Complex Sound Perception

Question 1

What are interaural level differences?

Answer 1

Move azimuth off to one side
One ear falls into sound shadow
Intensity difference between ears used as location cue
Difference may be as large as 30 dB
Affects higher frequencies

Question 2

What is a sound shadow?

Answer 2

Sounds ae bent around the head, or are diffracted by the edge of the head

Question 3

What are interaural time differences?

Answer 3

Difference in arrival times of the sound to each ear
neurons found in the auditory cortex and the superior olives that respond to certain interaural times differences
Affects lower frequencies

Question 4

What are phase differences?

Answer 4

Difference in phase between two waves at a point in time
Works better for lower frequencies

Question 5

What is the role of the pinna in auditory localization?

Answer 5

Delays/amplify some frequencies coming from certain directions/elevations
May decrease intensity of some mid-range frequencies but only if the source is behind the head

Question 6

What is the precedence effect?

Answer 6

Present two identical sounds from two speakers in different locations
At shorter delays, two sounds are fused into one
At longer delays, two separate sounds are perceived (echo threshold)
Facilitates hearing in a complex environment

Question 7

What is echolocation?

Answer 7

Some animals sound out ultrasonic waves and the reflections off of objects are used to locate obstacles and prey

Question 8

Can people utilize echolocation?

Answer 8

Visually impaired people do
With practice, any blindfolded participant can do it as long as they aren’t wearing earplugs

Question 9

What is reverberation?

Answer 9

Reflection of sound by walls, ceiling, and floor
Increases the duration of sound, also aids in localization

Question 10

What is reverb time?

Answer 10

Time for sound to decrease to 1/1000th of original pressure

Question 11

What happens if the reverb time is too short?

Answer 11

Music sounds dead

Question 12

What happens if the reverb time is too long?

Answer 12

Music sounds muddy

Question 13

What reverb time should concert halls have?

Answer 13

1.5-2.0 seconds

Question 14

What is the initial time delay gap?

Answer 14

Reflections of sound should start to follow direct sound by no more than 20-30 ms

Question 15

What happens if reflecting ceiling panels are too small and disperse?

Answer 15

They absorb too much low-frequency sound

Question 16

What is the seat-dip effect?

Answer 16

Significant deterioration of bass reverberation as sound passes over rows of seats

Question 17

Why are concave walls bad for concert halls?

Answer 17

They cause echoes and distortions

Question 18

What is primitive grouping?

Answer 18

Continuous flow of sound is analyzed into separate chunks and groups

Question 19

What are the important variables to include in a primitive grouping?

Answer 19

Intensity, temporal change, frequency change, location, timbre

Question 20

How does primitive grouping occur?

Answer 20

According to:
-similar patterns over time (sequential)
-similar frequency spectra (simultaneous)

Question 21

What does primitive grouping result in?

Answer 21

Separate auditory streams: groups of sounds that seem to belong together

Question 22

What is schema-driven grouping?

Answer 22

Higher level knowledge guides the grouping and listening processes
Sound input is analyzed for particular patterns

Question 23

What is absolute pitch?

Answer 23

Extreme accuracy (>90%) in identifying an isolated musical note without a reference tone

Question 24

How did music evolve?

Answer 24

With culture

Question 25

What can music activate?

Answer 25

Pleasure centers of the brain

Question 26

Why did music evolve?

Answer 26

For aiding in courtship
For promoting social cohesion in large groups
A byproduct of other evolutionary adaptations

Question 27

What are some difficulties in studying music and the brain?

Answer 27

Observations of patients with brain injuries are contradictory
Brain imaging studies have been incomplete
Music is complex
Large individual differences

Question 28

What happened to Ravel?

Answer 28

Had focal cerebral degeneration
Conceptual abilities remained intact = could hear and remember his music, but could not write
Brain does not have a specific center for music

Question 29

What cortices handle the early stages of music perception?

Answer 29

Primary and secondary auditory cortices

Question 30

What processes more complex music patterns?

Answer 30

Secondary auditory cortex

Question 31

What do tertiary regions do?

Answer 31

Integrates patterns into a coherent musical whole

Question 32

What does the left hemisphere process in relation to music?

Answer 32

Intervals and rhythm

Question 33

What does the right hemisphere process in relation to music?

Answer 33

Holistic traits like meter and melodic contour

Question 34

What happens in the brain when we listen to music and when we imagine it?

Answer 34

The same areas in the temporal lobe are activated

Question 35

What did Rauscher, Shaw, and Ky find?

Answer 35

Listening to Mozart temporarily enhanced abstract/spatial reasoning

Question 36

What did shaw conclude about music and brain functions?

Answer 36

Music uniquely enhances higher brain functions required for mathematics, chess, science, and engineering

Question 37

Is the Mozart effect legit?

Answer 37

No, we haven’t been able to replicate the original study