Enfant prodige is a person under the age of 10 who produces meaningful output at the level of an adult expert. Why and how do they happen?

This is 5-year-old Alberto Cartuccia Cingolani playing Mozart's Piano Sonata No. 16 in C major.

https://video.nostr.build/62ae6270e2cb437e0d54eb2f1616e91d4b1f37afdeafddc7fcc613f22eca6845.mp4