Psychology of Perception Ch. 11

The audibility curve of a six-month-old infant _____.

is similar to the audibility curve for an adult

The correct order of the ossicles in the middle ear (from ear drum to oval window) is _____.

malleus; incus; stapes

The motion of the basilar membrane results in _____.

movement of both the organ of Corti and the tectorial membrane

DeCasper and Fifer used _____ as the dependent variable to test if two-day-old infants could identify the sound of the mother's voice.

pattern of nipple sucking

Auditory nerve fibers fire in synchrony with the rising and falling pressure of the pure tone, a phenomenon called

phase locking

_____ is the property of increasing pitch that accompanies increases in the tone's frequency

Tone height

When listening to music, which method will help ensure you hear all of the frequencies represented in the piece?

Turn the volume up (e.g., 80 dB) so the music is loud.

The question "If a tree falls in a forest and no one is there to hear it, would there be a sound?" is useful because it highlights that "sound" can be _____.

both a perceptual response and a physical stimulus

Bendor and Wang (2005), when presenting a complex tone with a 182 Hz fundamental frequency to a marmoset, found a neuron that responded to a 182-Hz tone when presented alone but not when any of the harmonics were presented alone. The neuron that responded just to 182-Hz tone is an example of a(n) _____ neuron.

pitch

Adding an 880 Hz tone and a 1320 Hz tone to a 440 Hz tone will result in _____.

a complex tone

Which of the following does not need an outer or middle ear to hear effectively?

fish

Pitch is primarily determined by the _____ of the sound wave

frequency

A complex tone can be created by starting with a pure tone, called the _____, and adding frequencies that are multiples of this first frequency

fundamental frequency

A frequency spectrum shows a tone that is composed of a frequency of 440 Hz, 880 Hz, and 1320 Hz. The 880 Hz and 1320 Hz frequencies are called _____ in this example

harmonics

Research supports that an infant's ability to recognize the mother's voice is due to _____.

hearing the mother talk while in the womb

The bending of the cilia of the _____ causes a release of small bursts of neurotransmitter.

inner hair cells

When the tip links in the cilia stretch, ion channels open and _____.

potassium flows into the cell

Hearing loss that occurs as a function of age is called _____.

presbycusis

The function of the auditory canal is to enhance the intensities of some frequency sounds by means of _____

resonance

As the frequency increases, the place on the membrane that vibrates the most moves from _____.

the apex at the end of the cochlea toward the base at the oval window.

The outer hair cells respond to sound by slightly tilting and changing length. Because of the consequence of this, the action of the outer hair cells is called the _____.

the cochlear amplifier

If a pregnant mother reads the original version of The Cat in The Hat aloud while pregnant, which version of The Cat in The Hat would the infant prefer after birth?

the original version, as it had been read to them prenatally

The outer ear consists of _____.

the pinnae, the auditory canal, and the tympanic membrane

Békésy's place theory of hearing proposes that the frequency of a sound is ____

the place along the basilar membrane that vibrates the most

A complex tone composed of a 440 Hz tone, an 880 Hz tone, and a 1320 HZ tone is presented. Which part of the basilar membrane will respond?

the three different areas characteristic of each individual component

A piano tone played backwards will sound more likely an organ than a piano because _____.

the tone's original decay has become the attack, and vice versa

The cochlear implant makes use of _____.

the tonotopic map of frequencies on the cochlea

The sound quality that is related to the sounds clarity, "nasalness" or "reedy-ness" is _____.

timbre

The role of the middle ear is _____.

to amplify vibrations from the air for transmission through liquid

A guinea pig tonotopic map shows that a receptor close to the apex will respond to a tone of _____ Hz.

60

The unit of measurement for sound wave frequency is _____.

Hertz

Kat wants to buy a "dog whistle" that her dog can hear but she can't. She should get a whistle that emits sounds in the range between ____ and _____ Hz.

30,000; 40,000

The speed of sound through air is _____.

340 meters per second

The sound pressure level increases ____ as the decibel level increases from 40 to 80 dBs

10 times

As you increase the decibel level from 80 dB to 100 dB, the sound pressure ratio goes from _____ to _____.

10,000; 100,000

At their highest settings, portable music players can reach ____, which is _____ OSHA's recommended maximum.

100; 15 dB higher than

Alessandra is at a concert and can "feel" the music. The music is most likely being played at _____ dBs

130

. The range of human hearing is between _____ Hz.

20-20,000

Describe the methods, results, and implications of research on the infant's ability to recognize the mother's voice.

