Whether any of this contributed to the quality of attention he brought to characters in extremis — characters managing the distance between their presented self and their interior reality — is one of those questions that biography cannot answer. Cinema is not documentary evidence of its makers’ psychology. A performance is not a confession.
What is true is that the discovery, when it came, was received by a man who had spent a decade and a half making a career out of understanding and embodying human complexity. He did not find complexity unfamiliar. He found it, ultimately, clarifying.
Ethel May Nicholson died in 1970 having raised her grandson to be one of the most watched people in American culture without telling him who he was in the most basic biological sense. June Nicholson died in 1963 having given birth to a boy who grew up calling her sis, a boy who would go on to be nominated for an Academy Award in the year after her death.
Neither of them knew what he would become. They knew what they had made, in the house on the New Jersey shore, and they kept the fact of making it to themselves.
The discovery that came in 1974 from a phone call he was not expecting did not change who Jack Nicholson was. He was already thirty-seven, already formed, already the person the household on the Jersey Shore had produced. What it changed was his understanding of where that person had come from.
He said it made things clearer. That is exactly what it sounds like: a man of thirty-seven, looking back at a life already substantially built, finding that a piece of information he had not known he was missing had been sitting in his family’s past the whole time.