Despite the long-held belief that personality traits are set in stone, numerous studies have found evidence to the contrary. Now research reveals that a changing character can influence life satisfaction even more than economic upheaval.

Past studies have revealed that personality is the single biggest factor in how we perceive our own well-being, accounting for 35 percent of individual differences in life satisfaction. Research on well-being, however, has focused on less important factors, such as income and job status, because of the misperception that personality is generally fixed after early adulthood.

The new study, published in March in Social Indicators Research, investigated how evolving character traits relate to life satisfaction. Researchers at the University of Manchester in England assessed 8,625 people aged 15 to 93 at two points, four years apart. They measured the Big Five personality traits (openness to experience, conscientiousness, extroversion, agreeableness and neuroticism) and tracked fluctuations in external aspects of subjects' lives, including marital status, income and employment status.

The data reveal that the participants' character changed during those four years at least as much as demographic factors, such as marital status or employment. And those small personality shifts were more closely tied to life satisfaction than the other indicators were. For instance, people who grew less agreeable reported feeling less fulfilled in life than they had felt four years earlier, whereas those who became more open reported greater contentment.

This study did not attempt to find out what caused the subjects' personalities to transform, but other recent work has shown that certain experiences can change specific traits. For instance, psychological trauma—such as that experienced by combat soldiers—has been linked with decreases in agreeableness and conscientiousness.

Scientists have also successfully designed programs to increase openness, which tends to predict better health and a longer life. A December 2012 experiment published in Psychology and Aging found that a training program increased openness among older adults. A different study found that openness grew with the enhanced bodily awareness that comes from dancing and possibly other forms of physical activity.

“Not only does personality change occur, but it is an important influence and a possible route to greater well-being,” says research psychologist Christopher Boyce, now at the University of Stirling in Scotland, lead author of the Social Indicators Research study.