"You really think Holden Caulfield is a hero? That's interesting," Scarlett Johansson is arguing with Chris Evans over whether Marvel Comics' Sentinel of Liberty really does have anything in common with US literature's most famous disaffected teenager. But having now played Steve Rogers, first in 2011's Captain America: The First Avenger and now high-octane sequel The Winter Soldier in addition to 2012's Avengers extravaganza, the Boston-born actor is convinced that the patriotic crime-fighter and the youthful protagonist of J.D. Salinger's 1951 novel both fulfil a deep intrinsic need.
"We've always needed heroes and we always will," Evans says. "That's why we have Greek mythology. Since the beginning of time, people have told stories and looked up to heroes, whether they're superheroes or Catcher in the Rye. They're all heroes."
However, Johansson, who reprises her role as the deadly Black Widow, is not so sure. "I'll have to think about that for a while," says the New York-born 29-year-old, who admits to enjoying some superhero blockbusters while growing up in the late 80s.
"I liked the Batman movies that Tim Burton did and I loved Indiana Jones. I guess I loved the flawed heroes but then everyone does. It's just like Holden Caulfield - okay, I'll take that!
"But the superhero is a little bit more - I don't want to say damaged - but there's just a part of that character that we can all relate to. That's what makes those stories work when you watch this fantastic film, read a book or a comic, you can imagine this fantastic experience and it's then brought back down to earth so you can relate that to yourself. That's what makes the perfect superhero but do we need that?
I don't know but we wouldn't be able to identify the villain if we didn't also have the hero."
With his brown hair and bushy beard, Evans makes for a more laid-back figure than the blond-haired, blue-eyed super-soldier he portrays on screen. But despite his enhanced strength and extraordinary ability to galvanise those around him, he insists that deep down Steve Rogers is just another regular guy.
"I look at it as just playing a character; it just so happens that he has superpowers," he says. "As an actor, you don't think 'I'm going to do a movie about a poet and then I'm going to go play Captain America'. They're all just characters, you're still playing a person and it's still the same muscle that you're flexing when you're acting."
Taking inspiration from 70s political thrillers like Three Days of the Condor, The Winter Soldier pits Cap against a shadowy adversary from his past as the Marvel cinematic universe's central security organisation S.H.I.E.L.D. is rocked by a timely, Edward Snowden-esque surveillance scandal.
"The directors Anthony and Joe Russo have done a good job with this movie of giving him not so much internal burdens but external troubles," says Evans. "For Cap, trying to understand who he really works for is a challenge and there's also the issue of whether or not society as a whole aligns with his particular set of morals and values.
"It's tough for him as he ends up questioning whether or not he's a pawn in the greater scheme of something that he disagrees with morally. There is conflict but it's not necessarily that brooding against everything that other superheroes might bring to the table. He starts off with a bit more of a clean slate and begins bumping into the world around him."
Captain America is screening now.