Anthony DeCasper and William Fifer (1980) demonstrated the capacity of infants to recognize their mothers' voices in newborns by showing that 2-day-old infants will modify their sucking on a nipple in order to hear the sound of their mother's voice. They first observed that infants usually suck on a nipple in bursts separated by pauses. They fitted infants with earphones and let the length of the pause in the infant's sucking determine whether the infant heard a recording of the mother's voice or a recording of a stranger's voice. For half of the infants, long pauses activated the tape of the mother's voice, and short pauses activated the tape of the stranger's voice. For the other half, these conditions were reversed. DeCasper and Fifer found that the babies regulated the pauses in their sucking so that they heard their mother's voice more than the stranger's voice. This is a remarkable accomplishment for a 2-day-old, especially because most had been with their mothers for only a few hours between birth and the time they were tested.

Briefly describe the major principle of Békésy's place theory of hearing

Békésy determined how the basilar membrane vibrates to different frequencies by observing the vibration of the basilar membrane. He accomplished this by boring a hole in cochleas taken from animal and human cadavers. He presented different frequencies of sound and observed the membrane's vibration by using a technique similar to that used to create stop-action photographs of high-speed events (Békésy, 1960). When he observed the membrane's position at different points in time, he saw that the basilar membrane's vibration as a traveling wave, like the motion that occurs when a person holds the end of a rope and "snaps" it, sending a wave traveling down the rope. Békésy's most important finding was that the place that vibrates the most depends on the frequency of the tone. As the frequency increases, the place on the membrane that vibrates the most moves from the apex at the end of the cochlea toward the base at the oval window. Thus, the place of maximum vibration, which is near the apex of the basilar membrane for a 25-Hz tone, has moved to nearer the base for a 1,600-Hz tone. Because the place of maximum vibration depends on frequency, this means that basilar membrane vibration effectively functions as a filter that sorts tones by frequency.

What are the major components of a cochlear implant?

Békésy's discovery that each place on the basilar membrane is associated with a particular frequency has led to the development of a device called a cochlear implant, which is used to create hearing in people with deafness caused by damage to the hair cells in the cochlea. When the hair cells are damaged, hearing aids are ineffective because the damaged hair cells cannot convert the amplified sound provided by the hearing aid into electrical signals. The cochlear implant consists of (1) a microphone that receives sound signals from the environment; (2) a sound processor that divides the sound received by the microphone into a number of frequency bands; (3) a transmitter that sends these signals to (4) an array of 12-22 electrodes that are implanted along the length of the cochlea. These electrodes stimulate the cochlea at different places along its length, depending on the intensities of the frequencies in the stimuli received by the microphone. This stimulation activates auditory nerve fibers along the cochlea, which send signals toward the brain. The hearing that results enables people to recognize everyday sounds such as horns honking, doors closing, water running, and in some cases, speech.

Define loudness, pitch, and timbre and relate each to the physical sound stimulus.

Loudness is the perceptual quality most closely related to the level or amplitude of an auditory stimulus, which is expressed in decibels. Pitch, the perceptual quality we describe as "high" or "low," can be defined as the property of auditory sensation in terms of which sounds may be ordered on a musical scale (Bendor & Wang, 2005). The idea that pitch is associated with the musical scale is reflected in another definition of pitch, which states that pitch is that aspect of auditory sensation whose variation is associated with musical melodies (Plack, 2014). While often associated with music, pitch is also a property of speech (low-pitched or high-pitched voice) and other natural sounds. Timbre is closely related to the harmonic structure of a tone. The difference in the harmonics of different instruments is not the only factor that creates the distinctive timbres of musical instruments. Timbre also depends on the time course of a tone's attack (the buildup of sound at the beginning of the tone) and of the tone's decay (the decrease in sound at the end of the tone).

Discuss how noise-induced hearing loss can occur, and what can be done to reduce the chances of noise-induced hearing loss

