Temporal landmarks: Why milestones matter

How many times have you been asked the world’s least interesting question on your birthday?

So, how does it feel to be ##?

It feels the same as yesterday. Especially once we’re past the step-ladder of grade levels and drinking ages, we experience aging as a smooth gradient – today is pretty much the same as yesterday, and tomorrow will probably be pretty similar as well.

But we don’t act like it. In how we actually live, birthdays do matter, and milestone ones even more so.

Along with new years, new months, holidays, and even Mondays, these dates are known as “temporal landmarks,” days that help us portion out and mark the passage of time. And they hold a little bit of psychological magic.

University of Pennsylvania researchers Hengchen Dai, Katherine L. Milkman, and Jason Riis wrote about this effect in a popular 2014 paper, “The Fresh Start Effect: Temporal Landmarks Motivate Aspirational Behavior.” In three studies, they found the following:

• Google searches for the term “diet” spiked at the beginning of each calendar cycle – new weeks, months, and years. Furthermore, for each day past the start of the week or month, search volume continues to decrease steadily until the next milestone.
• Undergraduate gym attendance surges, by as much as 47%, at the beginning of a new semester or after a school break, as well as right after a student’s birthday (except for their 21st birthday, for obvious reasons).
• People were more likely to make goals via “commitment contracts” at the beginning of the week/month/year vs. the end of the week/month/year – as well as in the first month since their birthday.

Other studies have found that even just the anticipation of an upcoming temporal landmark can influence our decision-making. In one study, participants were asked when they wanted an email reminder for a new goal – and they were 3.5 times more likely to choose a date labeled as the “first day of spring” instead of just “the third Thursday in March.” We’ve all done this – it’s already Thursday, and the week is basically over, so I’m going to start writing that new chapter on Monday.

Then there’s evidence that the BIG milestones lead us to equally big thinking. In a 2014 paper by Adam L. Alter and Hal E. Hershfield, the authors found that people increasingly search for meaning as they approach a new decade of life. As we see 30, 40, 50, and other round numbers on the horizon, we’re more likely to ponder our satisfaction or dissatisfaction with life – and to respond by signing up for marathons or even engaging in extramarital affairs.

“9-enders,” as the researchers call the 29, 39, 49, etc. year-olds, “are particularly preoccupied with aging and meaningfulness, which is linked to a rise in behaviors that suggest a search for or crisis of meaning. Although some of these effects were small, they occur in domains with consequential life outcomes.”

As an aside, we only care about these dates because we just so happen to have 10 fingers and 10 toes, and therefore we count in base 10. The Mayans chose to use a base 20 system – and I’d bet their existential crises cropped up at the ages of 20, 40, and 60.

Birthdays, anniversaries, and holidays are how we notch the passage of time. They help us remember where we’ve been and figure out where we want to go. They’re made up, but they’re not meaningless.

I actually have my own temporal landmark coming up this week. On October 10, it will be one year since Simply Put hit shelves. It’s been quite a ride, from being named the best new business book by the IBPA book awards to appearing on over 100 podcasts. I hope that you’ll help me celebrate by grabbing a copy of your own and dropping a review.