"The [older] group's love of their land is a common theme and gives them a purpose in life. Most of them are still working in their homes and on the land. They think, 'This is my life and I'm not going to give it up,'" Anna Scelzo, first author of the study with the Department of Mental Health and Substance Abuse in Chiavarese, Italy, explained.
"We also found that this group tended to be domineering, stubborn and needed a sense of control, which can be a desirable trait as they are true to their convictions and care less about what others think," Scelzo said.
"This tendency to control the environment suggests notable grit that is balanced by a need to adapt to changing circumstances."
Many in the elderly group spoke about their passion for life, sometimes despite heartache and sadness.
"I am always thinking for the best. There is always a solution in life. This is what my father has taught me: to always face difficulties and hope for the best," one participant said.
The new study is also unique in that it examined long life from a psychological perspective.
"There have been a number of studies on very old adults, but they have mostly focused on genetics rather than their mental health or personalities," Jeste pointed out.
"Studying the strategies of exceptionally long-lived and lived-well individuals, who not just survive but also thrive and flourish, enhances our understanding of health and functional capacities in all age groups," he said.
So, while the study does not conclude that stubbornness is guaranteed to make you live longer, a strong correlation was noted. Jeste also points out that the study shows "well-being and wisdom increase with aging" despite a decrease in physical health.
Beyond stubbornness and strong mental health, numerous recent studies have suggested correlations between particular habits and longer life.
A survey of previous research published last month suggests that drinking three to four cups of coffee per day is connected with lower risks of premature death, heart disease, diabetes, liver disease, dementia and some cancers. Other scientific studies suggest that calorie restrictive diets, dancing and having sex regularly may all slow down the aging process as well.