AP PSYCH 3.5 Auditory Sensation and Perception

Sound Waves

• Sound waves have various qualities that we interpret differently
• High frequency sounds have more waves in a shorter distance
• High amplitude sounds have higher distance between the peak and trough of the wave
  • The opposite is true for low frequency/amplitude sounds

The Ear

• The ear’s function is to intake sound waves and to transduct those waves into neural impulses our brain can understand

Outer Ear

• This includes the pinna, external auditory canal, and tympanic membrane
• The pinna is the flesh and cartilage around the ear canal
  • It’s odd shape helps funnel as much sound as possible into the ear
• The external auditory canal is the tunnel that sound travels though
• The tympanic membrane, or ear drum, divides the outer from the middle ear
  • The tympanic membrane vibrates when sound reaches it, transferring it to the ossicles
• The overall function of the outer ear is to gather, concentrate, and amplify sound waves

Middle Ear

• Sound waves are now traveling through solids, not the air
• The hammer, anvil, and stirrup are three very small bones, also known as ossicles
• They receive vibrations from the eardrum

Inner Ear

• Sound waves are traveling through the liquid in the cochlea
• The cochlea is a spiraled tube with little hairs, cilia, inside
• The cilia receive the vibrations are are linked to the auditory nerve
• Cilia are the site of transduction

Hearing Phenomenon

Hearing Loss

• There are two different kinds of hearing loss

Sensorineural Hearing Loss

• Hearing loss due to impairment of the cilia and/or auditory nerve
• This will effect both ears
• It impacts volume, clarity, and range of sounds heard
• The more common type of hearing loss
• Often because of aging, can also be from trauma (either a single event or chronic) and diseases

Conductive Hearing Loss

• This is caused by an impairment in the outer ear, ear drum, and/or ossicles
• This may affect only one ear
• Sound waves are not progressing normally through the ear and causes distortion
• May be because of blockage, physical trauma