Unit 4(D):Unit 4(D):HearingHearing

Mr. McCormickMr. McCormick

A.P. PsychologyA.P. Psychology

Do-NowDo-Now(Discussion)(Discussion)

Why does one’s Why does one’s voicevoice sound so sound so different different when it is when it is recordedrecorded and and played backplayed back??

HearingHearing

Audition:Audition: The sense or act of hearingThe sense or act of hearing

The Stimulus Input: Sound WavesThe Stimulus Input: Sound Waves

Sound waves are compressing and Sound waves are compressing and expanding air moleculesexpanding air molecules

Frequency:Frequency: The number of complete wavelengths that The number of complete wavelengths that

pass a point in a given time (for example, per pass a point in a given time (for example, per second)second)

Pitch:Pitch: A tone’s experienced highness or lownessA tone’s experienced highness or lowness

The Stimulus Input: Sound WavesThe Stimulus Input: Sound Waves

Amplitude:Amplitude: The height of a sound waveThe height of a sound wave Measures the energy/intensity of the waveMeasures the energy/intensity of the wave LoudnessLoudness Measured in decibelsMeasured in decibels

Typical Decibel LevelsTypical Decibel Levels

Loudness of SoundLoudness of Sound

70dB

120dB

The EarThe Ear

The CochleaThe Cochlea

Perceiving PitchPerceiving Pitch

Place Theory:Place Theory: Links the pitch we hear with the place where the cochlea’s Links the pitch we hear with the place where the cochlea’s

membrane is stimulatedmembrane is stimulated Different frequencies vibrate in different places of the cochleaDifferent frequencies vibrate in different places of the cochlea Problem: Problem: low-pitched sounds not localizedlow-pitched sounds not localized

Frequency Theory:Frequency Theory: The rate of nerve impulses traveling up the auditory nerve The rate of nerve impulses traveling up the auditory nerve

matches the frequency of a tone, enabling us to sense its pitchmatches the frequency of a tone, enabling us to sense its pitch The entire cochlea is believed to vibrate at a particular frequencyThe entire cochlea is believed to vibrate at a particular frequency Problem: Problem: high-pitched sounds (1,000 waves/second) travel high-pitched sounds (1,000 waves/second) travel

faster than neuronsfaster than neurons

Locating SoundsLocating Sounds

Because we have two ears, sounds that reach one ear Because we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.faster than the other ear cause us to localize the sound.

Locating SoundsLocating Sounds

Why is it Why is it difficultdifficult to to locatelocate a sound when it a sound when it occurs directly occurs directly aheadahead, , behindbehind, , overheadoverhead, , or or beneath beneath us?us?

It is easier to locate a sound when it It is easier to locate a sound when it comes from either side of us; for this comes from either side of us; for this reason, to pinpoint a sound, we often need reason, to pinpoint a sound, we often need to cock our head, allowing each ear to to cock our head, allowing each ear to receive a slightly different message.receive a slightly different message.

Hearing Loss and Deaf CultureHearing Loss and Deaf Culture

Conduction Hearing Loss:Conduction Hearing Loss: Caused by damage to the mechanical system that Caused by damage to the mechanical system that

conducts sound waves to the cochleaconducts sound waves to the cochlea E.g. punctured eardrumE.g. punctured eardrum

Sensorineural Hearing Loss:Sensorineural Hearing Loss: Caused by damage to the cochlea’s receptor cells or Caused by damage to the cochlea’s receptor cells or

to the auditory nervesto the auditory nerves ““Nerve Deafness”Nerve Deafness” Biological changes associated with heredity, aging, Biological changes associated with heredity, aging,

and prolonged exposure to ear-splitting noise or musicand prolonged exposure to ear-splitting noise or music

Hearing Loss and Deaf CultureHearing Loss and Deaf Culture

Cochlear Implant:Cochlear Implant: A device for converting sounds into electrical A device for converting sounds into electrical

signals and stimulating the auditory nerve signals and stimulating the auditory nerve through electrodes threaded into the cochleathrough electrodes threaded into the cochlea

Hearing Loss and Deaf CultureHearing Loss and Deaf Culture

What are the What are the benefitsbenefits and and limitationslimitations of of using using sign language sign language exclusivelyexclusively in a in a hearing worldhearing world??

What should the What should the hearing world’s hearing world’s responseresponse be to the use of be to the use of sign languagesign language??

ReviewReview

What is What is determineddetermined by the by the frequencyfrequency of a of a sound? The sound? The amplitudeamplitude? ?

Discuss the Discuss the pathpath in which in which soundsound travels travels between entering the between entering the earear and reaching the and reaching the brainbrain..

How do we How do we locatelocate soundssounds??

What is the What is the differencedifference between between ConductionConduction and and Sensorineural Hearing LossSensorineural Hearing Loss??

HomeworkHomework

Unit 4 FRQUnit 4 FRQ

Unit 4 Quiz:Unit 4 Quiz: “Sensation and Perception”“Sensation and Perception”

Unit 4 Test:Unit 4 Test: “Sensation and Perception”“Sensation and Perception”

Chapter 5 Outline:Chapter 5 Outline: “States of “States of Consciousness”Consciousness”