Chapter 10- Hearing in the Environment

Question 1

Interaural Time Difference (ITD)

Answer 1

The difference in time between arrivals of sound at one ear versus the other.

Question 2

Azimuth

Answer 2

The angle of a sound source on the horizontal plane relative to a point in the center of the head between the ears. Azimuth is measured in degrees, with 0 degrees being straight ahead. The angle increases clockwise toward the right, with 180 degrees being directly behind.

Question 3

Medial Superior Olive (MSO)

Answer 3

A relay station in the brainstem where inputs from both ears contribute to detection of the interaural time difference.

Question 4

Interaural Level Difference (ILD)

Answer 4

The difference between levels (intensities) of sound at one ear versus the other.

Question 5

Lateral Superior Olive (LSO)

Answer 5

A relay station in the brainstem where inputs from both ears contribute to detection of the interaural level difference.

Question 6

Cone of Confusion

Answer 6

A region of positions in space where all sounds produce the same time and level (intensity) differences (ITDs and ILDs).

Question 7

Directional Transfer Function (DTF)

Answer 7

A measure that describes how the pinna, ear canal, head, and torso change the intensity of sounds with different frequencies that arrive at each ear from different locations in space (azimuth and elevation).

Question 8

Inverse-Square Law

Answer 8

A principle stating that as distance from a source increases, intensity decreases faster such that decreases in intensity is equal to the distance squared. This general law also applies to optics and other forms of energy.

Question 9

Harmonic Spectrum

Answer 9

The spectrum of a complex sound in which energy is at integer multiples of the fundamental frequency.

Question 10

Fundamental Frequency

Answer 10

The lowest-frequency component of a complex period sound.

Question 11

Timbre

Answer 11

The psychological sensation by which a listener can judge that two sounds with the same loudness and pitch are dissimilar. Timbre quality is conveyed by harmonics and other high frequencies.

Question 12

Attack

Answer 12

The part of a sound during which amplitude increases (onset)

Question 13

Decay

Answer 13

The part of a sound during which amplitude decreases (offset)

Question 14

Auditory Scene Analysis

Answer 14

Processing an auditory scene consisting of multiple sound sources into separate sound images.

Question 15

Auditory Stream Segregation

Answer 15

The perceptual organization of a complex acoustic signal into separate auditory events for which each stream is heard as a separate event.

Question 16

Similarity

Answer 16

Gestalt grouping rule stating that the tendency of two sounds to group together will increase as the acoustic similarity between them increases.

Question 17

Common Fate

Answer 17

Gestalt grouping rule stating that the tendency of sounds to group together will increase if they begin and/or end at the same time.

Question 18

Good Continuation

Answer 18

Gestalt grouping rule stating that sounds will tend to group together as continuous if they seem to share a common path, similar to a shared contour for vision.

Question 19

Acoustic Startle Reflex

Answer 19

The very rapid motor response to a sudden sound. Very few neurons are involved in the basic startle reflex, which can also be affected by emotional state.

Question 20

Inattentional Deafness

Answer 20

The failure to notice a fully-audible, but unexpected sound because attention was engaged on auditory stream.