mixing the different senses together
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Sensory interaction occurs when different senses influence each other.
For example:
a burst of sound makes a dim light source more visible.
flavor is an experience not only of taste, but also of smell and texture.
seeing text or lip movement, or even feeling the puff of air from consonants, affects what words we hear.
Synaesthesia is a condition when perception in one sense is triggered by a sensation in a DIFFERENT sense.
Some people experience synaesthesia all the time, reporting that, “the number 7 gives me a salty taste” or “rock music seems purple.”
Click to reveal bullets.

29. Taste
Traditionally, taste sensations consisted of sweet, salty, sour, and bitter tastes. Recently, receptors for a fifth taste have been discovered called “Umami”.
OBJECTIVE 19| Describe the sense of taste, and explain the principle of sensory interaction.
Sweet
Sour
Salty
Bitter
Umami
(savoriness)
(Fresh
Chicken)

30. Survival Functions of Basic Tastes
Sweet = Energy Source
Salty = Sodium essential to physiological processes
Sour = Potentially toxic acid
Bitter = Potential poisons
Umami = Proteins to grow and repair tissue

31. Taste Taste is different from flavor (hold nose & eat = no flavor!)
Taste = bitterness, saltiness, sourness & sweetness
***a 5th!!! = Umami: described as a savory meaty taste, best experienced as the flavor enhancer MSG
A chemical sense
Taste receptors reproduce themselves every week or two.
As you grow older, # of taste buds decreases as does taste sensitivity

32. How do we experience taste?
Inside each tiny bump on top & sides of tongue = 200+ taste buds & each has a pore that catches food chemicals. Each taste bud pore has taste receptor cells that project hairs that sense food molecules.
Chemicals in food dissolve in saliva & get into the crevices between papilae on the tongue
Causes neurons to fire, sending a nerve impulse to parietal, temporal & limbic system
Taste can be identified within 1/10 of a second

33. Tongue Map = Myth!
In the late 1800’s, a German Ph.D. student studied tongue’s
sensitivity to different tastes, which he plotted on a graph.
The graph of his data was done “impressionistically,”
meaning he didn’t rely on his actual data to create the
graph. For over 75 years, scholars took his graph at face
value, perpetuating the myth of the tongue map.

34. Sensory Interaction
When one sense affects another sense, sensory interaction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor.

35. Smell (Olfaction): The most primitive and evocative sense
Smell is a chemical sense that bypasses the brain’s sensory switchboard…thalamus
Smallest whiff can trigger intense memories; even forgotten ones. Smell is connected to emotion & memory
Our sense of smell is weak compared to animals…esp. animals on all fours w/ heads close to ground. We have million olfactory receptor cells & a bloodhound has 200 million!!!!
Women tend to have better sense of smell
20-40 yrs old = sharpest time, smell decreases as people get older
Anosmia: The complete loss of smell

36. Age, Gender, and Smell
Ability to identify smell peaks during early adulthood, but steadily declines after that. Women are better at detecting odors than men.

37. Smell
Like taste, smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 million receptors to sense smell. Unlike taste, there are many different forms of smell.
OBJECTIVE 20| Describe the sense of smell and explain why specific odors so easily trigger memories.

38. How do we experience smell?
Complex protein in nasal gland called odorant binding protein (OBP) binds to odor molecules
Then activates receptors high in nasal cavity in tissue called olfactory epithelium
These cells are replaced every few weeks
Axons from receptors go to the olfactory bulb
Then routed through the olfactory tract to the temporal lobes primary smell cortex & to parts of the limbic system involved in memory & emotion.

39. Smell and Memories
The brain region for smell (in red) is closely connected with the brain regions involved with memory (limbic system). That is why strong memories are made through the sense of smell.

40. Body Position and Movement
The sense of our body parts’ position and movement is called kinesthesis. The vestibular sense monitors the head (and body’s) position.
OBJECTIVE 21| Distinguish between kinesthesis and vestibular sense.
Bob Daemmrich/ The Image Works
Whirling Dervishes
Wire Walk

41. Sensing Body Position and Movement
Kinesthesis (“movement feeling”) refers to sensing the movement and position of individual body parts relative to each other.
How it works: sensors in the joints and muscles send signals that coordinate with signals from the skin, eyes, and ears
Without kinesthesis, we would need to watch our limbs constantly to coordinate movement.
Click to reveal bullets.

42. Vestibular Sense
-semicircular canals & the vestibular sacs which connect the canals w/ the cochlea, contain fluid that moves when your head rotates or tilts. Movement stimulates hairlike receptors, which send message to cerebellum, enabling you to sense your body position & maintain balance