30. organization of aud. scene

Question 1

Auditory scene def?

Answer 1

All the sound entering the ears during the current interval of time

Question 2

Auditory scene analysis def?

Answer 2

• The process of extracting and GROUPING together frequencies
• separating frqs from specific sources from the mixture of all frqs from all sources in the auditory scene

Question 3

Auditory stream def?

Answer 3

• An assortment of frequencies occurring over time
• all emitted by the SAME SOUND SOURCE (or related sources)
• seem to “go together”

Question 4

Auditory stream segregation

Answer 4

The process of perceptual ORGANIZATION of the auditory scene into a set of distinct auditory streams

Question 5

What are the 2 major categories of grouping?

Answer 5

1. simultaneous grouping
2. sequential grouping

Question 6

Simultaneous grouping def? What are the 2 subdivisions??

Answer 6

• ways to group sounds that occur simultaneously
• based on a short, given interval of time

1. harmonic coherence
2. synchrony (or asynchrony)

Question 7

Harmonic coherence def?

Answer 7

• all multiples of a fundamental frq are perceived as a single auditory stream
• if one of the harmonics is changed to a NON-harmonic tone, it is perceived as a DIFF. auditory stream

Question 8

Synchrony (or asynchrony) def? Example with harmonics?

Which visual grouping principle is it similar to?

Answer 8

• frqs with synchronous onset, changes, and offsets are perceived as a single auditory stream
• if harmonics 1,3,5 start/end before harmonics 2,4, they will be perceived as DIFF auditory streams, even while they’re overlapping
• if frqs have sync. onset, but some change and others don’t, they’ll be perceived as diff streams as well
• similar to the visual principle of COMMON FATE / common motion

Question 9

Sequential grouping def? What are the 2 subdivisions?

Answer 9

• ways to group sounds that occur at different times (rather than simultaneously)
• grouping sequentially, over a period of time (not an instant)

1. frequency similarity
2. temporal proximity

Question 10

Frequency similarity def?

Answer 10

• group by frqs that are close / near to each other

Question 11

Frequency similarity - 2 examples from class?

Answer 11

1. single, galloping stream vs 2 diff streams
2. flanker and captor tones

Question 12

Explain the galloping stream example

Answer 12

• in both scenarios, the rhythm was the same. A & B are similar frqs, A & C are farther apart
• you perceive a single stream that is “galloping” when they’re close
  –> ABA, ABA, ABA…
• you perceive 2 streams when they’re far
  –> CCC
  AAAAAA

Question 13

Explain the flanker and captor tones example

Answer 13

• determining the directional change of the isolated target tones is easy
• flanker tones are distractors, add transitions and makes it hard to identify target
• captor tones:
  –> pattern of tones at same frq as flanker
  –> “capture” the flanker
  –> perceive as a single auditory stream
• once again, the target tones are isolated (separate stream), so its much easier with captor tones

Question 14

Temporal proximity def? Example?

Answer 14

• grouping is affected by how close the sounds are in time
• A is high frq, B is low frq. They’re played alternatingly
• if there’s a short time between them, you perceive 2 streams
• if there’s a longer time between sounds, you perceive 1 stream that alternates/warbles

Question 15

Perceptual completion of occluded sounds def?
What visual principle is this similar to?

Answer 15

• auditory system assumes a sound that’s interrupted (but continues) as a single stream
• similar to principle of good continuation

–> and interpolation (perceive missing edges/surfaces as continuing)