Module 10 How Do We Hear, Speak, and Make Music Flashcards
Thomas Gessimann
-Among most of the 26 species of singing primates, males and females sing duets
-All singing primates are monogamous, suggesting that singing may somehow relate to sexual behaviors
~Music may also play a role in primates’ parenting behaviors
-The human brain is specialized for analyzing certain aspects of music in the right temporal lobe, which complements the left temporal lobe’s specialization for analyzing aspects of speech
-Neanderthals have long fascinated researchers; the species originated about 300,000 years ago and disappeared about 30,000 years ago at some point they coexisted in Europe and the Middle East
-Researches long hypothesized the Neanderthal culture was significantly less developed than that of early Homo sapiens, yet their brain was as large or larger than Homo sapiens
Ivan Turk
-A paleontologist excavated a cave in not=rthern Slovenia that had been used by Neanderthals as a hunting ground
-Buried in the cave among a cache of stone tools was a leg bond of a young bear that looks as if it was fashioned into a flute
~The bone has holes aligned along one side that could not have been made by gnawing animals
*The holes’ spacing resembled positions found on a modern flute
Bob Fink
- A musicologist, analyzed the flute’s musical qualities
- He found eight-note scale similar to a do-re-mi scale could be played on the flute; but compared with the scale most familiar in European music, one note was slightly off
- The “blue” note, a staple of Jazz, is standard in musical scales throughout Africa and India today
Language
- Is the use of complex systems of communication and includes syntax (innate grammar)
- Although processing and production of certain forms of language may involve specific sensory input and structures of motor output
- Sign language uses visual input and motor output using the hands and arms, whereas spoken language uses auditory input and motor output using vocal cords
Compression Waves
-The undulating energy generated by the displacement of molecules of changing air pressure to emanate from the turning fork
Sound waves
- Mechanical displacement of molecules caused by changing pressure that possesses the physical properties of frequency, amplitude, and complexity.
- Also referred to as a compression wave
- In air travel at a fixed speed of 1100 feet (343 meters) per second and more than four times fates in water, but sound energy varies in wavelength
Cycle
-Is one complete peak and valley on the graph-the change from one maximum or minimum air pressure level of the sound wave to the next maximum or minimum level
Sound wave energy has three physical attributes
-Frequency
-Amplitude
-Complexity
~Produced by the displacement of air molecules
-The auditory system analyzes each property separately
Frequency
- Number of cycles a wave completes in a given time
- Sound wave frequencies are measured in cycles per second, called hertz
Hertz
- Measure of sound wave frequency (repetition rate); 1 heart equals 1 cycle per second
- 50 hertz is 50 cycles per second, 6000 hertz is 6000 cycles per second
Low pitch
-Have fewer wave frequencies (fewer cycles per second)
High Pitch
-Have more wave frequencies (more cycles per second)
Health young adult
-The hearing range is from 20 to 20,000 hertz
Low-frequencies
-Travel lone distance in water
High-frequencies
-Echo that bounce back from objects
Middle Con the piano
-Has a frequency of 264 hertz
Perfect Pitch
- Being able to name any note they hear
- Runs in families, suggesting a genetic influence
Amplitude
- Stimulus intensity; in audition, roughly equivalent to loudness, graphed by the increasing height of a sound wave
- Differences in perceived intensity, or loudness
- Differences are graphed by increasing the height of a sound wave
Decibels (dB)
- Measure of the relative physical intensity of sounds
- The strength of a sound relative to the threshold of human hearing as a standard, pegging at 0 decibels
- Typical speech sounds, measure about 40 dB
- Sounds that register more than about 70 dB we perceive as loud; those of less than about 20 dB WWE perceive as soft or quiet like a person whispering
Human nervous system
- Evolved to be sensitive to soft sounds and so it actually blows away by extremely loud ones
- People actually damage their hearing through exposure to very loud sounds or even by prolonged exposure to sounds that are only relatively loud
- Prolong exposure to sounds louder than 100 dB is likely to damage our hearing
Adrian Drake-Lee
- Found that rock musicians had a significant loss of sensitivity to sound waves, especially at about 6000 hertz
- After a typical 90 min concert, this loss was temporarily far worse; as much as a 40-fold increase in sound pressure was needed to reach a musician’s hearing threshold
