1. Sound and Hearing 4.9-4.13

2. Sound and the Ear • Outer ear : collects and channels sound waves to the eardrum in the middle ear. • Middle ear :eardrum sends vibrations through the hammer/anvil to the cochlea • Cochlea: small hair cells vibrate with the pitch. • These hair cells connect to nerves that go to the brain

3. Sound and the Ear • Decibels are our measure of sound intensity • The decibel scale is exponential: every 10 decibels is ten times louder. • Biggest difference between decibels is therefore at the higher end.

4. Locating Sound • Just like our binocular sight, our ears perceive the slight differences in timing and intensity to judge the direction of a sound. • We are quite bad at determining location of sounds above, below, or in front of us.

5. Hearing Loss and Deafness • Prolonged exposure to high decibel sounds can ruin one’s hair cells in the cochlea • Conductive: damage to middle ear • Sensorineural: damage to hair cells in cochlea or to the nerve itself • Hearing aids just increase the intensity of incoming sound waves. • To restore hearing to one with sensorineural damage, a cochlear implant can link up the connection • It gathers its own sounds via a microphone directly sends electric signals to the nerve cells

6. Is Deafness a Disability? • The use of cochlear implants is highly debated b/c many in the deaf community • Deafness does not guarantee a language impairment • Most deaf children have hearing parents, making communication difficult • The deaf community has its own customs, values, and organizations within our larger culture • Like with vision loss, the sensitivity of other senses will increase to compensate.