For years, Michelle Gielan was a journalist at CBS News, dutifully telling the public about everything from natural disasters and the financial recession to shootings and soldiers' funerals. But over time, the drumbeat of negative news got to her.

"I basically got tired of telling negative news stories," Gielan explained to The Huffington Post. "I wanted to see if there was a way to tell news stories, negative or positive, in a more effective way that would not only engage the public, but it would also create a long-term, quantifiable, sustainable positive change."

So Gielan enrolled as a master's student at the University of Pennsylvania under professor Martin Seligman, a proponent of "positive psychology" -- a branch of the field that focuses on mental and emotional well-being rather than disorder. What she found in the academic literature resonated with her own experience: Absorbing negative messages over time can lead people to what is known as "learned helplessness."

"It's the belief that our behavior doesn't matter in the face of challenges," Gielan said. "News organizations are constantly broadcasting messages to the American public that this world is extremely dangerous; that no matter what we do, our behavior does not matter; and that forward progress doesn't really happen that often."

Journalists tend to gravitate toward negative, sensational news because they think those stories sell. Feed the outrage machine, the thinking goes. But that turns out to be just one part of the picture.

Gielan's research shows that reporting on solutions to society's problems -- or at the very least, framing negative news in a way that doesn't suggest problems are intractable -- also sells. The more upbeat approach affects everything from readers moods to the likelihood they'll share content, the latter being a key goal of modern journalists.

Gielan calls solutions-oriented storytelling "transformative journalism," and she has compiled her findings into a new book, Broadcasting Happiness , which hit bookstands this month. (HuffPost Editor-in-Chief Arianna Huffington called her "an eloquent champion for rethinking the way we communicate.")

According to research done in conjunction with The Huffington Post, watching just three minutes of negative news in the morning makes viewers 27 percent more likely to report having a bad day six to eight hours later. Those who watched transformative stories, on the other hand, reported having a good day 88 percent of the time. It's the duration of the effect that is remarkable: Nobody is surprised that a positive news story will lift a person's spirits for a few moments, but the fact that people's moods are elevated hours later attests to the power of the effect.

The content of articles affects not only mood but behavior. Readers are more likely to read as well as share content that is cast in a positive light. In one study conducted at the University of Pennsylvanias Wharton School , researchers looked at the entries on the New York Times "most e-mailed" list over three days. After controlling for level of emotional arousal elicited by the stories, they found that positive articles were shared more often than negative ones.

Perhaps more important -- at least for the financial decision-makers at media organizations -- people who read positive news stories come to associate those feelings with the surrounding advertisements and the brands they represent. In one study, readers were 24 percent more likely to purchase a product if its ad was juxtaposed with a positive news story than a negative one. They were more likely to remember the ads, too.

"If you have content that is engaging -- if people feel positive about it -- it positively influences all of these advertising measures," Gielan said. "What that says is that it's better for advertisers, which in turn is better for business. It provides a financial motivation to start to rethink the way we cover news."

This doesn't mean, however, that journalists have to ignore negative events and only write about dogs saving their owners' lives. Beyond reporting the unfortunate facts, stories can be framed to show what people are doing to address the problem or to tell viewers what they themselves can do. Gielan provided the example of focusing a car crash story on the survivor working toward recovery or ending a story about an earthquake with links that allow readers to donate to relief organizations.

"You're talking about ... not necessarily only reporting on feel-good stories but reporting on even sad stories in a way that doesn't convey the message that the world is broken and you can't do anything about it," she said.

Gielan hopes her research will help the media reconsider how they tell stories. To that end, her book includes a "Journalist Manifesto," available for free online , laying out the case for focusing on solutions and suggesting ways that journalists can tell transformative stories.

In the end, Gielan isn't just looking to transform journalism but society itself.

"Focusing on solutions is extremely important in activating people," Gielan said. "When we engage with the public in a way that creates an atmosphere of social interaction, it can produce higher-quality potential solutions while reinforcing the message that everyone has a role to play in creating collective success."

Watch Gielan speak with HuffPost Live about how the media can change the way they cover news (above).