- Symphony orchestras also produce dangerously high sound levels and that hearing loss is common among symphony musicians
- Prolonged listening through headphones or earbuds to music played soundly on personal music players is responsible for significant hearing loss in many young people
Tinnitus
- Ringing in the ears
- Described as ringing, whining, whistling, clicking, hissing, or roaring, and it may be soft or loud, low, or high pitched
- Can be intermittent or it can be continuous
- Estimated to affect about 10 to 15% of people under the age of 40 worldwide; its prevalence doubles with advanced age
- No medications provide effective treatment for tinnitus, and prevention is recommended
- The best way to prevent tinnitus is to avoid prolonged exposure to high-intensity would level of 70 dB or higher and to wear earplugs when those situations are unavoidable
Two broad categories of Tinnitus
- Objective
- Subjective
Objective Tinnitus
- Maybe the result of actual sound produced within the ear
- Muscle spasms around the middle ear or blood flow can cause sounds that some individuals can detect, which they report as an annoying tinnitus
Subjective Tinnitus
-More common form, is a condition of hearing a sound in the absence of an external auditory stimulus
-Most common is noise-induced damage to inner hair cells, which is why rates of tinnitus are very high among those who work in high-intensity sound environments such as war zones, certain heavy industries, and music production
-Other causes include ear infections, head and neck injuries, and exposure to certain drugs
~More than 260 medications-including aspirin-have has been reported to cause intermittent tinnitus as a side effect
Pure tones
- Single wave frequency
- Turning fork or pitch pipe
Complex tomes
- Mix wave frequencies together in combination
- Even when a musician plays a single note, the instrument is making a complex tone
Fundamental Frequencies
- Wave 1 is the rate at which the complex waveform patterns repeat
- Wave 2 through 20 are overtones
Overtones
-A set of higher-frequency soundwaves that vibrate at whole-number multiples of the fundamental frequency
Periodicity
-The fundamental frequency repeats at regular intervals
Noise
-Sounds that are aperiodic or random
The brain has evolved systems that analyze sounds for meaning
- Speech in the left temporal lobe
- Music in the right temporal lobe
Listening to a particular language
- Helps the brain analyze rapid speech, which is one reason people who are speaking languages unfamiliar to you often seem to be talking incredibly fast
- The brain does not know where the foreign words end and begins, so they seem to run together in a rapid-fire stream
The auditory system
- Have a mechanism for categorizing sounds as being the same despite small differences in pronunciation
- A major obstacle to mastering a foreign language after the age of 10 is the difficulty of learning which sound categories are treated as equivalent
Loudness
- The magnitude of a sound as judged by a person
- Is related to the amplitude of a soundwave measured in dB, but loudness is also subjective
Pitch
- The position of each tone on a musical scale, as judged by the listener
- Is clearly related to soundwave frequency, there is more to it than that
Prosody
- Melodic tone of the speaking voice
- Pitch contributes to the perceived melodic tone of a voice
Quality (Tember)
-Perceived characteristics that distinguish a particular sound from all other od similar pitch and loudness
The evolution of sound-processing systems for both language and music
-Accompanied by enhancement of specialized cortical regions, especially in the temporal lobes
Ear a biological masterpiece in three acts
- Outer ear
- Middle ear
- Inner ear
Pinna
-Funnel-like external structure of the outer ear
-Are made of cartilage and flesh
-Is designed to catch soundwaves in the surrounding environment and deflect them into the external ear canal
~To enhance sound detection when we want to hear better we often cup a hand around the pinna
Canal
- Extends a short distance from the pinna inside the head
- Are made of cartilage and flesh
- Amplifies sound waves and direct them to the eardrum
Eardrum
-When sound strikes, it vibrates, the rate of vibration varying with the frequency of the waves
Middle Ear
-An air-filled chamber that contains the three smallest bones in the human body, connected in a series
Ossicles
- Bone of the middle ear: includes hammer, anvil, and stirrup
- Amplifies the vibrations and conveys them to the membrane that covers the cochlea’s oval window
Oval Window
- Ossicle attach the eardrum
- an opening in the body casing of the cochlea
