I'm think it's mostly for younger ages. Black children are often mistaken as older than they are and it's partly because they reach puberty sooner than everyone else, especially black girls. I think the average age for black girl's is 8 while it's 11 or 12 for white and Asians.. Also there's the whole lower life expectancy thing which is mostly due to less available resources due to poor economic status
Definitely not outward appearance because us blacks slay