In just the last year, hundreds of academic papers have been published studying the health effects of expecting good things to happen, which researchers call "dispositional optimism." They've linked this positive outlook on life to everything from decreased feelings of loneliness to increased pain tolerance.

Oddly enough, three decades ago, the outlook for research on optimism didn't look very good. But then, in 1985, Michael F. Scheier and Charles S. Carver's published their seminal study, "Optimism, Coping, and Health: Assessment and Implications of Generalized Outcome Expectancies" in Health Psychology . Researchers immediately embraced the simple hopefulness test they included in the paper and their work has now been cited in at least 3,145 other published works. Just as importantly, by testing the effect of a personality variable on a person's physical health, Scheier and Carver helped bridge the gap between the worlds of psychology and biology. After the paper, scientists had a method for seriously studying the healing powers of positive thinking.

In the Q&A below, Scheier reflects on his influential work with Carver and shares how their humble study on human motivation ultimately inspired countless studies on mind-body interactions. He also assesses why their optimism scale was an instant hit in the scientific community, how their findings have been adapted by other researchers, and the future of our understanding of hope and well-being.

How did the research come about?

Chuck Carver from the University of Miami and I were doing research on human motivation. We were trying to understand how to think about goal-directed behavior, and expectancies were an important part of our approach. The idea was, and still is, that when people encounter difficulties doing what it is that they intend to do, some sort of mental calculation takes place that results in the generation of an outcome expectancy -- the person's subjective assessment of the likelihood that he or she will succeed. We thought these expectancies played a role in the nature of the affect that was experienced and the person's subsequent behavior.

Initially, we considered outcome expectancies in a very circumscribed way. We focused on specific situations manipulated in controlled experimental contexts to validate our ideas. For example, we studied snake phobics who approached a boa constrictor in a cage. We weren't interested in snakes or phobias per se but in how these expectations drove behaviors.

At some point in the early 1980s, things changed. A number of our colleagues in health psychology -- my wife, Karen Matthews, included -- urged or maybe even challenged us to consider applying some of our ideas to real-world settings, particularly those that might be relevant to well-being. Our formal area of study in graduate school was also personality, and I started to hear the voice of my advisor, Arnie Buss, in my head gently pushing us to do what it was that we had been trained to do.

This confluence of events started us thinking about expectancies in a broader way that might be more reflective of stable expectancies for positive or negative things to occur. And voila! We found ourselves interested in dispositional optimism, which we define as the general expectation that good, versus bad, things will happen across important life domains.

What were your goals? Was there a research gap you were hoping to fill back then?

Once we knew what we wanted to study, we looked around the literature to see if there was a scale that assessed dispositional optimism that was consistent with how we viewed the construct. We couldn't find anything that was right on the mark, so we set out to make our own measure for dispositional optimism using a self-report questionnaire (PDF of updated version). Along with that came the job of establishing the statistical characteristics, or psychometric properties, of the scale. This became part of the purpose of our original paper too.

We also wanted to show that differences in optimism and pessimism predicted some health-relevant outcomes, so we explored the development of physical symptoms reported among a group of undergraduates during a particularly stressful portion of the academic semester. We were fortunate to get the paper published in a journal, Health Psychology, that enabled a lot of researchers to become familiar with the scale, findings, and ideas.

"We know why optimists do better than pessimists," says Scheier. "Optimists are not simply being Pollyannas; they're problem solvers who try to improve the situation."

I think one reason the work was picked up so much is that we provided a tool that enabled scientists to ask their own questions and do their own research in the area. Prior to the publication of our scale, there were well-known testimonials on "the power of positive thinking," but there was no simple way to verify if the testimonials were correct. I think it also helped that our scale was easy to use and score. It only has six items on it! The brevity enabled lots of people to include it in their work, even if that involved very large epidemiological studies where issues of respondent burden and time limitations are paramount. As a result, an enormous amount of research on optimism has been generated over the years.

How far has our understanding of optimism come since?

