LOS ANGELES | After years of interviewing subjects for everything from "The Civil War" to "Baseball," filmmaker Ken Burns figures he has a pretty good inner lie detector.
"You know the fish gets bigger the farther away from the lake you get," he says. "But, for the most part, you can tell who's bull----ing and who's not."
The trick? Check those stories. "In case of soldiers, for example, they have a military service record. At some point, the ultimate litmus test is looking somebody in the eye."
For "The Dust Bowl," a chronicle of "the greatest man-made ecological disaster in American history," Burns heard countless stories from folks who lived through incredible dust storms.
"The comments had to stack up against the maximum badness it could be," Burn says.
And, adds Dayton Duncan, his Iowa-born collaborator, "It wasn't like swallowing dirt. It was swallowing dirt."
Subjects had no reason to fabricate stories about the 10-year period of "black blizzards," Burns adds because, "as our opening person says, 'It can't be exaggerated.'"
While a woman from Iowa -- Caroline Henderson -- serves as the initial guide into "The Dust Bowl," she was hardly alone. A series of eloquent letters she wrote merely served as one of the touchstones for Burns and Duncan.
"In the literature of the Dust Bowl, she's not hidden away," Duncan says. "If you do any due diligence, you'll find her letters."
In them, she traces her journey from Iowa to Mount Holyoke College to Oklahoma where she hoped to make it on her own.
"She emerges as a person who really reflects on what happened and embodies the human mistake," Duncan says. As one who learned the lesson about conservation and the dangers of over-farming, "she left her land in a trust with the provision that it not be plowed again."
A new awakening
Drought conditions today suggest another awakening is imminent, Burns says. But will we learn from the lesson? "We'll learn to the extent that we can override the monetary interests, which is almost impossible to do. Maybe people will realize we're not going to have land to make money from unless we make some changes real fast."
Folks living through the Dust Bowl had no idea it'd go on for a decade, the historians say. "They thought it was maybe going to rain tomorrow and they'd get some relief," Duncan says.
Today, that's a similar thought. "In 1934, 46 of the 48 states were going through severe drought," he adds. "Now, we're up in the high 20s. Is the drought right now like it was then? No, it's not. Is the recession as bad as the real Depression? No it's not. But there are echoes."
Burns says Americans should learn from the mistakes of the past but, strangely, they don't.
"We're always cognizant of the fact that American history has a nice warp and woof to it."
Stories from one documentary could easily weave into another. "The intertwining threads of all our stories are apparent to us. Stories we've told before are in this story."
And, through it all, the Burns/Duncan template can be boiled down to one "simply deceptive question: 'Who are you?' Who are those strange and complicated people who like to call themselves Americans?" Burns asks. "Each film investigates that. What you come up against is some uniqueness in every subject. You also come up with familiar things -- aspects of leadership, aspects of courage and perseverance, aspects of folly and greed. We are puritan and prurient at the same time. We are generous and greedy. It isn't the same old story, and yet it is."
While researching the "National Parks" documentary, Burns and Duncan were heartened by the ability of Americans to bring the buffalo back from near-extinction through government action.
Farming could face a similar crisis. "Over the last 40 years, a not-insignificant movement in the Midwest and the Plains has been aimed at sustainability," Duncan says. 'We've tried to learn from nature. Has it overwhelmed corporate farming? No it hasn't. Nevertheless, it is a hopeful sign."
Because they make documentaries about events that happened decades -- even centuries -- ago, Burns and Duncan have the ability to weigh plenty of viewpoints.
"We're like a good mutal fund manager," Burns says. "We can average them all out and get some sense of a consensus. But we know that history constantly changes. The future is fairly certain but the past is malleable because, as we learn things, we see it from a different perspective."
Case in point? The Vietnam war.
Burns is working on a new documentary about the conflict. Had he approached in the 1980s or 1990s, it might have had a different tone.
"But when we come out in 2016, more than 40 years after the fall of Saigon, we have the ability to average lots of different perspectives -- from gloom and doom to Pollyanna."
The best distance? "Who knows?" Burns says. "We always say we need 25 to 30 years, but I just finished a film with my daughter on the Central Park jogger, which was 23 years ago. There's a lot of stuff we know now that we didn't know then."