Here are some excerpts from a recent Newsweek article, entitled "This Is Your Brain on Optimism." It's an important article because it seems to confirm the physiological value of an optimistic attitude....
My emphasis added.
...The optimism bias, as it's called, accounts for the fact that we expect to live longer and be more successful than the average and we tend to underestimate the likelihood of getting a serious disease or a divorce. This tendency is adaptive—many researchers have claimed that a positive outlook motivates us to plan for our future and may even have an effect on our long-term physical health.
Optimism may be so necessary to our survival that it's hardwired in our brains. A new study published in the journal Nature further confirms the idea that having a rosy outlook is a personality trait with deep, neurological roots. Researchers found that the brains of optimistic people actually light up differently on a scan than those who tend to be more pessimistic when they think about future events.
...While we can't say for certain why some people respond more positively to life's events, it's increasingly clear that your mental outlook can have a big effect on your physical health. Optimism motivates individuals to take control of their lives, while depression has been found to have the opposite effect. It is often linked to a sense of hopelessness. "The problem with depression is that people are so pessimistic that they don't engage in actions that could make their lives better," says Elizabeth Phelps, one of the study authors and psychology professor at NYU.
...The exact nature of the relationship between optimism and good health is still unclear. Martin Seligman, who studies optimism and positive thinking at the University of Pennsylvania says that it might be that, optimists, as opposed to pessimists, are more likely to take care of their health because they believe in the potential positive outcomes. Or, it could be that optimistic people are more likeable and build better social networks, which have been associated with longevity. Another possibility is that optimistic people may have had less trauma or difficulty in their lives (a high number of negative events in a lifetime correlates with bad health). "All of these are plausible," says Seligman.
Painting: Optimism, by John Slaby