In the 1890s, Konstantin Stanislavski designed a style of live performance that emphasized internal rather than external acting. This would eventually, through the influence of Lee Strasberg and the Group Theatre, develop into what we now call "Method Acting."
"Method acting is a technique in which actors try to engender in themselves the thoughts and emotions of their characters in an effort to create lifelike performances. It can be contrasted with more classical forms of acting, in which actors simulate thoughts and emotions through external means, such as vocal intonation or facial expression. Though not all Method actors use the same approach, the "method" in Method acting usually refers to the practice by which actors draw upon their own emotions and memories in their portrayals, aided by a set of exercises and practices including sense memory and affective memory."
One of my theatre professors once told me that, during a show she directed, an actor's character was supposed to be nearly inconsolable about a death. The way my professor achieved this reaction was by telling the actor to imagine it was her child who died. That may sound kind of extreme, but the performance was spot on as a result.
Yesterday I wrote about writing your character's emotions based on what makes you feel the same way. Method Acting works in a similar fashion. The actors are made to consider the scene: Is your character happy? Angry? Sad? How would your character react to those emotions? Would they stomp away? Rage? Constrict in on themselves? Why would they react this way? What in their past influences their knee-jerk response to this stimulus?
To find this out we interview our characters, consider their reactions in various situations, and do a whole host of other exercises that help us as writers discover the character's methods of coping with all sorts of stress. This information is extremely useful to have, and can help add a level of truthiness (that's for you, Rick) to your character that might not otherwise be there.
But consider what might happen if we apply the theories of Method Acting to the same character. The result is, instead of simply knowing your character really well, you become your character as you're writing them. This has the potential to make for even more emotionally punchy stories, which can only improve your prose.
Just don't become like Daniel Day-Lewis (Wikipedia again):
"Method actors are often characterized as immersing themselves so totally in their characters that they continue to portray them even offstage or off-camera for the duration of a project. However, this is a popular misconception. While some actors, notably Daniel Day-Lewis, have employed this approach, it is generally not taught as part of the Method."