I change myself a lot. Some roles you don't want to be big, bulky, muscle-y guy and some roles you want to be a lean, marathon-runner physical type. And some roles you just don't want to be in shape.

You get a role like this in a big action movie [like Jack Reacher] and you can go one of two ways: you can paint in broad strokes, which happens a lot in action films, or you can get very detailed.

I'm a trained actor and I can always tone it down, I can always simplify the work I've done. But if I'm asked to bring the nuanced and complicated work, I'll have it in my pocket, and all that information helps.

I had done a little bit one other time. This character [in Jack Reacher] is a psychopath, but I had been hired by Carlton Cuse and Randall Wallace.

[ Tom Cruise] that kind of employee that's first to arrive, last to leave.

I'm not a method actor but it certainly does help to have that kind of dedication. I treated my preparation like I was in the military. I didn't go out ever. I went out for drinks probably twice in five months. I lived very monastically.

A sociopath can imitate emotions, where a psychopath really doesn't have that capacity. They can't fool people into thinking anything and they're usually lacking major empathy for anybody besides themselves.