Noise-induced hearing loss occurs when loud noises cause degeneration of the hair cells. This degeneration has been observed in examinations of the cochleas of people who have worked in noisy environments and have willed their ear structures to medical research. Damage to the organ of Corti is often observed in these cases. For example, examination of the cochlea of a man who worked in a steel mill indicated that his organ of Corti had collapsed and no receptor cells remained (Miller, 1974). More controlled studies of animals exposed to loud sounds provide further evidence that high-intensity sounds can damage or completely destroy inner hair cells (Liberman & Dodds, 1984). Because of the danger to hair cells posed by workplace noise, the United States Occupational Safety and Health Agency (OSHA) has mandated that workers not be exposed to sound levels greater than 85 dB for an 8-hour work shift. In addition to workplace noise, however, other sources of intense sound can cause hair cell damage leading to hearing loss. If you turn up the volume on your portable music player, you are exposing yourself to what hearing professionals call leisure noise. Other sources of leisure noise are activities such as recreational gun use, riding motorcycles, playing musical instruments, and working with power tools. A number of studies have demonstrated hearing loss in people who listen to portable music players (Okamoto et al., 2011; Peng et al., 2007), play in rock/pop bands (Schmuziger et al., 2006), use power tools (Dalton et al., 2001), and attend sports events (Hodgetts & Liu, 2006). The amount of hearing loss depends on the level of sound intensity and the duration of exposure. Given the high levels of sound that occur in these activities, such as the levels above 90 dB SPL that can occur for the 3 hours of a hockey game (Hodgetts & Liu, 2006), about 100 dB SPL for music venues such as clubs or concerts (Howgate & Plack, 2011), and levels as high as 90 dB SPL while using power tools in woodworking, it isn't surprising that both temporary and permanent hearing losses are associated with these leisure activities. These findings suggest that it might make sense to use ear protection when in particularly noisy environments and to turn down the volume on your portable music player.

Describe how the actions of the cochlea result in transduction.

The main structure of the inner ear is the liquid-filled cochlea, a snaillike structure. The most obvious feature of the uncoiled cochlea is that the upper half, called the scala vestibuli, and the lower half, called the scala tympani, are separated by a structure called the cochlear partition. This partition extends almost the entire length of the cochlea, from its base near the stapes to its apex at the far end. When we look at the cochlea in cross section, we see the organ of Corti, which contains the hair cells, the receptors for hearing. In addition, there are two membranes, the basilar membrane and the tectorial membrane, which also extend the length of the cochlea, and which play crucial roles in activating the hair cells. Cilia, thin processes that protrude from the tops of the hair cells, bend in response to pressure changes. The human ear contains one row of inner hair cells and about three rows of outer hair cells, with about 3,500 inner hair cells and 12,000 outer hair cells. The cilia of the tallest row of outer hair cells are embedded in the tectorial membrane and the cilia of the rest of the outer hair cells and all of the inner hair cells are not (Moller, 2006). The organ of Corti sitting on the basilar membrane, with the tectorial membrane arching over the hair cells, and is the staging ground for events that occur when vibration of the stapes in the middle ear sets the oval window into motion. The back and forth motion of the oval window transmits vibrations to the liquid inside the cochlea, which sets the basilar membrane into motion. The up-and- down motion of the basilar membrane has two results: (1) it sets the organ of Corti into an up-and-down vibration, and (2) it causes the tectorial membrane to move back and forth, as shown by the red arrow. These two motions mean that the tectorial membrane slides back and forward just above the hair cells. The movement of the tectorial membrane causes the cilia of the outer hair cells that are embedded in the membrane to bend. The cilia of the other outer hair cells and the inner hair cells also bend, but in response to pressure waves in the liquid surrounding the cilia. Transduction for hearing involves a sequence of events that creates ion flow. First, the cilia of the hair cells bend in one direction. This bending causes structures called tip links to stretch, and this opens tiny ion channels in the membrane of the cilia, which function like trapdoors. When the ion channels are open, positively charged potassium ions flow into the cell and an electrical signal results. When the cilia bend in the other direction, the tip links slacken, the ion channels close, and ion flow stops. Thus, the back-and-forth bending of the hair cells causes alternating bursts of electrical signals (when the cilia bend in one direction) and no electrical signals (when the cilia bend in the opposite direction). The electrical signals in the hair cells result in the release of neurotransmitters at the synapse separating the inner hair cells from the auditory nerve fibers and cause these auditory nerve fibers to fire.

Discuss the structures and functions of the middle ear.

When airborne sound waves reach the tympanic membrane at the end of the auditory canal, they set it into vibration, and this vibration is transmitted to structures in the middle ear, on the other side of the tympanic membrane. The middle ear is a small cavity, about 2 cubic centimeters in volume, that separates the outer and inner ears. This cavity contains the ossicles, the three smallest bones in the body. The first of these bones, the malleus (also known as the hammer), is set into vibration by the tympanic membrane, to which it is attached, and transmits its vibrations to the incus (or anvil), which, in turn, transmits its vibrations to the stapes (or stirrup). The stapes then transmits its vibrations to the inner ear by pushing on the membrane covering the oval window.

The function of the muscles of the middle ear is to _____.

dampen the ossicles vibrations at high intensities

The relationship between loudness and frequency can be shown graphically using _____.

equal loudness curves

The wave form pattern of a pure tone is a(n) _____.

sine wave

An important difference between vision and hearing is that _____.

sound waves can travel around corners but light waves cannot

Békésy discovered the traveling wave motion of the basilar membrane by _____.

stimulating the ear of human cadavers