KHA 114 Lecture Notes - Lecture 4: Umami, Visual Acuity, Olfaction
29 Jun 2018
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Psychology D:
- Basic property of sound is vibration
- The more denser the mass sound travels through the harder it is (liquid and
solid)
- Wave complexity determines time
- Pitch: wave frequency
oMeasured in hertz (Hz)
oAs we age we lose sensitivity to higher frequency
oFlexibility in the mechanisms in the ear
- Loudness: determined by amplitude of wave
oLower amplitude, fewer decibels, quieter
oMeasured decibles (db)
o50-60 decibels average talking loudness
o125 db (rock concert) vibrations cause pain
- Timbre: wave complexity
oCaused by the complexity of the wave, variations in the way the wave
is formed
oDifferentiations in similar notes
Sensing sound:
- Must think about the structure of ear, divided coarsely into three sections
oOuter ear: very simple function
Funnel sound waves to the eardrum (tympanic) in middle ear
Down the ear canal
oMiddle ear:
Ossicles: bones; hammer, anvil, stirrup
Eardrum vibrates, causes anvil to vibrate onto hammer and
stirrup
This process transits sounds to the cochlear
oInner ear:
Cochlea: bony but filled with fluid
Vibrations disturb fluid
Organ of Corti and basilar membrane:
Basal membrane contain hair cells, excites and shift
Shifting causing neural activity
Electrical impulses transmitted to brain
Once converted to electrical impulses, travel to brain and
perception kicks in
- Pitch perception: involves three complimentary theories
oPlace theory: simplest
Different tones/pitches excite different areas in BM
Neural and electrical impulses travel to different areas
Different sensitivity’s
Only accounts for higher pitch perception (5000Hz-20000Hz)
oFrequency theory: proposed to account for discrimination of 0-100Hz
Determined by the rates at which individual neurons fire
Fire slowly, low pitch, higher firing, higher pitch
find more resources at oneclass.com
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Document Summary
The more denser the mass sound travels through the harder it is (liquid and solid) Pitch: wave frequency: measured in hertz (hz, as we age we lose sensitivity to higher frequency, flexibility in the mechanisms in the ear. Loudness: determined by amplitude of wave: lower amplitude, fewer decibels, quieter, measured decibles (db, 50-60 decibels average talking loudness, 125 db (rock concert) vibrations cause pain. Timbre: wave complexity: caused by the complexity of the wave, variations in the way the wave is formed, differentiations in similar notes. Must think about the structure of ear, divided coarsely into three sections: outer ear: very simple function. Funnel sound waves to the eardrum (tympanic) in middle ear. Down the ear canal: middle ear: Eardrum vibrates, causes anvil to vibrate onto hammer and stirrup. This process transits sounds to the cochlear: inner ear: Basal membrane contain hair cells, excites and shift. Once converted to electrical impulses, travel to brain and perception kicks in.
