CHAPTER 12: Hearing in the Environment

Question 1

explain the difference between simultaneous grouping and sequential grouping

Answer 1

simultaneous grouping: the situation that occurs when sounds are perceptually grouped together because they occur simultaneously in time. Ex. things that move together, belong together
onset timing: sounds that start at different times are likely to come from different sources
Location: a single sound source tends to come from one location and move continuously

sequential grouping: in auditory scene analysis, grouping that occurs as sounds follow one another in time
Galloping: two sounds from different streams coming together

Question 2

what is azimuth?

Answer 2

in hearing, specifies locations that vary from left to right relative to the listener

Question 3

what is the cone of confusion?

Answer 3

a surface in the shape of a cone that extends out from the ear. Sounds originating from different locations on this surface all have interaural level difference and interaural time difference, so location information is provided by these cues is ambiguous

Question 4

explain interaural level difference (ILD) and interaural time difference (ITD)

Answer 4

interaural level difference: the difference in sound pressure between the left and right ears. The difference creates an acoustic shadow for the far ear.

interaural time difference: when a sound is positioned closer to one ear than to the other, the sound reaches the close ear slightly before reaching the far ear, so there is a difference in the time of arrival between the two ears. The ITD provides a cue for sound localization

Question 5

where is the anterior belt area and what function is it responsible for?

Answer 5

the front of the posterior belt is found in the temporal lobe, and is involved in percieving sound

Question 6

what is the Jeffress model

Answer 6

the neural mechanism of audiory localization that proposes that neurons are wired to recieve signals from the two ears, so that different neurons fire to different interaural time differences (ITD)

Question 7

where is and what does the posterior belt area do?

Answer 7

posterior (towards the back of the brain) area of the belt area, which is an area in the temporal lobe invovled in auditory processing

Question 8

explain the scale illusion

Answer 8

an illusion that occurs when successive notes of a scale are presented alternatively to the left and right ears. Even though each ear recieves notes that jump up and down in frequency, smoothly ascending or descending scales are heard in each ear. also called melodic channeling