Reading: Hearing

Hearing

The perception of acoustic vibrations that facilitates communication and connection to the environment.

Perceptual attributes of sound

Loudness

Loudness

The perceptual correlate of sound intensity or sound pressure.

Pitch

The perceptual correlate of waveform periodicity; faster repetition = higher pitch.

Harmonic complex tones

Sounds containing multiple frequencies that are integer multiples of a fundamental frequency (F0).

Pitch of the missing fundamental

Perception of the fundamental frequency even when it is absent or masked.

Timbre

The quality of sound that allows us to distinguish sounds with the same loudness

Outer ear

Composed of the pinna

Middle ear

Contains the malleus

Inner ear

Includes the cochlea

Inner hair cells

Transduce vibrations into neural signals transmitted to the auditory nerve.

Outer hair cells

Amplify sound-induced vibrations within the cochlea.

Tonotopy

Frequency-to-place mapping along the basilar membrane: low frequencies at apex

Phase locking

Timing of auditory nerve spikes represents frequency information

Masking

When one sound makes another sound more difficult to hear due to overlapping frequency or intensity.

Upward spread of masking

Low-frequency sounds are more likely to mask higher-frequency sounds at high intensity.

Informational masking

Central/perceptual masking occurring in the brain even when cochlear interactions are minimal.

Interaural time difference (ITD)

Difference in time a sound reaches each ear

Interaural level difference (ILD)

Difference in sound level between ears due to head shadow

Pinnae

Filter high-frequency sounds to help resolve front-back and up-down localization ambiguities.

Auditory scene analysis

The brain’s ability to separate complex sound mixtures into individual auditory objects or streams.

Computational auditory scene analysis (CASA)

Use of computational and neural models to understand auditory scene segregation.

Human hearing range

20 Hz to 20 kHz in young people with normal hearing.

Human hearing intensity range

0 dB SPL (~20 μPa) to 120 dB SPL (dangerously loud).

Cochlear implants

Devices that recreate cochlear function by converting sound into electrical signals to stimulate the auditory nerve.