Ch 12: Hearing in the environment Flashcards
What information can be used to localize auditory stimuli?
-see paper
What is the precedence effect?
-delay between two of the same sound
-if delay is shorter than 2ms, the sound fuses so it sounds like only one source
-if its longer than 35ms, two separate sounds are perceived (echo)
How can the visually impaired use sound for localization and locomotion?
-echolocation: reflection off objects used to locate location of objections
How does reverberation affect our experience of sound?
-reflection of sound by walls, ceiling, floor
-increases duration of the sound
-aids in localization
-less reverb as you get closer to the sound source
What are the two mechanisms responsible for auditory scene analysis? (gestalt stuff)
- PRIMITIVE GROUPING (bottom-up)
-simultaneous: how categorize sounds happening one after other
-pitch similarity, auditory continuity
-sequential: how group sounds happening @ same time
-location, onset synchrony
-timbre/pitch
- SCHEMA GROUPING (top-down)
-via experience/expectation
-attn = process more
Discuss the nature of absolute pitch.
-extreme accuracy 90% correct at ID musical note w/o reference note
-1/10k
-name key of piece of music
-influenced by timbre and tone chroma: similarity shared by musical tones that have the same name (ex C in one octave vs C in another octave)
-genetic, must start music young
How is music processed in the brain?
-hard to study b/c music so complex
-widespread brain activation, large individual diffs
-composer brain injury: conceptual abilities intact, can perceive music but not write new music
-suggests no one specific brain centre for music, since portions intact still
-primary and secondary auditory cortex handle early stages in music perception
-more complex for secondary, then even more complex for tertiary (integrate patterns into whole)
-beyond this area = association areas
IN GENERAL:
-L hem: intervals (distances between tones) and rhythm (durations of series of notes)
-R hem: recognizes holistic traits like meter (regular beat) and melodic contour (pattern of rising and falling pitches)
TUNING CURVED:
-neurons can shift their tuning curves to the frequency of a tone; became stronger over time w/o extra exposure
-learning can retune the brain so that more cells respond behaviourally to important sounds
-musicians have diff brain organization:
-more L auditory regions respond (specific to music, not non music tones)
-larger effect the younger you start music
-same temporal lobe brain activation for imagining music as actually listening
Describe the evidence for/against the “Mozart effect.”
FOR: -temporary improvement in spatial reasoning “equivalent of IQ score increase”
-improved spatial/temporal ability for 1/4 tests: enhances higher brain functions (preschool piano lessons)
-blood clot in brain go away via humming
AGAINST: -not replicable studies
-not studied over time
-results blown out of proportion via media coverage
-many studies lack control groups
-no demographic info given
CONCLUSION:
-nothing special about mozart
-music can improve mood which can lead to improved task performance maybe
-journals biased towards exciting findings
reverberation time
-time for sound to decrease to 1/1000th of original pressure
-too short = music sounds fead/flat
-too long = muddy
-concert halls should be 1.5-2s reverb
Jefress neural coincidence model
(THIS IS FOR BIRDS: its not so specific for mammals - loc coding for mammals is based more on broadly tuned neurons = POPULATION CODING, broadly tuned neurons interact to create a specific percept of certain loc)
-neurons wired so that when they receive signals from 2 ears, they can localize via the sound hitting ears at diff times triggers a specific neutron depending on the delay between L vs R sound hitting the ear
-its a coincidence!
-this is a model for interural time diff (VIA ITD NEURAL TUNING CURVE)
maybe you want to go over the specifics of how musical scene perception is grouped? (12.4)
see 12.4
WHAT and WHERE auditory pathways!
-see papee
