Download 669791508362MyersMod_LG_13

MODULE 13 PREVIEW
Our hearing, or audition, is highly adaptive; it is most sensitive to the sounds we most need to hear. The
process involves sound waves being transmitted to the fluid-filled cochlea, where they are converted to
neural messages and sent to the brain. Together, the place and frequency theories explain how we hear
both high-pitched and low-pitched sounds. Hearing loss may be caused by prolonged exposure to loud
noise or by diseases and age-related disorders.
The sense of touch is actually four senses—pressure, warmth, cold, and pain—that combine to
produce other sensations such as “hot.” Taste, a chemical sense, is a composite of sweet, sour, salty, and
bitter sensations, and of the aromas that interact with information from the taste buds. Smell, also a
chemical sense, does not have basic sensations as there are for touch and taste. Our effective functioning
also requires a kinesthetic sense and a vestibular sense, which together enable us to detect body position
and movement.
Experiments with sensory restriction demonstrate that while we do need stimulation, we also benefit
from periods of peace and relaxation.
GENERAL INSTRUCTIONAL OBJECTIVES
1. To discuss the auditory process.
2. To explore the physical and social challenges of hearing loss.
MODULE GUIDE
The Stimulus Input: Sound Waves and The Ear
1. Explain the auditory process, including the stimulus input and the structure and function of the ear.
Audition, or hearing, is highly adaptive. The pressure waves we experience as sound vary in amplitude
and frequency and correspondingly in perceived loudness and pitch. Decibels are the measuring unit for
sound energy. Through a mechanical chain of events, sound waves traveling through the auditory canal
cause minuscule vibrations in the eardrum. Transmitted via the bones of the middle ear (the hammer,
anvil, and stirrup) to the fluid-filled cochlea in the inner ear, these vibrations create movement in tiny
hair cells on the basilar membrane, triggering neural messages to the brain.
Exercise: Auditory Demonstrations on CD
Film: Hearing Things
PsychSim: The Auditory System
Transparencies: 67 The Intensity of Some Common Sounds, 68 How We Transform Sound Waves Into Nerve Impulses That
Our Brain Interprets
2. Explain the place and frequency theories of pitch perception.
Place theory presumes that we hear different pitches because different sound waves trigger activity at
different places along the cochlea’s basilar membrane. Thus, the brain can determine a sound’s pitch by
recognizing the place on the membrane from which it receives neural signals.
Frequency theory states that the rate of nerve impulses traveling up the auditory nerve matches the
frequency of a tone, thus enabling us to sense its pitch.
Place theory best explains how we sense high-pitched sounds, and frequency theory best explains how
we sense low-pitched sounds.
3. Describe how we locate sounds.
We localize sounds by detecting minute differences in the intensity and timing of the sounds received by
each ear.
Lecture: Recognizing Our Own Voice
Exercise: Locating Sounds
Transparency: 69 How We Locate Sounds
Hearing Loss and Deaf Culture
4. Discuss the nature and causes of hearing loss.
Problems with the mechanical system that conducts sound waves to the cochlea cause conduction hearing
loss. If the eardrum is punctured or if the tiny bones of the middle ear lose their ability to vibrate, the
ear’s ability to conduct vibrations diminishes. A hearing aid may restore hearing by amplifying the
vibrations.
Damage to the cochlea’s hair cell receptors or their associated nerves can cause sensorineural hearing
loss. Once destroyed, these tissues remain dead, although a hearing aid may amplify sound to stimulate
other hair cells. Disease, biological changes linked with aging, or prolonged exposure to ear-splitting
noise or music may cause sensorineural hearing loss.
Lecture: Hearing Loss
Video: Causes of Hearing Loss
Transparency: 70 Older People Suffer Hearing Loss for High Frequencies
5. Describe the effects of noise on hearing and behavior.
Those who live with hearing loss face social challenges. Cochlear implants can enable some hearing by
deaf children. But deaf-culture advocates, noting that sign is a complete language, question the
enhancement.