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