Chapter 12: Hearing and the Environment Flashcards
1
Q
Auditory space
A
sounds at different locations all around
2
Q
auditory localization
A
the locating of sound sources in auditory space
3
Q
location cues
A
cues created by the way sound interacts with the listener’s head and ears
4
Q
two types of location cues
A
binaural and spectral cues
5
Q
3 coordinates of auditory space
A
azimuth, elevation, and distance (AED)
6
Q
azimuth
A
extends from left to right
7
Q
elevation
A
extends up and down
8
Q
distance
A
how far the sound is from the listener
9
Q
binaural cues
A
Use information reaching both ears to determine the azimuth of sounds
10
Q
two types of binaural cues
A
interaural level difference and interaural time difference
11
Q
Interaural level differences (ILD)
A
based on the difference in the sound pressure level of the sounds reaching the two ears
12
Q
acoustic shadow
A
reduces the intensity of sounds that reach the far ear
13
Q
why does interaural level difference occur
A
the head creates an acoustic shadow
14
Q
what frequencies does ILD occur for?
A
high-frequency sounds
15
Q
Interaural time difference (ITD)
A
the time difference between when a sound reaches the left ear and when it reaches the right ear
16
Q
ITD if the sound is in front of the listener
A
ITD= 0
17
Q
when is ITD larger
A
when sounds are located more to the side
18
Q
what frequencies for ITD occur for?
A
low-frequency sounds
19
Q
what binaural cue is more dominant?
A
ITD
20
Q
cone of confusion
A
a surface in the shape of a cone that extends out from the ear. Sounds originating from different locations on this surface all have the same interaural level difference and interaural time difference, so location information provided by these cues is ambiguous
21
Q
spectral cues
A
cues in which information for localization is contained in differences in the distribution of frequencies that reach each ear from different locations
22
Q
why do spectral cues occur?
A
because before the sound enters the auditory canal, it is reflected from the head and within the various folds of the pinnae
23
Q
what frequencies do spectral cues occur for?
A
high-frequency spectra
24
Q
how are different patterns of frequencies created?
A
Differences in the way sounds bounce around within the pinna
25
moulding the pinnae
makes it difficult to locate sounds along the elevation coordinate
26
localization performance while wearing a mould overtime
improves until day 19, when participants had learned over time to associate new spectral cues to different directions of space
27
what happens when moulds on the pinna are removed?
they still had excellent localization (both sets of spectral cues remained intact
28
The Jeffress Neural Coincidence Model
Proposes that neurons are wired so that they received signals from the two ears
29
Coincidence detectors
only fire when both signals coincide by arriving at the neurons simultaneously
30
what happens when the sound source is directly in front of the listener according to the Jeffress model?
the sound reaches the left and right ears simultaneously and signals from the left and right ears reach the coincidence detector
31
ITD detectors
fire best to a particular ITD
32
what happens when the sound source is to one side according to the Jeffress model?
that ear receives the signal first, giving its signal a head start and causing the corresponding ITD detector to fire
33
ITD tuning curves
plot the neuron’s firing rate against ITD
34
neurological basis of binaural localization in birds
based on sharply tuned neurons
35
coding in birds' binaural localization
Type of place code because the ITD is indicated by the firing of neurons at a specific place in the nervous system
36
neurological basis of binaural localization in mammals
based on broadly tuned neurons
37
coding in mammals' binaural localization
Type of population code because the ITD is determined by the firing of many broadly tuned neurons working together
38
Neff et al., 1956 A1 and localization experiment
placed cats in between two boxes and rewarded them if they approached the sound of the buzzer located behind one of the boxes. This task wasn’t possible for those with lesioned auditory areas, demonstrating that an intact auditory cortex is necessary for accurate localization
39
Nodal et al., 2010 A1 and localization experiment
showed that lesioning the primary auditory cortex in ferrets decreased, but didn’t eliminate their ability to localize sounds
40
Malhotra & Lumber, 2007 A1 and localization experiment
showed that cooling the auditory cortex resulted in decreased localization ability
41
Anterior belt area
involved in perceiving complex sounds and patterns of sound
42
posterior belt area
involved in localizing sounds
43
what auditory pathway
Associated with perceiving sounds
44
location of what auditory pathway
Extends from the anterior belt to the front of the temporal lobe, then to the frontal cortex
45
where auditory pathway
Associated with localizing sounds
46
location of where auditory pathway
starts in the posterior core and belt and extends to the parietal and prefrontal cortices
47
direct sound
sound that reaches the ears directly
48
indirect sound
sound that reaches the ears after bouncing off the walls, ceiling, and floors
49
hearing outside is based on __
direct sound
50
hearing inside is based on ___
direct and indirect sound
51
lead speaker
the actual sound source
52
lag speaker
a single sound reflection
53
precedence effect
when a single sound appears to originate from near the lead speaker because we perceive the sound as coming from near the source that reaches our ears first
54
architectural acoustics
the study of how sounds are reflected in rooms
55
architectural acoustics are largely connected with ___
indirect sound changes in the quality of the sounds we hear in rooms
56
main factors affecting indirect sound
- Size of the room
- The amount of sound absorbed by the walls, ceiling, and floor
57
absorption vs. indirect sound
More sound absorbed= little indirect sound
58
reverberation time
the time it takes for sound to decrease to 1/1000th of its original pressure
