psychophysics and psychoacoustics Flashcards
thresholds
finding the limits of what can be perceived
not absolute
scaling
measuring private experience, your own qualitative experience
signal detection theory
measuring difficult decisions
ie/ seeing smt that might be cancer, but you are not 100 percent sure
makes a distinction between an observer’s ability to perceive a signal and their willingness to report it
sensory neuroscience
the biology of sensation and perception
neuroimaging
an image of the mind
ie/ binocular rivalry, showing two different images to your eyes and they compete to dominate your eye
what is psychophysics
the study of the relation between the physical stimulus and the psychological (experience we have, subjective) sensations - how these things work together
mental life and physical world. relationship between mind and body using mathematics
gustav fechner
1801-1887
invented psychophysics and could be considered the true founder of experimental psychology
what is the content of psychophysics
detection - tell smt is out there
discrimination - difference between stimuli
identification
scaling
detection
determining the minimum amount of a particular stimulus that is required for the individual to say a stimulus is present
absolute threshold
the stimulus energy above which the stimulus is detectable
Method of constant stimuli
fixed set of stimuli,ranging from rarely to almost always perceivable, are choseen in advance.
each presented one at a time, many times in random order.
each intensity, multiple times, in a random order.
create many stimuli with different intensities, in order to find the tiniest intensity that can be detected.
The problem of background noice
Variability-and nerons firing
internal and external sources
All of our sensory systems have evolved to account for the “spontaneous firing or resting rate” of our normally functioning neurons-meaning that our sensory systems are going to be more or less sensitive at different times
Internal sources
You can always hear something even in the quitest of places
need to detect presence of internal noise.
external sources
unintentional
sometimes they are not a problem
problem when stimuli magnitude is greater
method of limits
the magnitude of a stimulus is varied incrementally until the participant respond differently
more efficient if the experiment begins with the same stimuli of varied intensity
when they can hear a tone, tones presented in increasing intensity (when can you hear tone) or vice versa (when no longer hear tone)
change stimulus until person changes their response - transition from change in response in their threshold
ascending trials - no -> yes
descending trials - yes -> no
errors:
error of preservation
error of anticipation
controlling for errors
method of adjustment
similar to method of limits, but the participant control the stimulus directly
ie/ like adjusting the radio volume
to study how we perceive things we need to study
the properties of the physical world
the properties of our sensory system - convert neural impulse to something we can interpret
the higher - level processing which allows us to interpret the symbolic signals
Sensitivity
a value that defines the ease with which an observer can tell the difference between the presence and absence of a stimulus or the difference between two stimuli
how easy can you pick up signals(or difference) in the world.
Criterion
an internal threshold that is set by the observer
If the internal response(in nervous system) is above criterion< the observer gives one response.
Below criterion, the observer gives another response.
Discriminability
How well an observer can seperate the presence of a signal from its absence
measured by d’ (discriminability index, also called sensitivity)
Receiver Operating Characteristic(ROC)
plot false alarms on x-axis against hits on y-axis
Just-noticeable difference(JND)
the smallest detectable difference between two stimuli, or the minimum change that can be correctly judged as different from a reference stimulus(also known as difference threshold)
half of the interval of uncertainty
changed in a systematic way
webers law
the smallest change in a stimulus that can be detected is a constant proportion of the stimulus level.
delta I/I =k - fechner found a way to describe the relationship between mind and matter
Sound
The physical stimulus for the ear: vibratory pressure waves
Sounds cause molecules in the objects medium(usually air)
Vibrations cause pressure changes(waves)
Sound becomes less prominent as we move farther from the source
Sound waves move faster in denser substances
Sine Wave, Pure tone
The waveform for which variation as a function of time is a sine function
Amount of pressure in environment
Sounds can be described as a combination of sine waves
Wavelength
In sound, the time required for one cycle of repeating waveform
Frequency
The number of times per unit time that a pattern of pressure change repeats
How quickly sound pressure fluctuates and associated with pitch
Amplitude(or intensity)
The magnitude of displacement( increase or decrease) of a sound pressure wave, magnitude of sound wave, perception of loudness.
perception
the act of giving meaning or purpose to detected senses
Hertz(Hz)
A unit of measure for frequency- one Hz=One cycle(wavelength)per second
senstation
the ability to detect a stimulus and perhaps to turn that detection into a private experience
qualia
In reference to philosophy, private conscious experiences of sensation or perception.
computation models
Your ability to distinguish speech sounds depends almost entirely on the kinds of speech sounds that you heard while growing up. This is because, for all of your senses, perception is a combination of things one is born with and things that are acquired only through experience.
to describe precisely how the basic abilities that every infant possesses at birth become shaped by experience in a particular language environment to predict the way you perceive speech sounds.