A lot of research has been done since we published our first paper, and the vast majority has examined the relationship of optimism and well-being. I think it's now safe to say that optimism is clearly associated with better psychological health, as seen through lower levels of depressed mood, anxiety, and general distress, when facing difficult life circumstances, including situations involving recovery from illness and disease. A smaller, but still substantial, amount of research has studied associations with physical well-being. And I think most researchers at this point would agree that optimism is connected to positive physical health outcomes, including decreases in the likelihood of re-hospitalization following surgery, the risk of developing heart disease, and mortality.

We also know why optimists do better than pessimists. The answer lies in the differences between the coping strategies they use. Optimists are not simply being Pollyannas; they're problem solvers who try to improve the situation. And if it can't be altered, they're also more likely than pessimists to accept that reality and move on. Physically, they're more likely to engage in behaviors that help protect against disease and promote recovery from illness. They're less likely to smoke, drink, and have poor diets, and more likely to exercise, sleep well, and adhere to rehab programs. Pessimists, on the other hand, tend to deny, avoid, and distort the problems they confront, and dwell on their negative feelings. It's easy to see now why pessimists don't do so well compared to optimists.

What don't we know still?

Two things. First, how do optimism and pessimism develop? We know from studies with twins that dispositional optimism is heritable, although the specific genes that underlie the differences in personality have yet to be identified. It's also likely that parenting styles and early childhood environment play a role. For example, research has shown that children who grow up in impoverished families have a tendency toward pessimism in adulthood. Still, the specifics have not been delineated.

The other missing link has to do with how to construe optimism and pessimism. I've been describing them as though they are opposite ends of a continuum, and this may not be the case. Optimism and pessimism may represent related, but somewhat distinct dimensions. This possibility is suggested by the fact that not expecting bad things to happen, doesn't necessarily imply that the person expects good things to happen. The fact that they're somewhat separable leads to the question of what is important for the beneficial health outcomes we see: the absence of pessimism or the presence of optimism?

What have been some surprising reactions to your research?

Three reactions are noteworthy. One comes from the research community, the second from the media, and the third from patients.

For whatever reason, there has been a group of researchers who have been very skeptical of the findings. The work has been criticized because it's not really optimism and pessimism that drive results, but rather characteristics that are related to optimism, such as the depressed mood that comes along with a pessimistic orientation. Others have found fault with individual studies or large scale reviews that have been done. Much of this criticism is part of the healthy process of science, being dubious and wanting further verification, but some of the skepticism seems to go beyond that. It's never been clear to me why this has been the case.

As for the media, they seem to love the work. Whenever a major study gets published showing the benefits of optimism on health, the findings are picked up quickly and get widely distributed. Part of this is prompted, I think, by folklore that surrounds the concepts of optimism and pessimism. I think that people are intrigued that these caricatures have some basis in fact. Whatever the reason, our findings are quick to make their way to the public.

But perhaps what's most salient to me is the reaction that some patients have expressed about their recovery. They have told me that they feel guilty. They read that optimism is associated with better health among patients recovering from illness, and they think, "If only I would be more optimistic, I'd do better." Yet, they can't put themselves in that frame of mind. Family members may chastise them too for not promoting their recovery by simply expecting good things to happen. Perhaps it was naïve not to have imagined these reactions. Regardless, it is troubling that they have occurred.

How has this study affected your life?

My guess is that, if you asked the research community what I'm known for, they'd say the work that I've done on optimism and pessimism. I've spent the better part of my professional life studying optimism and it's effect on psychological and physical well-being. So if I'm known for something, it might as well be that. Still, the salience of this work has distracted people from other work that I've done that I think is equally interesting, including some of the ideas we've expressed about why people experience emotion.

I also spend a fair amount of time trying to figure out if I'm more optimistic or pessimistic, or how my wife and kids are. I'm guessing that I'm somewhere in the middle, which puts me in some sort of expectational limbo. On the other hand, maybe that view provides the detachment that is necessary to allow a researcher to approach work in an objective way.

Ultimately, I find it very gratifying that a large number of colleagues in the field have found the work valuable enough to incorporate into their own work. Collectively, we've been able to document that links between optimism and physical health do exist.