It's better to think good than feel good. That's the suggestion of research conducted at the University of Michigan, where scientists analyzed self-reported stroke and psychological data from more than 6,000 people over the age of 50. A University of Michigan news release reports that when the researchers rated participants optimism optimism levels on a 16-point scale they found that each point increase in optimism corresponded to a 9 percent decrease in acute stroke risk over a two-year follow-up period. The researchers believe that the protective effect of optimism may primarily be due to behavioral choices that people make, such as taking vitamins, eating a healthy diet and exercising, although some evidence suggests positive thinking might have a strictly biological impact as well.