About 98% of all people have absolute color recognition (green, blue, etc.) but Absolute Pitch (AP) is an extremely rare ability with only about 0.01% of the population able to tell the pitch of a tone without first hearing a reference tone. Absolute Pitch (sometimes called perfect pitch) includes the ability to sing a pitch accurately from just the name of the pitch (e.g. C, D#, Bb etc.), the ability to name all of the individual tones in a chord or name the frequency of a given tone. Most musicians can accurately tell the key of a song, and most decent singers can begin a song a capella in key without a starting reference tone, but these are generally examples of muscle memory or pitch memory rather than absolute pitch.
Most people have Relative Pitch – we can determine if one tone is higher than another, and if you have some musical experience you can probably determine the intervals between tones with some precision. People with well-trained ears can generally tell if the frequency of a tone deviates from the expected interval as compared to another tone.
Relative Pitch may also change or evolve as the person grows older. In one such case, a person with AP reported that in his early fifties he began identifying keys one half-tone higher (C to C#) than they actually were, and by his early seventies he was identifying keys one full tone higher (C to D).
We can learn relative pitch that may resemble absolute pitch, but scientists who have studied relative pitch are still not sure how it is developed.
Hereditary Theory – Some of us are born with AP and are taught pitch names early in life during the hyper-learning stage of our very earliest years.
Learning Theory – Probably the least popular theory among psychologists studying the phenomenon, this point of view states that everyone can learn AP with practice and repetition.
Imprinting Theory – Basically, imprinting is the reason why a duckling will forever follow the first thing it sees after hatching, psychologists believe that all children could be taught AP if done so at the appropriate learning stage.
Unlearning Theory – This theory states that everyone is born with AP but that the ability is trained out of us at an early age through reliance and training of such other methods as Relative Pitch.
Regardless of which theory you ascribe to, or maybe you don’t believe any of it, children can be taught relative pitch that may actually come to resemble absolute pitch through exposure to music and practice at an early age. But be careful! Relative Pitch can also be an unpleasant thing to possess, like at karaoke night or those nights you catch a really bad act at the club down the street.