Conversation so far:
In what ways did David McCullough experience growth?
In 1951, McCullough began attending Yale University.
Where did he grow up as a youth?
Pittsburgh.
How long did he live in Pittsburgh?
CANNOTANSWER.
Where did his parents come from?
CANNOTANSWER.
Where did he go to school?
to study English at Yale.

Question: When did he graduate?
Self-contained rewrite: When did David McCullough graduate?