Growing older gives us much to grumble about, but new findings may help to offset those woes: personality, scientists say, appears to improve with age. Some experts argue that personality is genetically programmed to stop changing at a certain age. Others assert that some aspects may morph throughout adulthood, but not much. The new work suggests that personality is plastic and that the changes that come with age are generally for the better.

Psychologists divide personality into five major traits: agreeableness, conscientiousness, neuroticism, openness and extraversion. According to researchers who subscribe to the notion that our genes dictate when our personalities stop changing, the "big five" are set for life by age 30. Some workers, however, contend that experiences that occur in adulthood--from beginning a career to having children--can mold personality too.

To begin to understand how personality traits might change through early and middle adulthood, Sanjay Srivastava of Stanford University and his colleagues studied how the average traits varied by age and gender. The study, published today in the Journal of Personality and Social Psychology, compared the personalities of 132,515 adults between the ages of 21 and 60 who completed an Internet "personality test." The survey was posted on the Web site and participants were those who had opted to answer the questionnaire for automatic feedback on their personality "ratings."

The team found that conscientiousness increased with age, with the biggest jumps occurring among those individuals in their 20s. Agreeableness also climbed with age, largely among thirty-somethings. Men and women differed in their relative neuroticism: as women aged, their neurotic tendencies declined, but this was not the case for men. Openness waned slightly for both sexes, as did extraversion in women.

"The changes in conscientiousness and agreeableness line up with when people increase their work responsibilities and then when they have kids," Srivastava says. But, he adds, they weren't studying the reasons why the changes occur, and they collected only basic demographic information. Now that Srivastava and his colleagues have ascertained that personality does indeed change throughout adulthood they plan to look into why it happens. "This is a hopeful message about aging," he observes. "It's so often viewed as a process of decline -- your hair falls out, your teeth fall out -- but we're seeing aging as a process of development. All the biggest changes were for the better."