59
long reverberation time
sounds become muddled
60
short reverberation time
sound becomes dead
61
ideal reverberation time
2 seconds, but 1.5 for opera houses
62
intimacy time
the time between when sound arrives directly from the stage and when the first reflection arrives
63
bass ratio
the ratio of low frequencies to middle frequencies that are reflected from walls and other surfaces
64
spaciousness factor
the fraction of all of the sound received by a listener that is indirect sound
65
ideal dimensions for acoustics
intimacy times of 20 msec and high bass ratios and spaciousness factors were associated with good acoustics
66
auditory scene
the array of sound sources at different locations in the environment
67
auditory scene analysis (ASA)
the process by which the stimuli produced by each source are separated
68
auditory stream segregation
the perception of a string of sounds as belonging together
69
simultaneous grouping
grouping that occurs at the same time
70
factors that affect simultaneous grouping
- location
- onset synchrony
- timbre
- pitch
- harmonicity
71
simultaneous grouping and location
when two sounds are separated in space, location helps us to separate them perceptually. When a source moves, it typically follows a continuous path
72
simultaneous grouping and onset synchrony
if sounds start at different times, they likely came from different sources
73
simultaneous grouping and timbre and pitch
sounds with the same timbre or pitch range are often produced by the same source
74
harmonicity
when we hear a harmonic series, we infer it came from a single source
75
sequential grouping
grouping that occurs as sounds follow one another in time
76
factors that affect sequential grouping
- similarity of pitch
- auditory continuity
- experience
77
sequential grouping and similarity of pitch
sounds produced by the same source are usually similar in pitch
78
sequential grouping and auditory continuity
sounds that stay constant or change smoothly are often produced by the same sound source
79
sequential grouping and experience
past experience influences grouping
80
Deutsch's scale illusion/ melodic channelling
an illusion that occurs when successive notes of a scale are presented alternately to the left and right ears. Even though each ear receives notes that jump up and down in frequency, smoothly ascending or descending scales are heard in each ear
81
memory schema
a representation of a familiar melody that is stored in a person’s memory
82
main similarity between auditory and visual perception
they both depend on guesses
83
perceptual grouping
putting parts together into a whole
84
how do tones with the same frequency activate the hair cells?
in the same way regardless of where they are coming from
85
where can people localize sounds most accurately
directly in front of them
86
where can people localize sounds least accurately?
to the sides and behind their heads
87
location cues in hearing vs. vision
Location cues are not contained in the receptor cells like on the retina in vision. Thus, the location of sounds must be calculated
88
are ILD & ITD effective for judging elevation?
ILD and ITD are not effective for judgments on elevation, since in many locations they may be zero
89
what do experiments on moulding the pinnae suggest?
that there might be two different sets of neurons: one for each set of cues
90
where are coincidence detectors located?
in the inferior colliculus
91
what is the mechanism behind ITD detectors?
place coding
92
when do broadly tuned neurons respond in the right hemisphere?
when sound is coming from the left
93
when do broadly tuned neurons respond in the left hemisphere?
when sound is coming from the right
94
a1 function
locating sound
95
What findings support the existence of the what and where auditory pathways?
Evidence from neural recordings, brain damage, and brain scanning
96
what's the main factor that affects perception in concert halls?
reverberation time
97
what factors affect perception in concert halls?
- reverberation time
- intimacy time
- bass ratio
- spaciousness factor
98
does auditory scene analysis happen in the cochlea?
no, it doesn’t happen at the cochlea since simultaneous sounds are together in the pattern of vibration of the basilar membrane
99
heuristics
help perceptually organize stimuli
100
example of auditory scene segregation
a compound melodic line
101
Bregman & Campbell's experiment
- Stimuli were in alternating high and low tones
- When stimuli are played slowly, the perception is hearing high and low tones alternating
- When the stimuli are played quickly, the listener hears two streams: one high & one low
102
perceptual heuristic
sounds with the same frequency come from the same source, which is usually true in the environment
103
proximity in time
sounds that occur in rapid succession usually come from the same source
104
how was proximity in time illustrated
in auditory streaming
105
Warren et al. experiment
- Tones were presented and interrupted by gaps of silence or noise
- In the silence condition, listeners perceive that the sound stopped during the gaps
- In the noise condition, the perception was that the sound continued behind the noise
106
Dowling experience and perception experiment
- The melody “Three Blind Mice” is played with notes alternating between octaves
- Listeners found it difficult to identify the song
- However, after they hear the normal melody, they can hear it in the modified version using the melody schema
- Demonstrates the effect of past experience on auditory perception
107
Visual capture/ the ventriloquist effect:
an observer perceives the sound as coming from the visual location rather than the source of the sound
108
two-flash illusion
had participants look at a screen with a stagnant light and asked them if it was flashing. If you simultaneously make them hear two beeps, they perceive two flashes.
109
what senses does the interaction between vision and hearing occur in?
it's multisensory
110
Thaler et al., 2011
used expert blind echolocators to create clicking sounds and observed these signals activated the brain
