Coruscation

The summer before her senior year, though, she took an internship at Goldman. If anything, it left her disillusioned. "I started to feel like it was all a bit of a fraud, all these charts and regressions and models." She turned down the subsequent job offer and took a year to travel to Cuba to shoot a documentary with Cahill. "Living in Cuba made me unafraid of whatever could happen to me. Nothing seemed as scary as waking up at 40 and realizing that I had not lived a very courageous life."

¶ So she moved to Hollywood. The three friends wrote some scripts together but decided they worked better in pairs. "Zal actually had a dream that he was bound and blindfolded and walking down to a basement. And I was like: 'Who was there? Maybe a woman who never leaves!' And we ended up with 'Sound of My Voice.' " Their other film, "Another Earth," which hinges on the discovery of a duplicate planet, came in part from a piece of video art Cahill made in which he interviewed himself in a split screen. "We were like, what if you could confront yourself? What if there was a duplicate you?"

¶ She, too, is haunted by the idea of a duplicate -- another Brit Marling, perhaps one who took the job at Goldman. "If I hadn't met Mike or Zal, I really wonder what I would be doing right now. I wonder if I would even be acting. I can't imagine what it would have been like to do it alone." There may be a duplicate Marling looming in the future as well -- one who perhaps succumbs to all this post-Sundance Hollywood attention and finds herself, say, starring in a romantic comedy opposite Ashton Kutcher. (She just finished filming her first big-budget thriller, "Arbitrage," directed by Nicholas Jarecki and starring Richard Gere.)