Sensation and Perception Final Exam
Decibel
20 change in this results in 10x the amount of air pressure; 6 increase of this makes things seem twice as loud
Range of hearing
20 hz to about 20,000 Hz
Location Heuristic
a single sound tends to come from one location and to move continuously
Visual capture
an observer perceives the sound as coming from the visual location rather than the source for the sound
Tonotopic map
cochlea shows an orderly map of frequencies along its length; apex responds best to low frequencies while base respond best to high frequencies
Interaural time difference
difference between the times sound reach the two ears
Interaural level difference
difference in sound pressure level reaching the two ears; head casts and acoustic shadow; works best for high frequency sounds
Inside rooms, we get
direct and indirect sound which gives the sound more body/fullness and gives a sense of size of the room
Fast tempo often perceived as
happy
Major keys are often perceived as
happy and peaceful
Larger amplitude corresponds to
louder sounds
Cochlea sound distribution
low frequencies are detected on the narrow end while high frequencies are detected on the wide end
Middle ear
made of malleus, incus, and stapes which helps to amplify sound to move dense fluid in inner ear ear
Outer ear
made of pinna, auditory canal, and tympanic membrane; serves protection function and enhances intensities of some sounds through resonance
Complex tone
many different frequencies at once; still sounds like one tone
Frequency
number of cycles per second; measured in Hz
Equal loudness curves
number of decibels that create the same loudness at different frequencies; low frequency sounds need to be louder to be heard
Phonemes
shortest segment of speech that changes meaning of a word; don't necessarily correspond to letters; difference due to acoustic signal; production is innate
Perception of meter is influenced by
stress patterns of a person's language (long-term experiences)
Auditory scene
the array of all sound sources in the environment
Jeffress model for ITD neurons
there is a line of neurons and when the signals from each ear reach the neuron at the same time then it will fire; wherever the neuron is activated demonstrates which ear is closer to the signal; inaccurate for mammals
Voice onset time
time between the beginning of the sound and the onset of vocal cord vibration
Intimacy time
time between when sound leaves its source and when the first reflection arrives; should be about 20 ms
Warren Experiment
tones presented interrupted by gaps of silence or noise; listeners perceived sound stopping in silent condition but continuing in noise condition
Mondegreens
when you mishear a lyric and think it says something different than it actually does
Emotivist approach to music
a listener's emotional response to music involves actually feeling the emotions
Creating metrical structure
accentuate some notes by using a stronger attack or by playing notes louder or longer
Tone envelope
attack, sustain, and decay of a sound
Music's beneficial cognitive outcomes
better memory; slowing down effects of aging or dementia; better hearing ability despite hearing loss
Musical training is linked to
better performance in mathematics; greater emotional sensitivity; improved language skills; greater sensitivity to timing
Inner ear
comprised of cochlea which holds hair cells that make the electrical signal
Pitch
corresponds to fundamental frequency; how high or low a sound sounds
Timbre
corresponds to harmonicity and envelope (e.g. piano sounds different than violin)
Loudness
corresponds to the amplitude
Beat
creates a framework for notes that create a rhythmic pattern and a melody; often accompanied by movement; pulse of music
When we are outside, we only get
direct sound
On average, people can localize sounds
directly in front of them most accurately and to the sides and behind their heads least accurately
Distance coordinates
distance of sound from the observer
Spaciousness factor
fraction of all the sound received by listener that is indirect (high best)
Formats
frequencies that have a lot of energy in the sound
Two parameters of sound
frequency and amplitude
Physical properties of sound
frequency, amplitude, harmonicity, and envelope
Two factors in timbre
height and number of harmonics and tone envelope
Higher frequency corresponds to
higher pitch
Frequency tuning curve
how different frequencies excite certain regions of the cochlea
Perceptual organization
how do we group sounds together as coming from the same source
Amplitude
how much does the air pressure change overtime; corresponds to loudness
Coarticulation
how sounds sound and transition are affected by the sounds that precede or follow it
Envelope
how the sound starts to how the sound ends
Categorical perception
humans hear the differences between categories but not the differences between categories of letters
Broca's area
in the frontal lobe close to the motor cortex; related to speech production and understanding grammar; damage to this area results in patients that produce meaningful but a-grammatical sentences
Congenital amusia
inability to recognize music but can recognize language; don't recognize tones as tones
Tone height
increasing pitch that accompanies increase in frequency
Harmonics
integer multiples of the fundamental frequency
Cognitivist approach to music
listeners can perceive the emotional meaning of a piece of music but don't actually feel the emotions
Binaural cues
location cues based on the comparison of the signals received by the left and right ears; interaural time and level difference
Spectrogram
looks at the energy for speech; shows frequency and intensity of sound over time
Segmentation problem
looks how we segregate a continuous stream of sound into words; largely use context
Distributed coding
neurons that respond differentially depending on the ITD to help localize; pretty much Jeffress model occurring multiple times
Pure tone
one single frequency, rare in the natural world
Meter
organization of beats into bars or measures; first beat in each is accented; number of beats per measure; cognitive function
Tonality
organizing pitches around the note associated with the composition's key
Periodicity pitch
phenomena where we perceive the same pitch even if the fundamental frequency is removed
Perceptual properties of sound
pitch, loudness, and timbre
Azimuth coordinates
position left to right of a sound
Tone chroma
position of a tone within an octave; equivalent sound in each octave; every octave is double the precious octave
Elevation coordinates
position up and down of a sound
Auditory scene analysis
process by which sound sources in the auditory scene are separated into individual perceptions; occurs in processing pathways in the brain
Bass ratio
ratio of low to middle frequencies reflected from surfaces (high is best)
Slow tempo often perceived as
sad and peaceful
Minor keys are often perceived as
scary and sad
Why is speech difficult?
segmentation problem; mondegreens; variability from context
All wiring in the hearing pathway is
sequential from the brain stem to thalamus to right or left auditory cortex
Indirect sound
sound that is reflected off surfaces to the listener
Direct sound
sound that reaches the listener's ears straight from the source
Proximity in time
sounds that occur in rapid succession usually come from the same source
Onset time
sounds that start at different times are likely to come from different sources; sounds that start at the same time are likely to come from same source
Auditory continuity
sounds that stay constant or change smoothly are usually from the same source
McGurk effect
speech perception is influenced by visual information
Ventral stream
starts in the anterior portion of the core and belt and extends to the prefrontal cortex; responsible for identifying sounds
Dorsal stream
starts in the posterior core and belt and extends to parietal and prefrontal cortices; responsible for locating sounds
Deutsch Experiment (Scale illusion)
stimuli where two sequences alternating in left and right ear; listeners perceive two smooth sequences by grouping the sounds by similarity in pitch
Bregman and Campbell experiment
stimuli with alternating high and low tones; when tones played slowly there is alternating perception; when playing tones quickly get linear high tone and linear low tone
Auditory space
surrounds an observer and exists wherever there is sound
Melody
the experience of a sequence of pitches as belonging together
Characteristic frequency
the frequency that excites an individual hair cell
Fundamental frequency
the lowest frequency represented in the tone
Reverberation time
the time it takes sound to decrease to 1/1000th of its original pressure; ideal times are between 1.5 and 2 seconds
Rhythm
the varying time pattern or durations created by notes
Wernicke's area
understanding and producing meaning in language; patients with damage in this area can do fluent but meaningless speech
Monaural cue
uses information from one ear; pinna affects how some sounds are reflected; best for judging elevation
evoked autobiographical memory
when a piece of music triggers a memory of some past experience; often associated with strong emotions