When I was on my first whitewater rafting trip several years ago, one of the safety instructors told us: “Assist in your own rescue.” If you’re thrown out of the raft, in other words, don’t just flail around in a panic—help your team get you back onboard.

Last week, in a bicycle spinning class at my gym, the instructor said that if the exertion was too much or too little at any point, we could dial up or dial down the tension knob that controlled the wheel. “You control your own tension,” she said.

As it turns out, those are the points being made in Positivity by Barbara L. Fredrickson. A professor of psychology at University of North Carolina at Chapel Hill and a researcher in the science of positive psychology, Fredrickson says that we all have within us the ability to change our response to the world, to manage our moods and improve not only our relationships, lives and health, but also our workplaces. To some extent, we can even make them more successful, she says.

If you are rolling your eyes right now, I understand. At a time like this, in the face of what could very well be a global depression, it sounds crazy to talk about using meditation and positive thought to effect change. What we really need, you might say, is to get the economy to start thinking positive thoughts.

But I thought Fredrickson might be on to something, so I stuck with her book.

If you’re put off by puffy self-help books, as I am, you can be assured that this is not one of them. It is vehemently anti-smiley face and free of cute illustrations. There is no “Fake it till you make it” philosophy here.

In fact, Fredrickson writes, lab experiments show that people whose positivity was not “heartfelt” had levels of the stress hormone cortisol as high as people who admitted their anger or depression.And such fakery is dangerous. In one study, scientists found that “insincere positivity put [men in the test] in as much coronary danger as did anger. Mountains of research tell us that anger kills. This new discovery suggests that insincere positivity may kill too.”

(That same experiment, by the way, uncovered a “tell” for fake positivity, which you can look for in your next staff meeting, if you’re so inclined. It’s called the “non-enjoyment smile.” The non-enjoyment smile engages the muscles that raise the lips, but doesn’t activate the muscles that circle the eyes.)

Although Positivity is not a workplace book per se, it does have some business applications: Managers with greater positivity are more accurate and careful in making their decisions; they are more effective interpersonally, Fredrickson says, citing research in the field. They “infect their work groups with greater positivity as well, which in turn produces better coordination among team members and reduces the effort needed to get their work done,” she writes.

The book also offers a description of an ongoing experiment among business teams. The high-performing team in the experiment had unusually high positivity ratio—about 6:1 (That means that for every negative statement or interaction, they performed six positive ones). The low-performing team’s ratio was 1:1. The average team came in at 2:1.

Finally, Fredrickson’s book is a tool kit for how to develop your own positivity and get to a 3:1 ratio at which positivity begins to have significant impacts in a person’s life. The book includes both a positivity self-test on paper, and a link to an online version to track whether you’re raising your positivity level: www.PositivityRatio.com.

Fredrickson talks frankly about the limitations of positivity: It won’t keep bad things from happening, she writes, and she offers a pretty harrowing example from her own life. She also describes how she used her field—her own medicine—to cope with her husband’s serious illness.

“As I see it, there are two basic responses to hardship,” she writes. “Despair or hope.” We can either wallow in misery or be buoyed by resilience, a skill that Fredrickson argues can be learned. We can, she says, control our own tension. And assist in our own rescue.