The performance aspects in "The Act of Killing" are explicit with "star" Anwar Congo and his fellow gangsters -- responsible for genocide in Indonesia in 1965 -- reenacting their mass killings in the style of some of their favorite Hollywood films.
Similarly, in "Stories We Tell," director Sarah Polley coaches her father Michael Polley on how to deliver his narration, which is based on his recollections of events depicted in the film. Adding to the layer of performance is the knowledge that both Polleys have worked as actors. To further blur the lines, the film relies on reconstructed mock home movie footage shot on a Super 8 camera.
The reality is viewing habits have changed what audiences expect from documentaries. Thanks to reality TV, "people are used to seeing great characters and sometimes those great characters are real people," said Schnack.
When director Morgan Neville set out to make "20 Feet from Stardom," he knew he had to focus on casting. After interviewing over 75 backup singers, Neville said the process was "essentially casting, figuring out who were the characters whose stories best represent the world that we're trying to portray."
In many cases, an issue-driven documentary will start with a topic and then try to find the right personality to walk the audience through the subject, but in the cases of these films, the characters ultimately drive the stories.
In fact, when Zach Heinzerling, director of "Cutie and the Boxer" started filming Ushio and Noriko Shinohara, he wasn't even sure there was going to be a film.
"Sometimes you have a topic and you do a number of pre-interviews and you sort of know what the story is gong to be more or less and you find the right characters to express and explain that story," said Heinzerling.
That was not the case with "Cutie and the Boxer." After moving to New York City at age 23, Heinzerling became friends with the couple initially through their artwork. "It was more of an organic relationship that would develop," he explained. "I would just go to their house and sometimes film and sometimes not film."
While the film was initially going to focus on their artwork, as Heinzerling got to know the couple better, it became clear that there was more to the story.
"It's less about the art and more about life and aging and marriage and love and creativity. Ultimately, it was the story that I felt was most universal and compelling, this relationship story and the drama inherent in the two of them in their every day lives," said Heinzerling.
Although reality TV operates in a different universe from these documentaries, they share the idea that observing people's lives -- as artificial and scripted as they may be in some reality TV shows -- is inherently interesting.
"Maybe documentaries are a slightly more artistic way of viewing reality TV," said "The Punk Singer" director Sini Anderson. "We want to connect with something that we perceive to be real."
As a performer, Kathleen Hanna, the "star" of "The Punk Singer" is, in some ways, performing for the camera even as she is completely at ease and unselfconscious. "She identifies herself as a feminist performance artist," said Anderson, who added, "In a sense, we're all performing whenever we're in front of anybody."
Although Hanna's story has a definite narrative arc, the most compelling element of the film is Hanna herself. Just watching a charismatic, strong character such as Hanna "perform" on stage and off makes for riveting drama.
Or, as Heinzerling puts it: "Everybody has a story and if you go far enough and spend enough time with them, the drama is innate. When you see someone in their own voice stripped down and honest, it's refreshing and easy to connect with."