Psychologists have long known that people confident in their ability to control their destinies are more likely to adjust well to growing old than those who feel that they drifi on the currents offate.
Two researchers who questioned hundreds of Swedish twins report that such confidence, or lack ofit, is partly genetic and partly drawn from experience.
The research was conducted at the Karolinska Institute-better known as the body that annually awards the Nobel Prue for medicine-by Nancy Pedersen of the hrstitute and Margaret Gatz, a professor of psychology at the University of Southem Califomia in Los Angeles. Their results were recently published in the United States in the Joumal of Gerontology.
"People who are confident of their ability to control their lives have an intemal locus of control", and have a better chance ofbeing well adjusted their old age, said Pedersen.
An "extemal locus of comrol", believing that outside forces determine the course oflife, has been linked to depression in latter years, she said. "We are trying to understand what makes people different. Whatmakes some people age gracefully and others have a more difficult time?"she said.
The study showed that while people have an irtborn predilection toward independence and self-confidence, about 70 percent of this personality trait is affected by a person's environment and lifetime experiences.
Pedersen's studies, with various collaborators, probe the aging process by comparing sets of twins, both identical and fratemal, many of whom were separated at an early age.