There are certain birthdays that go by without much thought. And then there are (for some people) the scary ones: 30, 40, 50 or 60.
Now there's research to show that as people approach these "milestone" ages, they're actually more likely to search for existential meaning and thus engage in particular behaviors. Like having an affair, committing suicide or signing up for a marathon.
That's according to new research published recently in the Proceedings of the National Academy of Sciences, called, “People Search for Meaning When They Approach a New Decade in Chronological Age."
Hal Hershfield, an assistant professor of marketing at the UCLA Anderson School of Management and one of the study's authors, explains that he and his co-author, NYU Stern professor Adam Alter, used existing data to "examine what sort of things might change as people are facing these new decades in their lives."
One of the first things they found, from an analysis of the World Values Survey, was that "when people were 29, 39, 49, or 59, they were slightly more likely to say that they were seeking meaning in their lives than when they were other ages."
By analyzing data from a dating website that caters to people who are looking for extramarital affairs, Hershfield and Alter found a significant overrepresentation of people who were "at the nines."
On the more positive side, by looking at the ages of first-time marathon runners, they found 25 percent more “nine-enders” than runners whose ages ended in any other digit.
The main takeaway, Hershfield says, is not that every 39-year-old is going to sign up for a marathon or have an affair, but that "if we're naturally inclined to take a step back and reflect [at these ages], we might as well harness that and try to use that tendency to reflect to do something that can maybe help us go into the next year or the next decade with a fresh start."