In a wide variety of fields, including chess and violin, the key to becoming an expert is

A) to have a better-than-average memory and overall intelligence.
B) to be born with a brain specially adapted to the field.
C) a well-rounded personality.
D) about ten years of careful practice.

Research has shown that about ten years (or ten thousand hours) of deliberate and focused practice, along with effective feedback and coaching, is the key to becoming an expert in various fields. This applies to both cognitive and physical skills and is independent of factors like memory, intelligence, or genetics. A well-rounded personality may be beneficial, but it is not a determining factor for expertise.