Audition

what determines the range of frequency perceptions?

the structure of the basilar membrane

shorter basilar membrane

you have a smaller range of hearing frequency

longer basilar membrane

you have a larger range of hearing frequency

sound waves

they must be initiated by something and then air molecules move and cause a chain reaction

amplitude

loudness, measured in decibels (dB)

high amplitude

louder

low amplitude

quieter

wavelength

pitch, measured in hertz (Hz)

lower wavelength

low pitch

purity

timbre, the perceived complexity of the sound

what are the 3 sections of the ear?

external, middle, and inner

the ear: external

made up of the pinna, auditory canal, and ear drum

the pinna

the folded cone on the outside of the ear, it collects the sound waves in the environment and determines where sound is coming from

the auditory/ear canal

this part receives and amplifies the sound waves

the ear drum

this is found at the back of the ear canal, also called the tympanic membrane

the ear: middle

found on the other side of the ear drum, contains 3 ossicles and the oval window

3 ossicles

hammer, anvil, and stirrup

the oval window

a small opening in the cochlea that causes fluid to be displaced

what happens when the oval window is pushed inward?

the fluid is pushed down

what happens when the oval window is pushed outward?

the fluid is pushed up

the ear: inner

basilar membrane and hair cells

outer hair cells

there are many, they share one direct link to the brain, amplify sounds, and are unmyelinated

inner hair cells

there are few, they have more connections to the brain, send pitch information, and are myelinated

basilar membrane

the external membrane of the hair cells

echolocation

the process where a receiver emits sound pulses and analyzes the echo

what is the purpose of echolocation?

to form a perceptual image of surrounding objects

co-evolution

the process where evolution/adaptation in traits of one species directly impact the evolution/adaptation of another species

longitudinal waves

how sound waves travel, parallel to the direction they go

transverse waves

how light waves travel, travelling perpendicular to the direction they go

what happens if you destroy/damage your ear drum/tympanic membrane?

you’ll lose your ability to hear (nothing amplifies sounds anymore)

cochlea

the fluid-filled coiled tube

what happens when the basilar membrane moves towards the narrow base?

there are high frequencies

what happens when the basilar membrane moves towards the wide apex?

there are low frequencies

tonotopic organization

the spatial organization of sound frequency on the basilar membrane and auditory brain structures

absolute pitch (AP)

the ability to identify pitch without reference to an external standard

what are the 2 binaural cues for localizing sound in space?

interaual time difference (ITD) + interaural intensity difference (IID)

interaural time difference

an auditory cue that explains how our ears receive sounds at different times because of the placement of incoming sounds, between ears

interaural intensity difference

an auditory cue that explains the difference in intensity of sound between our ears

head shadow effect

there is a region of reduced sound intensity that is caused by the head acting as an obstacle to the sound waves

which intensity cue words best for high frequency sounds?

interaural intensity difference (IID)

low frequency creates…

no sound shadows

high frequency creates…

sound shadows

binaural cues

cues that require inputs from both ears to extract information

azimuth

the horizontal angle wrt the head

elevation

the vertical angle wrt the head