Americans spend billions of dollars each year on books and seminars claiming to help people change their personalities. These books are built on the assumptions that personality can change, and that changing personality is good: Altering the basics of who you are will make you a better, healthier, happier person. Last week, I wrote about how the latest science of personality suggests that personality can indeed change—either through natural maturation, new responsibilities, or intentional strategies. But would changing your personality actually make you happier?

Recently, a series of studies in Australia looked to see whether changes in personality (regardless of the cause) were associated with increases in life satisfaction. The series drew on the country’s HILDA Survey (Household, Income and Labour Dynamics in Australia), which annually assesses the personality, life satisfaction, positive affect, and negative affect of a large, nationally representative sample of Australia’s population. In one of the studies, researchers examined the data from 11,104 Australians, ages 18 to 79, over the course of four years. They found that increases in extraversion, conscientiousness, and agreeableness were all associated with increased life satisfaction, whereas increases in neuroticism were associated with decreased life satisfaction.

Another study, conducted on more than 8,000 Australians, found that personality changes during this same time period occurred as often as changes in socio-economic factors, such as income, unemployment, and marital status. Together, these two studies add to a growing body of literature suggesting that personality changes are related to changes in life satisfaction, and that personality change can even be a better predictor of life satisfaction than many of the external variables that are normally considered in economic models of happiness.

Changes from within do matter—and these changes may indeed be undervalued in their role in determining happiness. In fact, they may even have strong economic consequences. The researchers calculated that a small decrease in neuroticism, for instance, could be worth $314,000—"the implied change in income that would be needed to raise life satisfaction by the same amount as [a change of] one standard deviation" in neuroticism, in the study's words. Considering the average U.S. household income is around $88,000, a little less anxiety perhaps could be worth leaps up the economic ladder.

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Not only can a personality makeover affect happiness, but a change in happiness, regardless of the source, can also have a big impact on personality. It’s possible, for instance, that circumstances that consistently make a person feel negative  (e.g., being in an abusive relationship) can lead that person to be more anxious or cautious than they would be otherwise. Environments that support well-being (e.g., a terrific job that pays well) may encourage someone to keep acting the way they do, or even to become more conscientious, agreeable, and so forth.

In another study drawing on the HILDA dataset from 2005 to 2009, the psychologist Christopher Soto investigated this possibility among a sample of 16,367 Australians, ages 15 to 93. Consistent with the other studies reviewed here, personality traits predicted subsequent changes in well-being. However, well-being also predicted subsequent changes in personality. People who began the study with high levels of extraversion, agreeableness, conscientiousness, and emotional stability showed increases in happiness, more frequent positive emotions, and less frequent negative emotions. But the reverse direction was also true: those with initially high levels of happiness tended to show growth in agreeableness, conscientiousness, emotional stability, and introversion over time.

These results suggest that a full understanding of the relationship between personality and happiness must take into account their reciprocal influence on each other. Indeed, these reciprocal effects can compound over time. As Soto shows, two people who only differ by six percentage points on a trait (e.g., 47th versus. 53rd percentile) at age 20 can differ by as much as 48 percentage points (26th vs. 74th percentile) at age 60, assuming that the original difference persists over time at the same rate.

Nevertheless, Soto found that when you compare the two directions of causality, you find that personality traits do have a stronger influence on well-being than well-being has on personality traits.  This, again, speaks to the power that patterns of thought, emotions, and behavior have over happiness.

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Inevitably, there are benefits and costs to changing personality that complicate any simple notions about how such a change would affect happiness. On the one hand, improving traits can bring out the best in someone. In general, the research shows, people who are more positive, assertive, hard-working, calm, kind, and creative behave in ways that help promote their own happiness. But there’s a fine line to be walked. Too much change may cause someone to feel inauthentic and unstable.

In a 2008 study, the business researcher Jason Riis and his colleagues assessed subjects’ willingness to take drugs intended to enhance their social, emotional, and cognitive traits, based on ads for the drugs. The researchers gave participants pharmaceutical drug ads to read that were framed as either enhancing the self (“Zeltor—Become More Than Who You Are”), or as enabling one’s true self (“Zeltor—Become Who You Are”). They found that people were reluctant to enhance traits that they saw as fundamental to their self-identity (e.g., social comfort), compared to traits considered less fundamental to self-identity (e.g., concentration ability), due to concerns that doing so would change their “fundamental self,” in the study’s words. Only when the ads emphasized that the drugs would serve as “enablers of one’s true self” did people become interested in taking them.

For many people, it seems, striking a balance between authenticity and personal growth is important for well-being. In an investigation of the “goldilocks hypothesis”—the idea that moderate personality change is more beneficial to happiness than too little or too much positive change— Chris Martin and Corey Keyes, psychologists at Emory University, analyzed a dataset of 1,725 Americans and found there was indeed a “just right” amount of positive change in sociality, agency, and conscientiousness that resulted in the highest level of happiness. Among adults with below-average levels of these traits, measured by having participants rate themselves on a series of adjectives (e.g., outgoing, self-confident, moody, organized), moderate amounts of increase produced the highest levels. The one exception was neuroticism: There seemed to be no point of diminishing returns when it came to decreases in this trait!

Too little personality change, meanwhile, risks making someone inflexible and rigid in their pursuits. The psychologists Adriana Miu and David Yeager found that teaching adolescents that it’s possible for people to change who they are (instilling in them what’s known as a “growth” mindset of personality) reduced depressive symptoms among them by nearly 40 percent over nine months, compared to a group of adolescents who were taught to believe that people cannot change (instilling in them a “fixed” mindset of personality). In fact, the subjects led to believe that people cannot change showed an even greater number of depressive symptoms.

The implication is that it’s good to accept and love who you are, but it’s also good to know that you can change for the better. Ideally, in approaching personality, a person should understand their repeated patterns of thoughts, emotions, and behaviors, and work on improving aspects of their personality that are hindering their happiness. But at the same time, people should not get too focused on drastically changing who they are.

As the psychologist Brian Little points out, “Don’t take your Big Five trait scores too seriously. … You are more nuanced than a single number or five single numbers.” He argues that people should focus on developing their deepest goals, values, interests, and personal projects. These are the things that research shows give life the greatest meaning, and form a more central part of identity than lower-level cognition and perceptions.  

To the extent that changing your personality helps you express your values and advance what you see as your purpose in life, it does hold the potential to make you happier. But the most beneficial changes—not only for increased happiness, but also for a deeper sense of identity and meaning—seem to be the ones that make you a more authentic version of who you already believe you are.