But people do eventually lose absolute pitch, it is simply too detailed to be functional in everyday life, meaning only a number of people are left with it into adulthood. If that's all we knew, we couldn't generalise any of the sounds we hear. It may also be a case of use it or lose it. There are studies indicating that people who learn musical instruments at a very young age have a higher incidence of absolute pitch. There are also studies showing a higher incidence among people that are blind, since the pitch of a moving car or a person's footsteps can provide important spatial clues.
Absolute pitch is also important for learning language.
One third of the world's languages are tonal languages, and absolute pitch is needed to understand the subtle differences between similar-sounding words. In the lead up to this study, Saffran demonstrated that infants use statistical learning, or the practice of detecting consistent patterns in sounds, as a foundation for learning language. This method of learning helps babies define where individual words begin and end in a spoken sentence. As Saffran reports in the journal Nature babies also seem to learn languages by finding patterns. She found that they have the capability to track the probability with which sounds, syllables and words occur together or certain distances apart.