Decibel(dB)
A unit of measure for the physical intensity(amplitude) of sound,ratios off sound pressure
A logarithmic scale(e.g., an increase of 6dB corresponds to a doubling of pressure)
dualism
The idea that the mind has an existence separate from the material
world of the body.
materialism
The idea that the only thing that exists is matter, and that all things, including the mind and con- sciousness, are the results of interaction between bits of matter.
panpsychism
The idea that the mind exists as a property of all matter—that is, that all matter has consciousness.
two point touch threshold
The mini- mum distance at which two stimuli (e.g., two simultaneous touches) are just perceptible as separate.
fetchner’s law
A principle describing the relationship between stimulus and resulting sensation that says the magni- tude of subjective sensation increases proportionally to the logarithm of the stimulus intensity.
Oscicles
Amplify sound waves
Hinged on ways that act like levers - increase pressure change
[ ] NRG from smaller from smaller-> larger SA
magnitude estimation
A psychophys- ical method in which the participant assigns values according to perceived magnitudes of the stimuli.
Stapes
Transmits vibration to oval window
Amplifies signal, increase force
steven’s power law
A principle describing the relationship between stimulus and resulting sensation that says the magnitude of subjective sensa- tion is proportional to the stimulus mag- nitude raised to an exponent.
docterine of specific nerve energies
A doctrine, formulated by Johannes Müller, stating that the nature of a sensation depends on which sensory fibers are stimulated, rather than how they are stimulated.
What are the three oscicles?
Malleus
Stapes
Incus
Oval window
Forms border between middle ear and inner ear
tymphanic canal
One of three fluidfilled passages in the cochlea. The tympanic canal extends from
the round window at the base of the cochlea to the helicotrema at the apex. Also called scala tympani.
Tympanic membrane
Ear drum
Ossilates when pressure waves hit
Moves in and out in response to pressure changes of sound waves
Border between outer and middle ear
vestibular canal
One of three fluid filled passages in the cochlea. The vestibular canal extends from the oval window at the base of the cochlea to the helicotrema at the apex. Also called scala vestibuli.
middle canal
One of three fluidfilled passages in the cochlea. The middle canal is sandwiched between the tym panic and vestibular canals and contains the cochlear partition. Also called scala media.
Pinna
What we see- funnel sound info into ear
Where sounds are first collected in environment- helps with localizing sound
helicotrema
The opening that con nects the tympanic and vestibular canals at the apex of the cochlea
stria vascularis
Specialized tissue lines one side of the middle canal and maintains the right balance of charged ions in the endolymph to keep hair cells working at their best.
reissner’s membrane
A thin sheath of tissue separating the vestibular and middle canals in the cochlea.
cochlear partition
The combined basilar membrane, tectorial membrane, and organ of Corti, which are together responsible for the transduction
round window
A soft area of tissue
at the base of the tympanic canal that releases excess pressure remaining from extremely intense sounds.
organ of corti
A structure on the basilar membrane of the cochlea that is composed of hair cells and dendrites of auditory nerve fibers.
hair cell
Any cell that has stereocilia for transducing mechanical movement in the inner ear into neural activity sent to the brain. Some hair cells also receive inputs from the brain.
auditory nerve
A collection of neurons that convey information from hair cells in the cochlea to the brainstem (afferent neurons) and from the brain stem to the hair cells (efferent neurons)
Purpose of earwax
Waterproofs(like your car) the ear canal prevent water from getting stuck in there
Lubricates the ear canal to keep it from getting dry and itchy
Natural antibiotic/antifungal because it is acidic
Captures dust and dirt
tectorial membrane
A gelatinous structure, attached on one end, that extends into the middle canal of the cochlea, floating above inner hair cells and touching outer hair cells.
place code
Tuning of different parts of the cochlea to different frequencies,
in which information about the partic ular frequency of an incoming sound wave is coded by the place along the cochlear partition that has the greatest mechanical displacement.
