In July 2010 Burt’s Bees, a personal-care products company, was undergoing enormous change as it began a global expansion into 19 new countries. In this kind of high-pressure situation, many leaders pester their deputies with frequent meetings or flood their in-boxes with urgent demands. In doing so, managers jack up everyone’s anxiety level, which activates the portion of the brain that processes threats—the amygdala—and steals resources from the prefrontal cortex, which is responsible for effective problem solving.

Burt’s Bees’s then-CEO, John Replogle, took a different tack. Each day, he’d send out an e-mail praising a team member for work related to the global rollout. He’d interrupt his own presentations on the launch to remind his managers to talk with their teams about the company’s values. He asked me to facilitate a three-hour session with employees on happiness in the midst of the expansion effort. As one member of the senior team told me a year later, Replogle’s emphasis on fostering positive leadership kept his managers engaged and cohesive as they successfully made the transition to a global company.

That outcome shouldn’t surprise us. Research shows that when people work with a positive mind-set, performance on nearly every level—productivity, creativity, engagement—improves. Yet happiness is perhaps the most misunderstood driver of performance. For one, most people believe that success precedes happiness. "Once I get a promotion, I’ll be happy," they think. Or, "Once I hit my sales target, I’ll feel great." But because success is a moving target—as soon as you hit your target, you raise it again—the happiness that results from success is fleeting.

In fact, it works the other way around: People who cultivate a positive mind-set perform better in the face of challenge. I call this the "happiness advantage"—every business outcome shows improvement when the brain is positive. I’ve observed this effect in my role as a researcher and lecturer in 48 countries on the connection between employee happiness and success. And I’m not alone: In a meta-analysis of 225 academic studies, researchers Sonja Lyubomirsky, Laura King, and Ed Diener found strong evidence of directional causality between life satisfaction and successful business outcomes.

Another common misconception is that our genetics, our environment, or a combination of the two determines how happy we are. To be sure, both factors have an impact. But one’s general sense of well-being is surprisingly malleable. The habits you cultivate, the way you interact with coworkers, how you think about stress—all these can be managed to increase your happiness and your chances of success.

Develop New Habits

Training your brain to be positive is not so different from training your muscles at the gym. Recent research on neuroplasticity—the ability of the brain to change even in adulthood—reveals that as you develop new habits, you rewire the brain.

Engaging in one brief positive exercise every day for as little as three weeks can have a lasting impact, my research suggests. For instance, in December 2008, just before the worst tax season in decades, I worked with tax managers at KPMG in New York and New Jersey to see if I could help them become happier. (I am an optimistic person, clearly.) I asked them to choose one of five activities that correlate with positive change:

1. Jot down three things they were grateful for.
2. Write a positive message to someone in their social support network.
3. Meditate at their desk for two minutes.
4. Exercise for 10 minutes.
5. Take two minutes to describe in a journal the most meaningful experience of the past 24 hours.

The participants performed their activity every day for three weeks. Several days after the training concluded, we evaluated both the participants and a control group to determine their general sense of well-being. How engaged were they? Were they depressed? On every metric, the experimental group’s scores were significantly higher than the control group’s. When we tested both groups again, four months later, the experimental group still showed significantly higher scores in optimism and life satisfaction. In fact, participants’ mean score on the life satisfaction scale—a metric widely accepted to be one of the greatest predictors of productivity and happiness at work—moved from 22.96 on a 35-point scale before the training to 27.23 four months later, a significant increase. Just one quick exercise a day kept these tax managers happier for months after the training program had ended. Happiness had become habitual.

Help Your Coworkers

Of the five activities described above, the most effective may be engaging positively with people in your social support network. Strong social support correlates with an astonishing number of desirable outcomes. For instance, research by Julianne Holt-Lunstad, Timothy Smith, and Bradley Layton shows that high levels of social support predict longevity as reliably as regular exercise does, and low social support is as damaging as high blood pressure.

The benefits of social support are not just physical. In a study of 1,648 students at Harvard that I conducted with Phil Stone and Tal Ben-Shahar, we found that social support was the greatest predictor of happiness during periods of high stress. In fact, the correlation between happiness and Zimet’s social support scale (the academic measure we used to assess students’ positive engagement with their social networks) was a whopping .71—for comparison, the correlation between smoking and cancer is .37.

That study focused on how much social support the students received. But in follow-on research I conducted in March 2011, I found that even more important to sustained happiness and engagement was the amount of social support the students provided. For example, how often does a student help others when they are overwhelmed with work? How often does he initiate social interactions on the job? Social support providers—people who picked up slack for others, invited coworkers to lunch, and organized office activities—were not only 10 times more likely to be engaged at work than those who kept to themselves; they were 40% more likely to get a promotion.

