Biographer and psychologist William Todd Schultz argues on an Oxford University Press blog that Truman Capote lied about his past because he needed to be telling a story about himself.
(If I understand correctly.)
Schultz comments:
Aren’t psychobiographers supposed to care about the facts? Yes, facts are crucial. Facts are the instruments of revelation. I love facts. But the reality is, remembered life is itself fiction, a constantly evolving construction. That being so, the raw material one works with is best approached as a “faction” — a composite of artful narrative and quantifiable life-history. And given the unreliability of memory, especially in someone like Capote, who saw his past as perfectible, all one can do is dive into the messy blurriness.
"All one can do" is throw up one's hands?
With Capote, probably the answer is yes. Heck, his last novel is half-real...and half-finished. And Schultz wrote a whole book -- from the reviews, a good one -- about the writing of Answered Prayers.