Inner ear
Translates sound into neural signals
afferent fiber
A neuron that carries sensory information to the central nervous system.
efferent fiber
A neuron that carries Wolfe6e_09.13.ai 3.25.2020 information from the central nervous system to the periphery
threshold tuning curve
A graph plotting the thresholds of a neuron in response to sine waves with varying frequencies at the lowest intensity that will give rise to a response.
characteristic frequency
The frequency to which a particular auditory nerve fiber is most sensitive
electromotility
The ability of outer hair cells to extend and contract which changes the stiffness and sensitivity of the cochlear partition.
phase locking
Firing of a single neu ron at one distinct point in the period (cycle) of a sound wave at a given fre quency. (The neuron need not fire on every cycle, but each firing will occur at the same point in the cycle.)
The cochlea
Vibrations cause stapes to push and pull the flexible oval window- in and out of vestibular canal which causes pressure change
Cochlea is a close tube(sound can’t pass in all directions)
temporal code
Tuning of different parts of the cochlea to different fre quencies, in which information about the particular frequency of an incoming sound wave is coded by the timing of neural firing as it relates to the period of the sound.
volley principle
The idea that multiple neurons can provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but does not fire on every period.
cochlear nucleus
The first brainstem nucleus at which afferent auditory nerve
fibers synapse.
superior olive
An early brainstem region in the auditory pathway where inputs from both ears converge.
equal loudness curve
A graph plotting sound pressure level (dB SPL) against the frequency for which a listener perceives constant loudness.
temporal integration
The process
by which a sound at a constant level is perceived as being louder when it is of greater duration. The term also applies to perceived brightness, which depends on the duration of light.
masking
Using a second sound, frequently noise, to make the detection of another sound more difficult.
white noise
Noise consisting of all audible frequencies in equal amounts. White noise in hearing is analogous to white light in vision, for which all wave lengths are present.
critical bandwidth
The range of frequencies conveyed within a channel in the auditory system.
Basilar membrane
Between middle & tymphanic canal
Movement changes as sound comes in
Tonictopically organized
conductive hearing loss
Hearing loss caused by problems with the bones of the middle ear.
otitis media
Inflammation of the mid dle ear, commonly in children as a result of infection.
otosclerosis
Abnormal growth of the middleear bones that causes hearing loss.
sensorineural hearing loss
Hearing loss due to defects in the cochlea or auditory nerve.
metabolic hearing loss
Hearing loss caused by degraded ability of the stria vascularis to provide sufficient nutrients and ions to the cochlear partition
Stereocilia
Hairlike extensions on the tips of hair cells in cochlea that initiate the release of neurotransmitters when they are flexed.
The tip of each stereocilium is connected to the side of its neighbor by a tiny filament called a tip link- to open and close gates.
phase
the relative timing of a singe wave
fourier analysis
a mathematical procedure by which any signal can be separated into component sine waves at different frequencies
separates various sine waves
fundamental frequency
the lowest-frequency component of a complex periodic sound, first harmonic
harmonic spectrum
the spectrum of a complex sound in which energy is at integer multiple of the fundamental frequency, typically caused by a simple vibrating source - each frequency component of a sound is called this
loudness
the psychological aspect sound related to perceived intensity or amplitude - bigger the amplitude larger the sound
pitch
the psychological aspect of sound related mainly to the fundamental frequency
low frequency sounds correspond to low pitches
high frequency sounds correspond to high pitches
timbre
the psychological sensation by which a listener can judge that two sounds with the same loudness and pitch are dissimilar - tell difference between them
conveyed by harmonics and other high frequencies
psychoacoustics
a branch of psychophysics in which the psychological correlates of the physical dimensions of sound are studies
audibility threshold
the lowest sound pressure level that can be reliably detected at a given frequency - can be reliably detected across the range of human hearing
equal-loudness curve
a graph plotting sound pressure level against the frequency for which a listener perceives constant loudness
for them to be heard equally loud