How does social support work in practice as a tool for employee happiness? Ochsner Health System, a large health care provider that I work with, uses an approach it calls the "10/5 Way" to increase social support among employees and patients. We educated 11,000 employees, leaders, and physicians about the impact of social support on the patient experience, and asked them to modify their behavior. When employees walk within 10 feet of another person in the hospital, they must make eye contact and smile. When they walk within 5 feet, they must say hello. Since the introduction of 10/5, Ochsner has experienced an increase in unique patient visits, a 5% increase in patients’ likelihood to recommend the organization, and a significant improvement in medical-practice provider scores. Social support appears to lead to not only happier employees but also more-satisfied clients.

Change Your Relationship with Stress

Stress is another central factor contributing to people’s happiness at work. Many companies offer training on how to mitigate stress, focusing on its negative health effects. The problem is, people then get stressed-out about being stressed-out.

It’s important to remember that stress has an upside. When I was working with Pfizer in February 2011, I asked senior managers to list the five experiences that most shaped who they are today. Nearly all the experiences they wrote down involved great stress—after all, few people grow on vacation. Pick any biography and you’ll see the same thing: Stress is not just an obstacle to growth; it can be the fuel for it.

Your attitude toward stress can dramatically change how it affects you. In a study Alia Crum, Peter Salovey, and I conducted at UBS in the midst of the banking crisis and massive restructuring, we asked managers to watch one of two videos, the first depicting stress as debilitating to performance and the second detailing the ways in which stress enhances the human brain and body. When we evaluated the employees six weeks later, we found that the individuals who had viewed the "enhancing" video scored higher on the Stress Mindset Scale—that is, they saw stress as enhancing, rather than diminishing, their performance. And those participants experienced a significant drop in health problems and a significant increase in happiness at work.

Stress is an inevitable part of work. The next time you’re feeling overwhelmed, try this exercise: Make a list of the stresses you’re under. Place them into two groups—the ones you can control (like a project or your in-box) and those you can’t (the stock market, housing prices). Choose one stress that you can control and come up with a small, concrete step you can take to reduce it. In this way you can nudge your brain back to a positive—and productive—mind-set.

It's clear that increasing your happiness improves your chances of success. Developing new habits, nurturing your coworkers, and thinking positively about stress are good ways to start.

This article was originally published in the January-February 2012 issue of Harvard Business Review. 

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Learning that you or a loved one has a chronic illness is news you never want to hear. The knowledge of such information is often accompanied by feelings of fear, anger, and depression, which can cause debilitating, unnecessary stress. By understanding more about your condition and adopting a positive outlook on life, you can set the course for a better future.

During my time at Harvard University, I focused on positive psychology, the scientific study of what makes people thrive. Research in the field has found a strong connection between an individual's mindset, social support system and well-being. Recently I have been able to leverage the research behind positive psychology to help people living with multiple sclerosis. Through a program called Everyday Matters sponsored by the National MS Society and Genzyme, I am working to provide tools and resources related to positive psychology, wellness, work/education, relationships, family, and empowerment to the community. As a chronic, unpredictable and often disabling disease, the power of positivity is extremely important in managing MS.

In my book The Happiness Advantage, I've outlined the advice I've been giving to Everyday Matters participants into simple tips that can help those not only with a chronic disease such as MS, but everyone, in achieving a more empowered existence. You can see my TED talk to hear more about this research, which is described in brief below:

Send an Appreciative Email

When you open your inbox for the first time each day, take two minutes to send an email to someone in your social support network (family member, friend, teacher, coach, coworker) praising him/her or thanking that person. Studies from Harvard show this is so powerful that there is actually a correlation between happiness and social connection of 0.7, significantly higher than the correlation between smoking and cancer. Social connection can be as predictive of your longevity as high blood pressure, obesity and smoking.

Smiling Is Contagious

Through a study involving 11,000 hospital employees over six months, it was found that smiling, making eye contact and simply saying hello within 10 feet of another person increased the hospital's patient satisfaction, the doctors' job satisfaction, and the likelihood to refer the hospital to others. This is because of the way neurons function in our body, lighting up at the receipt of a friendly gesture, telling our brains to smile when someone smiles at us and spreading the joy all around.

Give Thanks

Think of three things you are grateful for before you go to sleep for 21 days. We did a study on this, and at the end of the study, participants were significantly more optimistic, and further, the change wasn't temporary -- the positive mindset lasted even six months later. An added effect: Increasing your optimism can improve your productive energy by 31 percent!

Never Give Up On the Good Times

Take two minutes every day to write down every detail you can remember about one positive experience that occurred over the past 24 hours. As our brains can't tell much difference between visualization and actual experience, by rehashing a high point in the day you double the effect of that positive experience. Overall, this leads to greater life satisfaction and meaning. Studies have shown that women who wrote about positive experiences were 40 percent more likely to live to age 94 than their negative peers.

