Only around one in 10,000 people has the ability to correctly classify a note simply by hearing it. This phenomenon is called perfect, or absolute, pitch, and has been made famous by the well-known composers who are believed to have possessed such talents, such as Mozart and Beethoven.I had a woman choir teacher a long time ago who claimed to have what she called near perfect pitch. Knowing what note a certain song started with, she could have a frame of reference to put notes into and name them, but it wasn't a "instant identification" the way perfect pitch is said to be.
Graduate student Stephen Hedger, from the University of Chicago, US, had perfect pitch identified by objective tests. He explained what it meant.
"I'm able to name any musical note in isolation without the aid of a reference note. Someone with perfect pitch would be able to tell you a car alarm is honking in F sharp, for example. Generally it enables people to identify notes across a wide variety of octaves."
Mr Hedger was tricked by his colleague who secretly adjusted the pitch on an electronic keyboard as he was playing a tune. The notes were made flat by 33 cents - which is one-third of the distance between adjacent keys on a piano.
When the note was shifted back to its original correct key, it sounded drastically sharp to Hedger, who explained he found it "shocking" that he had not noticed the change.
A similar model was tested on 27 students with perfect pitch. They were played a piece of music for 45 minutes which was gradually changed over time to become flatter.
The subjects then perceived the flattened music as in tune, while the in-tune notes were perceived as slightly sharp.
Given the mechanism of human hearing, where different frequencies cause stimulation of a specific set of auditory nerve cells, perfect pitch ought to be hard wired into the human brain, and only post reception processing by the brain can account for the most human's seemingly plastic frequency hearing responses.
The inner ear contains the cochlea, which is a spiral shaped, fluid filled tube that is considered the organ of auditory transduction. It is divided lengthwise by the basilar membrane, a structure that vibrates when waves from the middle ear propagate through the cochlear fluid–membrane system. The basilar membrane is tonotopic, so that each frequency has a characteristic place of resonance along it. Characteristic frequencies are high at the basal entrance to the cochlea, and low at the apex. Basilar membrane motion causes the movement of the hair cells, specialized auditory receptors located within the basilar membrane. The space–time pattern of vibrations in the basilar membrane is converted to a spatial–temporal pattern of firings on the auditory nerve, which transmits information about the sound to the brainstem.So perhaps we need to think of perfect pitch not as a unique talent, but rather a mild brain deficit.