This film image released by IFC Films shows Casey Affleck in a scene from "Ain't Them Bodies Saints." (AP Photo/IFC Films) (Steve Dietl/AP)

Every Oscar season, film critics are asked the same question: Why do directors make short films, when there are so few venues for them outside festivals or the odd tag-on to a major feature film?

One of the answers can be found in the career of David Lowery, whose debut feature, “Ain’t Them Bodies Saints,” opens Aug. 23. An atmospheric Texas noir starring Rooney Mara, Casey Affleck, Ben Foster and Keith Carradine, “Ain’t Them Bodies Saints” has been likened to the work of Austin auteur Terrence Malick for its rich, poetic visual style and archetypal characters. But Lowery, 32, is clearly forging a style all his own, as redolent of Southern literature and music as the region’s film tradition. That signature was also stunningly visible in Lowery’s mesmerizing short film “Pioneer,” featuring the musician Will Oldham as a man telling his son an eerie bedtime story.

“Pioneer” became a quiet sensation on the festival circuit in 2011; it also helped persuade Mara and Affleck to work with Lowery, whose captivating writing, assured sense of pacing and careful, observant visual approach gave them confidence that “Ain’t Them Bodies Saints” would be a sure bet. They were right.

The Washington Post: “Ain’t Them Bodies Saints” is about a star-crossed couple, Ruth and Bob, who have a brush with crime, are forced to be apart and then struggle to come back together again. The film is full of stories and yarns that sound like folklore you might have overheard while growing up.

David Lowery: I wish I could say I overheard cool things like that. There are things in the film that are based on things I heard about, such as the Texas mafia and the crime scene there. But beyond that, the monologues and all that, I was just spinning yarns myself and on Casey’s part as well.

Casey Affleck: Well, not so much. It was mostly David’s writing.

TWP: David, you’re not a conventional “film geek.” What were your influences along the way?

DL: I didn’t go to film school. I was an English major, and I love a great novel. . . . The works of Cormac McCarthy certainly had a huge influence on me from high school onward, and that shows up in this movie very definitely. But the entire Southern Gothic literary tradition — Flannery O’Connor, William Faulkner — all of them I think had a great deal of influence on how I like to use language, and how I like stories to unfold. I like things to be clean but a little bit messy and unwieldy, and I think those novels and particularly the short stories of Flannery O’Connor are messy in the most beautiful way.

TWP: Rooney, do you know right away when you want to do something like “Ain’t Them Bodies Saints”?

Rooney Mara: I think I knew in the first 10 pages. The opening scene just really spoke to me right away, and then the whole script is so poetic and it’s just such a beautiful story.

CA: I read so many scripts and so often they have nothing unique or special or interesting about them, and this definitely has its own voice. David’s writing has a very unique voice that’s very earthy and lyrical, and the story is really compelling.

TWP: True, but it’s one thing to write a good script, it’s another thing to realize it cinematically. What gave you confidence that David could pull it off?

RM: I had seen his short film, they sent it to me when I was sent the script, and I loved [it]. I thought it was really interesting and just kind of odd.

CA: It’s a great match for this script, though. Sometimes you see somebody’s short film and you see the script and you go, ‘Yeah, but can he do this?’

TWP: Ruth and Bob spend most of “Ain’t Them Bodies Saints” apart; how did you develop the chemistry necessary to convince the audience of their overpowering love for each other?

RM: The way they set up the shooting was kind of perfect for it. Casey went and did all his stuff first, and then I came and we did our four days together and then he left and I finished off.

CA: I love Rooney. However, I feel like chemistry in general is so much about the context. Rooney and I could have a terrible relationship or no relationship and no affection, and if David had done his job, it would still come off as two people who really love each other.

RM: Sometimes when two people can’t stand each other, actually there’s more chemistry because there’s more tension.

TWP: Rooney, in the film you play a woman who winds up being an object for three different men, all of whom are always coming at her: one out of passion, one out of protection and one out of possession. Then Ruth ends up being ambushed by the love she feels for her own baby. How did you keep her from being completely passive?

RM: It was kind of hard actually, it was something I struggled with, not wanting her to be passive. Because she’s there to be like a Madonna figure. I don’t know if I figured it out, but it was something I thought about a lot. Ruth’s focus does end up being on her daughter, and that really is one of the main love stories in the film.

TWP: Rooney, you’ve just finished working with Malick, so between that project and this one I guess that makes you a real Texas girl now.

RM: I do love Texas. I never thought I would say that or feel that way. But now that I feel like I’m part of their Texas commune of bearded men, I do have an affection for Texas.