Cochlea
- Inner ear structure containing the auditory receptor cells
- These receptor cells and the cells that support them are collectively called the ORGAN of CORTI
Basilar Membrane
-Receptor surface in the cochlea that transduces sound waves into neural activity
Hair cells
- Specialized neurons in the cochlea tipped by cilia; when stimulated by waves in the cochlear fluid, the cilia bend and generate graded potentials in inner hair cells, the auditory receptors cells
- At the poine of peak displacement are stimulated, resulting in a maximal neural response in those cells
Tectorial Membrane
-The cilia of the outer hair cells that are embedded and overlay the membrane
Stirrup
-On the oval window makes the cochlear fluid move because the second membranous window in the cochlea (the round window) bulges outward as the stirrup presses inward on the oval window
Chain reaction
-The waves traveling through the cochlear fluid bend the basilar and tectorial membranes, and the bending membranes stimulate the cilia at the tips of the outer and inner hairs cells
Basilar Membrane
-All sound waves cause some displacement along the entire length of the membrane, but the amount of displacement at any point varies with the frequency of soundwaves
-Uncoiling near the oval window is maximally affected by frequencies as high as about 20,000 hertz, the upper limit of our hearing range
-Incoming signal composed of many frequencies causes several points to vibrate, exciting hair cells at all these points
-Much more sensitive to changes in frequency that id the rope in our analogy because the basilar membrane varies in thickness along its entire length
-Narrow and thick at its base, near the oval window, and wider and thinner at its tightly coiled apex
~The combinations of varying width and thicknesses enhances the effect of small frequency differences
*The cochlear receptors can code small differences in sound waves frequency as neural impulses
Both inner and outer hair cells
- Anchored in the basilar membrane
- The tips of the cilia of the outer hair cells are attached to the overlying tectorial membrane, but the cilia in the inner hair cells only loosely touch that membrane
- The movement of the basilar and tectorial membranes causes the cochlear fluid to flow past the cilia of the inner hair cells, bending them back and forth
Inner hair cells
- can be destroyed by prolonged exposure to intense sound pressure waves, infections, diseases, or certain chemicals and drugs
- Do not regenerate in mammals; this, once your inner hair cell has died, hearing loss is permanent
- Movement of only about 0.3 nm is sufficient to allow soundwave detection- that’s about the diameter of an atom
Outer hair cells
- Function by sharpening the cochlea’s resolving power, contracting or relaxing, and thereby changing tectorial membrane stiffness
- Have the motor function
- Contract or relax to alter the physical stimulus detected by the inner hair cells
- Send a message to the brainstem auditory areas and receive a replay that causes the cells to alter the tension on the tectorial membrane
- Also part of a mechanism that modulates auditory nerve firing, especially in response to intense sound pressure waves, and thus offer some protection against their damaging effects
The neurons of the auditory nerve have a spontaneous baseline rate
- Firing action potentials, and this rate is changed by the amount of neurotransmitter the hair cells release
- Turns out that movement of the cilia changes the inner hair cell’s polarization and its rate of neurotransmitter release
Inner hair cells continuously leak calcium
-This leakage causes a small but steady amount of neurotransmitters released into the synapse
-Movement of the cilia in one direction results in depolarization
~Calcium channels open and release more neurotransmitter onto the dendrites of the cells that form the auditory nerve, generating more nerve impulses
-Movement of the cilia in the other direction hyperpolarizes the cell membrane, and transmitter release decrease, thus decreasing activity in auditory neurons
Otoacoustic Emissions
-Spontaneous or evoked sound waves produced within the ear by the cochlea that escape from the ear
-Soundwaves produced by a healthy cochela
~The outer hair cells amplify soundwaves, providingan energy source that enhances cochlear sensitivity and frequency sensitivity
*Not all the energy thecocholea generates is dissipated within it, some escape towards the middle ear, which works efficiently in both directions, thus setting the eardrum inmotion
-The eardrum then acts as a loudspeaker, radiating soundwaves out of the ear
-Sensitive ,icrophones placed in the external ear canal can detect both types of otoacustic emissions
~Spontaneous
~Evoked