“It seems like yesterday.”
This statement, or something close to it, was repeated many times by survivors interviewed by media outlets on the 15th anniversary of the 9/11 terrorist attacks. Indeed, to most people old enough to remember that day, it does seem like yesterday. Except it was not yesterday; it is a full decade-and-a-half later. In that same period of time, 3-year olds grew into full-fledged adults. Clunky Blackberries, carried by a few, evolved into sleek smartphones carried by almost everyone. Facebook, LinkedIn, and Twitter all went from nonexistent to ever-present.
Similarly, time seems to speed up as we get older. When we were 5, Christmas took forever to get here as we anxiously awaited the fulfillment of our wish list. At 50, however, we remark, “It’s Christmas already? Again?” Of course, objectively, we know that a year always takes the same 365 days to pass (except on a leap year, of course), and that each of those days contains the same 24 hours. Yet we all know that this is not at all how it feels.
Why is it that some things that happened years ago seem like yesterday, while other things seem lost in the past? And why is it that time seems to pass faster as we get older? Why does it seem that our brains warp the perception of time based on circumstances and subject matter?
Psychologists have been noticing this feature of the human mind, and have been forming theories about its origins, since psychology began as a discipline. In 1890, William James wrote in his classic text, “Principles of Psychology,” that this phenomenon was essentially the result of life becoming increasingly boring as we age. In other words, adulthood is marked by fewer and fewer events worth remembering as we grow older. The younger we are, the more firsts we experience. As small children, almost every moment is filled with novel experiences. In adolescence and young adulthood, life has become more habitual, but there are still many firsts — first kiss, first car, first apartment. Looking at older adults, James grows rather glum about the thrill of living: “The days and weeks smooth themselves out and the years grow hollow and collapse.” Because they lack unique significance, our days pass us by in rapid succession, according to the theory.
Another long-standing theory is called the “ratio theory,” first proposed in 1877 by French psychologist Pierre Janet. According to this premise, days seem to pass more quickly because they equal an increasingly smaller portion of our entire lives. For example, one year is one-fifth (20 percent) of the entire lifespan of a 5-year-old, so a year to a tot of this age seems an eternity. By contrast, a year is only one-fortieth (2.5 percent) of a 40-year-old’s life.
The ratio theory, although offering a partial explanation of the phenomenon, does not quite fit people’s actual experience, however. In one study conducted at Munich University, participants were asked the question, “How fast did the last 10 years pass for you?” Interestingly, people of all ages reported that a decade felt like much less than 10 years. And as expected, the older they were, the shorter people perceived those 10 years to be. However, the tendency largely dissipated after age 50. People over 50 experienced the 10 years as much shorter than an actual decade, but the estimated passage of perceived time did not decrease by much after that age. In other words, the ratio of time-to-lifespan continued to decrease, but the perception of time speeding up did not increase by an equivalent amount, as the ratio theory would suggest it should.
The Munich researchers suggested a reason why 50 was an age at which time slows its perceived acceleration: Time doesn’t just fly “when we’re having fun,” as the old adage says, but whenever we are very busy. A 50-year-old perceives time passing more quickly than a 25-year-old because they have more responsibilities in life and in work. There is never enough time in the day to get everything done. The perception of time speeding up levels off in middle age because our busyness typically increases up to that point as we advance in our careers and become more involved with the activities of our growing children. Then, after 50, it levels off as we reach the zenith of our career and our children become more independent.