Absolute pitch

People with absolute pitch can reproduce notes that have once been heard without any help.  T
They can name a note when heard. It is mostly influenced by cultural exposure to music. Absolute pitch is much more common in people who, as born language, speak  "tonal" languages, like Chinese or Vietnamese. It has been suggested that most infants acquiren this ability when they learn to speak tonal languages.

An absolute listener's sense of hearing is typically no keener than that of a non-absolute ("normal") listener. 

Left and right hemisphere of a person with absolute pitch

The prevalence of absolute pitch is higher among those who are blind from birth as a result of optic nerve hypoplasia.

Absolute pitch is considerably more common among those whose early childhood was spent in East Asia. This might seem to be a genetic difference; but people of East Asian ancestry who are reared in North America are significantly less likely to develop absolute pitch than those raised in East Asia,so the difference is more probably explained by experience. The language that is spoken may be an important factor; many East Asians speak tonal languages such as Mandarin and Cantonese, while others (such as those in Japan and certain provinces of Korea) speak pitch-accent languages, and the prevalence of absolute pitch may be partly explained by exposure to pitches together with meaningful musical labels very early in life.

Absolute pitch ability has higher prevalence among those with Williams Syndrome and those with an autism spectrum disorder, with rates as high as 30% claimed, stating that the rate among musicians in general is far lower.