Auditory scene analysis

This is understood as the process by which the human auditory system organizes sound into perceptually meaningful elements.

Grouping them incorrectly can cause the listener to hear non-existent sounds built from the wrong combinations of the original components.

This is a skill which is highly developed by musicians, notably conductors who are able to listen to one, two, three or more instruments at the same time (segregating them), and following each as an independent line through auditory streaming[citation needed].

The job of ASA is to group incoming sensory information to form an accurate mental representation of the individual sounds.

In the real world, if the ASA is successful, a stream corresponds to a distinct environmental sound source producing a pattern that persists over time, such as a person talking, a piano playing, or a dog barking.

An interactive web page illustrating this streaming and the importance of frequency separation and speed can be found here.

If the generative tone is harmonic (= has a pitch salience) then such a representation is proved to be unique and requires the least amount of memory, i.e. is the least complex in the sense of Kolmogorov.

[9][10] Many experiments have studied the segregation of more complex patterns of sound, such as a sequence of high notes of different pitches, interleaved with low ones.

While the initial research on this topic was done on human adults, recent studies have shown that some ASA capabilities are present in newborn infants, showing that they are built-in, rather than learned through experience.

Currently, scientists are studying the activity of neurons in the auditory regions of the cerebral cortex to discover the mechanisms underlying ASA.