HEARING (and Balance)

1. HEARING (and Balance) Hearing: Audition Balance: Vestibular System

2. Sound Changes in AIR PRESSURE Amplitude = Loudness Frequency = Pitch 20-20,000 Hz 100-60,000 Hz 200-150,000 Hz 1-20,000 Hz

3. Sound is a vibration that travels as a wave through an elastic medium, such as air. Sound

4. Humans can hear frequencies between 50 and 20,000 cycles per second (Hz) 40Hz - 20,000Hz Hearing

5. Elephants and many whales can hear lower sounds (14-35Hz and 10-40Hz, respectively) These low frequencies permit communication over great distances, particularly in water Hearing

6. Processing speed can limit the ability to distinguish rapid variations in sound For example, the calls of Orca whales have rapid variations in pitch and rhythm that we cannot detect. Limits of Hearing

7. Emitting calls and hearing bounce-back Found in bats, dolphins, shrews, most whales, few birds Echolocation

8. The Ear

9. The Ear High frequency Low frequency Hair Cells!

10. The Ear to Brain • Localizing Sound: • Time difference to reach ears. • Intensity difference at each ear. One vs two ears?

11. Build an Ear Sensitivity?

12. The Ear to Brain Localizing Sound 1 2 3 4 5 11 12 13 14 15 6 7 8 9 10 One vs two ears?

13. Hearing McGurk Effect

14. Balance