Everyone has that one friend whose sense of time runs at an entirely different pace than the rest of the world. They're late to everything: coffee dates, doctor's appointments, and quite possibly their own funeral when the time comes. (If you don't know someone like this, you probably are that person.) Although it's tempting to chalk lateness up to being absentminded or outright lazy, in a recent study, researchers found that there's a weird reason for running late — one that appears mostly in young people, because our perception of time appears to change as we age.
In a study published in the Journal of Experimental Psychology: General last fall, researchers at Washington University in St. Louis, Missouri, compared the time management skills of 36 college undergraduates and 34 older adults. Being on time (or being super late) is largely dependent on something called time-based prospective memory. Basically, you use this kind of memory when you remember to do something at a certain time, like leaving to catch the train at 9 a.m. so you don't miss class.
The study was divided into two parts. First, participants took a trivia quiz and estimated how long it took. Half the participants worked while listening to background music — two longer songs or four short songs — while the other half took the quiz with no music playing. Although the quiz was always 11 minutes, there was no clock in the room, so participants had to guess the passage of time based on their own estimations.
In the second part of the study, everyone had 20 minutes to put together as many puzzle pieces as they could, while still leaving enough time to take the same quiz afterward. Essentially, participants had to remember how long it took to complete the quiz and choose an appropriate starting time without the help of a clock.
You'd think that people would make these estimations based on an internal clock, and that was true for older adults. As a whole, seniors tended to underestimate how long the first quiz took, leading them to take too long on the puzzle and miss the deadline for completing the second quiz, and this was true whether or not they were listening to music. In fact, most older adults reported ignoring the music entirely.
Here's the interesting part. In contrast to seniors, time management in young adults was heavily influenced by music. Those who listened to two long songs tended to perform like older adults; they underestimated the length of the first quiz and didn't finish the second round on time. However, undergraduates who listened to four short songs had the opposite problem, overestimating the length of the quiz and finishing the second round early.
This led researchers to conclude that young people were using the music to help them tell time rather than relying on an internal clock. "Results suggest for the first time that younger and older adults do not always utilize similar timing strategies, and as a result, can produce differential timing biases under the exact same environmental conditions," researchers wrote in the paper describing the study.
They also pointed out that external cues can be unreliable in the real world. "Something as simple as the number of songs you heard play on your phone during a run can influence whether you over- or under-estimate the duration of the run," said lead author Emily Waldum, according to Science Daily.
This isn't to say one way of telling time is better than the other; although things like music can be unreliable, senior adults didn't tend to finish their quizzes on time, either. But the study does suggest that our time management skills change with age — so maybe our perpetually late friends will start using their internal clocks eventually.