Have Fun

By adding 15 minutes of a fun, mindful activity to your day, like gardening, going on a walk or working out, your brain learns to believe that behaviors matter -- the core of optimism. In fact, in one study, researchers took people suffering from depressions and had half take an antidepressant and half do light aerobic exercise in order to train their brain to believe that their behavior matters. While there were equal drops in depression for the first few months, the group that added a habit of exercise had significantly lower chance of relapse back into depression 10 months later. Habits like the "Fun 15" help your brain record a victory, which creates a "cascade of success," where individuals start creating a constellation of positive habits around them, decreasing the likelihood for depression and despair.

Meditate

Take two minutes each day to stop what you're doing and watch your breath go in and out. This exercise trains your brain to do one thing at a time. Research suggests that a multitasking brain has a harder time falling asleep, is more stressed, and has lower energy. By taking time to relax the brain has a chance to undo the negative effects of trying to manage everything at once.

As part of Everyday Matters, we're following five people through personal text, video and photo journals as they learn to apply these tips in their everyday lives. To see how they are doing, comment on their journeys, to offer your own gratitude, or to access resources about positive psychology you can visit http://www.nationalmssociety.org/everyday-matters/index.aspx.

Happiness is a choice, even in the midst of a chronic illness. By taking small steps, large goals can be accomplished, enhancing the outlook and overall well-being of those living with or affected by a life-altering disease.

After giving a lecture at a large tech company, I got into a cab bound for the airport along with one of the attendees. As I searched for my seatbelt in the bottomless crevice of the back seat, I noticed that my fellow passenger was not wearing his seatbelt. I said something clever like "Afraid of seatbelts?" and he replied, "Nope, I'm an optimist."

That's not optimism. That's insanity. Optimism is good for many things, but it will definitely not keep other cars from hitting you, nor keep you from flying through the windshield. That is irrational optimism.

In The Happiness Advantage, I define rational optimism as "a realistic assessment of the present, while maintaining a belief that our behavior will eventually create a better reality." This is the type of leadership we want to develop at our companies and reward in the political sphere.

Unfortunately, most people do not distinguish between rational and irrational optimism. As a result, we have three fundamental misunderstandings about the role optimism plays at work.

First, "you're being an optimist" should not be an insult. What we should be saying is "you're an irrational optimist!" We are trying to say that person has a warped vision of reality, which is based on desire, not how things actually are. And that definitely should be an insult. Irrational optimism is why financial bubbles form, why we buy homes we can't afford, and why we prematurely put up banners that say "mission accomplished." Irrational optimists attempt to put on rose-colored glasses first, and therefore even their initial steps are Pollyannaish and flawed. You can't sugarcoat the present and still make good decisions for the future.

You probably know people who are irritatingly optimistic. That guy who talks about how great the weather is while people are being fired, or the pilot who seems chipper as she reports another hour delay on the tarmac, or the person who says "don't worry, be happy" when he shows up an hour late to pick you up at the airport. Don't be that guy. We find ourselves wanting to pop their bubbles because they affront our conception of reality.

None of this is the type of rational optimism we are referring to in positive psychology research. If people find you to be annoyingly cheerful, don't lose the optimism. Try today to first communicate that you recognize the existence and scope of a problem, then proceed to communicate your gratitude or hope that things will change. This approach will help other people to accept your mindset as both palatable and authentic.

Second, "I'm not a pessimist nor an optimist, I'm a realist" is a nonsensical statement. Both optimists and pessimists can make realistic assessments of the present. The difference between an optimist and a pessimist is how they then deal with the reality they perceive. According to researchers like Martin Seligman, pessimists see problems as "permanent and pervasive." Optimists see the problems, but they perceive them as "local and temporary." In other words, the problem is only one part of reality, and there are lots of other good things going on in other domains of our life. And if we continue to believe our behavior matters, we believe this too shall pass.

Third, the idea "it's good to have pessimists so we know what the problems are" is false. I've heard business leaders try to make a case that their pessimism was evolutionarily selected. But remember, both optimists and pessimists see the approaching saber-tooth tiger; there is just a difference in opinion about whether it can be dealt with. Some well-intentioned writers have railed against positive psychology because they mistakenly assume that optimism means turning a blind eye to injustice or ignoring loss. Only irrational optimists overlook problems and think that reality has no bearing upon the future. Rational optimists see problems, but unlike pessimists, they think they can do something about them.

On a related note, I have encountered a couple people who have read books like "The Secret" and erroneously become irrational optimists. They start to believe that mindset is all that matters. Rational optimists believe that mindset matters, but they also recognize that reality is part of the formula. You must change reality, not just wish it away.

Pessimism causes paralysis. Irrational optimism causes delusion. Only rational optimism allows us to actively confront the injustices and ills in society. Rational optimists see the tragedy in Japan, or understand the difficulty in treating breast cancer, or recognize the racial injustices in our educational system...but they are also the ones who search for ways to help the survivors, or believe a cure can be found, or continue to work to invent a better system.

To read more about how to become a rational optimist, check out Part 1 in The Happiness Advantage