People may dread a milestone birthday, like turning 30, 40 or 50, but it’s in the year leading up that they’re inspired to make major changes in their lives.
Those on the brink of a big birthday, known as 9-enders — someone who is 29, 39 or 49 — are more likely to reevaluate their lives and change their behaviors, positively or negatively, according to research recently published in journal Proceedings of the National Academy of Sciences of the United States of America.
“Most of us realize in those 9-ending years that we’re approaching a new decade, which pushes us to be more thoughtful,” said Adam Alter, associate professor of marketing at NYU Stern School of Business and an author of the research.
Eight-ending years and zero-ending years also bring about change, though not as pronounced, he said, likely because by then the latter group have already come to terms with the new decade they just entered.
These 9-enders, or those in the midst of entering a milestone like getting married or having a child, become more introspective and philosophical, Alter said, and question what is meaningful to them, whether they are fulfilled or if they’re happy. Sometimes, they conclude they’re where they’d like to be, and other times, they’re inspired to change.
The researchers found that marathon runners ages 29 and 39 finished races at better rates than those who were a few years younger, such as 27 and 28 or 37 and 38. But people also decide to make dangerous life changes during these years. The researchers analyzed Centers for Disease Control and Prevention data and found 9-enders have a higher suicide rate than people of other ages. They also found in self-reported research that 9-ender men are more likely to engage in extramarital hookups.
To make positive changes, Alter has a suggestion: Don’t just idly set goals, he said. “It’s best to create a system of behavior that incrementally moves you in the right direction,” he said. For example, if your goal is to write a 100,000-word book, create a system where you’re habitually writing every day. “That system turns an overwhelming goal into something that you can tackle in bite-sized chunks.”