Problem 8 Flashcards Preview

Perception > Problem 8 > Flashcards

Flashcards in Problem 8 Deck (39)
Loading flashcards...
1

Auditory space

Sounds of different locations

--> exists all around

2

Auditory localization

Locating of sound sources in auditory space

--> sounds stimulate the cochlea based on their sound frequencies, which causes a pattern of nerve firing

3

Localization cues

a) binaural cues

b) monaural cues

4

Azimuth/
Horizontal

Dimension that extends from left to right

5

Elevation/
Vertical

Dimension that extends up and down

6

Distance

Distance of the sound source to the listener

7

Binaural cues

Use information reaching both ears to determine the azimuth of sounds

--> sounds that are of to the side, reach one ear faster and is therefore louder there

8

Inter aural time difference
(ITD)

Difference between WHEN a sound reaches the left ear + when it reaches the right one

--> ITD locates low frequencies
--> judge the azimuth

9

Inter aural level difference
(ILD)

Difference in the SOUND PRESSURE level/ the level of sound reaching the two ears

--> ILD locates high frequencies
--> judge the azimuth

10

Acoustic shadow

Refers to the head being a barrier

--> reduces the intensity of high frequency sounds that reach the far ear

11

Cone of confusion

Points on this cone have the same ILD + ITD

--> thus, ITD + ILD provide ambiguous info about the elevation of a sound source

12

Monaural cues

Use information of only one ear to determine the elevation of sounds

13

Spectral cue

Primary monaural cue

--> info for localization is contained in the differences in the distribution of frequencies that reach each ear

14

Why are there differences in frequency distribution reaching each ear ?

Because before the sound enters the auditory canal, it is reflected from the head + within the various folds of pinnae


15

Jefress Model of auditory localization

Neurons are wired so they each receive signals from the 2 ears

--> at the beginning neurons only receive signals from either ear, if signals then reach a neuron together it will fire

16

Coincidence neurons

Neurons that only fire when both signals coincide by arriving at the neuron simultaneously

--> each neuron responds best to a specific ITD

---> presented in the superior + inferior colliculei

17

Binaural localization

Based on

a) sharply tuned neurons for birds

b) broadly tuned neurons for mammals

18

Place code

ITD is indicated by the firing of neurons at a specific place

--> code for birds

19

Distributed code

ITD is determined by the firing of many broadly tuned neurons working together

--> code for mammals


=> broadly tuned neurons in the right hemisphere respond best to sound coming from the left and vice versa

20

Which cortical areas provide information about the location of sound sources ?

- A1 area to a small extent

- Neurons in the belt area provide most precise + detailed info

21

Auditory what pathway

Starts in the anterior part of the core + belt

--> extends to the prefrontal cortex
--> responsible for identifying sounds

22

Auditory where pathway

Starts in the posterior part of the core + belt

--> extends into the prefrontal cortex
--> responsible for locating sounds

23

Direct sound

Sound reaching the ears directly from where it originated

24

Indirect sound

Sound reaching the ears from different locations

25

Precedence effect

We generally perceive sound as coming from its source, rather than from many different directions at once

26

Reverberation time

The time it takes for a sound to decrease to 1/1000th of its original pressure

--> it this time is too long it may echo, which is difficult to localize

27

Auditory scene

Array of sound sources at different locations in the environment

28

Which cues help separating sound sources ?

a) location cue

b) onset time
--> if 2 sounds start at slightly different times, they're from diff. locations

c) Pitch + timbre
--> sounds having same pitch have same location

d) Auditory continuity

e) melody schema

f) pitch proximity

29

Melody schema

Representation of a familiar melody that is stored in a persons memory

30

Auditory continuity

Sounds with the same frequency or smoothly changing frequencies are perceived as continuous

--> even when they are interrupted by a different stimulus