Whose Idea Was It Anyway?

Though very dark and not for every taste, "Prisoners" is hands-down the best film I've seen in 2013. If the director, writer or one of the six or seven principal actors does not get nominated for an Academy Award, something is seriously awry in Tinsel Town.

Every scene featuring the detective played by Jake Gyllenhal had me wondering how much creative collaboration went into his character. Was his detective's excessive eye-blinking in the script? Or, did it come from Gyllenhal? Accidentally or intentionally? Did the Director first suggest it? Or, did the Director notice the first time Gyllenhal accidentally blinked a great deal (was there something in his eye during a take?) and then ask him to make that tic a part of this high strung character? I'm endlessly fascinated how accidents and collaboration contribute to the end product in creative art. In what creative field did the most recent example of these phenomena occur to you? I've seriously lost track how many articles, books, etc. I've nerdishly devoured about Lennon & McCartney or the Gershwin brothers' accidents and collaboration.

Recently watched "Howard's End" for the second time. In a crucial scene near the end, Anthony Hopkins does a motion with his hand to cover part of his face after he's confronted with a deceit. It goes by in an instant, so subtle it's easy to miss. I pulled down my copy of the EM Forster novel - nothing in the book like that hand motion. Screenwriter? Hopkins? Director? Accident? Collaboration?