Study leader Howard S. Friedman, distinguished professor of psychology at the University of California, Riverside; Leslie R. Martin, a psychology professor at La Sierra University in Riverside; and staff researchers -- over a 20-year period -- analyzed data from a study of 1,500 bright children who were about 10 years old when the study began in 1921.
"Longevity Project participants who were the most cheerful and had the best sense of humor as kids lived shorter lives, on average, than those who were less cheerful and joking," Martin said in a statement. "It was the most prudent and persistent individuals who stayed healthiest and lived the longest."
Part of the explanation lies in studying the health behaviors of the study subject -- the cheerful, happy-go-lucky kids tended to take more risks with their health across the years, Friedman explained.
While an optimistic approach may be helpful in a crisis, "we found that as a general life-orientation, too much of a sense that 'everything will be just fine' can be dangerous because it can lead one to be careless about things that are important to health and long life," Friedman said.
The findings are published in the book "The Longevity Project: Surprising Discoveries for Health and Long Life from the Landmark Eight-Decade Study."